DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Huafeng; Colabello, Diane M.; Sklute, Elizabeth C.

The absolute absorption coefficient, α(E), is a critical design parameter for devices using semiconductors for light harvesting associated with renewable energy production, both for classic technologies such as photovoltaics and for emerging technologies such as direct solar fuel production. While α(E) is well-known for many classic simple semiconductors used in photovoltaic applications, the absolute values of α(E) are typically unknown for the complex semiconductors being explored for solar fuel production due to the absence of single crystals or crystalline epitaxial films that are needed for conventional methods of determining α(E). In this work, a simple self-referenced method for estimating bothmore » the refractive indices, n(E), and absolute absorption coefficients, α(E), for loose powder samples using diffuse reflectance data is demonstrated. In this method, the sample refractive index can be deduced by refining n to maximize the agreement between the relative absorption spectrum calculated from bidirectional reflectance data (calculated through a Hapke transform which depends on n) and integrating sphere diffuse reflectance data (calculated through a Kubleka–Munk transform which does not depend on n). This new method can be quickly used to screen the suitability of emerging semiconductor systems for light-harvesting applications. The effectiveness of this approach is tested using the simple classic semiconductors Ge and Fe 2O 3 as well as the complex semiconductors La 2MoO 5 and La 4Mo 2O 11. The method is shown to work well for powders with a narrow size distribution (exemplified by Fe 2O 3) and to be ineffective for semiconductors with a broad size distribution (exemplified by Ge). As such, it provides a means for rapidly estimating the absolute optical properties of complex solids which are only available as loose powders.« less

Explanation of the barrier heights of graphene Schottky contacts by the MIGS-and-electronegativity concept

NASA Astrophysics Data System (ADS)

Mönch, Winfried

2016-09-01

Graphene-semiconductor contacts exhibit rectifying properties and, in this respect, they behave in exactly the same way as a "conventional" metal-semiconductor or Schottky contacts. It will be demonstrated that, as often assumed, the Schottky-Mott rule does not describe the reported barrier heights of graphene-semiconductor contacts. With "conventional" Schottky contacts, the same conclusion was reached already in 1940. The physical reason is that the Schottky-Mott rule considers no interaction between the metal and the semiconductor. The barrier heights of "conventional" Schottky contacts were explained by the continuum of metal-induced gap states (MIGSs), where the differences of the metal and semiconductor electronegativities describe the size and the sign of the intrinsic electric-dipoles at the interfaces. It is demonstrated that the MIGS-and-electronegativity concept unambiguously also explains the experimentally observed barrier heights of graphene Schottky contacts. This conclusion includes also the barrier heights reported for MoS2 Schottky contacts with "conventional" metals as well as with graphene.

Flexible inorganic light emitting diodes based on semiconductor nanowires

PubMed Central

Guan, Nan; Dai, Xing; Babichev, Andrey V.; Julien, François H.

2017-01-01

The fabrication technologies and the performance of flexible nanowire light emitting diodes (LEDs) are reviewed. We first introduce the existing approaches for flexible LED fabrication, which are dominated by organic technologies, and we briefly discuss the increasing research effort on flexible inorganic LEDs achieved by micro-structuring and transfer of conventional thin films. Then, flexible nanowire-based LEDs are presented and two main fabrication technologies are discussed: direct growth on a flexible substrate and nanowire membrane formation and transfer. The performance of blue, green, white and bi-color flexible LEDs fabricated following the transfer approach is discussed in more detail. PMID:29568439

Silicon Carbide Sensors and Electronics for Harsh Environment Applications

NASA Technical Reports Server (NTRS)

Evans, Laura J.

2007-01-01

Silicon carbide (SiC) semiconductor has been studied for electronic and sensing applications in extreme environment (high temperature, extreme vibration, harsh chemical media, and high radiation) that is beyond the capability of conventional semiconductors such as silicon. This is due to its near inert chemistry, superior thermomechanical and electronic properties that include high breakdown voltage and wide bandgap. An overview of SiC sensors and electronics work ongoing at NASA Glenn Research Center (NASA GRC) will be presented. The main focus will be two technologies currently being investigated: 1) harsh environment SiC pressure transducers and 2) high temperature SiC electronics. Work highlighted will include the design, fabrication, and application of SiC sensors and electronics, with recent advancements in state-of-the-art discussed as well. These combined technologies are studied for the goal of developing advanced capabilities for measurement and control of aeropropulsion systems, as well as enhancing tools for exploration systems.

Abstracts of the International Conference (INFOS 83) on Insulating Films on Semiconductors Held at the University of Technology. Eindhoven (The Netherlands) on 11-13 April 1983.

DTIC Science & Technology

1983-04-13

progressed at the same pace. Initially the analogy with conventional well-known ion sensors, such as the glass membrane electrode, led to the...chemical and physical treatments. The standard etching processing using bromine in methanol can deplete cations and produce a surface layer of TeO2 .(l

Optimized structural designs for stretchable silicon integrated circuits.

PubMed

Kim, Dae-Hyeong; Liu, Zhuangjian; Kim, Yun-Soung; Wu, Jian; Song, Jizhou; Kim, Hoon-Sik; Huang, Yonggang; Hwang, Keh-Chih; Zhang, Yongwei; Rogers, John A

2009-12-01

Materials and design strategies for stretchable silicon integrated circuits that use non-coplanar mesh layouts and elastomeric substrates are presented. Detailed experimental and theoretical studies reveal many of the key underlying aspects of these systems. The results shpw, as an example, optimized mechanics and materials for circuits that exhibit maximum principal strains less than 0.2% even for applied strains of up to approximately 90%. Simple circuits, including complementary metal-oxide-semiconductor inverters and n-type metal-oxide-semiconductor differential amplifiers, validate these designs. The results suggest practical routes to high-performance electronics with linear elastic responses to large strain deformations, suitable for diverse applications that are not readily addressed with conventional wafer-based technologies.

Rapid Three-Dimensional Printing in Water Using Semiconductor-Metal Hybrid Nanoparticles as Photoinitiators.

PubMed

Pawar, Amol Ashok; Halivni, Shira; Waiskopf, Nir; Ben-Shahar, Yuval; Soreni-Harari, Michal; Bergbreiter, Sarah; Banin, Uri; Magdassi, Shlomo

2017-07-12

Additive manufacturing processes enable fabrication of complex and functional three-dimensional (3D) objects ranging from engine parts to artificial organs. Photopolymerization, which is the most versatile technology enabling such processes through 3D printing, utilizes photoinitiators that break into radicals upon light absorption. We report on a new family of photoinitiators for 3D printing based on hybrid semiconductor-metal nanoparticles. Unlike conventional photoinitiators that are consumed upon irradiation, these particles form radicals through a photocatalytic process. Light absorption by the semiconductor nanorod is followed by charge separation and electron transfer to the metal tip, enabling redox reactions to form radicals in aerobic conditions. In particular, we demonstrate their use in 3D printing in water, where they simultaneously form hydroxyl radicals for the polymerization and consume dissolved oxygen that is a known inhibitor. We also demonstrate their potential for two-photon polymerization due to their giant two-photon absorption cross section.

Opto-valleytronic imaging of atomically thin semiconductors

DOE PAGES

Neumann, Andre; Lindlau, Jessica; Colombier, Léo; ...

2017-01-16

Transition metal dichalcogenide semiconductors represent elementary components of layered heterostructures for emergent technologies beyond conventional opto-electronics. In their monolayer form they host electrons with quantized circular motion and associated valley polarization and valley coherence as key elements of opto-valleytronic functionality. Here, we introduce two-dimensional polarimetry as means of direct imaging of the valley pseudospin degree of freedom in monolayer transition metal dichalcogenides. Using MoS 2 as a representative material with valley-selective optical transitions, we establish quantitative image analysis for polarimetric maps of extended crystals, and identify valley polarization and valley coherence as sensitive probes of crystalline disorder. Moreover, we findmore » site-dependent thermal and non-thermal regimes of valley-polarized excitons in perpendicular magnetic fields. Finally, we demonstrate the potential of widefield polarimetry for rapid inspection of opto-valleytronic devices based on atomically thin semiconductors and heterostructures.« less

Opto-valleytronic imaging of atomically thin semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neumann, Andre; Lindlau, Jessica; Colombier, Léo

Transition metal dichalcogenide semiconductors represent elementary components of layered heterostructures for emergent technologies beyond conventional opto-electronics. In their monolayer form they host electrons with quantized circular motion and associated valley polarization and valley coherence as key elements of opto-valleytronic functionality. Here, we introduce two-dimensional polarimetry as means of direct imaging of the valley pseudospin degree of freedom in monolayer transition metal dichalcogenides. Using MoS 2 as a representative material with valley-selective optical transitions, we establish quantitative image analysis for polarimetric maps of extended crystals, and identify valley polarization and valley coherence as sensitive probes of crystalline disorder. Moreover, we findmore » site-dependent thermal and non-thermal regimes of valley-polarized excitons in perpendicular magnetic fields. Finally, we demonstrate the potential of widefield polarimetry for rapid inspection of opto-valleytronic devices based on atomically thin semiconductors and heterostructures.« less

Bonding and electronics of the MoTe2/Ge interface under strain

NASA Astrophysics Data System (ADS)

Szary, Maciej J.; Michalewicz, Marek T.; Radny, Marian W.

2017-05-01

Understanding the interface formation of a conventional semiconductor with a monolayer of transition-metal dichalcogenides provides a necessary platform for the anticipated applications of dichalcogenides in electronics and optoelectronics. We report here, based on the density functional theory, that under in-plane tensile strain, a 2H semiconducting phase of the molybdenum ditelluride (MoTe2) monolayer undergoes a semiconductor-to-metal transition and in this form bonds covalently to bilayers of Ge stacked in the [111] crystal direction. This gives rise to the stable bonding configuration of the MoTe2/Ge interface with the ±K valley metallic, electronic interface states exclusively of a Mo 4 d character. The atomically sharp Mo layer represents therefore an electrically active (conductive) subsurface δ -like two-dimensional profile that can exhibit a valley-Hall effect. Such system can develop into a key element of advanced semiconductor technology or a novel device concept.

Silicon and germanium nanowire electronics: physics of conventional and unconventional transistors

NASA Astrophysics Data System (ADS)

Weber, Walter M.; Mikolajick, Thomas

2017-06-01

Research in the field of electronics of 1D group-IV semiconductor structures has attracted increasing attention over the past 15 years. The exceptional combination of the unique 1D electronic transport properties with the mature material know-how of highly integrated silicon and germanium technology holds the promise of enhancing state-of-the-art electronics. In addition of providing conduction channels that can bring conventional field effect transistors to the uttermost scaling limits, the physics of 1D group IV nanowires endows new device principles. Such unconventional silicon and germanium nanowire devices are contenders for beyond complementary metal oxide semiconductor (CMOS) computing by virtue of their distinct switching behavior and higher expressive value. This review conveys to the reader a systematic recapitulation and analysis of the physics of silicon and germanium nanowires and the most relevant CMOS and CMOS-like devices built from silicon and germanium nanowires, including inversion mode, junctionless, steep-slope, quantum well and reconfigurable transistors.

Self-Referenced Method for Estimating Refractive Index and Absolute Absorption of Loose Semiconductor Powders

DOE PAGES

Huang, Huafeng; Colabello, Diane M.; Sklute, Elizabeth C.; ...

2017-04-23

The absolute absorption coefficient, α(E), is a critical design parameter for devices using semiconductors for light harvesting associated with renewable energy production, both for classic technologies such as photovoltaics and for emerging technologies such as direct solar fuel production. While α(E) is well-known for many classic simple semiconductors used in photovoltaic applications, the absolute values of α(E) are typically unknown for the complex semiconductors being explored for solar fuel production due to the absence of single crystals or crystalline epitaxial films that are needed for conventional methods of determining α(E). In this work, a simple self-referenced method for estimating bothmore » the refractive indices, n(E), and absolute absorption coefficients, α(E), for loose powder samples using diffuse reflectance data is demonstrated. In this method, the sample refractive index can be deduced by refining n to maximize the agreement between the relative absorption spectrum calculated from bidirectional reflectance data (calculated through a Hapke transform which depends on n) and integrating sphere diffuse reflectance data (calculated through a Kubleka–Munk transform which does not depend on n). This new method can be quickly used to screen the suitability of emerging semiconductor systems for light-harvesting applications. The effectiveness of this approach is tested using the simple classic semiconductors Ge and Fe 2O 3 as well as the complex semiconductors La 2MoO 5 and La 4Mo 2O 11. The method is shown to work well for powders with a narrow size distribution (exemplified by Fe 2O 3) and to be ineffective for semiconductors with a broad size distribution (exemplified by Ge). As such, it provides a means for rapidly estimating the absolute optical properties of complex solids which are only available as loose powders.« less

High- k Gate Dielectrics for Emerging Flexible and Stretchable Electronics.

PubMed

Wang, Binghao; Huang, Wei; Chi, Lifeng; Al-Hashimi, Mohammed; Marks, Tobin J; Facchetti, Antonio

2018-05-22

Recent advances in flexible and stretchable electronics (FSE), a technology diverging from the conventional rigid silicon technology, have stimulated fundamental scientific and technological research efforts. FSE aims at enabling disruptive applications such as flexible displays, wearable sensors, printed RFID tags on packaging, electronics on skin/organs, and Internet-of-things as well as possibly reducing the cost of electronic device fabrication. Thus, the key materials components of electronics, the semiconductor, the dielectric, and the conductor as well as the passive (substrate, planarization, passivation, and encapsulation layers) must exhibit electrical performance and mechanical properties compatible with FSE components and products. In this review, we summarize and analyze recent advances in materials concepts as well as in thin-film fabrication techniques for high- k (or high-capacitance) gate dielectrics when integrated with FSE-compatible semiconductors such as organics, metal oxides, quantum dot arrays, carbon nanotubes, graphene, and other 2D semiconductors. Since thin-film transistors (TFTs) are the key enablers of FSE devices, we discuss TFT structures and operation mechanisms after a discussion on the needs and general requirements of gate dielectrics. Also, the advantages of high- k dielectrics over low- k ones in TFT applications were elaborated. Next, after presenting the design and properties of high- k polymers and inorganic, electrolyte, and hybrid dielectric families, we focus on the most important fabrication methodologies for their deposition as TFT gate dielectric thin films. Furthermore, we provide a detailed summary of recent progress in performance of FSE TFTs based on these high- k dielectrics, focusing primarily on emerging semiconductor types. Finally, we conclude with an outlook and challenges section.

Quantum cascade lasers (QCL) for active hyperspectral imaging

NASA Astrophysics Data System (ADS)

Yang, Quankui; Fuchs, Frank; Wagner, Joachim

2014-04-01

There is an increasing demand for wavelength agile laser sources covering the mid-infrared (MIR, 3.5-12 µm) wavelength range, among others in active imaging. The MIR range comprises a particularly interesting part of the electromagnetic spectrum for active hyperspectral imaging applications, due to the fact that the characteristic `fingerprint' absorption spectra of many chemical compounds lie in that range. Conventional semiconductor diode laser technology runs out of steam at such long wavelengths. For many applications, MIR coherent light sources based on solid state lasers in combination with optical parametric oscillators are too complex and thus bulky and expensive. In contrast, quantum cascade lasers (QCLs) constitute a class of very compact and robust semiconductor-based lasers, which are able to cover the mentioned wavelength range using the same semiconductor material system. In this tutorial, a brief review will be given on the state-of-the-art of QCL technology. Special emphasis will be addressed on QCL variants with well-defined spectral properties and spectral tunability. As an example for the use of wavelength agile QCL for active hyperspectral imaging, stand-off detection of explosives based on imaging backscattering laser spectroscopy will be discussed.

High Temperature Electronics for Intelligent Harsh Environment Sensors

NASA Technical Reports Server (NTRS)

Evans, Laura J.

2008-01-01

The development of intelligent instrumentation systems is of high interest in both public and private sectors. In order to obtain this ideal in extreme environments (i.e., high temperature, extreme vibration, harsh chemical media, and high radiation), both sensors and electronics must be developed concurrently in order that the entire system will survive for extended periods of time. The semiconductor silicon carbide (SiC) has been studied for electronic and sensing applications in extreme environment that is beyond the capability of conventional semiconductors such as silicon. The advantages of SiC over conventional materials include its near inert chemistry, superior thermomechanical properties in harsh environments, and electronic properties that include high breakdown voltage and wide bandgap. An overview of SiC sensors and electronics work ongoing at NASA Glenn Research Center (NASA GRC) will be presented. The main focus will be two technologies currently being investigated: 1) harsh environment SiC pressure transducers and 2) high temperature SiC electronics. Work highlighted will include the design, fabrication, and application of SiC sensors and electronics, with recent advancements in state-of-the-art discussed as well. These combined technologies are studied for the goal of developing advanced capabilities for measurement and control of aeropropulsion systems, as well as enhancing tools for exploration systems.

SiC Technology

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.

1998-01-01

Silicon carbide (SiC)-based semiconductor electronic devices and circuits are presently being developed for use in high-temperature, high-power, and/or high-radiation conditions under which conventional semiconductors cannot adequately perform. Silicon carbide's ability to function under such extreme conditions is expected to enable significant improvements to a far-ranging variety of applications and systems. These range from greatly improved high-voltage switching [1- 4] for energy savings in public electric power distribution and electric motor drives to more powerful microwave electronics for radar and communications [5-7] to sensors and controls for cleaner-burning more fuel-efficient jet aircraft and automobile engines. In the particular area of power devices, theoretical appraisals have indicated that SiC power MOSFET's and diode rectifiers would operate over higher voltage and temperature ranges, have superior switching characteristics, and yet have die sizes nearly 20 times smaller than correspondingly rated silicon-based devices [8]. However, these tremendous theoretical advantages have yet to be realized in experimental SiC devices, primarily due to the fact that SiC's relatively immature crystal growth and device fabrication technologies are not yet sufficiently developed to the degree required for reliable incorporation into most electronic systems [9]. This chapter briefly surveys the SiC semiconductor electronics technology. In particular, the differences (both good and bad) between SiC electronics technology and well-known silicon VLSI technology are highlighted. Projected performance benefits of SiC electronics are highlighted for several large-scale applications. Key crystal growth and device-fabrication issues that presently limit the performance and capability of high temperature and/or high power SiC electronics are identified.

Silicon Carbide Technology

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.

2006-01-01

Silicon carbide based semiconductor electronic devices and circuits are presently being developed for use in high-temperature, high-power, and high-radiation conditions under which conventional semiconductors cannot adequately perform. Silicon carbide's ability to function under such extreme conditions is expected to enable significant improvements to a far-ranging variety of applications and systems. These range from greatly improved high-voltage switching for energy savings in public electric power distribution and electric motor drives to more powerful microwave electronics for radar and communications to sensors and controls for cleaner-burning more fuel-efficient jet aircraft and automobile engines. In the particular area of power devices, theoretical appraisals have indicated that SiC power MOSFET's and diode rectifiers would operate over higher voltage and temperature ranges, have superior switching characteristics, and yet have die sizes nearly 20 times smaller than correspondingly rated silicon-based devices [8]. However, these tremendous theoretical advantages have yet to be widely realized in commercially available SiC devices, primarily owing to the fact that SiC's relatively immature crystal growth and device fabrication technologies are not yet sufficiently developed to the degree required for reliable incorporation into most electronic systems. This chapter briefly surveys the SiC semiconductor electronics technology. In particular, the differences (both good and bad) between SiC electronics technology and the well-known silicon VLSI technology are highlighted. Projected performance benefits of SiC electronics are highlighted for several large-scale applications. Key crystal growth and device-fabrication issues that presently limit the performance and capability of high-temperature and high-power SiC electronics are identified.

Semiconductor ring lasers subject to both on-chip filtered optical feedback and external conventional optical feedback

NASA Astrophysics Data System (ADS)

Khoder, Mulham; Van der Sande, Guy; Danckaert, Jan; Verschaffelt, Guy

2016-05-01

It is well known that the performance of semiconductor lasers is very sensitive to external optical feedback. This feedback can lead to changes in lasing characteristics and a variety of dynamical effects including chaos and coherence collapse. One way to avoid this external feedback is by using optical isolation, but these isolators and their packaging will increase the cost of the total system. Semiconductor ring lasers nowadays are promising sources in photonic integrated circuits because they do not require cleaved facets or mirrors to form a laser cavity. Recently, some of us proposed to combine semiconductor ring lasers with on chip filtered optical feedback to achieve tunable lasers. The feedback is realized by employing two arrayed waveguide gratings to split/recombine light into different wavelength channels. Semiconductor optical amplifier gates are used to control the feedback strength. In this work, we investigate how such lasers with filtered feedback are influenced by an external conventional optical feedback. The experimental results show intensity fluctuations in the time traces in both the clockwise and counterclockwise directions due to the conventional feedback. We quantify the strength of the conventional feedback induced dynamics be extracting the standard deviation of the intensity fluctuations in the time traces. By using filtered feedback, we can shift the onset of the conventional feedback induced dynamics to larger values of the feedback rate [ Khoder et al, IEEE Photon. Technol. Lett. DOI: 10.1109/LPT.2016.2522184]. The on-chip filtered optical feedback thus makes the semiconductor ring laser less senstive to the effect of (long) conventional optical feedback. We think these conclusions can be extended to other types of lasers.

Environment, health and safety issues for sources used in MOVPE growth of compound semiconductors

NASA Astrophysics Data System (ADS)

Shenai-Khatkhate, Deodatta V.; Goyette, Randall J.; DiCarlo, Ronald L., Jr.; Dripps, Gregory

2004-12-01

As metalorganic vapor-phase epitaxy (MOVPE) is becoming well-established production technology, there are equally growing concerns associated with its bearing on personnel and community safety, environmental impact and maximum quantities of hazardous materials permissible in the device fabrication operations. Safety as well as responsible environmental care has always been of paramount importance in the MOVPE-based crystal growth of compound semiconductors. In this paper, we present the findings from workplace exposure monitoring studies on conventional MOVPE sources such as trimethylgallium, triethylgallium, trimethylantimony and diethylzinc. Also reviewed are the environmental, health and safety hazard aspects for metalorganic sources of routine elements, and the means to minimize the risks (i.e., engineering controls) involved while using these MOVPE sources.

Gatemon Benchmarking and Two-Qubit Operation

NASA Astrophysics Data System (ADS)

Casparis, Lucas; Larsen, Thorvald; Olsen, Michael; Petersson, Karl; Kuemmeth, Ferdinand; Krogstrup, Peter; Nygard, Jesper; Marcus, Charles

Recent experiments have demonstrated superconducting transmon qubits with semiconductor nanowire Josephson junctions. These hybrid gatemon qubits utilize field effect tunability singular to semiconductors to allow complete qubit control using gate voltages, potentially a technological advantage over conventional flux-controlled transmons. Here, we present experiments with a two-qubit gatemon circuit. We characterize qubit coherence and stability and use randomized benchmarking to demonstrate single-qubit gate errors of ~0.5 % for all gates, including voltage-controlled Z rotations. We show coherent capacitive coupling between two gatemons and coherent SWAP operations. Finally, we perform a two-qubit controlled-phase gate with an estimated fidelity of ~91 %, demonstrating the potential of gatemon qubits for building scalable quantum processors. We acknowledge financial support from Microsoft Project Q and the Danish National Research Foundation.

New method of 2-dimensional metrology using mask contouring

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Yamagata, Yoshikazu; Sugiyama, Akiyuki; Toyoda, Yasutaka

2008-10-01

We have developed a new method of accurately profiling and measuring of a mask shape by utilizing a Mask CD-SEM. The method is intended to realize high accuracy, stability and reproducibility of the Mask CD-SEM adopting an edge detection algorithm as the key technology used in CD-SEM for high accuracy CD measurement. In comparison with a conventional image processing method for contour profiling, this edge detection method is possible to create the profiles with much higher accuracy which is comparable with CD-SEM for semiconductor device CD measurement. This method realizes two-dimensional metrology for refined pattern that had been difficult to measure conventionally by utilizing high precision contour profile. In this report, we will introduce the algorithm in general, the experimental results and the application in practice. As shrinkage of design rule for semiconductor device has further advanced, an aggressive OPC (Optical Proximity Correction) is indispensable in RET (Resolution Enhancement Technology). From the view point of DFM (Design for Manufacturability), a dramatic increase of data processing cost for advanced MDP (Mask Data Preparation) for instance and surge of mask making cost have become a big concern to the device manufacturers. This is to say, demands for quality is becoming strenuous because of enormous quantity of data growth with increasing of refined pattern on photo mask manufacture. In the result, massive amount of simulated error occurs on mask inspection that causes lengthening of mask production and inspection period, cost increasing, and long delivery time. In a sense, it is a trade-off between the high accuracy RET and the mask production cost, while it gives a significant impact on the semiconductor market centered around the mask business. To cope with the problem, we propose the best method of a DFM solution using two-dimensional metrology for refined pattern.

Fabrication of Ultra-Thin Printed Organic TFT CMOS Logic Circuits Optimized for Low-Voltage Wearable Sensor Applications.

PubMed

Takeda, Yasunori; Hayasaka, Kazuma; Shiwaku, Rei; Yokosawa, Koji; Shiba, Takeo; Mamada, Masashi; Kumaki, Daisuke; Fukuda, Kenjiro; Tokito, Shizuo

2016-05-09

Ultrathin electronic circuits that can be manufactured by using conventional printing technologies are key elements necessary to realize wearable health sensors and next-generation flexible electronic devices. Due to their low level of power consumption, complementary (CMOS) circuits using both types of semiconductors can be easily employed in wireless devices. Here, we describe ultrathin CMOS logic circuits, for which not only the source/drain electrodes but also the semiconductor layers were printed. Both p-type and n-type organic thin film transistor devices were employed in a D-flip flop circuit in the newly developed stacked structure and exhibited excellent electrical characteristics, including good carrier mobilities of 0.34 and 0.21 cm(2) V(-1) sec(-1), and threshold voltages of nearly 0 V with low operating voltages. These printed organic CMOS D-flip flop circuits exhibit operating frequencies of 75 Hz and demonstrate great potential for flexible and printed electronics technology, particularly for wearable sensor applications with wireless connectivity.

Fabrication of Ultra-Thin Printed Organic TFT CMOS Logic Circuits Optimized for Low-Voltage Wearable Sensor Applications

PubMed Central

Takeda, Yasunori; Hayasaka, Kazuma; Shiwaku, Rei; Yokosawa, Koji; Shiba, Takeo; Mamada, Masashi; Kumaki, Daisuke; Fukuda, Kenjiro; Tokito, Shizuo

2016-01-01

Ultrathin electronic circuits that can be manufactured by using conventional printing technologies are key elements necessary to realize wearable health sensors and next-generation flexible electronic devices. Due to their low level of power consumption, complementary (CMOS) circuits using both types of semiconductors can be easily employed in wireless devices. Here, we describe ultrathin CMOS logic circuits, for which not only the source/drain electrodes but also the semiconductor layers were printed. Both p-type and n-type organic thin film transistor devices were employed in a D-flip flop circuit in the newly developed stacked structure and exhibited excellent electrical characteristics, including good carrier mobilities of 0.34 and 0.21 cm2 V−1 sec−1, and threshold voltages of nearly 0 V with low operating voltages. These printed organic CMOS D-flip flop circuits exhibit operating frequencies of 75 Hz and demonstrate great potential for flexible and printed electronics technology, particularly for wearable sensor applications with wireless connectivity. PMID:27157914

Detection of X-ray photons by solution-processed organic-inorganic perovskites

PubMed Central

Yakunin, Sergii; Sytnyk, Mykhailo; Kriegner, Dominik; Shrestha, Shreetu; Richter, Moses; Matt, Gebhard J.; Azimi, Hamed; Brabec, Christoph J.; Stangl, Julian; Kovalenko, Maksym V.; Heiss, Wolfgang

2017-01-01

The evolution of real-time medical diagnostic tools such as angiography and computer tomography from radiography based on photographic plates was enabled by the development of integrated solid-state X-ray photon detectors, based on conventional solid-state semiconductors. Recently, for optoelectronic devices operating in the visible and near infrared spectral regions, solution-processed organic and inorganic semiconductors have also attracted immense attention. Here we demonstrate a possibility to use such inexpensive semiconductors for sensitive detection of X-ray photons by direct photon-to-current conversion. In particular, methylammonium lead iodide perovskite (CH3NH3PbI3) offers a compelling combination of fast photoresponse and a high absorption cross-section for X-rays, owing to the heavy Pb and I atoms. Solution processed photodiodes as well as photoconductors are presented, exhibiting high values of X-ray sensitivity (up to 25 µC mGyair-1 cm-3) and responsivity (1.9×104 carriers/photon), which are commensurate with those obtained by the current solid-state technology. PMID:28553368

Oxide semiconductor thin-film transistors: a review of recent advances.

PubMed

Fortunato, E; Barquinha, P; Martins, R

2012-06-12

Transparent electronics is today one of the most advanced topics for a wide range of device applications. The key components are wide bandgap semiconductors, where oxides of different origins play an important role, not only as passive component but also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance. In this paper the recent progress in n- and p-type oxide based thin-film transistors (TFT) is reviewed, with special emphasis on solution-processed and p-type, and the major milestones already achieved with this emerging and very promising technology are summarizeed. After a short introduction where the main advantages of these semiconductors are presented, as well as the industry expectations, the beautiful history of TFTs is revisited, including the main landmarks in the last 80 years, finishing by referring to some papers that have played an important role in shaping transparent electronics. Then, an overview is presented of state of the art n-type TFTs processed by physical vapour deposition methods, and finally one of the most exciting, promising, and low cost but powerful technologies is discussed: solution-processed oxide TFTs. Moreover, a more detailed focus analysis will be given concerning p-type oxide TFTs, mainly centred on two of the most promising semiconductor candidates: copper oxide and tin oxide. The most recent data related to the production of complementary metal oxide semiconductor (CMOS) devices based on n- and p-type oxide TFT is also be presented. The last topic of this review is devoted to some emerging applications, finalizing with the main conclusions. Related work that originated at CENIMAT|I3N during the last six years is included in more detail, which has led to the fabrication of high performance n- and p-type oxide transistors as well as the fabrication of CMOS devices with and on paper. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Confined high-pressure chemical deposition of hydrogenated amorphous silicon.

PubMed

Baril, Neil F; He, Rongrui; Day, Todd D; Sparks, Justin R; Keshavarzi, Banafsheh; Krishnamurthi, Mahesh; Borhan, Ali; Gopalan, Venkatraman; Peacock, Anna C; Healy, Noel; Sazio, Pier J A; Badding, John V

2012-01-11

Hydrogenated amorphous silicon (a-Si:H) is one of the most technologically important semiconductors. The challenge in producing it from SiH(4) precursor is to overcome a significant kinetic barrier to decomposition at a low enough temperature to allow for hydrogen incorporation into a deposited film. The use of high precursor concentrations is one possible means to increase reaction rates at low enough temperatures, but in conventional reactors such an approach produces large numbers of homogeneously nucleated particles in the gas phase, rather than the desired heterogeneous deposition on a surface. We report that deposition in confined micro-/nanoreactors overcomes this difficulty, allowing for the use of silane concentrations many orders of magnitude higher than conventionally employed while still realizing well-developed films. a-Si:H micro-/nanowires can be deposited in this way in extreme aspect ratio, small-diameter optical fiber capillary templates. The semiconductor materials deposited have ~0.5 atom% hydrogen with passivated dangling bonds and good electronic properties. They should be suitable for a wide range of photonic and electronic applications such as nonlinear optical fibers and solar cells. © 2011 American Chemical Society

Exploration of operator method digital optical computers for application to NASA

NASA Technical Reports Server (NTRS)

1990-01-01

Digital optical computer design has been focused primarily towards parallel (single point-to-point interconnection) implementation. This architecture is compared to currently developing VHSIC systems. Using demonstrated multichannel acousto-optic devices, a figure of merit can be formulated. The focus is on a figure of merit termed Gate Interconnect Bandwidth Product (GIBP). Conventional parallel optical digital computer architecture demonstrates only marginal competitiveness at best when compared to projected semiconductor implements. Global, analog global, quasi-digital, and full digital interconnects are briefly examined as alternative to parallel digital computer architecture. Digital optical computing is becoming a very tough competitor to semiconductor technology since it can support a very high degree of three dimensional interconnect density and high degrees of Fan-In without capacitive loading effects at very low power consumption levels.

Silicon carbide: A unique platform for metal-oxide-semiconductor physics

NASA Astrophysics Data System (ADS)

Liu, Gang; Tuttle, Blair R.; Dhar, Sarit

2015-06-01

A sustainable energy future requires power electronics that can enable significantly higher efficiencies in the generation, distribution, and usage of electrical energy. Silicon carbide (4H-SiC) is one of the most technologically advanced wide bandgap semiconductor that can outperform conventional silicon in terms of power handling, maximum operating temperature, and power conversion efficiency in power modules. While SiC Schottky diode is a mature technology, SiC power Metal Oxide Semiconductor Field Effect Transistors are relatively novel and there is large room for performance improvement. Specifically, major initiatives are under way to improve the inversion channel mobility and gate oxide stability in order to further reduce the on-resistance and enhance the gate reliability. Both problems relate to the defects near the SiO2/SiC interface, which have been the focus of intensive studies for more than a decade. Here we review research on the SiC MOS physics and technology, including its brief history, the state-of-art, and the latest progress in this field. We focus on the two main scientific problems, namely, low channel mobility and bias temperature instability. The possible mechanisms behind these issues are discussed at the device physics level as well as the atomic scale, with the support of published physical analysis and theoretical studies results. Some of the most exciting recent progress in interface engineering for improving the channel mobility and fundamental understanding of channel transport is reviewed.

New Concentric Electrode Metal-Semiconductor-Metal Photodetectors

NASA Technical Reports Server (NTRS)

Towe, Elias

1996-01-01

A new metal-semiconductor-metal (MSM) photodetector geometry is proposed. The new device has concentric metal electrodes which exhibit a high degree of symmetry and a design flexibility absent in the conventional MSM device. The concentric electrodes are biased to alternating potentials as in the conventional interdigitated device. Because of the high symmetry configuration, however, the new device also has a lower effective capacitance. This device and the conventional MSM structure are analyzed within a common theoretical framework which allows for the comparison of the important performance characteristics.

Semiconductor Nanotechnology: Novel Materials and Devices for Electronics, Photonics, and Renewable Energy Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodnick, Stephen; Korkin, Anatoli; Krstic, Predrag S

2010-03-01

Electronic and photonic information technology and renewable energy alternatives, such as solar energy, fuel cells and batteries, have now reached an advanced stage in their development. Cost-effective improvements to current technological approaches have made great progress, but certain challenges remain. As feature sizes of the latest generations of electronic devices are approaching atomic dimensions, circuit speeds are now being limited by interconnect bottlenecks. This has prompted innovations such as the introduction of new materials into microelectronics manufacturing at an unprecedented rate and alternative technologies to silicon CMOS architectures. Despite the environmental impact of conventional fossil fuel consumption, the low costmore » of these energy sources has been a long-standing economic barrier to the development of alternative and more efficient renewable energy sources, fuel cells and batteries. In the face of mounting environmental concerns, interest in such alternative energy sources has grown. It is now widely accepted that nanotechnology offers potential solutions for securing future progress in information and energy technologies. The Canadian Semiconductor Technology Conference (CSTC) forum was established 25 years ago in Ottawa as an important symbol of the intrinsic strength of the Canadian semiconductor research and development community, and the Canadian semiconductor industry as a whole. In 2007, the 13th CSTC was held in Montreal, moving for the first time outside the national capital region. The first three meetings in the series of Nano and Giga Challenges in Electronics and Photonics NGCM2002 in Moscow, NGCM2004 in Krakow, and NGC2007 in Phoenix were focused on interdisciplinary research from the fundamentals of materials science to the development of new system architectures. In 2009 NGC2009 and the 14th Canadian Semiconductor Technology Conference (CSTC2009) were held as a joint event, hosted by McMaster University (10 14 August, Hamilton, Ontario, Canada) and the scope was expanded to include renewable energy research and development. This special issue of Nanotechnology is devoted to a better understanding of the function and design of semiconductor devices that are relevant to information technology (both electronics and photonics based) and renewable energy applications. The papers contained in this special issue are selected from the NGC/CSTC2009 symposium. Among them is a report by Ray LaPierre from McMaster University and colleagues at the University of Waterloo in Canada on the ability to manipulate single spins in nanowire quantum bits. The paper also reports the development of a testbed of a few qubits for general quantum information processing tasks [1]. Lower cost and greater energy conversion efficiency compared with thin film devices have led to a high level of activity in nanowire research related to photovoltaic applications. This special issue also contains results from an impedance spectroscopy study of core shell GaAs nanowires to throw light on the transport and recombination mechanisms relevant to solar cell research [2]. Information technology research and renewable energy sources are research areas of enormous public interest. This special issue addresses both theoretical and experimental achievements and provides a stimulating outlook for technological developments in these highly topical fields of research. References [1] Caram J, Sandoval C, Tirado M, Comedi D, Czaban J, Thompson D A and LaPierre R R 2010 Electrical characteristics of core shell p-n GaAs nanowire structures with Te as the n-dopant Nanotechnology 21 134007 [2] Baugh J, Fung J S and LaPierre R R 2010 Building a spin quantum bit register using semiconductor nanowires Nanotechnology 21 134018« less

EDITORIAL: Semiconductor nanotechnology: novel materials and devices for electronics, photonics and renewable energy applications Semiconductor nanotechnology: novel materials and devices for electronics, photonics and renewable energy applications

NASA Astrophysics Data System (ADS)

Goodnick, Stephen; Korkin, Anatoli; Krstic, Predrag; Mascher, Peter; Preston, John; Zaslavsky, Alex

2010-04-01

Electronic and photonic information technology and renewable energy alternatives, such as solar energy, fuel cells and batteries, have now reached an advanced stage in their development. Cost-effective improvements to current technological approaches have made great progress, but certain challenges remain. As feature sizes of the latest generations of electronic devices are approaching atomic dimensions, circuit speeds are now being limited by interconnect bottlenecks. This has prompted innovations such as the introduction of new materials into microelectronics manufacturing at an unprecedented rate and alternative technologies to silicon CMOS architectures. Despite the environmental impact of conventional fossil fuel consumption, the low cost of these energy sources has been a long-standing economic barrier to the development of alternative and more efficient renewable energy sources, fuel cells and batteries. In the face of mounting environmental concerns, interest in such alternative energy sources has grown. It is now widely accepted that nanotechnology offers potential solutions for securing future progress in information and energy technologies. The Canadian Semiconductor Technology Conference (CSTC) forum was established 25 years ago in Ottawa as an important symbol of the intrinsic strength of the Canadian semiconductor research and development community, and the Canadian semiconductor industry as a whole. In 2007, the 13th CSTC was held in Montreal, moving for the first time outside the national capital region. The first three meetings in the series of 'Nano and Giga Challenges in Electronics and Photonics'— NGCM2002 in Moscow, NGCM2004 in Krakow, and NGC2007 in Phoenix— were focused on interdisciplinary research from the fundamentals of materials science to the development of new system architectures. In 2009 NGC2009 and the 14th Canadian Semiconductor Technology Conference (CSTC2009) were held as a joint event, hosted by McMaster University (10-14 August, Hamilton, Ontario, Canada) and the scope was expanded to include renewable energy research and development. This special issue of Nanotechnology is devoted to a better understanding of the function and design of semiconductor devices that are relevant to information technology (both electronics and photonics based) and renewable energy applications. The papers contained in this special issue are selected from the NGC/CSTC2009 symposium. Among them is a report by Ray LaPierre from McMaster University and colleagues at the University of Waterloo in Canada on the ability to manipulate single spins in nanowire quantum bits. The paper also reports the development of a testbed of a few qubits for general quantum information processing tasks [1]. Lower cost and greater energy conversion efficiency compared with thin film devices have led to a high level of activity in nanowire research related to photovoltaic applications. This special issue also contains results from an impedance spectroscopy study of core-shell GaAs nanowires to throw light on the transport and recombination mechanisms relevant to solar cell research [2]. Information technology research and renewable energy sources are research areas of enormous public interest. This special issue addresses both theoretical and experimental achievements and provides a stimulating outlook for technological developments in these highly topical fields of research. References [1] Caram J, Sandoval C, Tirado M, Comedi D, Czaban J, Thompson D A and LaPierre R R 2101 Nanotechnology 21 134007 [2] Baugh J, Fung J S and LaPierre RR 2010 Nanotechnology 21 134018

Metal oxides for optoelectronic applications.

PubMed

Yu, Xinge; Marks, Tobin J; Facchetti, Antonio

2016-04-01

Metal oxides (MOs) are the most abundant materials in the Earth's crust and are ingredients in traditional ceramics. MO semiconductors are strikingly different from conventional inorganic semiconductors such as silicon and III-V compounds with respect to materials design concepts, electronic structure, charge transport mechanisms, defect states, thin-film processing and optoelectronic properties, thereby enabling both conventional and completely new functions. Recently, remarkable advances in MO semiconductors for electronics have been achieved, including the discovery and characterization of new transparent conducting oxides, realization of p-type along with traditional n-type MO semiconductors for transistors, p-n junctions and complementary circuits, formulations for printing MO electronics and, most importantly, commercialization of amorphous oxide semiconductors for flat panel displays. This Review surveys the uniqueness and universality of MOs versus other unconventional electronic materials in terms of materials chemistry and physics, electronic characteristics, thin-film fabrication strategies and selected applications in thin-film transistors, solar cells, diodes and memories.

Metal oxides for optoelectronic applications

NASA Astrophysics Data System (ADS)

Yu, Xinge; Marks, Tobin J.; Facchetti, Antonio

2016-04-01

Metal oxides (MOs) are the most abundant materials in the Earth's crust and are ingredients in traditional ceramics. MO semiconductors are strikingly different from conventional inorganic semiconductors such as silicon and III-V compounds with respect to materials design concepts, electronic structure, charge transport mechanisms, defect states, thin-film processing and optoelectronic properties, thereby enabling both conventional and completely new functions. Recently, remarkable advances in MO semiconductors for electronics have been achieved, including the discovery and characterization of new transparent conducting oxides, realization of p-type along with traditional n-type MO semiconductors for transistors, p-n junctions and complementary circuits, formulations for printing MO electronics and, most importantly, commercialization of amorphous oxide semiconductors for flat panel displays. This Review surveys the uniqueness and universality of MOs versus other unconventional electronic materials in terms of materials chemistry and physics, electronic characteristics, thin-film fabrication strategies and selected applications in thin-film transistors, solar cells, diodes and memories.

Architectures for Improved Organic Semiconductor Devices

NASA Astrophysics Data System (ADS)

Beck, Jonathan H.

Advancements in the microelectronics industry have brought increasing performance and decreasing prices to a wide range of users. Conventional silicon-based electronics have followed Moore's law to provide an ever-increasing integrated circuit transistor density, which drives processing power, solid-state memory density, and sensor technologies. As shrinking conventional integrated circuits became more challenging, researchers began exploring electronics with the potential to penetrate new applications with a low price of entry: "Electronics everywhere." The new generation of electronics is thin, light, flexible, and inexpensive. Organic electronics are part of the new generation of thin-film electronics, relying on the synthetic flexibility of carbon molecules to create organic semiconductors, absorbers, and emitters which perform useful tasks. Organic electronics can be fabricated with low energy input on a variety of novel substrates, including inexpensive plastic sheets. The potential ease of synthesis and fabrication of organic-based devices means that organic electronics can be made at very low cost. Successfully demonstrated organic semiconductor devices include photovoltaics, photodetectors, transistors, and light emitting diodes. Several challenges that face organic semiconductor devices are low performance relative to conventional devices, long-term device stability, and development of new organic-compatible processes and materials. While the absorption and emission performance of organic materials in photovoltaics and light emitting diodes is extraordinarily high for thin films, the charge conduction mobilities are generally low. Building highly efficient devices with low-mobility materials is one challenge. Many organic semiconductor films are unstable during fabrication, storage, and operation due to reactions with water, oxygen and hydroxide. A final challenge facing organic electronics is the need for new processes and materials for electrodes, semiconductors and substrates compatible with low-temperature, flexible, and oxygenated and aromatic solvent-free fabrication. Materials and processes must be capable of future high volume production in order to enable low costs. In this thesis we explore several techniques to improve organic semiconductor device performance and enable new fabrication processes. In Chapter 2, I describe the integration of sub-optical-wavelength nanostructured electrodes that improve fill factor and power conversion efficiency in organic photovoltaic devices. Photovoltaic fill factor performance is one of the primary challenges facing organic photovoltaics because most organic semiconductors have poor charge mobility. Our electrical and optical measurements and simulations indicate that nanostructured electrodes improve charge extraction in organic photovoltaics. In Chapter 3, I describe a general method for maximizing the efficiency of organic photovoltaic devices by simultaneously optimizing light absorption and charge carrier collection. We analyze the potential benefits of light trapping strategies for maximizing the overall power conversion efficiency of organic photovoltaic devices. This technique may be used to improve organic photovoltaic materials with low absorption, or short exciton diffusion and carrier-recombination lengths, opening up the device design space. In Chapter 4, I describe a process for high-quality graphene transfer onto chemically sensitive, weakly interacting organic semiconductor thin-films. Graphene is a promising flexible and highly transparent electrode for organic electronics; however, transferring graphene films onto organic semiconductor devices was previously impossible. We demonstrate a new transfer technique based on an elastomeric stamp coated with an fluorinated polymer release layer. We fabricate three classes of organic semiconductor devices: field effect transistors without high temperature annealing, transparent organic light-emitting diodes, and transparent small-molecule organic photovoltaic devices.

The future of automation for high-volume wafer fabrication and ASIC manufacturing

NASA Astrophysics Data System (ADS)

Hughes, Randall A.; Shott, John D.

1986-12-01

A framework is given to analyze the future trends in semiconductor manufacturing automation systems, focusing specifically on the needs of ASIC (application-specific integrated circuit) or custom integrated circuit manufacturing. Advances in technologies such as gate arrays and standard cells now make it significantly easier to obtain system cost and performance advantages by integrating nonstandard functions on silicon. ASICs are attractive to U.S. manufacturers because they place a premium on sophisticated design tools, familiarity with customer needs and applications, and fast turn-around fabrication. These are areas where U.S. manufacturers believe they have an advantage and, consequently, will not suffer from the severe price/manufacturing competition encountered in conventional high-volume semiconductor products. Previously, automation was often considered viable only for high-volume manufacturing, but automation becomes a necessity in the new ASIC environment.

Deformable inorganic semiconductor

NASA Astrophysics Data System (ADS)

Kim, Dae-Hyeong; Cha, Gi Doo

2018-05-01

Unlike conventional inorganic semiconductors, which are typically brittle, α-Ag2S exhibits room-temperature ductility with favourable electrical properties, offering promise for use in high-performance flexible and stretchable devices.

Extremely flexible nanoscale ultrathin body silicon integrated circuits on plastic.

PubMed

Shahrjerdi, Davood; Bedell, Stephen W

2013-01-09

In recent years, flexible devices based on nanoscale materials and structures have begun to emerge, exploiting semiconductor nanowires, graphene, and carbon nanotubes. This is primarily to circumvent the existing shortcomings of the conventional flexible electronics based on organic and amorphous semiconductors. The aim of this new class of flexible nanoelectronics is to attain high-performance devices with increased packing density. However, highly integrated flexible circuits with nanoscale transistors have not yet been demonstrated. Here, we show nanoscale flexible circuits on 60 Å thick silicon, including functional ring oscillators and memory cells. The 100-stage ring oscillators exhibit the stage delay of ~16 ps at a power supply voltage of 0.9 V, the best reported for any flexible circuits to date. The mechanical flexibility is achieved by employing the controlled spalling technology, enabling the large-area transfer of the ultrathin body silicon devices to a plastic substrate at room temperature. These results provide a simple and cost-effective pathway to enable ultralight flexible nanoelectronics with unprecedented level of system complexity based on mainstream silicon technology.

Deep-submicron Graphene Field-Effect Transistors with State-of-Art fmax

PubMed Central

Lyu, Hongming; Lu, Qi; Liu, Jinbiao; Wu, Xiaoming; Zhang, Jinyu; Li, Junfeng; Niu, Jiebin; Yu, Zhiping; Wu, Huaqiang; Qian, He

2016-01-01

In order to conquer the short-channel effects that limit conventional ultra-scale semiconductor devices, two-dimensional materials, as an option of ultimate thin channels, receive wide attention. Graphene, in particular, bears great expectations because of its supreme carrier mobility and saturation velocity. However, its main disadvantage, the lack of bandgap, has not been satisfactorily solved. As a result, maximum oscillation frequency (fmax) which indicates transistors’ power amplification ability has been disappointing. Here, we present submicron field-effect transistors with specially designed low-resistance gate and excellent source/drain contact, and therefore significantly improved fmax. The fabrication was assisted by the advanced 8-inch CMOS back-end-of-line technology. A 200-nm-gate-length GFET achieves fT/fmax = 35.4/50 GHz. All GFET samples with gate lengths ranging from 200 nm to 400 nm possess fmax 31–41% higher than fT, closely resembling Si n-channel MOSFETs at comparable technology nodes. These results re-strengthen the promise of graphene field-effect transistors in next generation semiconductor electronics. PMID:27775009

High mobility and high stability glassy metal-oxynitride materials and devices

NASA Astrophysics Data System (ADS)

Lee, Eunha; Kim, Taeho; Benayad, Anass; Hur, Jihyun; Park, Gyeong-Su; Jeon, Sanghun

2016-04-01

In thin film technology, future semiconductor and display products with high performance, high density, large area, and ultra high definition with three-dimensional functionalities require high performance thin film transistors (TFTs) with high stability. Zinc oxynitride, a composite of zinc oxide and zinc nitride, has been conceded as a strong substitute to conventional semiconductor film such as silicon and indium gallium zinc oxide due to high mobility value. However, zinc oxynitride has been suffered from poor reproducibility due to relatively low binding energy of nitrogen with zinc, resulting in the instability of composition and its device performance. Here we performed post argon plasma process on zinc oxynitride film, forming nano-crystalline structure in stable amorphous matrix which hampers the reaction of oxygen with zinc. Therefore, material properties and device performance of zinc oxynitride are greatly enhanced, exhibiting robust compositional stability even exposure to air, uniform phase, high electron mobility, negligible fast transient charging and low noise characteristics. Furthermore, We expect high mobility and high stability zinc oxynitride customized by plasma process to be applicable to a broad range of semiconductor and display devices.

Detection of Short-Waved Spin Waves in Individual Microscopic Spin-Wave Waveguides Using the Inverse Spin Hall Effect.

PubMed

Brächer, T; Fabre, M; Meyer, T; Fischer, T; Auffret, S; Boulle, O; Ebels, U; Pirro, P; Gaudin, G

2017-12-13

The miniaturization of complementary metal-oxide-semiconductor (CMOS) devices becomes increasingly difficult due to fundamental limitations and the increase of leakage currents. Large research efforts are devoted to find alternative concepts that allow for a larger data-density and lower power consumption than conventional semiconductor approaches. Spin waves have been identified as a potential technology that can complement and outperform CMOS in complex logic applications, profiting from the fact that these waves enable wave computing on the nanoscale. The practical application of spin waves, however, requires the demonstration of scalable, CMOS compatible spin-wave detection schemes in material systems compatible with standard spintronics as well as semiconductor circuitry. Here, we report on the wave-vector independent detection of short-waved spin waves with wavelengths down to 150 nm by the inverse spin Hall effect in spin-wave waveguides made from ultrathin Ta/Co 8 Fe 72 B 20 /MgO. These findings open up the path for miniaturized scalable interconnects between spin waves and CMOS and the use of ultrathin films made from standard spintronic materials in magnonics.

Review of the Semiconductor Industry and Technology Roadmap.

ERIC Educational Resources Information Center

Kumar, Sameer; Krenner, Nicole

2002-01-01

Points out that the semiconductor industry is extremely competitive and requires ongoing technological advances to improve performance while reducing costs to remain competitive and how essential it is to gain an understanding of important facets of the industry. Provides an overview of the initial and current semiconductor technology roadmap that…

Frequency control of a spin-torque oscillator using magnetostrictive anisotropy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Min Gyu Albert; Lee, Seok-Hee, E-mail: bgpark@kaist.ac.kr, E-mail: shlee@kaist.edu; Baek, Seung-heon Chris

2016-01-11

We report the working principle of a spin-torque oscillator, of which the frequency is efficiently controlled by manipulating the magnetostrictive anisotropy. To justify the scheme, we simulate a conventional magnetic-tunnel junction-based oscillator which is fabricated on a piezoelectric material. By applying mechanical stress to a free layer using a piezoelectric material, the oscillation frequency can be controlled to ensure a broad tuning range without a significant reduction of the dynamic resistance variation. Such controllability, which appears in the absence of an external magnetic field, will not only enable the integration of spin-torque oscillators and conventional complimentary metal-oxide semiconductor technology butmore » will also broaden the applicability of spin-torque oscillators.« less

Semiconductor laser using multimode interference principle

NASA Astrophysics Data System (ADS)

Gong, Zisu; Yin, Rui; Ji, Wei; Wu, Chonghao

2018-01-01

Multimode interference (MMI) structure is introduced in semiconductor laser used in optical communication system to realize higher power and better temperature tolerance. Using beam propagation method (BPM), Multimode interference laser diode (MMI-LD) is designed and fabricated in InGaAsP/InP based material. As a comparison, conventional semiconductor laser using straight single-mode waveguide is also fabricated in the same wafer. With a low injection current (about 230 mA), the output power of the implemented MMI-LD is up to 2.296 mW which is about four times higher than the output power of the conventional semiconductor laser. The implemented MMI-LD exhibits stable output operating at the wavelength of 1.52 μm and better temperature tolerance when the temperature varies from 283.15 K to 293.15 K.

Vertical Charge Transport and Negative Transconductance in Multilayer Molybdenum Disulfides.

PubMed

Liu, Yuan; Guo, Jian; He, Qiyuan; Wu, Hao; Cheng, Hung-Chieh; Ding, Mengning; Shakir, Imran; Gambin, Vincent; Huang, Yu; Duan, Xiangfeng

2017-09-13

Negative transconductance (NTC) devices have been heavily investigated for their potential in low power logical circuit, memory, oscillating, and high-speed switching applications. Previous NTC devices are largely attributed to two working mechanisms: quantum mechanical tunneling, and mobility degradation at high electrical field. Herein we report a systematic investigation of charge transport in multilayer two-dimensional semiconductors (2DSCs) with optimized van der Waals contact and for the first time demonstrate NTC and antibipolar characteristics in multilayer 2DSCs (such as MoS 2 , WSe 2 ). By varying the measurement temperature, bias voltage, and body thickness, we found the NTC behavior can be attributed to a vertical potential barrier in the multilayer 2DSCs and the competing mechanisms between intralayer lateral transport and interlayer vertical transport, thus representing a new working mechanism for NTC operation. Importantly, this vertical potential barrier arises from inhomogeneous carrier distribution in 2DSC from the near-substrate region to the bulk region, which is in contrast to conventional semiconductors with homogeneous doping defined by bulk dopants. We further show that the unique NTC behavior can be explored for creating frequency doublers and phase shift keying circuits with only one transistor, greatly simplifying the circuit design compared to conventional technology.

Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses to extreme mechanical deformations.

PubMed

Kim, Dae-Hyeong; Song, Jizhou; Choi, Won Mook; Kim, Hoon-Sik; Kim, Rak-Hwan; Liu, Zhuangjian; Huang, Yonggang Y; Hwang, Keh-Chih; Zhang, Yong-wei; Rogers, John A

2008-12-02

Electronic systems that offer elastic mechanical responses to high-strain deformations are of growing interest because of their ability to enable new biomedical devices and other applications whose requirements are impossible to satisfy with conventional wafer-based technologies or even with those that offer simple bendability. This article introduces materials and mechanical design strategies for classes of electronic circuits that offer extremely high stretchability, enabling them to accommodate even demanding configurations such as corkscrew twists with tight pitch (e.g., 90 degrees in approximately 1 cm) and linear stretching to "rubber-band" levels of strain (e.g., up to approximately 140%). The use of single crystalline silicon nanomaterials for the semiconductor provides performance in stretchable complementary metal-oxide-semiconductor (CMOS) integrated circuits approaching that of conventional devices with comparable feature sizes formed on silicon wafers. Comprehensive theoretical studies of the mechanics reveal the way in which the structural designs enable these extreme mechanical properties without fracturing the intrinsically brittle active materials or even inducing significant changes in their electrical properties. The results, as demonstrated through electrical measurements of arrays of transistors, CMOS inverters, ring oscillators, and differential amplifiers, suggest a valuable route to high-performance stretchable electronics.

Electrical characteristics of silicon nanowire CMOS inverters under illumination.

PubMed

Yoo, Jeuk; Kim, Yoonjoong; Lim, Doohyeok; Kim, Sangsig

2018-02-05

In this study, we examine the electrical characteristics of complementary metal-oxide-semiconductor (CMOS) inverters with silicon nanowire (SiNW) channels on transparent substrates under illumination. The electrical characteristics vary with the wavelength and power of light due to the variation in the generation rates of the electric-hole pairs. Compared to conventional optoelectronic devices that sense the on/off states by the variation in the current, our device achieves the sensing of the on/off states with more precision by using the voltage variation induced by the wavelength or intensity of light. The device was fabricated on transparent substrates to maximize the light absorption using conventional CMOS technologies. The key difference between our SiNW CMOS inverters and conventional optoelectronic devices is the ability to control the flow of charge carriers more effectively. The improved sensitivity accomplished with the use of SiNW CMOS inverters allows better control of the on/off states.

Monolithic integration of SOI waveguide photodetectors and transimpedance amplifiers

NASA Astrophysics Data System (ADS)

Li, Shuxia; Tarr, N. Garry; Ye, Winnie N.

2018-02-01

In the absence of commercial foundry technologies offering silicon-on-insulator (SOI) photonics combined with Complementary Metal Oxide Semiconductor (CMOS) transistors, monolithic integration of conventional electronics with SOI photonics is difficult. Here we explore the implementation of lateral bipolar junction transistors (LBJTs) and Junction Field Effect Transistors (JFETs) in a commercial SOI photonics technology lacking MOS devices but offering a variety of n- and p-type ion implants intended to provide waveguide modulators and photodetectors. The fabrication makes use of the commercial Institute of Microelectronics (IME) SOI photonics technology. Based on knowledge of device doping and geometry, simple compact LBJT and JFET device models are developed. These models are then used to design basic transimpedance amplifiers integrated with optical waveguides. The devices' experimental current-voltage characteristics results are reported.

A novel high-speed CMOS circuit based on a gang of capacitors

NASA Astrophysics Data System (ADS)

Sharroush, Sherif M.

2017-08-01

There is no doubt that complementary metal-oxide semiconductor (CMOS) circuits with wide fan-in suffers from the relatively sluggish operation. In this paper, a circuit that contains a gang of capacitors sharing their charge with each other is proposed as an alternative to long N-channel MOS and P-channel MOS stacks. The proposed scheme is investigated quantitatively and verified by simulation using the 45-nm CMOS technology with VDD = 1 V. The time delay, area and power consumption of the proposed scheme are investigated and compared with the conventional static CMOS logic circuit. It is verified that the proposed scheme achieves 52% saving in the average propagation delay for eight inputs and that it has a smaller area compared to the conventional CMOS logic when the number of inputs exceeds three and a smaller power consumption for a number of inputs exceeding two. The impacts of process variations, component mismatches and technology scaling on the proposed scheme are also investigated.

Co-integration of nano-scale vertical- and horizontal-channel metal-oxide-semiconductor field-effect transistors for low power CMOS technology.

PubMed

Sun, Min-Chul; Kim, Garam; Kim, Sang Wan; Kim, Hyun Woo; Kim, Hyungjin; Lee, Jong-Ho; Shin, Hyungcheol; Park, Byung-Gook

2012-07-01

In order to extend the conventional low power Si CMOS technology beyond the 20-nm node without SOI substrates, we propose a novel co-integration scheme to build horizontal- and vertical-channel MOSFETs together and verify the idea using TCAD simulations. From the fabrication viewpoint, it is highlighted that this scheme provides additional vertical devices with good scalability by adding a few steps to the conventional CMOS process flow for fin formation. In addition, the benefits of the co-integrated vertical devices are investigated using a TCAD device simulation. From this study, it is confirmed that the vertical device shows improved off-current control and a larger drive current when the body dimension is less than 20 nm, due to the electric field coupling effect at the double-gated channel. Finally, the benefits from the circuit design viewpoint, such as the larger midpoint gain and beta and lower power consumption, are confirmed by the mixed-mode circuit simulation study.

Fundamental energy limits of SET-based Brownian NAND and half-adder circuits. Preliminary findings from a physical-information-theoretic methodology

NASA Astrophysics Data System (ADS)

Ercan, İlke; Suyabatmaz, Enes

2018-06-01

The saturation in the efficiency and performance scaling of conventional electronic technologies brings about the development of novel computational paradigms. Brownian circuits are among the promising alternatives that can exploit fluctuations to increase the efficiency of information processing in nanocomputing. A Brownian cellular automaton, where signals propagate randomly and are driven by local transition rules, can be made computationally universal by embedding arbitrary asynchronous circuits on it. One of the potential realizations of such circuits is via single electron tunneling (SET) devices since SET technology enable simulation of noise and fluctuations in a fashion similar to Brownian search. In this paper, we perform a physical-information-theoretic analysis on the efficiency limitations in a Brownian NAND and half-adder circuits implemented using SET technology. The method we employed here establishes a solid ground that enables studying computational and physical features of this emerging technology on an equal footing, and yield fundamental lower bounds that provide valuable insights into how far its efficiency can be improved in principle. In order to provide a basis for comparison, we also analyze a NAND gate and half-adder circuit implemented in complementary metal oxide semiconductor technology to show how the fundamental bound of the Brownian circuit compares against a conventional paradigm.

K-band single-chip electron spin resonance detector.

PubMed

Anders, Jens; Angerhofer, Alexander; Boero, Giovanni

2012-04-01

We report on the design, fabrication, and characterization of an integrated detector for electron spin resonance spectroscopy operating at 27 GHz. The microsystem, consisting of an LC-oscillator and a frequency division module, is integrated onto a single silicon chip using a conventional complementary metal-oxide-semiconductor technology. The achieved room temperature spin sensitivity is about 10(8)spins/G Hz(1/2), with a sensitive volume of about (100 μm)(3). Operation at 77K is also demonstrated. Copyright © 2012 Elsevier Inc. All rights reserved.

Book of Knowledge (BOK) for NASA Electronic Packaging Roadmap

NASA Technical Reports Server (NTRS)

Ghaffarian, Reza

2015-01-01

The objective of this document is to update the NASA roadmap on packaging technologies (initially released in 2007) and to present the current trends toward further reducing size and increasing functionality. Due to the breadth of work being performed in the area of microelectronics packaging, this report presents only a number of key packaging technologies detailed in three industry roadmaps for conventional microelectronics and a more recently introduced roadmap for organic and printed electronics applications. The topics for each category were down-selected by reviewing the 2012 reports of the International Technology Roadmap for Semiconductor (ITRS), the 2013 roadmap reports of the International Electronics Manufacturing Initiative (iNEMI), the 2013 roadmap of association connecting electronics industry (IPC), the Organic Printed Electronics Association (OE-A). The report also summarizes the results of numerous articles and websites specifically discussing the trends in microelectronics packaging technologies.

Note: Operation of gamma-ray microcalorimeters at elevated count rates using filters with constraints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alpert, B. K.; Horansky, R. D.; Bennett, D. A.

Microcalorimeter sensors operated near 0.1 K can measure the energy of individual x- and gamma-ray photons with significantly more precision than conventional semiconductor technologies. Both microcalorimeter arrays and higher per pixel count rates are desirable to increase the total throughput of spectrometers based on these devices. The millisecond recovery time of gamma-ray microcalorimeters and the resulting pulse pileup are significant obstacles to high per pixel count rates. Here, we demonstrate operation of a microcalorimeter detector at elevated count rates by use of convolution filters designed to be orthogonal to the exponential tail of a preceding pulse. These filters allow operationmore » at 50% higher count rates than conventional filters while largely preserving sensor energy resolution.« less

Direct Effect of Dielectric Surface Energy on Carrier Transport in Organic Field-Effect Transistors.

PubMed

Zhou, Shujun; Tang, Qingxin; Tian, Hongkun; Zhao, Xiaoli; Tong, Yanhong; Barlow, Stephen; Marder, Seth R; Liu, Yichun

2018-05-09

The understanding of the characteristics of gate dielectric that leads to optimized carrier transport remains controversial, and the conventional studies applied organic semiconductor thin films, which introduces the effect of dielectric on the growth of the deposited semiconductor thin films and hence only can explore the indirect effects. Here, we introduce pregrown organic single crystals to eliminate the indirect effect (semiconductor growth) in the conventional studies and to undertake an investigation of the direct effect of dielectric on carrier transport. It is shown that the matching of the polar and dispersive components of surface energy between semiconductor and dielectric is favorable for higher mobility. This new empirical finding may show the direct relationship between dielectric and carrier transport for the optimized mobility of organic field-effect transistors and hence show a promising potential for the development of next-generation high-performance organic electronic devices.

Design of power electronics for TVC EMA systems

NASA Technical Reports Server (NTRS)

Nelms, R. Mark

1993-01-01

The Composite Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. This report presents the results of an investigation into the applicability of two new technologies, MOS-controlled thyristors (MCT's) and pulse density modulation (PDM), to the control of brushless dc motors in EMA systems. MCT's are new power semiconductor devices, which combine the high voltage and current capabilities of conventional thyristors and the low gate drive requirements of metal oxide semiconductor field effect transistors (MOSFET's). The commanded signals in a PDM system are synthesized using a series of sinusoidal pulses instead of a series of square pulses as in a pulse width modulation (PWM) system. A resonant dc link inverter is employed to generate the sinusoidal pulses in the PDM system. This inverter permits zero-voltage switching of all semiconductors which reduces switching losses and switching stresses. The objectives of this project are to develop and validate an analytical model of the MCT device when used in high power motor control applications and to design, fabricate, and test a prototype electronic circuit employing both MCT and PDM technology for controlling a brushless dc motor.

Enhanced biosensing resolution with foundry fabricated individually addressable dual-gated ISFETs.

PubMed

Duarte-Guevara, Carlos; Lai, Fei-Lung; Cheng, Chun-Wen; Reddy, Bobby; Salm, Eric; Swaminathan, Vikhram; Tsui, Ying-Kit; Tuan, Hsiao Chin; Kalnitsky, Alex; Liu, Yi-Shao; Bashir, Rashid

2014-08-19

The adaptation of semiconductor technologies for biological applications may lead to a new era of inexpensive, sensitive, and portable diagnostics. At the core of these developing technologies is the ion-sensitive field-effect transistor (ISFET), a biochemical to electrical transducer with seamless integration to electronic systems. We present a novel structure for a true dual-gated ISFET that is fabricated with a silicon-on-insulator (SOI) complementary metal-oxide-semiconductor process by Taiwan Semiconductor Manufacturing Company (TSMC). In contrast to conventional SOI ISFETs, each transistor has an individually addressable back-gate and a gate oxide that is directly exposed to the solution. The elimination of the commonly used floating gate architecture reduces the chance of electrostatic discharge and increases the potential achievable transistor density. We show that when operated in a "dual-gate" mode, the transistor response can exhibit sensitivities to pH changes beyond the Nernst limit. This enhancement in sensitivity was shown to increase the sensor's signal-to-noise ratio, allowing the device to resolve smaller pH changes. An improved resolution can be used to enhance small signals and increase the sensor accuracy when monitoring small pH dynamics in biological reactions. As a proof of concept, we demonstrate that the amplified sensitivity and improved resolution result in a shorter detection time and a larger output signal of a loop-mediated isothermal DNA amplification reaction (LAMP) targeting a pathogenic bacteria gene, showing benefits of the new structure for biosensing applications.

Programme and Abstracts. Workshop on Expert Evaluation and Control of Compound Semiconductor Materials and Technologies (1st) Held in Ecole Centrale De Lyon, France on 19 -22 May 1992. (EXAMTEC’ 92)

DTIC Science & Technology

1992-05-22

Evaluation and Control of Compound Semiconductor Materials and Technologies (EXMATEC󈨠) at Ecole Centrale de Lyon (Ecully, France, 19th to 22nd May...semiconductor technologies to manufacture advanced devices with improved reproducibility, better reliability and lower cost. -’Device structures...concepts are required for expert evaluation and control of still developing technologies . In this context, the EXMATEC series will constitute a major

Feasibility survey of thermoelectric conversion technology using semiconductors

NASA Astrophysics Data System (ADS)

1993-03-01

The paper takes notice to thermoelectric conversion technology using semiconductors and investigates it in a wide range from high temperature to low temperature to study its feasibility. It is found that in Bi-Te alloy elements applicable to a temperature range of around 200(degree)C, some are over 3.5(times)10(sup -3)K(sup -1) in performance index, and performance of the element can be practically improved in the near future. The thermoelectric power generation system using waste heat from the fuel cell power plant, which is 5-6% in conversion efficiency, can generate output more than 100kW and is expected to improve by approximately 1% in plant overall efficiency. The construction cost, however, is around 1.6-1.9 million yen/kW. The thermoelectric power generation plant which is modeled on No.2 generator of Hatchobaru geothermal power plant can generate electric output of 10-12.5MW, which is smaller than that of the conventional geothermal power generation. The construction cost is around 3.2-4.1 million yen/kW. Even if advantage of the system in running cost is considered, attractive systematization seems to be difficult.

Optimizing surface finishing processes through the use of novel solvents and systems

NASA Astrophysics Data System (ADS)

Quillen, M.; Holbrook, P.; Moore, J.

2007-03-01

As the semiconductor industry continues to implement the ITRS (International Technology Roadmap for Semiconductors) node targets that go beyond 45nm [1], the need for improved cleanliness between repeated process steps continues to grow. Wafer cleaning challenges cover many applications such as Cu/low-K integration, where trade-offs must be made between dielectric damage and residue by plasma etching and CMP or moisture uptake by aqueous cleaning products. [2-5] Some surface sensitive processes use the Marangoni tool design [6] where a conventional solvent such as IPA (isopropanol), combines with water to provide improved physical properties such as reduced contact angle and surface tension. This paper introduces the use of alternative solvents and their mixtures compared to pure IPA in removing ionics, moisture, and particles using immersion bench-chemistry models of various processes. A novel Eastman proprietary solvent, Eastman methyl acetate is observed to provide improvement in ionic, moisture capture, and particle removal, as compared to conventional IPA. [7] These benefits may be improved relative to pure IPA, simply by the addition of various additives. Some physical properties of the mixtures were found to be relatively unchanged even as measured performance improved. This report presents our attempts to cite and optimize these benefits through the use of laboratory models.

Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses to extreme mechanical deformations

PubMed Central

Kim, Dae-Hyeong; Song, Jizhou; Choi, Won Mook; Kim, Hoon-Sik; Kim, Rak-Hwan; Liu, Zhuangjian; Huang, Yonggang Y.; Hwang, Keh-Chih; Zhang, Yong-wei; Rogers, John A.

2008-01-01

Electronic systems that offer elastic mechanical responses to high-strain deformations are of growing interest because of their ability to enable new biomedical devices and other applications whose requirements are impossible to satisfy with conventional wafer-based technologies or even with those that offer simple bendability. This article introduces materials and mechanical design strategies for classes of electronic circuits that offer extremely high stretchability, enabling them to accommodate even demanding configurations such as corkscrew twists with tight pitch (e.g., 90° in ≈1 cm) and linear stretching to “rubber-band” levels of strain (e.g., up to ≈140%). The use of single crystalline silicon nanomaterials for the semiconductor provides performance in stretchable complementary metal-oxide-semiconductor (CMOS) integrated circuits approaching that of conventional devices with comparable feature sizes formed on silicon wafers. Comprehensive theoretical studies of the mechanics reveal the way in which the structural designs enable these extreme mechanical properties without fracturing the intrinsically brittle active materials or even inducing significant changes in their electrical properties. The results, as demonstrated through electrical measurements of arrays of transistors, CMOS inverters, ring oscillators, and differential amplifiers, suggest a valuable route to high-performance stretchable electronics. PMID:19015528

Technological and organizational diversity and technical advance in the early history of the American semiconductor industry

NASA Astrophysics Data System (ADS)

Cohen, W.; Holbrook, D.; Klepper, S.

1994-06-01

This study examines the early years of the semiconductor industry and focuses on the roles played by different size firms in technologically innovative processes. A large and diverse pool of firms participated in the growth of the industry. Three related technological areas were chosen for in-depth analysis: integrated circuits, materials technology, and device packaging. Large business producing vacuum tubes dominated the early production of semiconductor devices. As the market for new devices grew during the 1950's, new firms were founded and existing firms from other industries, e.g. aircraft builders and instrument makers, began to pursue semiconductor electronics. Small firms began to cater to the emerging industry by supplying materials and equipment. These firms contributed to the development of certain aspects of one thousand firms that were playing some part in the semiconductor industry.

Segmented AC-coupled readout from continuous collection electrodes in semiconductor sensors

DOEpatents

Sadrozinski, Hartmut F. W.; Seiden, Abraham; Cartiglia, Nicolo

2017-04-04

Position sensitive radiation detection is provided using a continuous electrode in a semiconductor radiation detector, as opposed to the conventional use of a segmented electrode. Time constants relating to AC coupling between the continuous electrode and segmented contacts to the electrode are selected to provide position resolution from the resulting configurations. The resulting detectors advantageously have a more uniform electric field than conventional detectors having segmented electrodes, and are expected to have much lower cost of production and of integration with readout electronics.

Frequency-noise cancellation in semiconductor lasers by nonlinear heterodyne detection.

PubMed

Bondurant, R S; Welford, D; Alexander, S B; Chan, V W

1986-12-01

The bit-error-rate (BER) performance of conventional noncoherent, heterodyne frequency-shift-keyed (FSK) optical communications systems can be surpassed by the use of a differential FSK modulation format and nonlinear postdetection processing at the receiver. A BER floor exists for conventional frequency-shift keying because of the frequency noise of the transmitter and local oscillator. The use of differential frequency-shift keying with nonlinear postdetection processing suppresses this BER floor for the semiconductor laser system considered here.

Semiconductor cooling by thin-film thermocouples

NASA Technical Reports Server (NTRS)

Tick, P. A.; Vilcans, J.

1970-01-01

Thin-film, metal alloy thermocouple junctions do not rectify, change circuit impedance only slightly, and require very little increase in space. Although they are less efficient cooling devices than semiconductor junctions, they may be applied to assist conventional cooling techniques for electronic devices.

Doping of wide-bandgap titanium-dioxide nanotubes: optical, electronic and magnetic properties

NASA Astrophysics Data System (ADS)

Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Cerkovnik, Logan Jerome; Nagpal, Prashant

2014-08-01

Doping semiconductors is an important step for their technological application. While doping bulk semiconductors can be easily achieved, incorporating dopants in semiconductor nanostructures has proven difficult. Here, we report a facile synthesis method for doping titanium-dioxide (TiO2) nanotubes that was enabled by a new electrochemical cell design. A variety of optical, electronic and magnetic dopants were incorporated into the hollow nanotubes, and from detailed studies it is shown that the doping level can be easily tuned from low to heavily-doped semiconductors. Using desired dopants - electronic (p- or n-doped), optical (ultraviolet bandgap to infrared absorption in co-doped nanotubes), and magnetic (from paramagnetic to ferromagnetic) properties can be tailored, and these technologically important nanotubes can be useful for a variety of applications in photovoltaics, display technologies, photocatalysis, and spintronic applications.Doping semiconductors is an important step for their technological application. While doping bulk semiconductors can be easily achieved, incorporating dopants in semiconductor nanostructures has proven difficult. Here, we report a facile synthesis method for doping titanium-dioxide (TiO2) nanotubes that was enabled by a new electrochemical cell design. A variety of optical, electronic and magnetic dopants were incorporated into the hollow nanotubes, and from detailed studies it is shown that the doping level can be easily tuned from low to heavily-doped semiconductors. Using desired dopants - electronic (p- or n-doped), optical (ultraviolet bandgap to infrared absorption in co-doped nanotubes), and magnetic (from paramagnetic to ferromagnetic) properties can be tailored, and these technologically important nanotubes can be useful for a variety of applications in photovoltaics, display technologies, photocatalysis, and spintronic applications. Electronic supplementary information (ESI) available: See DOI: 10.1039/c4nr02417f

Application of positron annihilation lifetime technique to the study of deep level transients in semiconductors

NASA Astrophysics Data System (ADS)

Deng, A. H.; Shan, Y. Y.; Fung, S.; Beling, C. D.

2002-03-01

Unlike its conventional applications in lattice defect characterization, positron annihilation lifetime technique was applied to study temperature-dependent deep level transients in semiconductors. Defect levels in the band gap can be determined as they are determined by conventional deep level transient spectroscopy (DLTS) studies. The promising advantage of this application of positron annihilation over the conventional DLTS is that it could further extract extra microstructure information of deep-level defects, such as whether a deep level defect is vacancy related or not. A demonstration of EL2 defect level transient study in GaAs was shown and the EL2 level of 0.82±0.02 eV was obtained by a standard Arrhenius analysis, similar to that in conventional DLTS studies.

Development of High-Power Hall Thruster Power Processing Units at NASA GRC

NASA Technical Reports Server (NTRS)

Pinero, Luis R.; Bozak, Karin E.; Santiago, Walter; Scheidegger, Robert J.; Birchenough, Arthur G.

2015-01-01

NASA GRC successfully designed, built and tested four different power processor concepts for high power Hall thrusters. Each design satisfies unique goals including the evaluation of a novel silicon carbide semiconductor technology, validation of innovative circuits to overcome the problems with high input voltage converter design, development of a direct-drive unit to demonstrate potential benefits, or simply identification of lessonslearned from the development of a PPU using a conventional design approach. Any of these designs could be developed further to satisfy NASA's needs for high power electric propulsion in the near future.

Development of analog watch with minute repeater

NASA Astrophysics Data System (ADS)

Okigami, Tomio; Aoyama, Shigeru; Osa, Takashi; Igarashi, Kiyotaka; Ikegami, Tomomi

A complementary metal oxide semiconductor with large scale integration was developed for an electronic minute repeater. It is equipped with the synthetic struck sound circuit to generate natural struck sound necessary for the minute repeater. This circuit consists of an envelope curve drawing circuit, frequency mixer, polyphonic mixer, and booster circuit made by using analog circuit technology. This large scale integration is a single chip microcomputer with motor drivers and input ports in addition to the synthetic struck sound circuit, and it is possible to make an electronic system of minute repeater at a very low cost in comparison with the conventional type.

Nanoscale patterning of electronic devices at the amorphous LaAlO3/SrTiO3 oxide interface using an electron sensitive polymer mask

NASA Astrophysics Data System (ADS)

Bjørlig, Anders V.; von Soosten, Merlin; Erlandsen, Ricci; Dahm, Rasmus Tindal; Zhang, Yu; Gan, Yulin; Chen, Yunzhong; Pryds, Nini; Jespersen, Thomas S.

2018-04-01

A simple approach is presented for designing complex oxide mesoscopic electronic devices based on the conducting interfaces of room temperature grown LaAlO3/SrTiO3 heterostructures. The technique is based entirely on methods known from conventional semiconductor processing technology, and we demonstrate a lateral resolution of ˜100 nm. We study the low temperature transport properties of nanoscale wires and demonstrate the feasibility of the technique for defining in-plane gates allowing local control of the electrostatic environment in mesoscopic devices.

Peptide targeting of quantum dots to human breast cancer cells

NASA Astrophysics Data System (ADS)

Haglund, Emily M.; Seale-Goldsmith, Mary-Margaret; Dhawan, Deepika; Stewart, Jane; Ramos-Vara, Jose; Cooper, Christy L.; Reece, Lisa M.; Husk, Timothy; Bergstrom, Donald; Knapp, Deborah; Leary, James F.

2008-02-01

Nanomedical approaches to diseases such as cancer provide great promise with respect to diagnostic and therapeutic applications. The impact of nanomedicine versus conventional therapies will be realized with regard to their specific cell targeting capabilities. Semiconductor nanoparticles have distinct advantages due to their chemical conjugation and detection characteristics. The attachment of a peptide sequence, LTVSPWY, was completed. These nanoparticles successfully targeted in vitro and in vivo systems. This technology can be utilized as a base mechanism for the construction of a multifunctional nanomedical system. Nanomedicine has great potential for impacting the treatment of specific diseases and healthcare delivery methods.

Sensors for process control Focus Team report

NASA Astrophysics Data System (ADS)

At the Semiconductor Technology Workshop, held in November 1992, the Semiconductor Industry Association (SIA) convened 179 semiconductor technology experts to assess the 15-year outlook for the semiconductor manufacturing industry. The output of the Workshop, a document entitled 'Semiconductor Technology: Workshop Working Group Reports,' contained an overall roadmap for the technology characteristics envisioned in integrated circuits (IC's) for the period 1992-2007. In addition, the document contained individual roadmaps for numerous key areas in IC manufacturing, such as film deposition, thermal processing, manufacturing systems, exposure technology, etc. The SIA Report did not contain a separate roadmap for contamination free manufacturing (CFM). A key component of CFM for the next 15 years is the use of sensors for (1) defect reduction, (2) improved product quality, (3) improved yield, (4) improved tool utilization through contamination reduction, and (5) real time process control in semiconductor fabrication. The objective of this Focus Team is to generate a Sensors for Process Control Roadmap. Implicit in this objective is the identification of gaps in current sensor technology so that research and development activity in the sensor industry can be stimulated to develop sensor systems capable of meeting the projected roadmap needs. Sensor performance features of interest include detection limit, specificity, sensitivity, ease of installation and maintenance, range, response time, accuracy, precision, ease and frequency of calibration, degree of automation, and adaptability to in-line process control applications.

Exploration of oxide-based diluted magnetic semiconductors toward transparent spintronics

NASA Astrophysics Data System (ADS)

Fukumura, T.; Yamada, Y.; Toyosaki, H.; Hasegawa, T.; Koinuma, H.; Kawasaki, M.

2004-02-01

A review is given for the recent progress of research in the field of oxide-based diluted magnetic semiconductor (DMS), which was triggered by combinatorial discovery of transparent ferromagnet. The possible advantages of oxide semiconductor as a host of DMS are described in comparison with conventional compound semiconductors. Limits and problems for identifying novel ferromagnetic DMS are described in view of recent reports in this field. Several characterization techniques are proposed in order to eliminate unidentified ferromagnetism of oxide-based DMS unidentified ferromagnetic oxide (UFO). Perspectives and possible devices are also given.

ISFET Based Microsensors for Environmental Monitoring

PubMed Central

Jimenez-Jorquera, Cecilia; Orozco, Jahir; Baldi, Antoni

2010-01-01

The use of microsensors for in-field monitoring of environmental parameters is gaining interest due to their advantages over conventional sensors. Among them microsensors based on semiconductor technology offer additional advantages such as small size, robustness, low output impedance and rapid response. Besides, the technology used allows integration of circuitry and multiple sensors in the same substrate and accordingly they can be implemented in compact probes for particular applications e.g., in situ monitoring and/or on-line measurements. In the field of microsensors for environmental applications, Ion Selective Field Effect Transistors (ISFETs) have a special interest. They are particularly helpful for measuring pH and other ions in small volumes and they can be integrated in compact flow cells for continuous measurements. In this paper the technologies used to fabricate ISFETs and a review of the role of ISFETs in the environmental field are presented. PMID:22315527

Dry etching technologies for the advanced binary film

NASA Astrophysics Data System (ADS)

Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Yoshimori, Tomoaki; Azumano, Hidehito; Muto, Makoto; Nonaka, Mikio

2011-11-01

ABF (Advanced Binary Film) developed by Hoya as a photomask for 32 (nm) and larger specifications provides excellent resistance to both mask cleaning and 193 (nm) excimer laser and thereby helps extend the lifetime of the mask itself compared to conventional photomasks and consequently reduces the semiconductor manufacturing cost [1,2,3]. Because ABF uses Ta-based films, which are different from Cr film or MoSi films commonly used for photomask, a new process is required for its etching technology. A patterning technology for ABF was established to perform the dry etching process for Ta-based films by using the knowledge gained from absorption layer etching for EUV mask that required the same Ta-film etching process [4]. Using the mask etching system ARES, which is manufactured by Shibaura Mechatronics, and its optimized etching process, a favorable CD (Critical Dimension) uniformity, a CD linearity and other etching characteristics were obtained in ABF patterning. Those results are reported here.

Development and applications of 3-dimensional integration nanotechnologies.

PubMed

Kim, Areum; Choi, Eunmi; Son, Hyungbin; Pyo, Sung Gyu

2014-02-01

Unlike conventional two-dimensional (2D) planar structures, signal or power is supplied through through-silicon via (TSV) in three-dimensional (3D) integration technology to replace wires for binding the chip/wafer. TSVs have becomes an essential technology, as they satisfy Moore's law. This 3D integration technology enables system and sensor functions at a nanoscale via the implementation of a highly integrated nano-semiconductor as well as the fabrication of a single chip with multiple functions. Thus, this technology is considered to be a new area of development for the systemization of the nano-bio area. In this review paper, the basic technology required for such 3D integration is described and methods to measure the bonding strength in order to measure the void occurring during bonding are introduced. Currently, CMOS image sensors and memory chips associated with nanotechnology are being realized on the basis of 3D integration technology. In this paper, we intend to describe the applications of high-performance nano-biosensor technology currently under development and the direction of development of a high performance lab-on-a-chip (LOC).

Electric-field-controlled ferromagnetism in high-Curie-temperature Mn0.05Ge0.95 quantum dots.

PubMed

Xiu, Faxian; Wang, Yong; Kim, Jiyoung; Hong, Augustin; Tang, Jianshi; Jacob, Ajey P; Zou, Jin; Wang, Kang L

2010-04-01

Electric-field manipulation of ferromagnetism has the potential for developing a new generation of electric devices to resolve the power consumption and variability issues in today's microelectronics industry. Among various dilute magnetic semiconductors (DMSs), group IV elements such as Si and Ge are the ideal material candidates because of their excellent compatibility with the conventional complementary metal-oxide-semiconductor (MOS) technology. Here we report, for the first time, the successful synthesis of self-assembled dilute magnetic Mn(0.05)Ge(0.95) quantum dots with ferromagnetic order above room temperature, and the demonstration of electric-field control of ferromagnetism in MOS ferromagnetic capacitors up to 100 K. We found that by applying electric fields to a MOS gate structure, the ferromagnetism of the channel layer can be effectively modulated through the change of hole concentration inside the quantum dots. Our results are fundamentally important in the understanding and to the realization of high-efficiency Ge-based spin field-effect transistors.

A CMOS-Compatible Poly-Si Nanowire Device with Hybrid Sensor/Memory Characteristics for System-on-Chip Applications

PubMed Central

Chen, Min-Cheng; Chen, Hao-Yu; Lin, Chia-Yi; Chien, Chao-Hsin; Hsieh, Tsung-Fan; Horng, Jim-Tong; Qiu, Jian-Tai; Huang, Chien-Chao; Ho, Chia-Hua; Yang, Fu-Liang

2012-01-01

This paper reports a versatile nano-sensor technology using “top-down” poly-silicon nanowire field-effect transistors (FETs) in the conventional Complementary Metal-Oxide Semiconductor (CMOS)-compatible semiconductor process. The nanowire manufacturing technique reduced nanowire width scaling to 50 nm without use of extra lithography equipment, and exhibited superior device uniformity. These n type polysilicon nanowire FETs have positive pH sensitivity (100 mV/pH) and sensitive deoxyribonucleic acid (DNA) detection ability (100 pM) at normal system operation voltages. Specially designed oxide-nitride-oxide buried oxide nanowire realizes an electrically Vth-adjustable sensor to compensate device variation. These nanowire FETs also enable non-volatile memory application for a large and steady Vth adjustment window (>2 V Programming/Erasing window). The CMOS-compatible manufacturing technique of polysilicon nanowire FETs offers a possible solution for commercial System-on-Chip biosensor application, which enables portable physiology monitoring and in situ recording. PMID:22666012

Direct Growth of Graphene Film on Germanium Substrate

PubMed Central

Wang, Gang; Zhang, Miao; Zhu, Yun; Ding, Guqiao; Jiang, Da; Guo, Qinglei; Liu, Su; Xie, Xiaoming; Chu, Paul K.; Di, Zengfeng; Wang, Xi

2013-01-01

Graphene has been predicted to play a role in post-silicon electronics due to the extraordinary carrier mobility. Chemical vapor deposition of graphene on transition metals has been considered as a major step towards commercial realization of graphene. However, fabrication based on transition metals involves an inevitable transfer step which can be as complicated as the deposition of graphene itself. By ambient-pressure chemical vapor deposition, we demonstrate large-scale and uniform depositon of high-quality graphene directly on a Ge substrate which is wafer scale and has been considered to replace conventional Si for the next generation of high-performance metal-oxide-semiconductor field-effect transistors (MOSFETs). The immiscible Ge-C system under equilibrium conditions dictates graphene depositon on Ge via a self-limiting and surface-mediated process rather than a precipitation process as observed from other metals with high carbon solubility. Our technique is compatible with modern microelectronics technology thus allowing integration with high-volume production of complementary metal-oxide-semiconductors (CMOS). PMID:23955352

Vertical power MOS transistor as a thermoelectric quasi-nanowire device

NASA Astrophysics Data System (ADS)

Roizin, Gregory; Beeri, Ofer; Peretz, Mor Mordechai; Gelbstein, Yaniv

2016-12-01

Nano-materials exhibit superior performance over bulk materials in a variety of applications such as direct heat to electricity thermoelectric generators (TEGs) and many more. However, a gap still exists for the integration of these nano-materials into practical applications. This study explores the feasibility of utilizing the advantages of nano-materials' thermo-electric properties, using regular bulk technology. Present-day TEGs are often applied by dedicated thermoelectric materials such as semiconductor alloys (e.g., PbTe, BiTe) whereas the standard semiconductor materials such as the doped silicon have not been widely addressed, with limited exceptions of nanowires. This study attempts to close the gap between the nano-materials' properties and the well-established bulk devices, approached for the first time by exploiting the nano-metric dimensions of the conductive channel in metal-oxide-semiconductor (MOS) structures. A significantly higher electrical current than expected from a bulk silicon device has been experimentally measured as a result of the application of a positive gate voltage and a temperature gradient between the "source" and the "drain" terminals of a commercial NMOS transistor. This finding implies on a "quasi-nanowire" behaviour of the transistor channel, which can be easily controlled by the transistor's gate voltage that is applied. This phenomenon enables a considerable improvement of silicon based TEGs, fabricated by traditional silicon technology. Four times higher ZT values (TEG quality factor) compared to conventional bulk silicon have been observed for an off-the-shelf silicon device. By optimizing the device, it is believed that even higher ZT values can be achieved.

A new PET scanner with semiconductor detectors enables better identification of intratumoral inhomogeneity.

PubMed

Shiga, Tohru; Morimoto, Yuichi; Kubo, Naoki; Katoh, Norio; Katoh, Chietsugu; Takeuchi, Wataru; Usui, Reiko; Hirata, Kenji; Kojima, Shinichi; Umegaki, Kikuo; Shirato, Hiroki; Tamaki, Nagara

2009-01-01

An autoradiography method revealed intratumoral inhomogeneity in various solid tumors. It is becoming increasingly important to estimate intratumoral inhomogeneity. However, with low spatial resolution and high scatter noise, it is difficult to detect intratumoral inhomogeneity in clinical settings. We developed a new PET system with CdTe semiconductor detectors to provide images with high spatial resolution and low scatter noise. Both phantom images and patients' images were analyzed to evaluate intratumoral inhomogeneity. This study was performed with a cold spot phantom that had 6-mm-diameter cold sphenoid defects, a dual-cylinder phantom with an adjusted concentration of 1:2, and an "H"-shaped hot phantom. These were surrounded with water. Phantom images and (18)F-FDG PET images of patients with nasopharyngeal cancer were compared with conventional bismuth germanate PET images. Profile curves for the phantoms were measured as peak-to-valley ratios to define contrast. Intratumoral inhomogeneity and tumor edge sharpness were evaluated on the images of the patients. The contrast obtained with the semiconductor PET scanner (1.53) was 28% higher than that obtained with the conventional scanner (1.20) for the 6-mm-diameter cold sphenoid phantom. The contrast obtained with the semiconductor PET scanner (1.43) was 27% higher than that obtained with the conventional scanner (1.13) for the dual-cylinder phantom. Similarly, the 2-mm cold region between 1-mm hot rods was identified only by the new PET scanner and not by the conventional scanner. The new PET scanner identified intratumoral inhomogeneity in more detail than the conventional scanner in 6 of 10 patients. The tumor edge was sharper on the images obtained with the new PET scanner than on those obtained with the conventional scanner. These phantom and clinical studies suggested that this new PET scanner has the potential for better identification of intratumoral inhomogeneity, probably because of its high spatial resolution and low scatter noise.

Optical devices featuring nonpolar textured semiconductor layers

DOEpatents

Moustakas, Theodore D; Moldawer, Adam; Bhattacharyya, Anirban; Abell, Joshua

2013-11-26

A semiconductor emitter, or precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate in a nonpolar orientation. The textured layers enhance light extraction, and the use of nonpolar orientation greatly enhances internal quantum efficiency compared to conventional devices. Both the internal and external quantum efficiencies of emitters of the invention can be 70-80% or higher. The invention provides highly efficient light emitting diodes suitable for solid state lighting.

A novel architecture of non-volatile magnetic arithmetic logic unit using magnetic tunnel junctions

NASA Astrophysics Data System (ADS)

Guo, Wei; Prenat, Guillaume; Dieny, Bernard

2014-04-01

Complementary metal-oxide-semiconductor (CMOS) technology is facing increasingly difficult obstacles such as power consumption and interconnection delay. Novel hybrid technologies and architectures are being investigated with the aim to circumvent some of these limits. In particular, hybrid CMOS/magnetic technology based on magnetic tunnel junctions (MTJs) is considered as a very promising approach thanks to the full compatibility of MTJs with CMOS technology. By tightly merging the conventional electronics with magnetism, both logic and memory functions can be implemented in the same device. As a result, non-volatility is directly brought into logic circuits, yielding significant improvement of device performances and new functionalities as well. We have conceived an innovative methodology to construct non-volatile magnetic arithmetic logic units (MALUs) combining spin-transfer torque MTJs with MOS transistors. The present 4-bit MALU utilizes 4 MTJ pairs to store its operation code (opcode). Its operations and performances have been confirmed and evaluated through electrical simulations.

New method of contour-based mask-shape compiler

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Sugiyama, Akiyuki; Onizawa, Akira; Sato, Hidetoshi; Toyoda, Yasutaka

2007-10-01

We have developed a new method of accurately profiling a mask shape by utilizing a Mask CD-SEM. The method is intended to realize high accuracy, stability and reproducibility of the Mask CD-SEM adopting an edge detection algorithm as the key technology used in CD-SEM for high accuracy CD measurement. In comparison with a conventional image processing method for contour profiling, it is possible to create the profiles with much higher accuracy which is comparable with CD-SEM for semiconductor device CD measurement. In this report, we will introduce the algorithm in general, the experimental results and the application in practice. As shrinkage of design rule for semiconductor device has further advanced, an aggressive OPC (Optical Proximity Correction) is indispensable in RET (Resolution Enhancement Technology). From the view point of DFM (Design for Manufacturability), a dramatic increase of data processing cost for advanced MDP (Mask Data Preparation) for instance and surge of mask making cost have become a big concern to the device manufacturers. In a sense, it is a trade-off between the high accuracy RET and the mask production cost, while it gives a significant impact on the semiconductor market centered around the mask business. To cope with the problem, we propose the best method for a DFM solution in which two dimensional data are extracted for an error free practical simulation by precise reproduction of a real mask shape in addition to the mask data simulation. The flow centering around the design data is fully automated and provides an environment where optimization and verification for fully automated model calibration with much less error is available. It also allows complete consolidation of input and output functions with an EDA system by constructing a design data oriented system structure. This method therefore is regarded as a strategic DFM approach in the semiconductor metrology.

A room-temperature magnetic semiconductor from a ferromagnetic metallic glass

NASA Astrophysics Data System (ADS)

Liu, Wenjian; Zhang, Hongxia; Shi, Jin-An; Wang, Zhongchang; Song, Cheng; Wang, Xiangrong; Lu, Siyuan; Zhou, Xiangjun; Gu, Lin; Louzguine-Luzgin, Dmitri V.; Chen, Mingwei; Yao, Kefu; Chen, Na

2016-12-01

Emerging for future spintronic/electronic applications, magnetic semiconductors have stimulated intense interest due to their promises for new functionalities and device concepts. So far, the so-called diluted magnetic semiconductors attract many attentions, yet it remains challenging to increase their Curie temperatures above room temperature, particularly those based on III-V semiconductors. In contrast to the concept of doping magnetic elements into conventional semiconductors to make diluted magnetic semiconductors, here we propose to oxidize originally ferromagnetic metals/alloys to form new species of magnetic semiconductors. We introduce oxygen into a ferromagnetic metallic glass to form a Co28.6Fe12.4Ta4.3B8.7O46 magnetic semiconductor with a Curie temperature above 600 K. The demonstration of p-n heterojunctions and electric field control of the room-temperature ferromagnetism in this material reflects its p-type semiconducting character, with a mobility of 0.1 cm2 V-1 s-1. Our findings may pave a new way to realize high Curie temperature magnetic semiconductors with unusual multifunctionalities.

Cation Exchange Reactions for Improved Quality and Diversity of Semiconductor Nanocrystals

NASA Astrophysics Data System (ADS)

Beberwyck, Brandon James

Observing the size and shape dependent physical properties of semiconductor nanocrystals requires synthetic methods capable of not only composition and crystalline phase control but also molecular scale uniformity for a particle consisting of tens to hundreds of thousands of atoms. The desire for synthetic methods that produce uniform nanocrystals of complex morphologies continues to increase as nanocrystals find roles in commercial applications, such as biolabeling and display technologies, that are simultaneously restricting material compositions. With these constraints, new synthetic strategies that decouple the nanocrystal's chemical composition from its morphology are necessary. This dissertation explores the cation exchange reaction of colloidal semiconductor nanocrystals, a template-based chemical transformation that enables the interconversion of nanocrystals between a variety of compositions while maintaining their size dispersity and morphology. Chapter 1 provides an introduction to the versatility of this replacement reaction as a synthetic method for semiconductor nanocrystals. An overview of the fundamentals of the cation exchange reaction and the diversity of products that are achievable is presented. Chapter 2 examines the optical properties of nanocrystal heterostructures produced through cation exchange reactions. The deleterious impact of exchange on the photoluminescence is correlated to residual impurities and a simple annealing protocol is demonstrated to achieve photoluminescence yields comparable to samples produced by conventional methods. Chapter 3 investigates the extension of the cation exchange reaction beyond ionic nanocrystals. Covalent III-V nanocrystal of high crystallinity and low size dispersity are synthesized by the cation exchange of cadmium pnictide nanocrystals with group 13 ions. Lastly, Chapter 4 highlights future studies to probe cation exchange reactions in colloidal semiconductor nanocrystals and progress that needs to be made for its adoption as a routine synthetic approach.

Semiconductor technology program. Progress briefs

NASA Technical Reports Server (NTRS)

Bullis, W. M.

1980-01-01

Measurement technology for semiconductor materials, process control, and devices is reviewed. Activities include: optical linewidth and thermal resistance measurements; device modeling; dopant density profiles; resonance ionization spectroscopy; and deep level measurements. Standardized oxide charge terminology is also described.

Semiconductors: Still a Wide Open Frontier for Scientists/Engineers

NASA Astrophysics Data System (ADS)

Seiler, David G.

1997-10-01

A 1995 Business Week article described several features of the explosive use of semiconductor chips today: ``Booming'' personal computer markets are driving high demand for microprocessors and memory chips; (2) New information superhighway markets will `ignite' sales of multimedia and communication chips; and (3) Demand for digital-signal-processing and data-compression chips, which speed up video and graphics, is `red hot.' A Washington Post article by Stan Hinden said that technology is creating an unstoppable demand for electronic elements. This ``digital pervasiveness'' means that a semiconductor chip is going into almost every high-tech product that people buy - cars, televisions, video recorders, telephones, radios, alarm clocks, coffee pots, etc. ``Semiconductors are everywhere.'' Silicon and compound semiconductors are absolutely essential and are pervasive enablers for DoD operations and systems. DoD's Critical Technologies Plan of 1991 says that ``Semiconductor materials and microelectronics are critically important and appropriately lead the list of critical defense technologies.'' These trends continue unabated. This talk describes some of the frontiers of semiconductors today and shows how scientists and engineers can effectively contribute to its advancement. Cooperative, multidisciplinary efforts are increasing. Specific examples will be given for scanning capacitance microscopy and thin-film metrology.

Semiconductors: A 21st Century Social Studies Topic.

ERIC Educational Resources Information Center

Sunal, Cynthia

2000-01-01

Addresses the reasons for exploring semiconductor technology and organic semiconductors in schools for either middle school or secondary students in an interdisciplinary social studies and science environment. Provides background information on transistors and semiconductors. Offers three social studies lessons and related science lessons if an…

High efficiency and non-Richardson thermionics in three dimensional Dirac materials

NASA Astrophysics Data System (ADS)

Huang, Sunchao; Sanderson, Matthew; Zhang, Yan; Zhang, Chao

2017-10-01

Three dimensional (3D) topological materials have a linear energy dispersion and exhibit many electronic properties superior to conventional materials such as fast response times, high mobility, and chiral transport. In this work, we demonstrate that 3D Dirac materials also have advantages over conventional semiconductors and graphene in thermionic applications. The low emission current suffered in graphene due to the vanishing density of states is enhanced by an increased group velocity in 3D Dirac materials. Furthermore, the thermal energy carried by electrons in 3D Dirac materials is twice of that in conventional materials with a parabolic electron energy dispersion. As a result, 3D Dirac materials have the best thermal efficiency or coefficient of performance when compared to conventional semiconductors and graphene. The generalized Richardson-Dushman law in 3D Dirac materials is derived. The law exhibits the interplay of the reduced density of states and enhanced emission velocity.

Band-Gap Engineering at a Semiconductor-Crystalline Oxide Interface

DOE PAGES

Jahangir-Moghadam, Mohammadreza; Ahmadi-Majlan, Kamyar; Shen, Xuan; ...

2015-02-09

The epitaxial growth of crystalline oxides on semiconductors provides a pathway to introduce new functionalities to semiconductor devices. Key to integrating the functionalities of oxides onto semiconductors is controlling the band alignment at interfaces between the two materials. Here we apply principles of band gap engineering traditionally used at heterojunctions between conventional semiconductors to control the band offset between a single crystalline oxide and a semiconductor. Reactive molecular beam epitaxy is used to realize atomically abrupt and structurally coherent interfaces between SrZr xTi 1-xO₃ and Ge, in which the band gap of the former is enhanced with Zr content x.more » We present structural and electrical characterization of SrZr xTi 1-xO₃-Ge heterojunctions and demonstrate a type-I band offset can be achieved. These results demonstrate that band gap engineering can be exploited to realize functional semiconductor crystalline oxide heterojunctions.« less

Generation of a femtosecond electron microbunch train from a photocathode using twofold Michelson interferometer

NASA Astrophysics Data System (ADS)

Shevelev, M.; Aryshev, A.; Terunuma, N.; Urakawa, J.

2017-10-01

The interest in producing ultrashort electron bunches has risen sharply among scientists working on the design of high-gradient wakefield accelerators. One attractive approach generating electron bunches is to illuminate a photocathode with a train of femtosecond laser pulses. In this paper we describe the design and testing of a laser system for an rf gun based on a commercial titanium-sapphire laser technology. The technology allows the production of four femtosecond laser pulses with a continuously variable pulse delay. We also use the designed system to demonstrate the experimental generation of an electron microbunch train obtained by illuminating a cesium-telluride semiconductor photocathode. We use conventional diagnostics to characterize the electron microbunches produced and confirm that it may be possible to control the main parameter of an electron microbunch train.

Research and development of biochip technologies in Taiwan

NASA Astrophysics Data System (ADS)

Ting, Solomon J.; Chiou, Arthur E. T.

2000-07-01

Recent advancements in several genome-sequencing projects have stimulated an enormous interest in microarray DNA chip technology, especially in the biomedical sciences and pharmaceutical industries. The DNA chips facilitated the miniaturization of conventional nucleic acid hybridizations, by either robotically spotting thousands of library cDNAs or in situ synthesis of high-density oligonucleotides onto solid supports. These innovations have found a wide range of applications in molecular biology, especially in studying gene expression and discovering new genes from the global view of genomic analysis. The research and development of this powerful tool has also received great attentions in Taiwan. In this paper, we report the current progresses of our DNA chip project, along with the current status of other biochip projects in Taiwan, such as protein chip, PCR chip, electrophoresis chip, olfactory chip, etc. The new development of biochip technologies integrates the biotechnology with the semiconductor processing, the micro- electro-mechanical, optoelectronic, and digital signal processing technologies. Most of these biochip technologies utilitze optical detection methods for data acquisition and analysis. The strengths and advantages of different approaches are compared and discussed in this report.

Radiation immune RAM semiconductor technology for the 80's. [Random Access Memory

NASA Technical Reports Server (NTRS)

Hanna, W. A.; Panagos, P.

1983-01-01

This paper presents current and short term future characteristics of RAM semiconductor technologies which were obtained by literature survey and discussions with cognizant Government and industry personnel. In particular, total ionizing dose tolerance and high energy particle susceptibility of the technologies are addressed. Technologies judged compatible with spacecraft applications are ranked to determine the best current and future technology for fast access (less than 60 ns), radiation tolerant RAM.

Charge pump-based MOSFET-only 1.5-bit pipelined ADC stage in digital CMOS technology

NASA Astrophysics Data System (ADS)

Singh, Anil; Agarwal, Alpana

2016-10-01

A simple low-power and low-area metal-oxide-semiconductor field-effect transistor-only fully differential 1.5-bit pipelined analog-to-digital converter stage is proposed and designed in Taiwan Semiconductor Manufacturing Company 0.18 μm-technology using BSIM3v3 parameters with supply voltage of 1.8 V in inexpensive digital complementary metal-oxide semiconductor (CMOS) technology. It is based on charge pump technique to achieve the desired voltage gain of 2, independent of capacitor mismatch and avoiding the need of power hungry operational amplifier-based architecture to reduce the power, Si area and cost. Various capacitances are implemented by metal-oxide semiconductor capacitors, offering compatibility with cheaper digital CMOS process in order to reduce the much required manufacturing cost.

Ultra-high heat flux cooling characteristics of cryogenic micro-solid nitrogen particles and its application to semiconductor wafer cleaning technology

NASA Astrophysics Data System (ADS)

Ishimoto, Jun; Oh, U.; Guanghan, Zhao; Koike, Tomoki; Ochiai, Naoya

2014-01-01

The ultra-high heat flux cooling characteristics and impingement behavior of cryogenic micro-solid nitrogen (SN2) particles in relation to a heated wafer substrate were investigated for application to next generation semiconductor wafer cleaning technology. The fundamental characteristics of cooling heat transfer and photoresist removal-cleaning performance using micro-solid nitrogen particulate spray impinging on a heated substrate were numerically investigated and experimentally measured by a new type of integrated computational-experimental technique. This study contributes not only advanced cryogenic cooling technology for high thermal emission devices, but also to the field of nano device engineering including the semiconductor wafer cleaning technology.

Suppression of planar defects in the molecular beam epitaxy of GaAs/ErAs/GaAs heterostructures

NASA Astrophysics Data System (ADS)

Crook, Adam M.; Nair, Hari P.; Ferrer, Domingo A.; Bank, Seth R.

2011-08-01

We present a growth method that overcomes the mismatch in rotational symmetry of ErAs and conventional III-V semiconductors, allowing for epitaxially integrated semimetal/semiconductor heterostructures. Transmission electron microscopy and reflection high-energy electron diffraction reveal defect-free overgrowth of ErAs layers, consisting of >2× the total amount of ErAs that can be embedded with conventional layer-by-layer growth methods. We utilize epitaxial ErAs nanoparticles, overgrown with GaAs, as a seed to grow full films of ErAs. Growth proceeds by diffusion of erbium atoms through the GaAs spacer, which remains registered to the underlying substrate, preventing planar defect formation during subsequent GaAs growth. This growth method is promising for metal/semiconductor heterostructures that serve as embedded Ohmic contacts to epitaxial layers and epitaxially integrated active plasmonic devices.

Characteristics of Superjunction Lateral-Double-Diffusion Metal Oxide Semiconductor Field Effect Transistor and Degradation after Electrical Stress

NASA Astrophysics Data System (ADS)

Lin, Jyh‑Ling; Lin, Ming‑Jang; Lin, Li‑Jheng

2006-04-01

The superjunction lateral double diffusion metal oxide semiconductor field effect has recently received considerable attention. Introducing heavily doped p-type strips to the n-type drift region increases the horizontal depletion capability. Consequently, the doping concentration of the drift region is higher and the conduction resistance is lower than those of conventional lateral-double-diffusion metal oxide semiconductor field effect transistors (LDMOSFETs). These characteristics may increase breakdown voltage (\\mathit{BV}) and reduce specific on-resistance (Ron,sp). In this study, we focus on the electrical characteristics of conventional LDMOSFETs on silicon bulk, silicon-on-insulator (SOI) LDMOSFETs and superjunction LDMOSFETs after bias stress. Additionally, the \\mathit{BV} and Ron,sp of superjunction LDMOSFETs with different N/P drift region widths and different dosages are discussed. Simulation tools, including two-dimensional (2-D) TSPREM-4/MEDICI and three-dimensional (3-D) DAVINCI, were employed to determine the device characteristics.

High Performance Molybdenum Disulfide Amorphous Silicon Heterojunction Photodetector

PubMed Central

Esmaeili-Rad, Mohammad R.; Salahuddin, Sayeef

2013-01-01

One important use of layered semiconductors such as molybdenum disulfide (MoS2) could be in making novel heterojunction devices leading to functionalities unachievable using conventional semiconductors. Here we demonstrate a metal-semiconductor-metal heterojunction photodetector, made of MoS2 and amorphous silicon (a-Si), with rise and fall times of about 0.3 ms. The transient response does not show persistent (residual) photoconductivity, unlike conventional a-Si devices where it may last 3–5 ms, thus making this heterojunction roughly 10X faster. A photoresponsivity of 210 mA/W is measured at green light, the wavelength used in commercial imaging systems, which is 2−4X larger than that of a-Si and best reported MoS2 devices. The device could find applications in large area electronics, such as biomedical imaging, where a fast response is critical. PMID:23907598

Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs

PubMed Central

Brady, Gerald J.; Way, Austin J.; Safron, Nathaniel S.; Evensen, Harold T.; Gopalan, Padma; Arnold, Michael S.

2016-01-01

Carbon nanotubes (CNTs) are tantalizing candidates for semiconductor electronics because of their exceptional charge transport properties and one-dimensional electrostatics. Ballistic transport approaching the quantum conductance limit of 2G0 = 4e2/h has been achieved in field-effect transistors (FETs) containing one CNT. However, constraints in CNT sorting, processing, alignment, and contacts give rise to nonidealities when CNTs are implemented in densely packed parallel arrays such as those needed for technology, resulting in a conductance per CNT far from 2G0. The consequence has been that, whereas CNTs are ultimately expected to yield FETs that are more conductive than conventional semiconductors, CNTs, instead, have underperformed channel materials, such as Si, by sixfold or more. We report quasi-ballistic CNT array FETs at a density of 47 CNTs μm−1, fabricated through a combination of CNT purification, solution-based assembly, and CNT treatment. The conductance is as high as 0.46 G0 per CNT. In parallel, the conductance of the arrays reaches 1.7 mS μm−1, which is seven times higher than the previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density is as high as 900 μA μm−1 and is similar to or exceeds that of Si FETs when compared at and equivalent gate oxide thickness and at the same off-state current density. The on-state current density exceeds that of GaAs FETs as well. This breakthrough in CNT array performance is a critical advance toward the exploitation of CNTs in logic, high-speed communications, and other semiconductor electronics technologies. PMID:27617293

Quasi-ballistic carbon nanotube array transistors with current density exceeding Si and GaAs.

PubMed

Brady, Gerald J; Way, Austin J; Safron, Nathaniel S; Evensen, Harold T; Gopalan, Padma; Arnold, Michael S

2016-09-01

Carbon nanotubes (CNTs) are tantalizing candidates for semiconductor electronics because of their exceptional charge transport properties and one-dimensional electrostatics. Ballistic transport approaching the quantum conductance limit of 2G 0 = 4e (2)/h has been achieved in field-effect transistors (FETs) containing one CNT. However, constraints in CNT sorting, processing, alignment, and contacts give rise to nonidealities when CNTs are implemented in densely packed parallel arrays such as those needed for technology, resulting in a conductance per CNT far from 2G 0. The consequence has been that, whereas CNTs are ultimately expected to yield FETs that are more conductive than conventional semiconductors, CNTs, instead, have underperformed channel materials, such as Si, by sixfold or more. We report quasi-ballistic CNT array FETs at a density of 47 CNTs μm(-1), fabricated through a combination of CNT purification, solution-based assembly, and CNT treatment. The conductance is as high as 0.46 G 0 per CNT. In parallel, the conductance of the arrays reaches 1.7 mS μm(-1), which is seven times higher than the previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density is as high as 900 μA μm(-1) and is similar to or exceeds that of Si FETs when compared at and equivalent gate oxide thickness and at the same off-state current density. The on-state current density exceeds that of GaAs FETs as well. This breakthrough in CNT array performance is a critical advance toward the exploitation of CNTs in logic, high-speed communications, and other semiconductor electronics technologies.

A room-temperature magnetic semiconductor from a ferromagnetic metallic glass.

PubMed

Liu, Wenjian; Zhang, Hongxia; Shi, Jin-An; Wang, Zhongchang; Song, Cheng; Wang, Xiangrong; Lu, Siyuan; Zhou, Xiangjun; Gu, Lin; Louzguine-Luzgin, Dmitri V; Chen, Mingwei; Yao, Kefu; Chen, Na

2016-12-08

Emerging for future spintronic/electronic applications, magnetic semiconductors have stimulated intense interest due to their promises for new functionalities and device concepts. So far, the so-called diluted magnetic semiconductors attract many attentions, yet it remains challenging to increase their Curie temperatures above room temperature, particularly those based on III-V semiconductors. In contrast to the concept of doping magnetic elements into conventional semiconductors to make diluted magnetic semiconductors, here we propose to oxidize originally ferromagnetic metals/alloys to form new species of magnetic semiconductors. We introduce oxygen into a ferromagnetic metallic glass to form a Co 28.6 Fe 12.4 Ta 4.3 B 8.7 O 46 magnetic semiconductor with a Curie temperature above 600 K. The demonstration of p-n heterojunctions and electric field control of the room-temperature ferromagnetism in this material reflects its p-type semiconducting character, with a mobility of 0.1 cm 2  V -1  s -1 . Our findings may pave a new way to realize high Curie temperature magnetic semiconductors with unusual multifunctionalities.

A room-temperature magnetic semiconductor from a ferromagnetic metallic glass

PubMed Central

Liu, Wenjian; Zhang, Hongxia; Shi, Jin-an; Wang, Zhongchang; Song, Cheng; Wang, Xiangrong; Lu, Siyuan; Zhou, Xiangjun; Gu, Lin; Louzguine-Luzgin, Dmitri V.; Chen, Mingwei; Yao, Kefu; Chen, Na

2016-01-01

Emerging for future spintronic/electronic applications, magnetic semiconductors have stimulated intense interest due to their promises for new functionalities and device concepts. So far, the so-called diluted magnetic semiconductors attract many attentions, yet it remains challenging to increase their Curie temperatures above room temperature, particularly those based on III–V semiconductors. In contrast to the concept of doping magnetic elements into conventional semiconductors to make diluted magnetic semiconductors, here we propose to oxidize originally ferromagnetic metals/alloys to form new species of magnetic semiconductors. We introduce oxygen into a ferromagnetic metallic glass to form a Co28.6Fe12.4Ta4.3B8.7O46 magnetic semiconductor with a Curie temperature above 600 K. The demonstration of p–n heterojunctions and electric field control of the room-temperature ferromagnetism in this material reflects its p-type semiconducting character, with a mobility of 0.1 cm2 V−1 s−1. Our findings may pave a new way to realize high Curie temperature magnetic semiconductors with unusual multifunctionalities. PMID:27929059

New technologies for UV detectors

NASA Technical Reports Server (NTRS)

Joseph, C. L.

1993-01-01

Several technologies are currently being developed, leading to substantial improvements in the performance of UV detectors or significant reductions in power or weight. Four technologies discussed are (1) thin-film coatings to enhance the UV sensitivity of CCD's, (2) highly innovative magnet assemblies that dramatically reduce weight and result in virtually no external flux, (3) new techniques for curving microchannel plates (MCP's) so that single plates can be used to prevent ion feedback and present highly localized charge clouds to an anode structure, and (4) high-performance alternatives to glass-based MCP's. In item (2), for example, very robust magnets are made out of rare earth materials such as samarium cobalt, and cladding magnets are employed to prevent flux from escaping from the detector into the external environment. These new ultralight magnet assemblies are able to create strong, exceptionally uniform magnetic fields for image intensification and focusing of photoelectrons. The principle advantage of such detectors is the quantum efficiencies of 70-80 percent obtained throughout ultraviolet wavelengths (900-2000 A), the highest of any device. Despite the improvements achieved under item (3), high-performance alternatives to conventional glass-based MCP's potentially offer three distinct new advantages that include (1) a 30-100-fold improvement in dynamic range resulting in correspondingly higher signal-to-noise ratios, (2) the use of pure dielectric and semiconductor materials that will not outgas contaminants that eventually destroy photocathodes, and (3) channels that have constant spacing providing long-ranged order since the plates are made using photolithography techniques from the semiconductor industry. The manufacturers of these advanced-technology MCP's, however, are a couple of years away from actually producing a functioning image intensifier. In contrast to the use of CCD's for optical, ground based observations, there is no single detector technology in the ultraviolet that dominates or is as universally suitable for all applications. Thus, several technological problems, recent advances, and the impact that these new enabling technologies represent for UV applications are addressed.

A new era of semiconductor genetics using ion-sensitive field-effect transistors: the gene-sensitive integrated cell.

PubMed

Toumazou, Christofer; Thay, Tan Sri Lim Kok; Georgiou, Pantelis

2014-03-28

Semiconductor genetics is now disrupting the field of healthcare owing to the rapid parallelization and scaling of DNA sensing using ion-sensitive field-effect transistors (ISFETs) fabricated using commercial complementary metal -oxide semiconductor technology. The enabling concept of DNA reaction monitoring introduced by Toumazou has made this a reality and we are now seeing relentless scaling with Moore's law ultimately achieving the $100 genome. In this paper, we present the next evolution of this technology through the creation of the gene-sensitive integrated cell (GSIC) for label-free real-time analysis based on ISFETs. This device is derived from the traditional metal-oxide semiconductor field-effect transistor (MOSFET) and has electrical performance identical to that of a MOSFET in a standard semiconductor process, yet is capable of incorporating DNA reaction chemistries for applications in single nucleotide polymorphism microarrays and DNA sequencing. Just as application-specific integrated circuits, which are developed in much the same way, have shaped our consumer electronics industry and modern communications and memory technology, so, too, do GSICs based on a single underlying technology principle have the capacity to transform the life science and healthcare industries.

A semiconductor bridge ignited hot gas piston ejector

NASA Technical Reports Server (NTRS)

Grubelich, M. C.; Bickes, Robert W., Jr.

1993-01-01

The topics are presented in viewgraph form and include the following: semiconductor bridge technology (SCB); SCB philosophy; technology transfer; simplified sketch of SCB; SCB processing; SCB design; SCB test assembly; 5 mJ SCB burst based on a polaroid photograph; micro-convective heat transfer hypothesis; SCB fire set; comparison of SCB and hot-wire actuators; satellite firing sets; logic fire set; SCB smart component; SCB smart firing set; semiconductor design considerations; and the adjustable actuator system.

From Bell Labs to Silicon Valley: A Saga of Technology Transfer, 1954-1961

NASA Astrophysics Data System (ADS)

Riordan, Michael

2009-03-01

Although Bell Telephone Laboratories invented the transistor and developed most of the associated semiconductor technology, the integrated circuit or microchip emerged elsewhere--at Texas Instruments and Fairchild Semiconductor Company. I recount how the silicon technology required to make microchips possible was first developed at Bell Labs in the mid-1950s. Much of it reached the San Francisco Bay Area when transistor pioneer William Shockley left Bell Labs in 1955 to establish the Shockley Semiconductor Laboratory in Mountain View, hiring a team of engineers and scientists to develop and manufacture transistors and related semiconductor devices. But eight of them--including Gordon Moore and Robert Noyce, eventually the co-founders of Intel--resigned en masse in September 1957 to start Fairchild, bringing with them the scientific and technological expertise they had acquired and further developed at Shockley's firm. This event marked the birth of Silicon Valley, both technologically and culturally. By March 1961 the company was marketing its Micrologic integrated circuits, the first commercial silicon microchips, based on the planar processing technique developed at Fairchild by Jean Hoerni.

Sensors, nano-electronics and photonics for the Army of 2030 and beyond

NASA Astrophysics Data System (ADS)

Perconti, Philip; Alberts, W. C. K.; Bajaj, Jagmohan; Schuster, Jonathan; Reed, Meredith

2016-02-01

The US Army's future operating concept will rely heavily on sensors, nano-electronics and photonics technologies to rapidly develop situational understanding in challenging and complex environments. Recent technology breakthroughs in integrated 3D multiscale semiconductor modeling (from atoms-to-sensors), combined with ARL's Open Campus business model for collaborative research provide a unique opportunity to accelerate the adoption of new technology for reduced size, weight, power, and cost of Army equipment. This paper presents recent research efforts on multi-scale modeling at the US Army Research Laboratory (ARL) and proposes the establishment of a modeling consortium or center for semiconductor materials modeling. ARL's proposed Center for Semiconductor Materials Modeling brings together government, academia, and industry in a collaborative fashion to continuously push semiconductor research forward for the mutual benefit of all Army partners.

Numerical investigation of metal-semiconductor-insulator-semiconductor passivated hole contacts based on atomic layer deposited AlO x

NASA Astrophysics Data System (ADS)

Ke, Cangming; Xin, Zheng; Ling, Zhi Peng; Aberle, Armin G.; Stangl, Rolf

2017-08-01

Excellent c-Si tunnel layer surface passivation has been obtained recently in our lab, using atomic layer deposited aluminium oxide (ALD AlO x ) in the tunnel layer regime of 0.9 to 1.5 nm, investigated to be applied for contact passivation. Using the correspondingly measured interface properties, this paper compares the theoretical collection efficiency of a conventional metal-semiconductor (MS) contact on diffused p+ Si to a metal-semiconductor-insulator-semiconductor (MSIS) contact on diffused p+ Si or on undoped n-type c-Si. The influences of (1) the tunnel layer passivation quality at the tunnel oxide interface (Q f and D it), (2) the tunnel layer thickness and the electron and hole tunnelling mass, (3) the tunnel oxide material, and (4) the semiconductor capping layer material properties are investigated numerically by evaluation of solar cell efficiency, open-circuit voltage, and fill factor.

Operation and biasing for single device equivalent to CMOS

DOEpatents

Welch, James D.

2001-01-01

Disclosed are semiconductor devices including at least one junction which is rectifying whether the semiconductor is caused to be N or P-type, by the presence of field induced carriers. In particular, inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to conventional multiple device CMOS systems, which can be operated as modulators, are disclosed as are a non-latching SCR and an approach to blocking parasitic currents. Operation of the gate voltage channel induced semiconductor single devices with operating characteristics similar to multiple device CMOS systems under typical bias schemes is described, and simple demonstrative five mask fabrication procedures for the inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to multiple device CMOS systems are also presented.

Patterning roadmap: 2017 prospects

NASA Astrophysics Data System (ADS)

Neisser, Mark

2017-06-01

Road mapping of semiconductor chips has been underway for over 20 years, first with the International Technology Roadmap for Semiconductors (ITRS) roadmap and now with the International Roadmap for Devices and Systems (IRDS) roadmap. The original roadmap was mostly driven bottom up and was developed to ensure that the large numbers of semiconductor producers and suppliers had good information to base their research and development on. The current roadmap is generated more top-down, where the customers of semiconductor chips anticipate what will be needed in the future and the roadmap projects what will be needed to fulfill that demand. The More Moore section of the roadmap projects that advanced logic will drive higher-resolution patterning, rather than memory chips. Potential solutions for patterning future logic nodes can be derived as extensions of `next-generation' patterning technologies currently under development. Advanced patterning has made great progress, and two `next-generation' patterning technologies, EUV and nanoimprint lithography, have potential to be in production as early as 2018. The potential adoption of two different next-generation patterning technologies suggests that patterning technology is becoming more specialized. This is good for the industry in that it lowers overall costs, but may lead to slower progress in extending any one patterning technology in the future.

Technology Roadmaps for Compound Semiconductors

PubMed Central

Bennett, Herbert S.

2000-01-01

The roles cited for compound semiconductors in public versions of existing technology roadmaps from the National Electronics Manufacturing Initiative, Inc., Optoelectronics Industry Development Association, Microelectronics Advanced Research Initiative on Optoelectronic Interconnects, and Optoelectronics Industry and Technology Development Association (OITDA) are discussed and compared within the context of trends in the Si CMOS industry. In particular, the extent to which these technology roadmaps treat compound semiconductors at the materials processing and device levels will be presented for specific applications. For example, OITDA’s Optical Communications Technology Roadmap directly connects the information demand of delivering 100 Mbit/s to the home to the requirement of producing 200 GHz heterojunction bipolar transistors with 30 nm bases and InP high electron mobility transistors with 100 nm gates. Some general actions for progress towards the proposed International Technology Roadmap for Compound Semiconductors (ITRCS) and methods for determining the value of an ITRCS will be suggested. But, in the final analysis, the value added by an ITRCS will depend on how industry leaders respond. The technical challenges and economic opportunities of delivering high quality digital video to consumers provide concrete examples of where the above actions and methods could be applied. PMID:27551615

Center for Semiconductor Materials and Device Modeling: expanding collaborative research opportunities between government, academia, and industry

NASA Astrophysics Data System (ADS)

Perconti, Philip; Bedair, Sarah S.; Bajaj, Jagmohan; Schuster, Jonathan; Reed, Meredith

2016-09-01

To increase Soldier readiness and enhance situational understanding in ever-changing and complex environments, there is a need for rapid development and deployment of Army technologies utilizing sensors, photonics, and electronics. Fundamental aspects of these technologies include the research and development of semiconductor materials and devices which are ubiquitous in numerous applications. Since many Army technologies are considered niche, there is a lack of significant industry investment in the fundamental research and understanding of semiconductor technologies relevant to the Army. To address this issue, the US Army Research Laboratory is establishing a Center for Semiconductor Materials and Device Modeling and seeks to leverage expertise and resources across academia, government and industry. Several key research areas—highlighted and addressed in this paper—have been identified by ARL and external partners and will be pursued in a collaborative fashion by this Center. This paper will also address the mechanisms by which the Center is being established and will operate.

Random bit generation at tunable rates using a chaotic semiconductor laser under distributed feedback.

PubMed

Li, Xiao-Zhou; Li, Song-Sui; Zhuang, Jun-Ping; Chan, Sze-Chun

2015-09-01

A semiconductor laser with distributed feedback from a fiber Bragg grating (FBG) is investigated for random bit generation (RBG). The feedback perturbs the laser to emit chaotically with the intensity being sampled periodically. The samples are then converted into random bits by a simple postprocessing of self-differencing and selecting bits. Unlike a conventional mirror that provides localized feedback, the FBG provides distributed feedback which effectively suppresses the information of the round-trip feedback delay time. Randomness is ensured even when the sampling period is commensurate with the feedback delay between the laser and the grating. Consequently, in RBG, the FBG feedback enables continuous tuning of the output bit rate, reduces the minimum sampling period, and increases the number of bits selected per sample. RBG is experimentally investigated at a sampling period continuously tunable from over 16 ns down to 50 ps, while the feedback delay is fixed at 7.7 ns. By selecting 5 least-significant bits per sample, output bit rates from 0.3 to 100 Gbps are achieved with randomness examined by the National Institute of Standards and Technology test suite.

High- and Reproducible-Performance Graphene/II-VI Semiconductor Film Hybrid Photodetectors

PubMed Central

Huang, Fan; Jia, Feixiang; Cai, Caoyuan; Xu, Zhihao; Wu, Congjun; Ma, Yang; Fei, Guangtao; Wang, Min

2016-01-01

High- and reproducible-performance photodetectors are critical to the development of many technologies, which mainly include one-dimensional (1D) nanostructure based and film based photodetectors. The former suffer from a huge performance variation because the performance is quite sensitive to the synthesis microenvironment of 1D nanostructure. Herein, we show that the graphene/semiconductor film hybrid photodetectors not only possess a high performance but also have a reproducible performance. As a demo, the as-produced graphene/ZnS film hybrid photodetector shows a high responsivity of 1.7 × 107 A/W and a fast response speed of 50 ms, and shows a highly reproducible performance, in terms of narrow distribution of photocurrent (38–65 μA) and response speed (40–60 ms) for 20 devices. Graphene/ZnSe film and graphene/CdSe film hybrid photodetectors fabricated by this method also show a high and reproducible performance. The general method is compatible with the conventional planar process, and would be easily standardized and thus pay a way for the photodetector applications. PMID:27349692

Interfacing spin qubits in quantum dots and donors—hot, dense, and coherent

NASA Astrophysics Data System (ADS)

Vandersypen, L. M. K.; Bluhm, H.; Clarke, J. S.; Dzurak, A. S.; Ishihara, R.; Morello, A.; Reilly, D. J.; Schreiber, L. R.; Veldhorst, M.

2017-09-01

Semiconductor spins are one of the few qubit realizations that remain a serious candidate for the implementation of large-scale quantum circuits. Excellent scalability is often argued for spin qubits defined by lithography and controlled via electrical signals, based on the success of conventional semiconductor integrated circuits. However, the wiring and interconnect requirements for quantum circuits are completely different from those for classical circuits, as individual direct current, pulsed and in some cases microwave control signals need to be routed from external sources to every qubit. This is further complicated by the requirement that these spin qubits currently operate at temperatures below 100 mK. Here, we review several strategies that are considered to address this crucial challenge in scaling quantum circuits based on electron spin qubits. Key assets of spin qubits include the potential to operate at 1 to 4 K, the high density of quantum dots or donors combined with possibilities to space them apart as needed, the extremely long-spin coherence times, and the rich options for integration with classical electronics based on the same technology.

Mega-pixel PQR laser chips for interconnect, display ITS, and biocell-tweezers OEIC

NASA Astrophysics Data System (ADS)

Kwon, O'Dae; Yoon, J. H.; Kim, D. K.; Kim, Y. C.; Lee, S. E.; Kim, S. S.

2008-02-01

We describe a photonic quantum ring (PQR) laser device of three dimensional toroidal whispering gallery cavity. We have succeeded in fabricating the first genuine mega-pixel laser chips via regular semiconductor technology. This has been realized since the present injection laser emitting surface-normal dominant 3D whispering gallery modes (WGMs) can be operated CW with extremely low operating currents (μA-nA per pixel), together with the lasing temperature stabilities well above 140 deg C with minimal redshifts, which solves the well-known integration problems facing the conventional VCSEL. Such properties unusual for quantum well lasers become usual because the active region, involving vertically confining DBR structure in addition to the 2D concave WGM geometry, induces a 'photonic quantum ring (PQR)-like' carrier distribution through a photonic quantum corral effect. A few applications of such mega-pixel PQR chips are explained as follows: (A) Next-generation 3D semiconductor technologies demand a strategy on the inter-chip and intra-chip optical interconnect schemes with a key to the high-density emitter array. (B) Due to mounting traffic problems and fatalities ITS technology today is looking for a revolutionary change in the technology. We will thus outline how 'SLEEP-ITS' can emerge with the PQR's position-sensing capability. (C) We describe a recent PQR 'hole' laser of convex WGM: Mega-pixel PQR 'hole' laser chips are even easier to fabricate than PQR 'mesa' lasers. Genuine Laguerre-Gaussian (LG) beam patterns of PQR holes are very promising for biocell manipulations like sorting mouse myeloid leukemia (M1s) cells. (D) Energy saving and 3D speckle-free POR laser can outdo LEDs in view of red GaAs and blue GaN devices fabricated recently.

Semiconductor technology program: Progress briefs

NASA Technical Reports Server (NTRS)

Galloway, K. F.; Scace, R. I.; Walters, E. J.

1981-01-01

Measurement technology for semiconductor materials, process control, and devices, is discussed. Silicon and silicon based devices are emphasized. Highlighted activities include semiinsulating GaAs characterization, an automatic scanning spectroscopic ellipsometer, linewidth measurement and coherence, bandgap narrowing effects in silicon, the evaluation of electrical linewidth uniformity, and arsenicomplanted profiles in silicon.

Experimental demonstration of distributed feedback semiconductor lasers based on reconstruction-equivalent-chirp technology.

PubMed

Li, Jingsi; Wang, Huan; Chen, Xiangfei; Yin, Zuowei; Shi, Yuechun; Lu, Yanqing; Dai, Yitang; Zhu, Hongliang

2009-03-30

In this paper we report, to the best of our knowledge, the first experimental realization of distributed feedback (DFB) semiconductor lasers based on reconstruction-equivalent-chirp (REC) technology. Lasers with different lasing wavelengths are achieved simultaneously on one chip, which shows a potential for the REC technology in combination with the photonic integrated circuits (PIC) technology to be a possible method for monolithic integration, in that its fabrication is as powerful as electron beam technology and the cost and time-consuming are almost the same as standard holographic technology.

AFM-IR: Technology and Applications in Nanoscale Infrared Spectroscopy and Chemical Imaging.

PubMed

Dazzi, Alexandre; Prater, Craig B

2016-12-13

Atomic force microscopy-based infrared spectroscopy (AFM-IR) is a rapidly emerging technique that provides chemical analysis and compositional mapping with spatial resolution far below conventional optical diffraction limits. AFM-IR works by using the tip of an AFM probe to locally detect thermal expansion in a sample resulting from absorption of infrared radiation. AFM-IR thus can provide the spatial resolution of AFM in combination with the chemical analysis and compositional imaging capabilities of infrared spectroscopy. This article briefly reviews the development and underlying technology of AFM-IR, including recent advances, and then surveys a wide range of applications and investigations using AFM-IR. AFM-IR applications that will be discussed include those in polymers, life sciences, photonics, solar cells, semiconductors, pharmaceuticals, and cultural heritage. In the Supporting Information , the authors provide a theoretical section that reviews the physics underlying the AFM-IR measurement and detection mechanisms.

Nanoelectronics: Opportunities for future space applications

NASA Technical Reports Server (NTRS)

Frazier, Gary

1995-01-01

Further improvements in the performance of integrated electronics will eventually halt due to practical fundamental limits on our ability to downsize transistors and interconnect wiring. Avoiding these limits requires a revolutionary approach to switching device technology and computing architecture. Nanoelectronics, the technology of exploiting physics on the nanometer scale for computation and communication, attempts to avoid conventional limits by developing new approaches to switching, circuitry, and system integration. This presentation overviews the basic principles that operate on the nanometer scale that can be assembled into practical devices and circuits. Quantum resonant tunneling (RT) is used as the center-piece of the overview since RT devices already operate at high temperature (120 degrees C) and can be scaled, in principle, to a few nanometers in semiconductors. Near- and long-term applications of GaAs and silicon quantum devices are suggested for signal and information processing, memory, optoelectronics, and radio frequency (RF) communication.

A rugged 650 V SOI-based high-voltage half-bridge IGBT gate driver IC for motor drive applications

NASA Astrophysics Data System (ADS)

Hua, Qing; Li, Zehong; Zhang, Bo; Chen, Weizhong; Huang, Xiangjun; Feng, Yuxiang

2015-05-01

This paper proposes a rugged high-voltage N-channel insulated gate bipolar transistor (IGBT) gate driver integrated circuit. The device integrates a high-side and a low-side output stages on a single chip, which is designed specifically for motor drive applications. High-voltage level shift technology enables the high-side stage of this device to operate up to 650 V. The logic inputs are complementary metal oxide semiconductor (CMOS)/transistor transistor logic compatible down to 3.3 V. Undervoltage protection functionality with hysteresis characteristic has also been integrated to enhance the device reliability. The device is fabricated in a 1.0 μm, 650 V high-voltage bipolar CMOS double-diffused metal oxide semiconductor (BCD) on silicon-on-insulator (SOI) process. Deep trench dielectric isolation technology is employed to provide complete electrical isolation with advantages such as reduced parasitic effects, excellent noise immunity and low leakage current. Experimental results show that the isolation voltage of this device can be up to approximately 779 V at 25°C, and the leakage current is only 5 nA at 650 V, which is 15% higher and 67% lower than the conventional ones. In addition, it delivers an excellent thermal stability and needs very low quiescent current and offers a high gate driver capability which is needed to adequately drive IGBTs that have large input capacitances.

JPRS Report (Erratum), Science & Technology, Japan, Selections from MITI White Paper on Industrial Technology Trends and Issues

DTIC Science & Technology

1989-08-30

year period in the following products: Technology Field Product New materials Composite materials Amorphous alloys Macromolecule separation...plastics 8. Composite materials B. Parts 9. Optical fiber 10. Semiconductor lasers 11. CCD 12. Semiconductor memory elements 13. Microcomputers...separation. Composite materials (containing carbon fiber) (1) Aerospace users required strict specifi cations for carbon fiber, resulting in

Progress in silicon carbide semiconductor technology

NASA Technical Reports Server (NTRS)

Powell, J. A.; Neudeck, P. G.; Matus, L. G.; Petit, J. B.

1992-01-01

Silicon carbide semiconductor technology has been advancing rapidly over the last several years. Advances have been made in boule growth, thin film growth, and device fabrication. This paper wi11 review reasons for the renewed interest in SiC, and will review recent developments in both crystal growth and device fabrication.

Courseware Development for Semiconductor Technology and Its Application into Instruction

ERIC Educational Resources Information Center

Tsai, Shu-chiao

2009-01-01

This study reports on the development of ESP (English for specific purposes) courseware for semiconductor technology and its integration as a "silent partner" into instruction. This kind of team-teaching could help overcome current problems encountered in developing ESP in Taiwan. The content of the material under discussion includes…

High throughput web inspection system using time-stretch real-time imaging

NASA Astrophysics Data System (ADS)

Kim, Chanju

Photonic time-stretch is a novel technology that enables capturing of fast, rare and non-repetitive events. Therefore, it operates in real-time with ability to record over long period of time while having fine temporal resolution. The powerful property of photonic time-stretch has already been employed in various fields of application such as analog-to-digital conversion, spectroscopy, laser scanner and microscopy. Further expanding the scope, we fully exploit the time-stretch technology to demonstrate a high throughput web inspection system. Web inspection, namely surface inspection is a nondestructive evaluation method which is crucial for semiconductor wafer and thin film production. We successfully report a dark-field web inspection system with line scan speed of 90.9 MHz which is up to 1000 times faster than conventional inspection instruments. The manufacturing of high quality semiconductor wafer and thin film may directly benefit from this technology as it can easily locate defects with area of less than 10 microm x 10 microm where it allows maximum web flow speed of 1.8 km/s. The thesis provides an overview of our web inspection technique, followed by description of the photonic time-stretch technique which is the keystone in our system. A detailed explanation of each component is covered to provide quantitative understanding of the system. Finally, imaging results from a hard-disk sample and flexible films are presented along with performance analysis of the system. This project was the first application of time-stretch to industrial inspection, and was conducted under financial support and with close involvement by Hitachi, Ltd.

Narrowband light detection via internal quantum efficiency manipulation of organic photodiodes

NASA Astrophysics Data System (ADS)

Armin, Ardalan; Jansen-van Vuuren, Ross D.; Kopidakis, Nikos; Burn, Paul L.; Meredith, Paul

2015-02-01

Spectrally selective light detection is vital for full-colour and near-infrared (NIR) imaging and machine vision. This is not possible with traditional broadband-absorbing inorganic semiconductors without input filtering, and is yet to be achieved for narrowband absorbing organic semiconductors. We demonstrate the first sub-100 nm full-width-at-half-maximum visible-blind red and NIR photodetectors with state-of-the-art performance across critical response metrics. These devices are based on organic photodiodes with optically thick junctions. Paradoxically, we use broadband-absorbing organic semiconductors and utilize the electro-optical properties of the junction to create the narrowest NIR-band photoresponses yet demonstrated. In this context, these photodiodes outperform the encumbent technology (input filtered inorganic semiconductor diodes) and emerging technologies such as narrow absorber organic semiconductors or quantum nanocrystals. The design concept allows for response tuning and is generic for other spectral windows. Furthermore, it is material-agnostic and applicable to other disordered and polycrystalline semiconductors.

Narrowband Light Detection via Internal Quantum Efficiency Manipulation of Organic Photodiodes

DOE PAGES

Armin, A.; Jansen-van Vuuren, R. D.; Kopidakis, N.; ...

2015-02-01

Spectrally selective light detection is vital for full-colour and near-infrared (NIR) imaging and machine vision. This is not possible with traditional broadband-absorbing inorganic semiconductors without input filtering, and is yet to be achieved for narrowband absorbing organic semiconductors. We demonstrate the first sub-100 nm full-width-at-half-maximum visible-blind red and NIR photodetectors with state-of-the-art performance across critical response metrics. These devices are based on organic photodiodes with optically thick junctions. Paradoxically, we use broadband-absorbing organic semiconductors and utilize the electro-optical properties of the junction to create the narrowest NIR-band photoresponses yet demonstrated. In this context, these photodiodes outperform the encumbent technology (inputmore » filtered inorganic semiconductor diodes) and emerging technologies such as narrow absorber organic semiconductors or quantum nanocrystals. The design concept allows for response tuning and is generic for other spectral windows. Furthermore, it is materialagnostic and applicable to other disordered and polycrystalline semiconductors.« less

Semiconductor technology in protein kinase research and drug discovery: sensing a revolution.

PubMed

Bhalla, Nikhil; Di Lorenzo, Mirella; Estrela, Pedro; Pula, Giordano

2017-02-01

Since the discovery of protein kinase activity in 1954, close to 600 kinases have been discovered that have crucial roles in cell physiology. In several pathological conditions, aberrant protein kinase activity leads to abnormal cell and tissue physiology. Therefore, protein kinase inhibitors are investigated as potential treatments for several diseases, including dementia, diabetes, cancer and autoimmune and cardiovascular disease. Modern semiconductor technology has recently been applied to accelerate the discovery of novel protein kinase inhibitors that could become the standard-of-care drugs of tomorrow. Here, we describe current techniques and novel applications of semiconductor technologies in protein kinase inhibitor drug discovery. Copyright © 2016 Elsevier Ltd. All rights reserved.

Semiconductor Technology and U.S. National Security

DTIC Science & Technology

2010-04-21

control regime as hindrances to compete in the global market.45 Interestingly, DOD’s Defense Technology Security Administration ( DTSA ) reviews export...licenses and only advises DOS or DOC.46 DTSA has neither compliance nor enforcement authority. There is no lead organization or a centralized...which lists several semiconductor technologies, is out of date and not used, even by DOD’s DTSA .51 In order to remove certain export controls on

Implementation of Ferroelectric Memories for Space Applications

NASA Technical Reports Server (NTRS)

Philpy, Stephen C.; Derbenwick, Gary F.; Kamp, David A.; Isaacson, Alan F.

2000-01-01

Ferroelectric random access semiconductor memories (FeRAMs) are an ideal nonvolatile solution for space applications. These memories have low power performance, high endurance and fast write times. By combining commercial ferroelectric memory technology with radiation hardened CMOS technology, nonvolatile semiconductor memories for space applications can be attained. Of the few radiation hardened semiconductor manufacturers, none have embraced the development of radiation hardened FeRAMs, due a limited commercial space market and funding limitations. Government funding may be necessary to assure the development of radiation hardened ferroelectric memories for space applications.

Design and Fabrication of Millimeter Wave Hexagonal Nano-Ferrite Circulator on Silicon CMOS Substrate

NASA Astrophysics Data System (ADS)

Oukacha, Hassan

The rapid advancement of Complementary Metal Oxide Semiconductor (CMOS) technology has formed the backbone of the modern computing revolution enabling the development of computationally intensive electronic devices that are smaller, faster, less expensive, and consume less power. This well-established technology has transformed the mobile computing and communications industries by providing high levels of system integration on a single substrate, high reliability and low manufacturing cost. The driving force behind this computing revolution is the scaling of semiconductor devices to smaller geometries which has resulted in faster switching speeds and the promise of replacing traditional, bulky radio frequency (RF) components with miniaturized devices. Such devices play an important role in our society enabling ubiquitous computing and on-demand data access. This thesis presents the design and development of a magnetic circulator component in a standard 180 nm CMOS process. The design approach involves integration of nanoscale ferrite materials on a CMOS chip to avoid using bulky magnetic materials employed in conventional circulators. This device constitutes the next generation broadband millimeter-wave circulator integrated in CMOS using ferrite materials operating in the 60GHz frequency band. The unlicensed ultra-high frequency spectrum around 60GHz offers many benefits: very high immunity to interference, high security, and frequency re-use. Results of both simulations and measurements are presented in this thesis. The presented results show the benefits of this technique and the potential that it has in incorporating a complete system-on-chip (SoC) that includes low noise amplifier, power amplier, and antenna. This system-on-chip can be used in the same applications where the conventional circulator has been employed, including communication systems, radar systems, navigation and air traffic control, and military equipment. This set of applications of circulator shows how crucial this device is to many industries and the need for smaller, cost effective RF components.

Hybrid semiconductor fiber lasers for telecommunications

NASA Astrophysics Data System (ADS)

Khalili, Alireza

2006-12-01

Highly stable edge emitting semiconductor lasers are of utmost importance in most telecommunications applications where high-speed data transmission sets strict limits on the purity of the laser signal. Unfortunately, most edge emitting semiconductor lasers, unlike gaseous or solid-state laser sources, operate with many closely spaced axial modes, which accounts for the observed instability and large spikes in the output spectrum of such lasers. Consequently, in most telecom applications distributed feedback (DFB) or distributed Bragg reflector (DBR) techniques are used to ensure stability and single-frequency operation, further adding to the cost and complexity of such lasers. Additionally, coupling of the highly elliptical output beam of these lasers to singlemode fibers complicates the packaging procedure and sub-micron alignment of various optical components is often necessary. Utilizing the evanescent coupling between a semiconductor antiresonant reflecting optical waveguide (ARROW) and a side polished fiber, this thesis presents an alternative side-coupled laser module that eliminates the need for the cumbersome multi-component alignment processes of conventional laser packages, and creates an inherent mode selection mechanism that guarantees singlemode radiation into the fiber without any gratings. We have been able to demonstrate the first side-coupled fiber semiconductor laser in this technology, coupling more than 3mW of power at 850nm directly into a 5/125mum singlemode fiber. This mixed-cavity architecture yields a high thermal stability (˜0.06nm/°C), and negligible spectral spikes are observed. Theoretical background and simulation results, as well as several supplementary materials are also presented to further rationalize the experimental data. A side-coupled light-emitter and pre-amplifier are also proposed and discussed. We also study different architectures for attaining higher efficiency, higher output power, and wavelength tunability in such lasers. Finally, we discuss possible venues for integration of these side-coupled devices in a telecommunication system. Approved for publication.

Emergence of resonant mode-locking via delayed feedback in quantum dot semiconductor lasers.

PubMed

Tykalewicz, B; Goulding, D; Hegarty, S P; Huyet, G; Erneux, T; Kelleher, B; Viktorov, E A

2016-02-22

With conventional semiconductor lasers undergoing external optical feedback, a chaotic output is typically observed even for moderate levels of the feedback strength. In this paper we examine single mode quantum dot lasers under strong optical feedback conditions and show that an entirely new dynamical regime is found consisting of spontaneous mode-locking via a resonance between the relaxation oscillation frequency and the external cavity repetition rate. Experimental observations are supported by detailed numerical simulations of rate equations appropriate for this laser type. The phenomenon constitutes an entirely new mode-locking mechanism in semiconductor lasers.

Semiconductor surface protection material

NASA Technical Reports Server (NTRS)

Packard, R. D. (Inventor)

1973-01-01

A method and a product for protecting semiconductor surfaces is disclosed. The protective coating material is prepared by heating a suitable protective resin with an organic solvent which is solid at room temperature and converting the resulting solution into sheets by a conventional casting operation. Pieces of such sheets of suitable shape and thickness are placed on the semiconductor areas to be coated and heat and vacuum are then applied to melt the sheet and to drive off the solvent and cure the resin. A uniform adherent coating, free of bubbles and other defects, is thus obtained exactly where it is desired.

Optical processing for semiconductor device fabrication

NASA Technical Reports Server (NTRS)

Sopori, Bhushan L.

1994-01-01

A new technique for semiconductor device processing is described that uses optical energy to produce local heating/melting in the vicinity of a preselected interface of the device. This process, called optical processing, invokes assistance of photons to enhance interface reactions such as diffusion and melting, as compared to the use of thermal heating alone. Optical processing is performed in a 'cold wall' furnace, and requires considerably lower energies than furnace or rapid thermal annealing. This technique can produce some device structures with unique properties that cannot be produced by conventional thermal processing. Some applications of optical processing involving semiconductor-metal interfaces are described.

Design for manufacturability production management activity report

NASA Astrophysics Data System (ADS)

Miyazaki, Norihiko; Sato, T.; Honma, M.; Yoshioka, N.; Hosono, K.; Onodera, T.; Itoh, H.; Suzuki, H.; Uga, T.; Kadota, K.; Iriki, N.

2006-05-01

Design For Manufacturability Production Management (DFM-PM) Subcommittee has been started in succession to Reticle Management Subcommittee (RMS) in Semiconductor Manufacturing Technology Committee for Japan (SMTCJ) from 2005. Our activity focuses on the SoC (System On Chip) Business, and it pursues the improvement of communication in manufacturing technique. The first theme of activity is the investigation and examination of the new trends about production (manufacturer) technology and related information, and proposals of business solution. The second theme is the standardization activity about manufacture technology and the cooperation with related semiconductors' organizations. And the third theme is holding workshop and support for promotion and spread of the standardization technology throughout semiconductor companies. We expand a range of scope from design technology to wafer pattern reliability and we will propose the competition domain, the collaboration area and the standardization technology on DFM. Furthermore, we will be able to make up a SoC business model as the 45nm node technology beyond manufacturing platform in cooperating with the design information and the production information by utilizing EDA technology.

Direct detection of sub-GeV dark matter with semiconductor targets

DOE PAGES

Essig, Rouven; Fernández-Serra, Marivi; Mardon, Jeremy; ...

2016-05-09

Dark matter in the sub-GeV mass range is a theoretically motivated but largely unexplored paradigm. Such light masses are out of reach for conventional nuclear recoil direct detection experiments, but may be detected through the small ionization signals caused by dark matter-electron scattering. Semiconductors are well-studied and are particularly promising target materials because their O(1 eV) band gaps allow for ionization signals from dark matter particles as light as a few hundred keV. Current direct detection technologies are being adapted for dark matter-electron scattering. In this paper, we provide the theoretical calculations for dark matter-electron scattering rate in semiconductors, overcomingmore » several complications that stem from the many-body nature of the problem. We use density functional theory to numerically calculate the rates for dark matter-electron scattering in silicon and germanium, and estimate the sensitivity for upcoming experiments such as DAMIC and SuperCDMS. We find that the reach for these upcoming experiments has the potential to be orders of magnitude beyond current direct detection constraints and that sub-GeV dark matter has a sizable modulation signal. We also give the first direct detection limits on sub-GeV dark matter from its scattering off electrons in a semiconductor target (silicon) based on published results from DAMIC. We make available publicly our code, QEdark, with which we calculate our results. Our results can be used by experimental collaborations to calculate their own sensitivities based on their specific setup. In conclusion, the searches we propose will probe vast new regions of unexplored dark matter model and parameter space.« less

Reconfigurable topological photonic crystal

NASA Astrophysics Data System (ADS)

Shalaev, Mikhail I.; Desnavi, Sameerah; Walasik, Wiktor; Litchinitser, Natalia M.

2018-02-01

Topological insulators are materials that conduct on the surface and insulate in their interior due to non-trivial topology of the band structure. The edge states on the interface between topological (non-trivial) and conventional (trivial) insulators are topologically protected from scattering due to structural defects and disorders. Recently, it was shown that photonic crystals (PCs) can serve as a platform for realizing a scatter-free propagation of light waves. In conventional PCs, imperfections, structural disorders, and surface roughness lead to significant losses. The breakthrough in overcoming these problems is likely to come from the synergy of the topological PCs and silicon-based photonics technology that enables high integration density, lossless propagation, and immunity to fabrication imperfections. For many applications, reconfigurability and capability to control the propagation of these non-trivial photonic edge states is essential. One way to facilitate such dynamic control is to use liquid crystals (LCs), which allow to modify the refractive index with external electric field. Here, we demonstrate dynamic control of topological edge states by modifying the refractive index of a LC background medium. Background index is changed depending on the orientation of a LC, while preserving the topology of the system. This results in a change of the spectral position of the photonic bandgap and the topological edge states. The proposed concept might be implemented using conventional semiconductor technology, and can be used for robust energy transport in integrated photonic devices, all-optical circuity, and optical communication systems.

Defects activated photoluminescence in two-dimensional semiconductors: interplay between bound, charged, and free excitons

PubMed Central

Tongay, Sefaattin; Suh, Joonki; Ataca, Can; Fan, Wen; Luce, Alexander; Kang, Jeong Seuk; Liu, Jonathan; Ko, Changhyun; Raghunathanan, Rajamani; Zhou, Jian; Ogletree, Frank; Li, Jingbo; Grossman, Jeffrey C.; Wu, Junqiao

2013-01-01

Point defects in semiconductors can trap free charge carriers and localize excitons. The interaction between these defects and charge carriers becomes stronger at reduced dimensionalities, and is expected to greatly influence physical properties of the hosting material. We investigated effects of anion vacancies in monolayer transition metal dichalcogenides as two-dimensional (2D) semiconductors where the vacancies density is controlled by α-particle irradiation or thermal-annealing. We found a new, sub-bandgap emission peak as well as increase in overall photoluminescence intensity as a result of the vacancy generation. Interestingly, these effects are absent when measured in vacuum. We conclude that in opposite to conventional wisdom, optical quality at room temperature cannot be used as criteria to assess crystal quality of the 2D semiconductors. Our results not only shed light on defect and exciton physics of 2D semiconductors, but also offer a new route toward tailoring optical properties of 2D semiconductors by defect engineering. PMID:24029823

78 FR 24234 - Certain Semiconductor Chips With DRAM Circuitry, and Modules and Products Containing Same; Notice...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-24

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-819] Certain Semiconductor Chips With DRAM Circuitry, and Modules and Products Containing Same; Notice of Request for Statements on the... order barring the entry of unlicensed DRAM semiconductor chips manufactured by Nanya Technology...

T-gate geometric (solution for submicrometer gate length) HEMT: Physical analysis, modeling and implementation as parasitic elements and its usage as dual gate for variable gain amplifiers

NASA Astrophysics Data System (ADS)

Gupta, Ritesh; Rathi, Servin; Kaur, Ravneet; Gupta, Mridula; Gupta, R. S.

2009-03-01

In order to achieve superior RF performance, short gate length is required for the compound semiconductor field effect transistors, but the limitation in lithography for submicrometer gate lengths leads to the formation of various metal-insulator geometries like T-gate [Sandeep R. Bahl, Jesus A. del Alamo, Physics of breakdown in InAlAs/ n +-InGaAs heterostructure field-effect transistors, IEEE Trans. Electron Devices 41 (12) (1994) 2268-2275]. These geometries are the combination of various Metal-Semiconductor (MS)/Metal-Air-Semiconductor (MAS) contacts. Moreover, field plates [S. Karmalkar, M.S. Shur, G. Simin, M. Asif Khan, Field-plate engineering for HFETs, IEEE Trans. Electron Devices 52 (2005) 2534-2540] are also being fabricated these days, mainly at the drain end ( Γ-gate) having Metal-Insulator-Semiconductor (MIS) instead of MAS contact with the intention of increasing the breakdown voltage of the device. To realize the effect of upper gate electrode in the T-gate structure and field plates, an analytical model has been proposed in the present article by dividing the whole structure into MS/MIS contact regions, applying current continuity among them and solving iteratively. The model proposed for Metal-Insulator Semiconductor High Electron Mobility Transistor (MISHEMT) [R. Gupta, S.K. Aggarwal, M. Gupta, R.S. Gupta, Analytical model for metal insulator semiconductor high electron mobility transistor (MISHEMT) for its high frequency and high power applications, J. Semicond. Technol. Sci. 6 (3) (2006) 189-198], is equally applicable to High Electron Mobility Transistors (HEMT) and has been used to formulate this model. In this paper, various structures and geometries have been compared to anticipate the need of T-gate modeling. The effect of MIS contacts has been implemented as parasitic resistance and capacitance and has also been studied to control the middle conventional gate as in dual gate technology by applying separate voltages across it. The results obtained using the proposed analytical scheme has been compared with simulated and experimental results, to prove the validity of our model.

Biasing, operation and parasitic current limitation in single device equivalent to CMOS, and other semiconductor systems

DOEpatents

Welch, James D.

2003-09-23

Disclosed are semiconductor devices including at least one junction which is rectifying whether the semiconductor is caused to be N or P-type, by the presence of applied gate voltage field induced carriers in essentially intrinsic, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at substantially equal doping levels, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at different doping levels, and containing a single metallurgical doping type, and functional combinations thereof. In particular, inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to conventional multiple device CMOS systems, which can be operated as modulators, are disclosed as are a non-latching SCR and an approach to blocking parasitic currents utilizing material(s) which form rectifying junctions with both N and P-type semiconductor whether metallurigically or field induced.

EDITORIAL The 23rd Nordic Semiconductor Meeting The 23rd Nordic Semiconductor Meeting

NASA Astrophysics Data System (ADS)

Ólafsson, Sveinn; Sveinbjörnsson, Einar

2010-12-01

A Nordic Semiconductor Meeting is held every other year with the venue rotating amongst the Nordic countries of Denmark, Finland, Iceland, Norway and Sweden. The focus of these meetings remains 'original research and science being carried out on semiconductor materials, devices and systems'. Reports on industrial activity have usually featured. The topics have ranged from fundamental research on point defects in a semiconductor to system architecture of semiconductor electronic devices. Proceedings from these events are regularly published as a topical issue of Physica Scripta. All of the papers in this topical issue have undergone critical peer review and we wish to thank the reviewers and the authors for their cooperation, which has been instrumental in meeting the high scientific standards and quality of the series. This meeting of the 23rd Nordic Semiconductor community, NSM 2009, was held at Háskólatorg at the campus of the University of Iceland, Reykjavik, Iceland, 14-17 June 2009. Support was provided by the University of Iceland. Almost 50 participants presented a broad range of topics covering semiconductor materials and devices as well as related material science interests. The conference provided a forum for Nordic and international scientists to present and discuss new results and ideas concerning the fundamentals and applications of semiconductor materials. The meeting aim was to advance the progress of Nordic science and thus aid in future worldwide technological advances concerning technology, education, energy and the environment. Topics Theory and fundamental physics of semiconductors Emerging semiconductor technologies (for example III-V integration on Si, novel Si devices, graphene) Energy and semiconductors Optical phenomena and optical devices MEMS and sensors Program 14 June Registration 13:00-17:00 15 June Meeting program 09:30-17:00 and Poster Session I 16 June Meeting program 09:30-17:00 and Poster Session II 17 June Excursion and dinner on Icelandic National Day In connection with the conference, a summer school for 40 research students was organized by the Nordic LENS network. The summer school took place in Reykjavik on 11-14 June. For more information on the school please visit the website. The next Nordic Semiconductor meeting, NSM 2011, is scheduled to take place in Aarhus, Denmark, 19-22 June 2011. A full participant list is available in the PDF of this article.

Experimental demonstration of a multi-wavelength distributed feedback semiconductor laser array with an equivalent chirped grating profile based on the equivalent chirp technology.

PubMed

Li, Wangzhe; Zhang, Xia; Yao, Jianping

2013-08-26

We report, to the best of our knowledge, the first realization of a multi-wavelength distributed feedback (DFB) semiconductor laser array with an equivalent chirped grating profile based on equivalent chirp technology. All the lasers in the laser array have an identical grating period with an equivalent chirped grating structure, which are realized by nonuniform sampling of the gratings. Different wavelengths are achieved by changing the sampling functions. A multi-wavelength DFB semiconductor laser array is fabricated and the lasing performance is evaluated. The results show that the equivalent chirp technology is an effective solution for monolithic integration of a multi-wavelength laser array with potential for large volume fabrication.

Interplay of Phonon and Exciton-Mediated Superconductivity in Hybrid Semiconductor-Superconductor Structures.

PubMed

Skopelitis, Petros; Cherotchenko, Evgenia D; Kavokin, Alexey V; Posazhennikova, Anna

2018-03-09

We predict a strong enhancement of the critical temperature in a conventional Bardeen-Cooper-Schrieffer (BCS) superconductor in the presence of a bosonic condensate of exciton polaritons. The effect depends strongly on the ratio of the cutoff frequencies for phonon and exciton-polariton mediated BCS superconductivity, respectively. We also discuss a possible design of hybrid semiconductor-superconductor structures suitable for the experimental observation of such an effect.

Electronic structure of the organic semiconductor copper phthalocyanine: experiment and theory.

PubMed

Aristov, V Yu; Molodtsova, O V; Maslyuk, V V; Vyalikh, D V; Zhilin, V M; Ossipyan, Yu A; Bredow, T; Mertig, I; Knupfer, M

2008-01-21

The electronic structure of the organic semiconductor copper-phthalocyanine (CuPc) has been determined by a combination of conventional and resonant photoemission, near-edge x-ray absorption, as well as by the first-principles calculations. The experimentally obtained electronic valence band structure of CuPc is in very good agreement with the calculated density of states results, allowing the derivation of detailed site specific information.

Interplay of Phonon and Exciton-Mediated Superconductivity in Hybrid Semiconductor-Superconductor Structures

NASA Astrophysics Data System (ADS)

Skopelitis, Petros; Cherotchenko, Evgenia D.; Kavokin, Alexey V.; Posazhennikova, Anna

2018-03-01

We predict a strong enhancement of the critical temperature in a conventional Bardeen-Cooper-Schrieffer (BCS) superconductor in the presence of a bosonic condensate of exciton polaritons. The effect depends strongly on the ratio of the cutoff frequencies for phonon and exciton-polariton mediated BCS superconductivity, respectively. We also discuss a possible design of hybrid semiconductor-superconductor structures suitable for the experimental observation of such an effect.

X-ray topography as a process control tool in semiconductor and microcircuit manufacture

NASA Technical Reports Server (NTRS)

Parker, D. L.; Porter, W. A.

1977-01-01

A bent wafer camera, designed to identify crystal lattice defects in semiconductor materials, was investigated. The camera makes use of conventional X-ray topographs and an innovative slightly bent wafer which allows rays from the point source to strike all portions of the wafer simultaneously. In addition to being utilized in solving production process control problems, this camera design substantially reduces the cost per topograph.

Cancer and reproductive risks in the semiconductor industry.

PubMed

LaDou, Joseph; Bailar, John C

2007-01-01

Although many reproductive toxicants and carcinogens are used in the manufacture of semiconductor chips, and worrisome findings have been reported, no broad epidemiologic study has been conducted to define possible risks in a comprehensive way. With few exceptions, the American semiconductor industry has not supported access for independent studies. Older technologies are exported to newly industrialized countries as newer technologies are installed in Japan, the United States, and Europe. Thus there is particular concern about the many workers, mostly in countries that are still industrializing, who have jobs that use chemicals, technologies, and equipment that are no longer in use in developed countries. Since most countries lack cancer registries and have inadequate reproductive and cancer reporting mechanisms, industry efforts to control exposures to carcinogens are of particular importance. Government agencies, the courts, industry, publishers, and academia, on occasion, collude to ignore or to downplay the importance of occupational diseases. Examples of how this happens in the semiconductor industry are presented.

Automated imprint mask cleaning for step-and-flash imprint lithography

NASA Astrophysics Data System (ADS)

Singh, Sherjang; Chen, Ssuwei; Selinidis, Kosta; Fletcher, Brian; McMackin, Ian; Thompson, Ecron; Resnick, Douglas J.; Dress, Peter; Dietze, Uwe

2009-03-01

Step-and-Flash Imprint Lithography (S-FIL) is a promising lithography strategy for semiconductor manufacturing at device nodes below 32nm. The S-FIL 1:1 pattern transfer technology utilizes a field-by-field ink jet dispense of a low viscosity liquid resist to fill the relief pattern of the device layer etched into the glass mask. Compared to other sub 40nm CD lithography methods, the resulting high resolution, high throughput through clustering, 3D patterning capability, low process complexity, and low cost of ownership (CoO) of S-FIL makes it a widely accepted technology for patterned media as well as a promising mainstream option for future CMOS applications. Preservation of mask cleanliness is essential to avoid risk of repeated printing of defects. The development of mask cleaning processes capable of removing particles adhered to the mask surface without damaging the mask is critical to meet high volume manufacturing requirements. In this paper we have presented various methods of residual (cross-linked) resist removal and final imprint mask cleaning demonstrated on the HamaTech MaskTrack automated mask cleaning system. Conventional and non-conventional (acid free) methods of particle removal have been compared and the effect of mask cleaning on pattern damage and CD integrity is also studied.

Increased Biocompatibility and Bioactivity after Energetic PVD Surface Treatments

PubMed Central

Mändl, Stephan

2009-01-01

Ion implantation, a common technology in semiconductor processing, has been applied to biomaterials since the 1960s. Using energetic ion bombardment, a general term which includes conventional ion implantation plasma immersion ion implantation (PIII) and ion beam assisted thin film deposition, functionalization of surfaces is possible. By varying and adjusting the process parameters, several surface properties can be attuned simultaneously. Extensive research details improvements in the biocompatibility, mainly by reducing corrosion rates and increasing wear resistance after surface modification. Recently, enhanced bioactivity strongly correlated with the surface topography and less with the surface chemistry has been reported, with an increased roughness on the nanometer scale induced by self-organisation processes during ion bombardment leading to faster cellular adhesion processes.

On the Fabrication and Behavior of Diamond Microelectromechanical Sensors (DMEMS)

NASA Technical Reports Server (NTRS)

Holmes, K.; Davidson, J. L.; Kang, W. P.; Howell, M.

2001-01-01

CVD (chemically vapor deposited) diamond films can be processed similar to "conventional" semiconductor device fabrication and as such can be used to achieve microelectromechanical structures (MEMS) also similar to, for example, silicon technology. Very small cantilever beams, membranes, stripes, tips, etc. can be constructed in doped and undoped diamond films and offer an array of choices in diamond with its known superior properties such as elastic modulus, high temperature semiconduction, high thermal conductivity, very low coefficient of expansion and numerous other diamond parameters. This paper will review the construction and behavior of the second generation DMEMS devices comprised as an accelerometer with a diamond diaphragm for use in very high G applications and a diamond pressure sensor for very high temperature and frequency response.

Compressive Sensing Image Sensors-Hardware Implementation

PubMed Central

Dadkhah, Mohammadreza; Deen, M. Jamal; Shirani, Shahram

2013-01-01

The compressive sensing (CS) paradigm uses simultaneous sensing and compression to provide an efficient image acquisition technique. The main advantages of the CS method include high resolution imaging using low resolution sensor arrays and faster image acquisition. Since the imaging philosophy in CS imagers is different from conventional imaging systems, new physical structures have been developed for cameras that use the CS technique. In this paper, a review of different hardware implementations of CS encoding in optical and electrical domains is presented. Considering the recent advances in CMOS (complementary metal–oxide–semiconductor) technologies and the feasibility of performing on-chip signal processing, important practical issues in the implementation of CS in CMOS sensors are emphasized. In addition, the CS coding for video capture is discussed. PMID:23584123

A strain-isolation design for stretchable electronics

NASA Astrophysics Data System (ADS)

Wu, Jian; Li, Ming; Chen, Wei-Qiu; Kim, Dae-Hyeong; Kim, Yun-Soung; Huang, Yong-Gang; Hwang, Keh-Chih; Kang, Zhan; Rogers, John A.

2010-12-01

Stretchable electronics represents a direction of recent development in next-generation semiconductor devices. Such systems have the potential to offer the performance of conventional wafer-based technologies, but they can be stretched like a rubber band, twisted like a rope, bent over a pencil, and folded like a piece of paper. Isolating the active devices from strains associated with such deformations is an important aspect of design. One strategy involves the shielding of the electronics from deformation of the substrate through insertion of a compliant adhesive layer. This paper establishes a simple, analytical model and validates the results by the finite element method. The results show that a relatively thick, compliant adhesive is effective to reduce the strain in the electronics, as is a relatively short film.

Bibliography of Soviet Laser Developments, No. 18, October - December 1974

DTIC Science & Technology

1975-04-25

IIV Lasers, Laser Theory , Laser Biological Effects, Laser Communications, Laser Computer Technology, Holography, Laser Chemical Effects...spectros.copy of laser materials; ultrashort pulse generation; crystal growing; theoretical aspects of advanced lasers; and general laser theory Laser...Semiconductor: Mixed Junction 5 6. Semiconductor: Heterojunction ^ 7. Semiconductor: Theory 8. Nd:Glass B. Liquid Lasers 1

Advanced 3-V semiconductor technology assessment. [space communications

NASA Technical Reports Server (NTRS)

Nowogrodzki, M.

1983-01-01

Against a background of an extensive survey of the present state of the art in the field of III-V semiconductors for operation at microwave frequencies (or gigabit rate speeds), likely requirements of future space communications systems are identified, competing technologies and physical device limitations are discussed, and difficulties in implementing emerging technologies are projected. On the basis of these analyses, specific research and development programs required for the development of future systems components are recommended.

Lateral resolution improvement in scanning nonlinear dielectric microscopy by measuring super-higher-order nonlinear dielectric constants

NASA Astrophysics Data System (ADS)

Chinone, N.; Yamasue, K.; Hiranaga, Y.; Honda, K.; Cho, Y.

2012-11-01

Scanning nonlinear dielectric microscopy (SNDM) can be used to visualize polarization distributions in ferroelectric materials and dopant profiles in semiconductor devices. Without using a special sharp tip, we achieved an improved lateral resolution in SNDM through the measurement of super-higher-order nonlinearity up to the fourth order. We observed a multidomain single crystal congruent LiTaO3 (CLT) sample, and a cross section of a metal-oxide-semiconductor (MOS) field-effect-transistor (FET). The imaged domain boundaries of the CLT were narrower in the super-higher-order images than in the conventional image. Compared to the conventional method, the super-higher-order method resolved the more detailed structure of the MOSFET.

Strongly exchange-coupled triplet pairs in an organic semiconductor

NASA Astrophysics Data System (ADS)

Weiss, Leah R.; Bayliss, Sam L.; Kraffert, Felix; Thorley, Karl J.; Anthony, John E.; Bittl, Robert; Friend, Richard H.; Rao, Akshay; Greenham, Neil C.; Behrends, Jan

2017-02-01

From biological complexes to devices based on organic semiconductors, spin interactions play a key role in the function of molecular systems. For instance, triplet-pair reactions impact operation of organic light-emitting diodes as well as photovoltaic devices. Conventional models for triplet pairs assume they interact only weakly. Here, using electron spin resonance, we observe long-lived, strongly interacting triplet pairs in an organic semiconductor, generated via singlet fission. Using coherent spin manipulation of these two-triplet states, we identify exchange-coupled (spin-2) quintet complexes coexisting with weakly coupled (spin-1) triplets. We measure strongly coupled pairs with a lifetime approaching 3 μs and a spin coherence time approaching 1 μs, at 10 K. Our results pave the way for the utilization of high-spin systems in organic semiconductors.

Will Future Measurement Needs of the Semiconductor Industry Be Met?

PubMed

Bennett, Herbert S

2007-01-01

We discuss the ability of the nation's measurement system to meet future metrology needs of the semiconductor industry. Lacking an acceptable metric for assessing the health of metrology for the semiconductor industry, we identify a limited set of unmet measurement needs. Assuming that this set of needs may serve as proxy for the galaxy of semiconductor measurement needs, we examine it from the perspective of what will be required to continue the semiconductor industry's powerful impact in the world's macro-economy and maintain its exceptional record of numerous technological innovations. This paper concludes with suggestions about ways to strengthen the measurement system for the semiconductor industry.

Silicon carbide semiconductor technology for high temperature and radiation environments

NASA Technical Reports Server (NTRS)

Matus, Lawrence G.

1993-01-01

Viewgraphs on silicon carbide semiconductor technology and its potential for enabling electronic devices to function in high temperature and high radiation environments are presented. Topics covered include silicon carbide; sublimation growth of 6H-SiC boules; SiC chemical vapor deposition reaction system; 6H silicon carbide p-n junction diode; silicon carbide MOSFET; and silicon carbide JFET radiation response.

Microelectronics used for Semiconductor Imaging Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heijne, Erik H. M.

Semiconductor crystal technology, microelectronics developments and nuclear particle detection have been in a relation of symbiosis, all the way from the beginning. The increase of complexity in electronics chips can now be applied to obtain much more information on the incident nuclear radiation. Some basic technologies are described, in order to acquire insight in possibilities and limitations for the most recent detectors.

GUARD RING SEMICONDUCTOR JUNCTION

DOEpatents

Goulding, F.S.; Hansen, W.L.

1963-12-01

A semiconductor diode having a very low noise characteristic when used under reverse bias is described. Surface leakage currents, which in conventional diodes greatly contribute to noise, are prevented from mixing with the desired signal currents. A p-n junction is formed with a thin layer of heavily doped semiconductor material disposed on a lightly doped, physically thick base material. An annular groove cuts through the thin layer and into the base for a short distance, dividing the thin layer into a peripheral guard ring that encircles the central region. Noise signal currents are shunted through the guard ring, leaving the central region free from such currents. (AEC)

A Study of 4-level DC-DC Boost Inverter with Passive Component Reduction Consideration

NASA Astrophysics Data System (ADS)

Kasiran, A. N.; Ponniran, A.; Harimon, M. A.; Hamzah, H. H.

2018-04-01

This study is to analyze design principles of boost inductor and capacitor used in the 4-level DC-DC boost converter to realize size reduction of passive component referring to their attributes. The important feature of this circuit is that most of the boost-up energy is transferred from the capacitor-clamped to the output side which the small inductance can be used at the input side. The inductance of the boost inductor is designed by referring the inductor current ripple. On the other hand, the capacitance of the capacitor-clamped is designed by considering voltage stress on semiconductor devices and also the used switching frequency. Besides that, according to the design specifications, the required inductance in 4-level DC-DC boost converter is decreased compared to a conventional conventional DC-DC boost converter. Meanwhile, voltage stress on semiconductor device is depending on the maximum voltage ripple of the capacitor-clamped. A 50 W 4-level DC-DC boost converter prototype has been constructed. The results show that the inductor current ripple was 1.15 A when the inductors, 1 mH and 0.11 mH were used in the conventional and 4-level DC-DC boost converters, respectively. Thus, based on the experimental results, it shows that the reduction of passive components by referring to their attributes in 4-level DC-DC boost converter is achieved. Moreover, the decreasing of voltage stress on the semiconductor devices is an advantage for the selection of low ON-resistance of the devices which will contribute to the reduction of the semiconductor conduction loss. The integration result of boost converter and H-bridge inverter is also shown.

Thermal Flow Sensors for Harsh Environments.

PubMed

Balakrishnan, Vivekananthan; Phan, Hoang-Phuong; Dinh, Toan; Dao, Dzung Viet; Nguyen, Nam-Trung

2017-09-08

Flow sensing in hostile environments is of increasing interest for applications in the automotive, aerospace, and chemical and resource industries. There are thermal and non-thermal approaches for high-temperature flow measurement. Compared to their non-thermal counterparts, thermal flow sensors have recently attracted a great deal of interest due to the ease of fabrication, lack of moving parts and higher sensitivity. In recent years, various thermal flow sensors have been developed to operate at temperatures above 500 °C. Microelectronic technologies such as silicon-on-insulator (SOI), and complementary metal-oxide semiconductor (CMOS) have been used to make thermal flow sensors. Thermal sensors with various heating and sensing materials such as metals, semiconductors, polymers and ceramics can be selected according to the targeted working temperature. The performance of these thermal flow sensors is evaluated based on parameters such as thermal response time, flow sensitivity. The data from thermal flow sensors reviewed in this paper indicate that the sensing principle is suitable for the operation under harsh environments. Finally, the paper discusses the packaging of the sensor, which is the most important aspect of any high-temperature sensing application. Other than the conventional wire-bonding, various novel packaging techniques have been developed for high-temperature application.

Novel growth techniques of group-IV based semiconductors on insulator for next-generation electronics

NASA Astrophysics Data System (ADS)

Miyao, Masanobu; Sadoh, Taizoh

2017-05-01

Recent progress in the crystal growth of group-IV-based semiconductor-on-insulators is reviewed from physical and technological viewpoints. Liquid-phase growth based on SiGe-mixing-triggered rapid-melting growth enables formation of hybrid (100) (110) (111)-orientation Ge-on-insulator (GOI) structures, which show defect-free GOI with very high carrier mobility (˜1040 cm2 V-1 s-1). Additionally, SiGe mixed-crystals with laterally uniform composition were obtained by eliminating segregation phenomena during the melt-back process. Low-temperature solid-phase growth has been explored by combining this process with ion-beam irradiation, additional doping of group-IV elements, metal induced lateral crystallization with/without electric field, and metal-induced layer exchange crystallization. These efforts have enabled crystal growth on insulators below 400 °C, achieving high carrier mobility (160-320 cm2 V-1 s-1). Moreover, orientation-controlled SiGe and Ge films on insulators have been obtained below the softening temperatures of conventional plastic films (˜300 °C). Detailed characterization provides an understanding of physical phenomena behind these crystal growth techniques. Applying these methods when fabricating next-generation electronics is also discussed.

Thermal Flow Sensors for Harsh Environments

PubMed Central

Dinh, Toan; Dao, Dzung Viet

2017-01-01

Flow sensing in hostile environments is of increasing interest for applications in the automotive, aerospace, and chemical and resource industries. There are thermal and non-thermal approaches for high-temperature flow measurement. Compared to their non-thermal counterparts, thermal flow sensors have recently attracted a great deal of interest due to the ease of fabrication, lack of moving parts and higher sensitivity. In recent years, various thermal flow sensors have been developed to operate at temperatures above 500 °C. Microelectronic technologies such as silicon-on-insulator (SOI), and complementary metal-oxide semiconductor (CMOS) have been used to make thermal flow sensors. Thermal sensors with various heating and sensing materials such as metals, semiconductors, polymers and ceramics can be selected according to the targeted working temperature. The performance of these thermal flow sensors is evaluated based on parameters such as thermal response time, flow sensitivity. The data from thermal flow sensors reviewed in this paper indicate that the sensing principle is suitable for the operation under harsh environments. Finally, the paper discusses the packaging of the sensor, which is the most important aspect of any high-temperature sensing application. Other than the conventional wire-bonding, various novel packaging techniques have been developed for high-temperature application. PMID:28885595

Lithography for enabling advances in integrated circuits and devices.

PubMed

Garner, C Michael

2012-08-28

Because the transistor was fabricated in volume, lithography has enabled the increase in density of devices and integrated circuits. With the invention of the integrated circuit, lithography enabled the integration of higher densities of field-effect transistors through evolutionary applications of optical lithography. In 1994, the semiconductor industry determined that continuing the increase in density transistors was increasingly difficult and required coordinated development of lithography and process capabilities. It established the US National Technology Roadmap for Semiconductors and this was expanded in 1999 to the International Technology Roadmap for Semiconductors to align multiple industries to provide the complex capabilities to continue increasing the density of integrated circuits to nanometre scales. Since the 1960s, lithography has become increasingly complex with the evolution from contact printers, to steppers, pattern reduction technology at i-line, 248 nm and 193 nm wavelengths, which required dramatic improvements of mask-making technology, photolithography printing and alignment capabilities and photoresist capabilities. At the same time, pattern transfer has evolved from wet etching of features, to plasma etch and more complex etching capabilities to fabricate features that are currently 32 nm in high-volume production. To continue increasing the density of devices and interconnects, new pattern transfer technologies will be needed with options for the future including extreme ultraviolet lithography, imprint technology and directed self-assembly. While complementary metal oxide semiconductors will continue to be extended for many years, these advanced pattern transfer technologies may enable development of novel memory and logic technologies based on different physical phenomena in the future to enhance and extend information processing.

Post exposure bake unit equipped with wafer-shape compensation technology

NASA Astrophysics Data System (ADS)

Goto, Shigehiro; Morita, Akihiko; Oyama, Kenichi; Hori, Shimpei; Matsuchika, Keiji; Taniguchi, Hideyuki

2007-03-01

In 193nm lithography, it is well known that Critical Dimension Uniformity (CDU) within wafer is especially influenced by temperature variation during Post Exposure Bake (PEB) process. This temperature variation has been considered to be caused by the hot plate unit, and improvement of temperature uniformity within hot plate itself has been focused to achieve higher CDU. However, we have found that the impact of the wafer shape on temperature uniformity within wafer can not be ignored when the conventional PEB processing system is applied to an advanced resist technology. There are two factors concerned with the wafer shape. First, gravity force of the wafer itself generates wafer shape bending because wafer is simply supported by a few proximity gaps on the conventional hot plate. Next, through the semiconductor manufacturing process, wafer is gradually warped due to the difference of the surface stress between silicon and deposited film layers (Ex. Si-Oxide, Si-Nitride). Therefore, the variation of the clearance between wafer backside and hot plate surface leads to non-uniform thermal conductivity within wafer during PEB processing, and eventually impacts on the CDU within wafer. To overcome this problem concerned with wafer shape during PEB processing, we have developed the new hot plate equipped with the wafer shape compensation technology. As a result of evaluation, we have confirmed that this new PEB system has an advantage not only for warped wafer but also for flat (bare) wafer.

Chemical vapor deposition and characterization of polysilanes polymer based thin films and their applications in compound semiconductors and silicon devices

NASA Astrophysics Data System (ADS)

Oulachgar, El Hassane

As the semiconductors industry is moving toward nanodevices, there is growing need to develop new materials and thin films deposition processes which could enable strict control of the atomic composition and structure of thin film materials in order to achieve precise control on their electrical and optical properties. The accurate control of thin film characteristics will become increasingly important as the miniaturization of semiconductor devices continue. There is no doubt that chemical synthesis of new materials and their self assembly will play a major role in the design and fabrication of next generation semiconductor devices. The objective of this work is to investigate the chemical vapor deposition (CVD) process of thin film using a polymeric precursor as a source material. This process offers many advantages including low deposition cost, hazard free working environment, and most importantly the ability to customize the polymer source material through polymer synthesis and polymer functionalization. The combination between polymer synthesis and CVD process will enable the design of new generation of complex thin film materials with a wide range of improved chemical, mechanical, electrical and optical properties which cannot be easily achieved through conventional CVD processes based on gases and small molecule precursors. In this thesis we mainly focused on polysilanes polymers and more specifically poly(dimethylsilanes). The interest in these polymers is motivated by their distinctive electronic and photonic properties which are attributed to the delocalization of the sigma-electron along the Si-Si backbone chain. These characteristics make polysilane polymers very promising in a broad range of applications as a dielectric, a semiconductor and a conductor. The polymer-based CVD process could be eventually extended to other polymer source materials such as polygermanes, as well as and a variety of other inorganic and hybrid organic-inorganic polymers. This work has demonstrated that a polysilane polymeric source can be used to deposit a wide range of thin film materials exhibiting similar properties with conventional ceramic materials such as silicon carbide (SiC), silicon oxynitride (SiON), silicon oxycarbide (SiOC) silicon dioxide (SiO2) and silicon nitride (Si3N4). The strict control of the deposition process allows precise control of the electrical, optical and chemical properties of polymer-based thin films within a broad range. This work has also demonstrated for the first time that poly(dimethylsilmaes) polymers deposited by CVD can be used to effectively passivate both silicon and gallium arsenide MOS devices. This finding makes polymer-based thin films obtained by CVD very promising for the development of high-kappa dielectric materials for next generation high-mobility CMOS technology. Keywords. Thin films, Polymers, Vapor Phase Deposition, CVD, Nanodielectrics, Organosilanes, Polysilanes, GaAs Passivation, MOSFET, Silicon Oxynitride, Integrated Waveguide, Silicon Carbide, Compound Semiconductors.

New developments in power semiconductors

NASA Technical Reports Server (NTRS)

Sundberg, G. R.

1983-01-01

This paper represents an overview of some recent power semiconductor developments and spotlights new technologies that may have significant impact for aircraft electric secondary power. Primary emphasis will be on NASA-Lewis-supported developments in transistors, diodes, a new family of semiconductors, and solid-state remote power controllers. Several semiconductor companies that are moving into the power arena with devices rated at 400 V and 50 A and above are listed, with a brief look at a few devices.

Organic Spin-Valves and Beyond: Spin Injection and Transport in Organic Semiconductors and the Effect of Interfacial Engineering.

PubMed

Jang, Hyuk-Jae; Richter, Curt A

2017-01-01

Since the first observation of the spin-valve effect through organic semiconductors, efforts to realize novel spintronic technologies based on organic semiconductors have been rapidly growing. However, a complete understanding of spin-polarized carrier injection and transport in organic semiconductors is still lacking and under debate. For example, there is still no clear understanding of major spin-flip mechanisms in organic semiconductors and the role of hybrid metal-organic interfaces in spin injection. Recent findings suggest that organic single crystals can provide spin-transport media with much less structural disorder relative to organic thin films, thus reducing momentum scattering. Additionally, modification of the band energetics, morphology, and even spin magnetic moment at the metal-organic interface by interface engineering can greatly impact the efficiency of spin-polarized carrier injection. Here, progress on efficient spin-polarized carrier injection into organic semiconductors from ferromagnetic metals by using various interface engineering techniques is presented, such as inserting a metallic interlayer, a molecular self-assembled monolayer (SAM), and a ballistic carrier emitter. In addition, efforts to realize long spin transport in single-crystalline organic semiconductors are discussed. The focus here is on understanding and maximizing spin-polarized carrier injection and transport in organic semiconductors and insight is provided for the realization of emerging organic spintronics technologies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Ultrathin Single Crystalline Relaxor Ferroelectric Integrated on a High Mobility Semiconductor.

PubMed

Moghadam, Reza M; Xiao, Zhiyong; Ahmadi-Majlan, Kamyar; Grimley, Everett D; Bowden, Mark; Ong, Phuong-Vu; Chambers, Scott A; Lebeau, James M; Hong, Xia; Sushko, Peter V; Ngai, Joseph H

2017-10-11

The epitaxial growth of multifunctional oxides on semiconductors has opened a pathway to introduce new functionalities to semiconductor device technologies. In particular, the integration of gate materials that enable nonvolatile or hysteretic functionality in field-effect transistors could lead to device technologies that consume less power or allow for novel modalities in computing. Here we present electrical characterization of ultrathin single crystalline SrZr x Ti 1-x O 3 (x = 0.7) films epitaxially grown on a high mobility semiconductor, Ge. Epitaxial films of SrZr x Ti 1-x O 3 exhibit relaxor behavior, characterized by a hysteretic polarization that can modulate the surface potential of Ge. We find that gate layers as thin as 5 nm corresponding to an equivalent-oxide thickness of just 1.0 nm exhibit a ∼2 V hysteretic window in the capacitance-voltage characteristics. The development of hysteretic metal-oxide-semiconductor capacitors with nanoscale gate thicknesses opens new vistas for nanoelectronic devices.

Electron gas grid semiconductor radiation detectors

DOEpatents

Lee, Edwin Y.; James, Ralph B.

2002-01-01

An electron gas grid semiconductor radiation detector (EGGSRAD) useful for gamma-ray and x-ray spectrometers and imaging systems is described. The radiation detector employs doping of the semiconductor and variation of the semiconductor detector material to form a two-dimensional electron gas, and to allow transistor action within the detector. This radiation detector provides superior energy resolution and radiation detection sensitivity over the conventional semiconductor radiation detector and the "electron-only" semiconductor radiation detectors which utilize a grid electrode near the anode. In a first embodiment, the EGGSRAD incorporates delta-doped layers adjacent the anode which produce an internal free electron grid well to which an external grid electrode can be attached. In a second embodiment, a quantum well is formed between two of the delta-doped layers, and the quantum well forms the internal free electron gas grid to which an external grid electrode can be attached. Two other embodiments which are similar to the first and second embodiment involve a graded bandgap formed by changing the composition of the semiconductor material near the first and last of the delta-doped layers to increase or decrease the conduction band energy adjacent to the delta-doped layers.

A silicon-on-insulator complementary-metal-oxide-semiconductor compatible flexible electronics technology

NASA Astrophysics Data System (ADS)

Tu, Hongen; Xu, Yong

2012-07-01

This paper reports a simple flexible electronics technology that is compatible with silicon-on-insulator (SOI) complementary-metal-oxide-semiconductor (CMOS) processes. Compared with existing technologies such as direct fabrication on flexible substrates and transfer printing, the main advantage of this technology is its post-SOI-CMOS compatibility. Consequently, high-performance and high-density CMOS circuits can be first fabricated on SOI wafers using commercial foundry and then be integrated into flexible substrates. The yield is also improved by eliminating the transfer printing step. Furthermore, this technology allows the integration of various sensors and microfluidic devices. To prove the concept of this technology, flexible MOSFETs have been demonstrated.

Designing new classes of high-power, high-brightness VECSELs

NASA Astrophysics Data System (ADS)

Moloney, J. V.; Zakharian, A. R.; Hader, J.; Koch, Stephan W.

2005-10-01

Optically-pumped vertical external cavity semiconductor lasers offer the exciting possibility of designing kW-class solid state lasers that provide significant advantages over their doped YAG, thin-disk YAG and fiber counterparts. The basic VECSEL/OPSL (optically-pumped semiconductor laser) structure consists of a very thin (approximately 6 micron thick) active mirror consisting of a DBR high-reflectivity stack followed by a multiple quantum well resonant periodic (RPG) structure. An external mirror (reflectivity typically between 94%-98%) provides conventional optical feedback to the active semiconductor mirror chip. The "cold" cavity needs to be designed to take into account the semiconductor sub-cavity resonance shift with temperature and, importantly, the more rapid shift of the semiconductor material gain peak with temperature. Thermal management proves critical in optimizing the device for serious power scaling. We will describe a closed-loop procedure that begins with a design of the semiconductor active epi structure. This feeds into the sub-cavity optimization, optical and thermal transport within the active structure and thermal transport though the various heat sinking elements. Novel schemes for power scaling beyond current record performances will be discussed.

Time-Resolved Photoluminescence Microscopy for the Analysis of Semiconductor-Based Paint Layers

PubMed Central

Mosca, Sara; Gonzalez, Victor; Eveno, Myriam

2017-01-01

In conservation, science semiconductors occur as the constituent matter of the so-called semiconductor pigments, produced following the Industrial Revolution and extensively used by modern painters. With recent research highlighting the occurrence of various degradation phenomena in semiconductor paints, it is clear that their detection by conventional optical fluorescence imaging and microscopy is limited by the complexity of historical painting materials. Here, we illustrate and prove the capabilities of time-resolved photoluminescence (TRPL) microscopy, equipped with both spectral and lifetime sensitivity at timescales ranging from nanoseconds to hundreds of microseconds, for the analysis of cross-sections of paint layers made of luminescent semiconductor pigments. The method is sensitive to heterogeneities within micro-samples and provides valuable information for the interpretation of the nature of the emissions in samples. A case study is presented on micro samples from a painting by Henri Matisse and serves to demonstrate how TRPL can be used to identify the semiconductor pigments zinc white and cadmium yellow, and to inform future investigations of the degradation of a cadmium yellow paint. PMID:29160862

Electrical Characterization of Semiconductor Materials and Devices

NASA Astrophysics Data System (ADS)

Deen, M.; Pascal, Fabien

Semiconductor materials and devices continue to occupy a preeminent technological position due to their importance when building integrated electronic systems used in a wide range of applications from computers, cell-phones, personal digital assistants, digital cameras and electronic entertainment systems, to electronic instrumentation for medical diagnositics and environmental monitoring. Key ingredients of this technological dominance have been the rapid advances made in the quality and processing of materials - semiconductors, conductors and dielectrics - which have given metal oxide semiconductor device technology its important characteristics of negligible standby power dissipation, good input-output isolation, surface potential control and reliable operation. However, when assessing material quality and device reliability, it is important to have fast, nondestructive, accurate and easy-to-use electrical characterization techniques available, so that important parameters such as carrier doping density, type and mobility of carriers, interface quality, oxide trap density, semiconductor bulk defect density, contact and other parasitic resistances and oxide electrical integrity can be determined. This chapter describes some of the more widely employed and popular techniques that are used to determine these important parameters. The techniques presented in this chapter range in both complexity and test structure requirements from simple current-voltage measurements to more sophisticated low-frequency noise, charge pumping and deep-level transient spectroscopy techniques.

A novel productivity-driven logic element for field-programmable devices

NASA Astrophysics Data System (ADS)

Marconi, Thomas; Bertels, Koen; Gaydadjiev, Georgi

2014-06-01

Although various techniques have been proposed for power reduction in field-programmable devices (FPDs), they are still all based on conventional logic elements (LEs). In the conventional LE, the output of the combinational logic (e.g. the look-up table (LUT) in many field-programmable gate arrays (FPGAs)) is connected to the input of the storage element; while the D flip-flop (DFF) is always clocked even when not necessary. Such unnecessary transitions waste power. To address this problem, we propose a novel productivity-driven LE with reduced number of transitions. The differences between our LE and the conventional LE are in the FFs-type used and the internal LE organisation. In our LEs, DFFs have been replaced by T flip-flops with the T input permanently connected to logic value 1. Instead of connecting the output of the combinational logic to the FF input, we use it as the FF clock. The proposed LE has been validated via Simulation Program with Integrated Circuit Emphasis (SPICE) simulations for a 45-nm Complementary Metal-Oxide-Semiconductor (CMOS) technology as well as via a real Computer-Aided Design (CAD) tools on a real FPGA using the standard Microelectronic Center of North Carolina (MCNC) benchmark circuits. The experimental results show that FPDs using our proposal not only have 48% lower total power but also run 17% faster than conventional FPDs on average.

Evolution of corundum-structured III-oxide semiconductors: Growth, properties, and devices

NASA Astrophysics Data System (ADS)

Fujita, Shizuo; Oda, Masaya; Kaneko, Kentaro; Hitora, Toshimi

2016-12-01

The recent progress and development of corundum-structured III-oxide semiconductors are reviewed. They allow bandgap engineering from 3.7 to ∼9 eV and function engineering, leading to highly durable electronic devices and deep ultraviolet optical devices as well as multifunctional devices. Mist chemical vapor deposition can be a simple and safe growth technology and is advantageous for reducing energy and cost for the growth. This is favorable for the wide commercial use of devices at low cost. The III-oxide semiconductors are promising candidates for new devices contributing to sustainable social, economic, and technological development for the future.

Transition-Metal Substitution Doping in Synthetic Atomically Thin Semiconductors

DOE PAGES

Gao, Jian; Kim, Young Duck; Liang, Liangbo; ...

2016-09-20

Semiconductor impurity doping has enabled an entire generation of technology. The emergence of alternative semiconductor material systems, such as transition metal dichalcogenides (TMDCs), requires the development of scalable doping strategies. We report an unprecedented one-pot synthesis for transition-metal substitution in large-area, synthetic monolayer TMDCs. Electron microscopy, optical and electronic transport characterization and ab initio calculations indicate that our doping strategy preserves the attractive qualities of TMDC monolayers, including semiconducting transport and strong direct-gap luminescence. These results are expected to encourage exploration of transition-metal substitution in two-dimensional systems, potentially enabling next-generation optoelectronic technology in the atomically-thin regime.

Will Future Measurement Needs of the Semiconductor Industry Be Met?

PubMed Central

Bennett, Herbert S.

2007-01-01

We discuss the ability of the nation’s measurement system to meet future metrology needs of the semiconductor industry. Lacking an acceptable metric for assessing the health of metrology for the semiconductor industry, we identify a limited set of unmet measurement needs. Assuming that this set of needs may serve as proxy for the galaxy of semiconductor measurement needs, we examine it from the perspective of what will be required to continue the semiconductor industry’s powerful impact in the world’s macro-economy and maintain its exceptional record of numerous technological innovations. This paper concludes with suggestions about ways to strengthen the measurement system for the semiconductor industry. PMID:27110452

Bringing order to the world of nanowire devices by phase shift lithography.

PubMed

Subannajui, Kittitat; Güder, Firat; Zacharias, Margit

2011-09-14

Semiconductor nanowire devices have several properties which match future requirements of scaling down the size of electronics. In typical microelectronics production, a number of microstructures are aligned precisely on top of each other during the fabrication process. In the case of nanowires, this mandatory condition is still hard to achieve. A technological breakthrough is needed to accurately place nanowires at any specific position and then form devices in mass production. In this article, an upscalable process combining conventional micromachining with phase shift lithography will be demonstrated as a suitable tool for nanowire device technology. Vertical Si and ZnO nanowires are demonstrated on very large (several cm(2)) areas. We demonstrate how the nanowire positions can be controlled, and the resulting nanowires are used for device fabrication. As an example Si/ZnO heterojunction diode arrays are fabricated. The electrical characterization of the produced devices has also been performed to confirm the functionality of the fabricated diodes.

A Physically Transient Form of Silicon Electronics, With Integrated Sensors, Actuators and Power Supply

PubMed Central

Hwang, Suk-Won; Tao, Hu; Kim, Dae-Hyeong; Cheng, Huanyu; Song, Jun-Kyul; Rill, Elliott; Brenckle, Mark A.; Panilaitis, Bruce; Won, Sang Min; Kim, Yun-Soung; Yu, Ki Jun; Ameen, Abid; Li, Rui; Su, Yewang; Yang, Miaomiao; Kaplan, David L.; Zakin, Mitchell R.; Slepian, Marvin J.; Huang, Yonggang; Omenetto, Fiorenzo G.; Rogers, John A.

2013-01-01

A remarkable feature of modern silicon electronics is its ability to remain functionally and physically invariant, almost indefinitely for many practical purposes. Here, we introduce a silicon-based technology that offers the opposite behavior: it gradually vanishes over time, in a well-controlled, programmed manner. Devices that are ‘transient’ in this sense create application possibilities that cannot be addressed with conventional electronics, such as active implants that exist for medically useful timeframes, but then completely dissolve and disappear via resorption by the body. We report a comprehensive set of materials, manufacturing schemes, device components and theoretical design tools for a complementary metal oxide semiconductor (CMOS) electronics of this type, together with four different classes of sensors and actuators in addressable arrays, two options for power supply and a wireless control strategy. A transient silicon device capable of delivering thermal therapy in an implantable mode and its demonstration in animal models illustrate a system-level example of this technology. PMID:23019646

Highly indistinguishable and strongly entangled photons from symmetric GaAs quantum dots.

PubMed

Huber, Daniel; Reindl, Marcus; Huo, Yongheng; Huang, Huiying; Wildmann, Johannes S; Schmidt, Oliver G; Rastelli, Armando; Trotta, Rinaldo

2017-05-26

The development of scalable sources of non-classical light is fundamental to unlocking the technological potential of quantum photonics. Semiconductor quantum dots are emerging as near-optimal sources of indistinguishable single photons. However, their performance as sources of entangled-photon pairs are still modest compared to parametric down converters. Photons emitted from conventional Stranski-Krastanov InGaAs quantum dots have shown non-optimal levels of entanglement and indistinguishability. For quantum networks, both criteria must be met simultaneously. Here, we show that this is possible with a system that has received limited attention so far: GaAs quantum dots. They can emit triggered polarization-entangled photons with high purity (g (2) (0) = 0.002±0.002), high indistinguishability (0.93±0.07 for 2 ns pulse separation) and high entanglement fidelity (0.94±0.01). Our results show that GaAs might be the material of choice for quantum-dot entanglement sources in future quantum technologies.

Highly indistinguishable and strongly entangled photons from symmetric GaAs quantum dots

PubMed Central

Huber, Daniel; Reindl, Marcus; Huo, Yongheng; Huang, Huiying; Wildmann, Johannes S.; Schmidt, Oliver G.; Rastelli, Armando; Trotta, Rinaldo

2017-01-01

The development of scalable sources of non-classical light is fundamental to unlocking the technological potential of quantum photonics. Semiconductor quantum dots are emerging as near-optimal sources of indistinguishable single photons. However, their performance as sources of entangled-photon pairs are still modest compared to parametric down converters. Photons emitted from conventional Stranski–Krastanov InGaAs quantum dots have shown non-optimal levels of entanglement and indistinguishability. For quantum networks, both criteria must be met simultaneously. Here, we show that this is possible with a system that has received limited attention so far: GaAs quantum dots. They can emit triggered polarization-entangled photons with high purity (g(2)(0) = 0.002±0.002), high indistinguishability (0.93±0.07 for 2 ns pulse separation) and high entanglement fidelity (0.94±0.01). Our results show that GaAs might be the material of choice for quantum-dot entanglement sources in future quantum technologies. PMID:28548081

Microfabricated Chemical Sensors for Aerospace Fire Detection Applications

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Neudeck, Philip G.; Fralick, Gustave; Thomas, Valarie; Makel, D.; Liu, C. C.; Ward, B.; Wu, Q. H.

2001-01-01

The detection of fires on-board commercial aircraft is extremely important for safety reasons. Although dependable fire detection equipment presently exists within the cabin, detection of fire within the cargo hold has been less reliable and susceptible to false alarms. A second, independent method of fire detection to complement the conventional smoke detection techniques, such as the measurement of chemical species indicative of a fire, will help reduce false alarms and improve aircraft safety. Although many chemical species are indicative of a fire, two species of particular interest are CO and CO2. This paper discusses microfabricated chemical sensor development tailored to meet the needs of fire safety applications. This development is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors. 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity. 3) The development of high temperature semiconductors, especially silicon carbide. The individual sensor being developed and their level of maturity will be presented.

Mask strategy at International SEMATECH

NASA Astrophysics Data System (ADS)

Kimmel, Kurt R.

2002-08-01

International SEMATECH (ISMT) is a consortium consisting of 13 leading semiconductor manufacturers from around the globe. Its objective is to develop the infrastructure necessary for its member companies to realize the International Technology Roadmap for Semiconductors (ITRS) through efficiencies of shared development resources and knowledge. The largest area of effort is lithography, recognized as a crucial enabler for microelectronics technology progress. Within the Lithography Division, most of the efforts center on mask-related issues. The development strategy at International SEMATCH will be presented and the interlock of lithography projects clarified. Because of the limited size of the mask production equipment market, the business case is weak for aggressive investment commensurate with the pace of the International Technology Roadmap for Semiconductors. With masks becoming the overwhelming component of lithography cost, new ways of reducing or eliminating mask costs are being explored. Will mask technology survive without a strong business case? Will the mask industry limit the growth of the semiconductor industry? Are advanced masks worth their escalating cost? An analysis of mask cost from the perspective of mask value imparted to the user is presented with examples and generic formulas for the reader to apply independently. A key part to the success for both International SEMATECH and the industry globally will be partnerships on both the local level between mask-maker and mask-user, and the macro level where global collaborations will be necessary to resolve technology development cost challenges.

Insulator Charging in RF MEMS Capacitive Switches

DTIC Science & Technology

2005-06-01

and Simulations,” Journal of Microelectromechanical Systems, 8: 208-217 (June 1999). 5. Neaman , Donald. Semiconductor Physics & Devices. Boston...227-230 (2001). 5. Sze, S.M. Semiconductor Devices: Physics and Technology. New York: Wiley, 1985. 6. Neaman , Donald A. Semiconductor Physics...Radiation Response of Hafnium-Silicate Capacitors,” IEEE Transactions on Nuclear Science, 49: 3191-3196 (December 2002). 3. Neaman , D.A

Electrochemical liquid-liquid-solid (ec-LLS) crystal growth: a low-temperature strategy for covalent semiconductor crystal growth.

PubMed

Fahrenkrug, Eli; Maldonado, Stephen

2015-07-21

This Account describes a new electrochemical synthetic strategy for direct growth of crystalline covalent group IV and III-V semiconductor materials at or near ambient temperature conditions. This strategy, which we call "electrochemical liquid-liquid-solid" (ec-LLS) crystal growth, marries the semiconductor solvation properties of liquid metal melts with the utility and simplicity of conventional electrodeposition. A low-temperature liquid metal (i.e., Hg, Ga, or alloy thereof) acts simultaneously as the source of electrons for the heterogeneous reduction of oxidized semiconductor precursors dissolved in an electrolyte as well as the solvent for dissolution of the zero-valent semiconductor. Supersaturation of the semiconductor in the liquid metal triggers eventual crystal nucleation and growth. In this way, the liquid electrolyte-liquid metal-solid crystal phase boundary strongly influences crystal growth. As a synthetic strategy, ec-LLS has several intrinsic features that are attractive for preparing covalent semiconductor crystals. First, ec-LLS does not require high temperatures, toxic precursors, or high-energy-density semiconductor reagents. This largely simplifies equipment complexity and expense. In practice, ec-LLS can be performed with only a beaker filled with electrolyte and an electrical circuit capable of supplying a defined current (e.g., a battery in series with a resistor). By this same token, ec-LLS is compatible with thermally and chemically sensitive substrates (e.g., plastics) that cannot be used as deposition substrates in conventional syntheses of covalent semiconductors. Second, ec-LLS affords control over a host of crystal shapes and sizes through simple changes in common experimental parameters. As described in detail herein, large and small semiconductor crystals can be grown both homogeneously within a liquid metal electrode and heterogeneously at the interface of a liquid metal electrode and a seed substrate, depending on the particular details chosen for ec-LLS. Third, the rate of introduction of zero-valent materials into the liquid metal is precisely gated with a high degree of resolution by the applied potential/current. The intent of this Account is to summarize the key elements of ec-LLS identified to date, first contextualizing this method with respect to other semiconductor crystal growth methods and then highlighting some unique capabilities of ec-LLS. Specifically, we detail ec-LLS as a platform to prepare Ge and Si crystals from bulk- (∼1 cm(3)), micro- (∼10(-10) cm(3)), and nano-sized (∼10(-16) cm(3)) liquid metal electrodes in common solvents at low temperature. In addition, we describe our successes in the preparation of more compositionally complex binary covalent III-V semiconductors.

A photovoltaic device structure based on internal electron emission.

PubMed

McFarland, Eric W; Tang, Jing

2003-02-06

There has been an active search for cost-effective photovoltaic devices since the development of the first solar cells in the 1950s (refs 1-3). In conventional solid-state solar cells, electron-hole pairs are created by light absorption in a semiconductor, with charge separation and collection accomplished under the influence of electric fields within the semiconductor. Here we report a multilayer photovoltaic device structure in which photon absorption instead occurs in photoreceptors deposited on the surface of an ultrathin metal-semiconductor junction Schottky diode. Photoexcited electrons are transferred to the metal and travel ballistically to--and over--the Schottky barrier, so providing the photocurrent output. Low-energy (approximately 1 eV) electrons have surprisingly long ballistic path lengths in noble metals, allowing a large fraction of the electrons to be collected. Unlike conventional cells, the semiconductor in this device serves only for majority charge transport and separation. Devices fabricated using a fluorescein photoreceptor on an Au/TiO2/Ti multilayer structure had typical open-circuit photovoltages of 600-800 mV and short-circuit photocurrents of 10-18 micro A cm(-2) under 100 mW cm(-2) visible band illumination: the internal quantum efficiency (electrons measured per photon absorbed) was 10 per cent. This alternative approach to photovoltaic energy conversion might provide the basis for durable low-cost solar cells using a variety of materials.

Theory of thermionic emission from a two-dimensional conductor and its application to a graphene-semiconductor Schottky junction

NASA Astrophysics Data System (ADS)

Trushin, Maxim

2018-04-01

The standard theory of thermionic emission developed for three-dimensional semiconductors does not apply to two-dimensional materials even for making qualitative predictions because of the vanishing out-of-plane quasiparticle velocity. This study reveals the fundamental origin of the out-of-plane charge carrier motion in a two-dimensional conductor due to the finite quasiparticle lifetime and huge uncertainty of the out-of-plane momentum. The theory is applied to a Schottky junction between graphene and a bulk semiconductor to derive a thermionic constant, which, in contrast to the conventional Richardson constant, is determined by the Schottky barrier height and Fermi level in graphene.

Reconditioning of semiconductor substrates to remove photoresist during semiconductor device fabrication

DOEpatents

Farino, Anthony J.

2004-01-27

A method for reconditioning the surface of a semiconductor substrate to remove an unwanted (i.e. defective) layer of photoresist is disclosed. The method adapts a conventional automated spinner which is used to rotate the substrate at high speed while a stream of a first solvent (e.g. acetone) is used to dissolve the photoresist. A stream of a second solvent (e.g. methanol) is then used to clean the substrate at a lower speed, with the substrate being allowed to dry with continued rotation. The method of the present invention can be used within a photolithography track so that the substrates need never leave the track for reconditioning.

Lock-in thermography approach for imaging the efficiency of light emitters and optical coolers

NASA Astrophysics Data System (ADS)

Radevici, Ivan; Tiira, Jonna; Oksanen, Jani

2017-02-01

Developing optical cooling technologies requires access to reliable efficiency measurement techniques and ability to detect spatial variations in the efficiency and light emission of the devices. We investigate the possibility to combine the calorimetric efficiency measurement principles with lock-in thermography (LIT) and conventional luminescence microscopy to enable spatially resolved measurement of the efficiency, current spreading and local device heating of double diode structures (DDS) serving as test vessels for developing thermophotonic cooling devices. Our approach enables spatially resolved characterization and localization of the losses of the double diode structures as well as other light emitting semiconductor devices. In particular, the approach may allow directly observing effects like current crowding and surface recombination on the light emission and heating of the DDS devices.

Solid state photon upconversion utilizing thermally activated delayed fluorescence molecules as triplet sensitizer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Tony C.; Congreve, Daniel N.; Baldo, Marc A., E-mail: baldo@mit.edu

2015-07-20

The ability to upconvert light is useful for a range of applications, from biological imaging to solar cells. But modern technologies have struggled to upconvert incoherent incident light at low intensities. Here, we report solid state photon upconversion employing triplet-triplet exciton annihilation in an organic semiconductor, sensitized by a thermally activated-delayed fluorescence (TADF) dye. Compared to conventional phosphorescent sensitizers, the TADF dye maximizes the wavelength shift in upconversion due to its small singlet-triplet splitting. The efficiency of energy transfer from the TADF dye is 9.1%, and the conversion yield of sensitizer exciton pairs to singlet excitons in the annihilator ismore » 1.1%. Our results demonstrate upconversion in solid state geometries and with non-heavy metal-based sensitizer materials.« less

An assessment of the hardness of miniature vacuum tubes to high-voltage transients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orvis, W.J.

1990-03-01

Miniature vacuum tubes are vacuum switching and control devices fabricated on a silicon wafer, using the same technology as is used to make integrated circuits. They operate in much the same manner as conventional vacuum tubes, but with two important differences: they are micron sized devices, and they employ field emission instead of thermionic emission as the electron source. As these devices have a vacuum as their active region, they will be extremely hard to nuclear radiation and relatively insensitive to temperature effects, they are also expected to be extremely fast devices. We have estimated here that their hardness tomore » high-voltage transients will be at least as good as existing semiconductor devices and possibly better. 5 figs.« less

Pixel detectors for use in retina neurophysiology studies

NASA Astrophysics Data System (ADS)

Cunningham, W.; Mathieson, K.; Horn, M.; Melone, J.; McEwan, F. A.; Blue, A.; O'Shea, V.; Smith, K. M.; Litke, A.; Chichilnisky, E. J.; Rahman, M.

2003-08-01

One area of major inter-disciplinary co-operation is between the particle physics and bio-medical communities. The type of large detector arrays and fast electronics developed in laboratories like CERN are becoming used for a wide range of medical and biological experiments. In the present work fabrication technology developed for producing semiconductor radiation detectors has been applied to produce arrays which have been used in neuro-physiological experiments on retinal tissue. We have exploited UVIII, a low molecular weight resist, that has permitted large area electron beam lithography. This allows the resolution to go below that of conventional photolithography and hence the production of densely packed ˜500 electrode arrays with feature sizes down to below 2 μm. The neural signals from significant areas of the retina may thus be captured.

THz transceiver characterization : LDRD project 139363 final report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nordquist, Christopher Daniel; Wanke, Michael Clement; Cich, Michael Joseph

2009-09-01

LDRD Project 139363 supported experiments to quantify the performance characteristics of monolithically integrated Schottky diode + quantum cascade laser (QCL) heterodyne mixers at terahertz (THz) frequencies. These integrated mixers are the first all-semiconductor THz devices to successfully incorporate a rectifying diode directly into the optical waveguide of a QCL, obviating the conventional optical coupling between a THz local oscillator and rectifier in a heterodyne mixer system. This integrated mixer was shown to function as a true heterodyne receiver of an externally received THz signal, a breakthrough which may lead to more widespread acceptance of this new THz technology paradigm. Inmore » addition, questions about QCL mode shifting in response to temperature, bias, and external feedback, and to what extent internal frequency locking can improve stability have been answered under this project.« less

Highly integrated 3×3 silicon thermo-optical switch using a single combined phase shifter for optical interconnects.

PubMed

Wang, Wanjun; Zhou, Haifeng; Yang, Jianyi; Wang, Minghua; Jiang, Xiaoqing

2012-06-15

We report on an experimental 3×3 thermo-optical switch on silicon on insulator. By controlling a single combined phase shifter, light from any input waveguide can be directed to any output waveguide, showing a simple control method and highly integrated structure as compared to the conventional multiway optical switches. Furthermore, the proposed optical switch can be generalized to be a 1×N and N×N optical switch without an extra phase shifter. The switch is fabricated by complementary metal oxide semiconductor technology. By experiment, full 3×3 switching functionality is demonstrated at a wavelength of 1.55 μm, with an average cross talk of -11.1  dB and a power consumption of 97.5 mW.

The United States digital recording industry

NASA Technical Reports Server (NTRS)

Simonds, John L.

1993-01-01

The recording industry resembles the semiconductor industry in several aspects. Both are large (greater than $60 Billion/year revenues); both are considered critical technologies supporting national objectives; both are experiencing increased competition from foreign suppliers; they recognize significant opportunities for both technological and market growth in the decade to come; and both realize that a key to this future growth lies in alliances among industry, academia, and government. The semiconductor industry has made significant investments in alliances relating to manufacturing technologies (SEMATECH) and to joint long-term technology research centered in universities (SRC). The federal government has provided funding support of these efforts in recognition of the critical roles semiconductor technologies play in national interests. The recording industry is now also forming critical alliances, but has been slower in starting and in gaining broad recognition by government agencies and legislators that the industry needs federal support. Traditionally, the recording industry has been viewed as mature, stable, and, while critical to national interests, able to chart and fund its own course toward future national needs. That perception is fortunately changing.

Point Defects in Two-Dimensional Layered Semiconductors: Physics and Its Applications

NASA Astrophysics Data System (ADS)

Suh, Joonki

Recent advances in material science and semiconductor processing have been achieved largely based on in-depth understanding, efficient management and advanced application of point defects in host semiconductors, thus finding the relevant techniques such as doping and defect engineering as a traditional scientific and technological solution. Meanwhile, two- dimensional (2D) layered semiconductors currently draw tremendous attentions due to industrial needs and their rich physics at the nanoscale; as we approach the end of critical device dimensions in silicon-based technology, ultra-thin semiconductors have the potential as next- generation channel materials, and new physics also emerges at such reduced dimensions where confinement of electrons, phonons, and other quasi-particles is significant. It is therefore rewarding and interesting to understand and redefine the impact of lattice defects by investigating their interactions with energy/charge carriers of the host matter. Potentially, the established understanding will provide unprecedented opportunities for realizing new functionalities and enhancing the performance of energy harvesting and optoelectronic devices. In this thesis, multiple novel 2D layered semiconductors, such as bismuth and transition- metal chalcogenides, are explored. Following an introduction of conventional effects induced by point defects in semiconductors, the related physics of electronically active amphoteric defects is revisited in greater details. This can elucidate the complication of a two-dimensional electron gas coexisting with the topological states on the surface of bismuth chalcogenides, recently suggested as topological insulators. Therefore, native point defects are still one of the keys to understand and exploit topological insulators. In addition to from a fundamental science point of view, the effects of point defects on the integrated thermal-electrical transport, as well as the entropy-transporting process in thermoelectric materials are thoroughly investigated. Point defects can potentially beat the undesired coupling, often term "thermoelectric Bermuda triangle", among electrical conductivity, thermal conductivity and thermopower. The maximum thermoelectric performance is demonstrated with an intermediate density of defects when they beneficially and multi-functionally act as electron donors, as well as strongly energy-dependent electron and phonon scatterers. Therefore, this is a good example of how fundamental defect physics can be applied for practical devices toward renewable energy technology. Another interesting field of layered nanomaterials is on transition-metal dichalcogenides (TMDs), sensational candidates for 2D semiconductor physics and applications. At the reduced dimensionality of 2D where a far stronger correlation between point defects and charge carriers is expected, it is studied how chalcogen vacancies alter optical properties of monolayer TMDs. A new, sub-bandgap broad emission lines as well as increase in the overall photoluminescence intensity at low temperatures are reported as a result of high quantum efficiency of excitons, i.e., bound electron-hole pairs, localized at defect sites. On electrical transport, both n- and p-type materials are needed to form junctions and support bipolar carrier conduction while typically only one type of doping is stable for a particular TMD. For example, MoS2 is natively n-type, thus the lack of p-type doping hampers the development of charge-splitting p-n junctions of MoS2. To address this issue, we demonstrate stable p-type conduction in MoS2 by substitutional Nb doping up to the degenerate level. Proof-of-concept, van der Waals p-n homo-junctions based on vertically stacked MoS2 layers are also fabricated which enable gate-tuneable current rectification. Various electronic devices fabricated are stable in ambient air even without additional treatment such as capping layer protection, thanks to the substitutionality nature of the doping; this is in stark contrast to the existing approach of using molecular doping, which usually suffers from volatility and reactivity with air and/or water molecules.

EDITORIAL: The 24th Nordic Semiconductor Meeting The 24th Nordic Semiconductor Meeting

NASA Astrophysics Data System (ADS)

Páll Gunnlaugsson, Haraldur; Nylandsted Larsen, Arne; Uhrenfeldt, Christian

2012-03-01

A Nordic Semiconductor Meeting is held every other year with the venue rotating amongst the Nordic countries of Denmark, Finland, Iceland, Norway and Sweden. The focus of these meetings remains 'original research and science being carried out on semiconductor materials, devices and systems'. Reports on industrial activity have usually featured. The topics have ranged from fundamental research on point defects in a semiconductor to system architecture of semiconductor electronic devices. Proceedings from these events are regularly published as a Topical Issue of Physica Scripta. All of the papers in this Topical Issue have undergone critical peer review and we wish to thank the reviewers and the authors for their cooperation, which has been instrumental in meeting the high scientific standards and quality of the series. This 24th meeting of the Nordic Semiconductor community, NSM 2011, was held at Fuglsøcentret, close to Aarhus, Denmark, 19-22 June 2011. Support was provided by the Carlsberg Foundation, Danfysik and the semiconductor group at Aarhus University. Over 30 participants presented a broad range of topics covering semiconductor materials and devices as well as related material science interests. The conference provided a forum for Nordic and international scientists to present and discuss new results and ideas concerning the fundamentals and applications of semiconductor materials. The aim of the meeting was to advance the progress of Nordic science and thus aid in future worldwide technological advances concerning technology, education, energy and the environment. The 25th Nordic Semiconductor Meeting will be organized in June 2013 in Finland, chaired by Dr Filip Tuomisto, Aalto University. A Nordic Summer School on Semiconductor Science will be organized in connection with the conference (just before), chaired by Dr Jonatan Slotte, Aalto University. Information on these events can be found at physics.aalto.fi/nsm2013. List of participants Søren Vejling AndersenAalborg University, Aalborg, Denmark Pia BomholtAarhus University, Aarhus, Denmark Hafliði P GíslasonUniversity of Iceland, Reykjavik, Iceland Haraldur Páll GunnlaugssonAarhus University, Aarhus, Denmark John HansenAarhus University, Aarhus, Denmark Britta JohansenAarhus University, Aarhus, Denmark Volodymyr KhranovskyyLinköping University, Linköping, Sweden Arne Nylandsted LarsenAarhus University, Denmark Helge MalmbekkUniversity of Oslo, Oslo, Norway Erik Stensrud MarsteinInstitute for Energy Technology, Kjeller, Norway Antonio MartiUniversidad Politécnica de Madrid, Madrid, Spain Torben MølholtUniversity of Iceland, Reykjavik, Iceland Sveinn ÓlafssonUniversity of Iceland, Reykjavik, Iceland Thomas PedersenTechnical University of Denmark, Kgs. Lyngby, Denmark Thomas Garm PedersenAalborg University, Aalborg, Denmark Dirch Hjorth PetersenTechnical University of Denmark, Kgs. Lyngby, Denmark Vincent QuemenerUniversity of Oslo, Oslo, Norway Henry RadamsonKTH Royal Institute of Technology, Kista, Sweden Bahman RaeissiUniversity of Oslo, Oslo, Norway Jonatan SlotteAalto University, Aalto, Finland Xin SongUniversity of Oslo, Oslo, Norway Einar Örn SveinbjörnssonUniversity of Iceland, Reykjavik, Iceland Mikael SyväjärviLinköping University, Linköping, Sweden Chi Kwong TangUniversity of Oslo, Oslo, Norway Erik V ThomsenTechnical University of Denmark, Kgs. Lyngby, Denmark Christian UhrenfeldtAarhus University, Aarhus, Denmark Hans Ulrik UlriksenAalborg University, Aalborg, Denmark Muhammad UsmanKTH Royal Institute of Technology, Kista, Sweden Lasse VinesUniversity of Oslo, Oslo, Norway Ulrich WahlUnidade de Física e Aceleradores, Sacavém, Portugal Helge WemanNTNU, Trondheim, Norway Gerd WeyerAarhus University, Denmark

Ultrashort pulsed laser ablation for decollation of solid state lithium-ion batteries

NASA Astrophysics Data System (ADS)

Hördemann, C.; Anand, H.; Gillner, A.

2017-08-01

Rechargeable lithium-ion batteries with liquid electrolytes are the main energy source for many electronic devices that we use in our everyday lives. However, one of the main drawbacks of this energy storage technology is the use of liquid electrolyte, which can be hazardous to the user as well as the environment. Moreover, lithium-ion batteries are limited in voltage, energy density and operating temperature range. One of the most novel and promising battery technologies available to overcome the above-mentioned drawbacks is the Solid-State Lithium-Ion Battery (SSLB). This battery type can be produced without limitations to the geometry and is also bendable, which is not possible with conventional batteries1 . Additionally, SSLBs are characterized by high volumetric and gravimetric energy density and are intrinsically safe since no liquid electrolyte is used2-4. Nevertheless, the manufacturing costs of these batteries are still high. The existing production-technologies are comparable to the processes used in the semiconductor industry and single cells are produced in batches with masked-deposition at low deposition rates. In order to decrease manufacturing costs and to move towards continuous production, Roll2Roll production methods are being proposed5, 6. These methods offer the possibility of producing large quantities of substrates with deposited SSLB-layers. From this coated substrate, single cells can be cut out. For the flexible decollation of SSLB-cells from the substrate, new manufacturing technologies have to be developed since blade-cutting, punching or conventional laser-cutting processes lead to short circuiting between the layers. Here, ultra-short pulsed laser ablation and cutting allows the flexible decollation of SSLBs. Through selective ablation of individual layers, an area for the cutting kerf is prepared to ensure a shortcut-free decollation.

Microplasma fabrication: from semiconductor technology for 2D-chips and microfluidic channels to rapid prototyping and 3D-printing of microplasma devices

NASA Astrophysics Data System (ADS)

Shatford, R.; Karanassios, Vassili

2014-05-01

Microplasmas are receiving attention in recent conferences and current scientific literature. In our laboratory, microplasmas-on-chips proved to be particularly attractive. The 2D- and 3D-chips we developed became hybrid because they were fitted with a quartz plate (quartz was used due to its transparency to UV). Fabrication of 2D- and 3D-chips for microplasma research is described. The fabrication methods described ranged from semiconductor fabrication technology, to Computer Numerical Control (CNC) machining, to 3D-printing. These methods may prove to be useful for those contemplating in entering microplasma research but have no access to expensive semiconductor fabrication equipment.

Semiconductor chips, genes, and stem cells: new wine for new bottles?

PubMed

Rose, Simone A

2012-01-01

This Article analogizes early semiconductor technology and its surrounding economics with isolated genes, stem cells, and related bioproducts, and their surrounding economics, to make the case for sui generis (of its own class) intellectual property protection for isolated bioproducts. Just as early semiconductors failed to meet the patent social bargain requiring novelty and non-obviousness in the 1980s, isolated genes and stem cells currently fail to meet the patent bargain requirements of non-obviousness and eligible subject matter that entitle them to traditional intellectual property protection. Like early semiconductor chip designs, nevertheless, the high cost of upstream bioproduct research and development, coupled with the need to sustain continued economic growth of the biotechnology industry, mandates that Congress provide some level of exclusive rights to ensure continued funding for this research. Sui generis intellectual property protection for isolated bioproducts would preserve the incentive to continue innovation in the field. As illustrated by the semiconductor industry, however, such sui generis protection for this technology must include limitations that address the need to provide an appropriate level of public access to facilitate downstream product development and enrich the public domain.

Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Burger, Arnold; Dudley, Michael; Matyi, Richard J.; Ramachandran, Narayanan; Sha, Yi-Gao; Volz, Martin; Shih, Hung-Dah

1998-01-01

Interest in optical devices which can operate in the visible spectrum has motivated research interest in the II-VI wide band gap semiconductor materials. The recent challenge for semiconductor opto-electronics is the development of a laser which can operate at short visible wavelengths, In the past several years, major advances in thin film technology such as molecular beam epitaxy and metal organic chemical vapor deposition have demonstrated the applicability of II-VI materials to important devices such as light-emitting diodes, lasers, and ultraviolet detectors.The demonstration of its optical bistable properties in bulk and thin film forms also make ZnSe a possible candidate material for the building blocks of a digital optical computer. Despite this, developments in the crystal growth of bulk II-VI semiconductor materials has not advanced far enough to provide the low price, high quality substrates needed for the thin film growth technology. The electrical and optical properties of semiconductor materials depend on the native point defects, (the deviation from stoichiometry), and the impurity or dopant distribution. To date, the bulk growth of ZnSe substrates has been plagued with problems related to defects such as non-uniform distributions of native defects, impurities and dopants, lattice strain, dislocations, grain boundaries, and second phase inclusions which greatly effect the device performance. In the bulk crystal growth of some technologically important semiconductors, such as ZnTe, CdS, ZnSe and ZnS, vapor growth techniques have significant advantages over melt growth techniques due to the high melting points of these materials.

Photocapacitive MIS infrared detectors

NASA Technical Reports Server (NTRS)

Sher, A.; Lu, S. S.-M.; Moriarty, J. A.; Crouch, R. K.; Miller, W. E.

1978-01-01

A new class of room-temperature infrared detectors has been developed through use of metal-insulator-semiconductor (MIS) or metal-insulator-semiconductor-insulator-metal (MISIM) slabs. The detectors, which have been fabricated from Si, Ge and GaAs, rely for operation on the electrical capacitance variations induced by modulated incident radiation. The peak detectivity for a 1000-A Si MISIM detector is comparable to that of a conventional Si detector functioning in the photovoltaic mode. Optimization of the photocapacitive-mode detection sensitivity is discussed.

Two-Dimensional Semiconductor Optoelectronics Based on van der Waals Heterostructures.

PubMed

Lee, Jae Yoon; Shin, Jun-Hwan; Lee, Gwan-Hyoung; Lee, Chul-Ho

2016-10-27

Two-dimensional (2D) semiconductors such as transition metal dichalcogenides (TMDCs) and black phosphorous have drawn tremendous attention as an emerging optical material due to their unique and remarkable optical properties. In addition, the ability to create the atomically-controlled van der Waals (vdW) heterostructures enables realizing novel optoelectronic devices that are distinct from conventional bulk counterparts. In this short review, we first present the atomic and electronic structures of 2D semiconducting TMDCs and their exceptional optical properties, and further discuss the fabrication and distinctive features of vdW heterostructures assembled from different kinds of 2D materials with various physical properties. We then focus on reviewing the recent progress on the fabrication of 2D semiconductor optoelectronic devices based on vdW heterostructures including photodetectors, solar cells, and light-emitting devices. Finally, we highlight the perspectives and challenges of optoelectronics based on 2D semiconductor heterostructures.

Van der Waals metal-semiconductor junction: Weak Fermi level pinning enables effective tuning of Schottky barrier

PubMed Central

Liu, Yuanyue; Stradins, Paul; Wei, Su-Huai

2016-01-01

Two-dimensional (2D) semiconductors have shown great potential for electronic and optoelectronic applications. However, their development is limited by a large Schottky barrier (SB) at the metal-semiconductor junction (MSJ), which is difficult to tune by using conventional metals because of the effect of strong Fermi level pinning (FLP). We show that this problem can be overcome by using 2D metals, which are bounded with 2D semiconductors through van der Waals (vdW) interactions. This success relies on a weak FLP at the vdW MSJ, which is attributed to the suppression of metal-induced gap states. Consequently, the SB becomes tunable and can vanish with proper 2D metals (for example, H-NbS2). This work not only offers new insights into the fundamental properties of heterojunctions but also uncovers the great potential of 2D metals for device applications. PMID:27152360

Two-Dimensional Semiconductor Optoelectronics Based on van der Waals Heterostructures

PubMed Central

Lee, Jae Yoon; Shin, Jun-Hwan; Lee, Gwan-Hyoung; Lee, Chul-Ho

2016-01-01

Two-dimensional (2D) semiconductors such as transition metal dichalcogenides (TMDCs) and black phosphorous have drawn tremendous attention as an emerging optical material due to their unique and remarkable optical properties. In addition, the ability to create the atomically-controlled van der Waals (vdW) heterostructures enables realizing novel optoelectronic devices that are distinct from conventional bulk counterparts. In this short review, we first present the atomic and electronic structures of 2D semiconducting TMDCs and their exceptional optical properties, and further discuss the fabrication and distinctive features of vdW heterostructures assembled from different kinds of 2D materials with various physical properties. We then focus on reviewing the recent progress on the fabrication of 2D semiconductor optoelectronic devices based on vdW heterostructures including photodetectors, solar cells, and light-emitting devices. Finally, we highlight the perspectives and challenges of optoelectronics based on 2D semiconductor heterostructures. PMID:28335321

Van der Waals metal-semiconductor junction: Weak Fermi level pinning enables effective tuning of Schottky barrier

DOE PAGES

Liu, Yuanyue; Stradins, Paul; Wei, Su -Huai

2016-04-22

Two-dimensional (2D) semiconductors have shown great potential for electronic and optoelectronic applications. However, their development is limited by a large Schottky barrier (SB) at the metal-semiconductor junction (MSJ), which is difficult to tune by using conventional metals because of the effect of strong Fermi level pinning (FLP). We show that this problem can be overcome by using 2D metals, which are bounded with 2D semiconductors through van der Waals (vdW) interactions. This success relies on a weak FLP at the vdW MSJ, which is attributed to the suppression of metal-induced gap states. Consequently, the SB becomes tunable and can vanishmore » with proper 2D metals (for example, H-NbS2). This work not only offers new insights into the fundamental properties of heterojunctions but also uncovers the great potential of 2D metals for device applications.« less

Photoemission-based microelectronic devices

PubMed Central

Forati, Ebrahim; Dill, Tyler J.; Tao, Andrea R.; Sievenpiper, Dan

2016-01-01

The vast majority of modern microelectronic devices rely on carriers within semiconductors due to their integrability. Therefore, the performance of these devices is limited due to natural semiconductor properties such as band gap and electron velocity. Replacing the semiconductor channel in conventional microelectronic devices with a gas or vacuum channel may scale their speed, wavelength and power beyond what is available today. However, liberating electrons into gas/vacuum in a practical microelectronic device is quite challenging. It often requires heating, applying high voltages, or using lasers with short wavelengths or high powers. Here, we show that the interaction between an engineered resonant surface and a low-power infrared laser can cause enough photoemission via electron tunnelling to implement feasible microelectronic devices such as transistors, switches and modulators. The proposed photoemission-based devices benefit from the advantages of gas-plasma/vacuum electronic devices while preserving the integrability of semiconductor-based devices. PMID:27811946

Recent progress in tungsten oxides based memristors and their neuromorphological applications

NASA Astrophysics Data System (ADS)

Qu, Bo; Younis, Adnan; Chu, Dewei

2016-09-01

The advance in conventional silicon based semiconductor industry is now becoming indeterminacy as it still along the road of Moore's Law and concomitant problems associated with it are the emergence of a number of practical issues such as short channel effect. In terms of memory applications, it is generally believed that transistors based memory devices will approach to their scaling limits up to 2018. Therefore, one of the most prominent challenges today in semiconductor industry is the need of a new memory technology which is able to combine the best characterises of current devices. The resistive switching memories which are regarded as "memristors" thus gain great attentions thanks to their specific nonlinear electrical properties. More importantly, their behaviour resembles with the transmission characteristic of synapse in biology. Therefore, the research of synapses biomimetic devices based on memristor will certainly bring a great research prospect in studying synapse emulation as well as building artificial neural networks. Tungsten oxides (WO x ) exhibits many essential characteristics as a great candidate for memristive devices including: accredited endurance (over 105 cycles), stoichiometric flexibility, complimentary metal-oxide-semiconductor (CMOS) process compatibility and configurable properties including non-volatile rectification, memorization and learning functions. Herein, recent progress on Tungsten oxide based materials and its associating memory devices had been reviewed. The possible implementation of this material as a bio-inspired artificial synapse is also highlighted. The penultimate section summaries the current research progress for tungsten oxide based biological synapses and end up with several proposals that have been suggested for possible future developments.

Design and Analysis of CMOS-Compatible III-V Compound Electron-Hole Bilayer Tunneling Field-Effect Transistor for Ultra-Low-Power Applications.

PubMed

Kim, Sung Yoon; Seo, Jae Hwa; Yoon, Young Jun; Lee, Ho-Young; Lee, Seong Min; Cho, Seongjae; Kang, In Man

2015-10-01

In this work, we design and analyze complementary metal-oxide-semiconductor (CMOS)-compatible III-V compound electron-hole bilayer (EHB) tunneling field-effect transistors (TFETs) by using two-dimensional (2D) technology computer-aided design (TCAD) simulations. A recently proposed EHB TFET exploits a bias-induced band-to-band tunneling (BTBT) across the electron-hole bilayer by an electric field from the top and bottom gates. This is in contrast to conventional planar p(+)-p(-)-n TFETs, which utilize BTBT across the source-to-channel junction. We applied III-V compound semiconductor materials to the EHB TFETs in order to enhance the current drivability and switching performance. Devices based on various compound semiconductor materials have been designed and analyzed in terms of their primary DC characteristics. In addition, the operational principles were validated by close examination of the electron concentrations and energy-band diagrams under various operation conditions. The simulation results of the optimally designed In0.533Ga0.47As EHB TFET show outstanding performance, with an on-state current (Ion) of 249.5 μA/μm, subthreshold swing (S) of 11.4 mV/dec, and threshold voltage (Vth) of 50 mV at VDS = 0.5 V. Based on the DC-optimized InGaAs EHB TFET, the CMOS inverter circuit was simulated in views of static and dynamic behaviors of the p-channel device with exchanges between top and bottom gates or between source and drain electrodes maintaining the device structure.

Inkjet printing of single-crystal films.

PubMed

Minemawari, Hiromi; Yamada, Toshikazu; Matsui, Hiroyuki; Tsutsumi, Jun'ya; Haas, Simon; Chiba, Ryosuke; Kumai, Reiji; Hasegawa, Tatsuo

2011-07-13

The use of single crystals has been fundamental to the development of semiconductor microelectronics and solid-state science. Whether based on inorganic or organic materials, the devices that show the highest performance rely on single-crystal interfaces, with their nearly perfect translational symmetry and exceptionally high chemical purity. Attention has recently been focused on developing simple ways of producing electronic devices by means of printing technologies. 'Printed electronics' is being explored for the manufacture of large-area and flexible electronic devices by the patterned application of functional inks containing soluble or dispersed semiconducting materials. However, because of the strong self-organizing tendency of the deposited materials, the production of semiconducting thin films of high crystallinity (indispensable for realizing high carrier mobility) may be incompatible with conventional printing processes. Here we develop a method that combines the technique of antisolvent crystallization with inkjet printing to produce organic semiconducting thin films of high crystallinity. Specifically, we show that mixing fine droplets of an antisolvent and a solution of an active semiconducting component within a confined area on an amorphous substrate can trigger the controlled formation of exceptionally uniform single-crystal or polycrystalline thin films that grow at the liquid-air interfaces. Using this approach, we have printed single crystals of the organic semiconductor 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C(8)-BTBT) (ref. 15), yielding thin-film transistors with average carrier mobilities as high as 16.4 cm(2) V(-1) s(-1). This printing technique constitutes a major step towards the use of high-performance single-crystal semiconductor devices for large-area and flexible electronics applications.

Enhanced thermaly managed packaging for III-nitride light emitters

NASA Astrophysics Data System (ADS)

Kudsieh, Nicolas

In this Dissertation our work on `enhanced thermally managed packaging of high power semiconductor light sources for solid state lighting (SSL)' is presented. The motivation of this research and development is to design thermally high stable cost-efficient packaging of single and multi-chip arrays of III-nitrides wide bandgap semiconductor light sources through mathematical modeling and simulations. Major issues linked with this technology are device overheating which causes serious degradation in their illumination intensity and decrease in the lifetime. In the introduction the basics of III-nitrides WBG semiconductor light emitters are presented along with necessary thermal management of high power cingulated and multi-chip LEDs and laser diodes. This work starts at chip level followed by its extension to fully packaged lighting modules and devices. Different III-nitride structures of multi-quantum well InGaN/GaN and AlGaN/GaN based LEDs and LDs were analyzed using advanced modeling and simulation for different packaging designs and high thermal conductivity materials. Study started with basic surface mounted devices using conventional packaging strategies and was concluded with the latest thermal management of chip-on-plate (COP) method. Newly discovered high thermal conductivity materials have also been incorporated for this work. Our study also presents the new approach of 2D heat spreaders using such materials for SSL and micro LED array packaging. Most of the work has been presented in international conferences proceedings and peer review journals. Some of the latest work has also been submitted to well reputed international journals which are currently been reviewed for publication. .

Organic semiconductor growth and morphology considerations for organic thin-film transistors.

PubMed

Virkar, Ajay A; Mannsfeld, Stefan; Bao, Zhenan; Stingelin, Natalie

2010-09-08

Analogous to conventional inorganic semiconductors, the performance of organic semiconductors is directly related to their molecular packing, crystallinity, growth mode, and purity. In order to achieve the best possible performance, it is critical to understand how organic semiconductors nucleate and grow. Clever use of surface and dielectric modification chemistry can allow one to control the growth and morphology, which greatly influence the electrical properties of the organic transistor. In this Review, the nucleation and growth of organic semiconductors on dielectric surfaces is addressed. The first part of the Review concentrates on small-molecule organic semiconductors. The role of deposition conditions on film formation is described. The modification of the dielectric interface using polymers or self-assembled mono-layers and their effect on organic-semiconductor growth and performance is also discussed. The goal of this Review is primarily to discuss the thin-film formation of organic semiconducting species. The patterning of single crystals is discussed, while their nucleation and growth has been described elsewhere (see the Review by Liu et. al).([¹]) The second part of the Review focuses on polymeric semiconductors. The dependence of physico-chemical properties, such as chain length (i.e., molecular weight) of the constituting macromolecule, and the influence of small molecular species on, e.g., melting temperature, as well as routes to induce order in such macromolecules, are described.

Foundational Forces & Hidden Variables in Technology Commercialization

NASA Astrophysics Data System (ADS)

Barnett, Brandon

2011-03-01

The science of physics seems vastly different from the process of technology commercialization. Physics strives to understand our world through the experimental deduction of immutable laws and dependent variables and the resulting macro-scale phenomenon. In comparison, the~goal of business is to make a profit by addressing the needs, preferences, and whims of individuals in a market. It may seem that this environment is too dynamic to identify all the hidden variables and deduct the foundational forces that impact a business's ability to commercialize innovative technologies. One example of a business ``force'' is found in the semiconductor industry. In 1965, Intel co-founder Gordon Moore predicted that the number of transistors incorporated in a chip will approximately double every 24 months. Known as Moore's Law, this prediction has become the guiding principle for the semiconductor industry for the last 40 years. Of course, Moore's Law is not really a law of nature; rather it is the result of efforts by Intel and the entire semiconductor industry. A closer examination suggests that there are foundational principles of business that underlie the macro-scale phenomenon of Moore's Law. Principles of profitability, incentive, and strategic alignment have resulted in a coordinated influx of resources that has driven technologies to market, increasing the profitability of the semiconductor industry and optimizing the fitness of its participants. New innovations in technology are subject to these same principles. So, in addition to traditional market forces, these often unrecognized forces and variables create challenges for new technology commercialization. In this talk, I will draw from ethnographic research, complex adaptive theory, and industry data to suggest a framework with which to think about new technology commercialization. Intel's bio-silicon initiative provides a case study.

Proposal to probe quantum nonlocality of Majorana fermions in tunneling experiments

NASA Astrophysics Data System (ADS)

Sau, Jay D.; Swingle, Brian; Tewari, Sumanta

2015-07-01

Topological Majorana fermion (MF) quasiparticles have been recently suggested to exist in semiconductor quantum wires with proximity induced superconductivity and a Zeeman field. Although the experimentally observed zero bias tunneling peak and a fractional ac-Josephson effect can be taken as necessary signatures of MFs, neither of them constitutes a sufficient "smoking gun" experiment. Since one pair of Majorana fermions share a single conventional fermionic degree of freedom, MFs are in a sense fractionalized excitations. Based on this fractionalization we propose a tunneling experiment that furnishes a nearly unique signature of end state MFs in semiconductor quantum wires. In particular, we show that a "teleportation"-like experiment is not enough to distinguish MFs from pairs of MFs, which are equivalent to conventional zero energy states, but our proposed tunneling experiment, in principle, can make this distinction.

Arrays of Nano Tunnel Junctions as Infrared Image Sensors

NASA Technical Reports Server (NTRS)

Son, Kyung-Ah; Moon, Jeong S.; Prokopuk, Nicholas

2006-01-01

Infrared image sensors based on high density rectangular planar arrays of nano tunnel junctions have been proposed. These sensors would differ fundamentally from prior infrared sensors based, variously, on bolometry or conventional semiconductor photodetection. Infrared image sensors based on conventional semiconductor photodetection must typically be cooled to cryogenic temperatures to reduce noise to acceptably low levels. Some bolometer-type infrared sensors can be operated at room temperature, but they exhibit low detectivities and long response times, which limit their utility. The proposed infrared image sensors could be operated at room temperature without incurring excessive noise, and would exhibit high detectivities and short response times. Other advantages would include low power demand, high resolution, and tailorability of spectral response. Neither bolometers nor conventional semiconductor photodetectors, the basic detector units as proposed would partly resemble rectennas. Nanometer-scale tunnel junctions would be created by crossing of nanowires with quantum-mechanical-barrier layers in the form of thin layers of electrically insulating material between them (see figure). A microscopic dipole antenna sized and shaped to respond maximally in the infrared wavelength range that one seeks to detect would be formed integrally with the nanowires at each junction. An incident signal in that wavelength range would become coupled into the antenna and, through the antenna, to the junction. At the junction, the flow of electrons between the crossing wires would be dominated by quantum-mechanical tunneling rather than thermionic emission. Relative to thermionic emission, quantum mechanical tunneling is a fast process.

Design and demonstration of an intracortical probe technology with tunable modulus.

PubMed

Simon, Dustin M; Charkhkar, Hamid; St John, Conan; Rajendran, Sakthi; Kang, Tong; Reit, Radu; Arreaga-Salas, David; McHail, Daniel G; Knaack, Gretchen L; Sloan, Andrew; Grasse, Dane; Dumas, Theodore C; Rennaker, Robert L; Pancrazio, Joseph J; Voit, Walter E

2017-01-01

Intracortical probe technology, consisting of arrays of microelectrodes, offers a means of recording the bioelectrical activity from neural tissue. A major limitation of existing intracortical probe technology pertains to limited lifetime of 6 months to a year of recording after implantation. A major contributor to device failure is widely believed to be the interfacial mechanical mismatch of conventional stiff intracortical devices and the surrounding brain tissue. We describe the design, development, and demonstration of a novel functional intracortical probe technology that has a tunable Young's modulus from ∼2 GPa to ∼50 MPa. This technology leverages advances in dynamically softening materials, specifically thiol-ene/acrylate thermoset polymers, which exhibit minimal swelling of < 3% weight upon softening in vitro. We demonstrate that a shape memory polymer-based multichannel intracortical probe can be fabricated, that the mechanical properties are stable for at least 2 months and that the device is capable of single unit recordings for durations up to 77 days in vivo. This novel technology, which is amenable to processes suitable for manufacturing via standard semiconductor fabrication techniques, offers the capability of softening in vivo to reduce the tissue-device modulus mismatch to ultimately improve long term viability of neural recordings. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 159-168, 2017. © 2016 Wiley Periodicals, Inc.

Light sources based on semiconductor current filaments

DOEpatents

Zutavern, Fred J.; Loubriel, Guillermo M.; Buttram, Malcolm T.; Mar, Alan; Helgeson, Wesley D.; O'Malley, Martin W.; Hjalmarson, Harold P.; Baca, Albert G.; Chow, Weng W.; Vawter, G. Allen

2003-01-01

The present invention provides a new type of semiconductor light source that can produce a high peak power output and is not injection, e-beam, or optically pumped. The present invention is capable of producing high quality coherent or incoherent optical emission. The present invention is based on current filaments, unlike conventional semiconductor lasers that are based on p-n junctions. The present invention provides a light source formed by an electron-hole plasma inside a current filament. The electron-hole plasma can be several hundred microns in diameter and several centimeters long. A current filament can be initiated optically or with an e-beam, but can be pumped electrically across a large insulating region. A current filament can be produced in high gain photoconductive semiconductor switches. The light source provided by the present invention has a potentially large volume and therefore a potentially large energy per pulse or peak power available from a single (coherent) semiconductor laser. Like other semiconductor lasers, these light sources will emit radiation at the wavelength near the bandgap energy (for GaAs 875 nm or near infra red). Immediate potential applications of the present invention include high energy, short pulse, compact, low cost lasers and other incoherent light sources.

Radiation Effects in Dual Heat Sinks for Cooling of Concentrated Photovoltaics

DTIC Science & Technology

2016-06-01

Schematic of a Concentrated Photovoltaic System . Source: [4]..................2 Figure 2. Temperature-Efficiency Curves of Select Solar Cells. Adapted from...in contrast to conventional systems . Conventional photovoltaics simply have incident solar radiation impinge on a semiconductor, CPV uses magnifying...reduce system cost. Figure 1 shows a concept schematic of a basic CPV system . Figure 1. Schematic of a Concentrated Photovoltaic System . Source

Resistance change effect in SrTiO3/Si (001) isotype heterojunction

NASA Astrophysics Data System (ADS)

Huang, Xiushi; Gao, Zhaomeng; Li, Pei; Wang, Longfei; Liu, Xiansheng; Zhang, Weifeng; Guo, Haizhong

2018-02-01

Resistance switching has been observed in double and multi-layer structures of ferroelectric films. The higher switching ratio opens up a vast path for emerging ferroelectric semiconductor devices. An n-n+ isotype heterojunction has been fabricated by depositing an oxide SrTiO3 layer on a conventional n-type Si (001) substrate (SrTiO3/Si) by pulsed laser disposition. Rectification and resistive switching behaviors in the n-n+ SrTiO3/Si heterojunction were observed by a conductive atomic force microscopy, and the n-n+ SrTiO3/Si heterojunction exhibits excellent endurance and retention characteristics. The possible mechanism was proposed based on the band structure of the n-n+ SrTiO3/Si heterojunction, and the observed electrical behaviors could be attributed to the modulation effect of the electric field reversal on the width of accumulation and the depletion region, as well as the height of potential of the n-n+ junction formed at the STO/Si interface. Moreover, oxygen vacancies are also indicated to play a crucial role in causing insulator to semiconductor transition. These results open the way to potential application in future microelectronic devices based on perovskite oxide layers on conventional semiconductors.

Hot Carrier-Based Near-Field Thermophotovoltaic Energy Conversion.

PubMed

St-Gelais, Raphael; Bhatt, Gaurang Ravindra; Zhu, Linxiao; Fan, Shanhui; Lipson, Michal

2017-03-28

Near-field thermophotovoltaics (NFTPV) is a promising approach for direct conversion of heat to electrical power. This technology relies on the drastic enhancement of radiative heat transfer (compared to conventional blackbody radiation) that occurs when objects at different temperatures are brought to deep subwavelength distances (typically <100 nm) from each other. Achieving such radiative heat transfer between a hot object and a photovoltaic (PV) cell could allow direct conversion of heat to electricity with a greater efficiency than using current solid-state technologies (e.g., thermoelectric generators). One of the main challenges in the development of this technology, however, is its incompatibility with conventional silicon PV cells. Thermal radiation is weak at frequencies larger than the ∼1.1 eV bandgap of silicon, such that PV cells with lower excitation energies (typically 0.4-0.6 eV) are required for NFTPV. Using low bandgap III-V semiconductors to circumvent this limitation, as proposed in most theoretical works, is challenging and therefore has never been achieved experimentally. In this work, we show that hot carrier PV cells based on Schottky junctions between silicon and metallic films could provide an attractive solution for achieving high efficiency NFTPV electricity generation. Hot carrier science is currently an important field of research and several approaches are investigated for increasing the quantum efficiency (QE) of hot carrier generation beyond conventional Fowler model predictions. If the Fowler limit can indeed be overcome, we show that hot carrier-based NFTPV systems-after optimization of their thermal radiation spectrum-could allow electricity generation with up to 10-30% conversion efficiencies and 10-500 W/cm 2 generated power densities (at 900-1500 K temperatures). We also discuss how the unique properties of thermal radiation in the extreme near-field are especially well suited for investigating recently proposed approaches for high QE hot carrier junctions. We therefore expect our work to be of interest for the field of hot carrier science and-by relying solely on conventional thin film materials-to provide a path for the experimental demonstration of NFTPV energy conversion.

High-Temperature Electronics: A Role for Wide Bandgap Semiconductors?

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Okojie, Robert S.; Chen, Liang-Yu

2002-01-01

It is increasingly recognized that semiconductor based electronics that can function at ambient temperatures higher than 150 C without external cooling could greatly benefit a variety of important applications, especially-in the automotive, aerospace, and energy production industries. The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300 C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog very large scale integrated circuits in this temperature range. However, practical operation of silicon power devices at ambient temperatures above 200 C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once the technology for realizing these devices become sufficiently developed that they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

HfSe2 and ZrSe2: Two-dimensional semiconductors with native high-κ oxides

PubMed Central

Mleczko, Michal J.; Zhang, Chaofan; Lee, Hye Ryoung; Kuo, Hsueh-Hui; Magyari-Köpe, Blanka; Moore, Robert G.; Shen, Zhi-Xun; Fisher, Ian R.; Nishi, Yoshio; Pop, Eric

2017-01-01

The success of silicon as a dominant semiconductor technology has been enabled by its moderate band gap (1.1 eV), permitting low-voltage operation at reduced leakage current, and the existence of SiO2 as a high-quality “native” insulator. In contrast, other mainstream semiconductors lack stable oxides and must rely on deposited insulators, presenting numerous compatibility challenges. We demonstrate that layered two-dimensional (2D) semiconductors HfSe2 and ZrSe2 have band gaps of 0.9 to 1.2 eV (bulk to monolayer) and technologically desirable “high-κ” native dielectrics HfO2 and ZrO2, respectively. We use spectroscopic and computational studies to elucidate their electronic band structure and then fabricate air-stable transistors down to three-layer thickness with careful processing and dielectric encapsulation. Electronic measurements reveal promising performance (on/off ratio > 106; on current, ~30 μA/μm), with native oxides reducing the effects of interfacial traps. These are the first 2D materials to demonstrate technologically relevant properties of silicon, in addition to unique compatibility with high-κ dielectrics, and scaling benefits from their atomically thin nature. PMID:28819644

Progress in ion torrent semiconductor chip based sequencing.

PubMed

Merriman, Barry; Rothberg, Jonathan M

2012-12-01

In order for next-generation sequencing to become widely used as a diagnostic in the healthcare industry, sequencing instrumentation will need to be mass produced with a high degree of quality and economy. One way to achieve this is to recast DNA sequencing in a format that fully leverages the manufacturing base created for computer chips, complementary metal-oxide semiconductor chip fabrication, which is the current pinnacle of large scale, high quality, low-cost manufacturing of high technology. To achieve this, ideally the entire sensory apparatus of the sequencer would be embodied in a standard semiconductor chip, manufactured in the same fab facilities used for logic and memory chips. Recently, such a sequencing chip, and the associated sequencing platform, has been developed and commercialized by Ion Torrent, a division of Life Technologies, Inc. Here we provide an overview of this semiconductor chip based sequencing technology, and summarize the progress made since its commercial introduction. We described in detail the progress in chip scaling, sequencing throughput, read length, and accuracy. We also summarize the enhancements in the associated platform, including sample preparation, data processing, and engagement of the broader development community through open source and crowdsourcing initiatives. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nonequilibrium carrier dynamics in transition metal dichalcogenide semiconductors

NASA Astrophysics Data System (ADS)

Steinhoff, A.; Florian, M.; Rösner, M.; Lorke, M.; Wehling, T. O.; Gies, C.; Jahnke, F.

2016-09-01

When exploring new materials for their potential in (opto)electronic device applications, it is important to understand the role of various carrier interaction and scattering processes. In atomically thin transition metal dichalcogenide semiconductors, the Coulomb interaction is known to be much stronger than in quantum wells of conventional semiconductors like GaAs, as witnessed by the 50 times larger exciton binding energy. The question arises, whether this directly translates into equivalently faster carrier-carrier Coulomb scattering of excited carriers. Here we show that a combination of ab initio band-structure and many-body theory predicts Coulomb-mediated carrier relaxation on a sub-100 fs time scale for a wide range of excitation densities, which is less than an order of magnitude faster than in quantum wells.

Process Control in Production-Worthy Plasma Doping Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winder, Edmund J.; Fang Ziwei; Arevalo, Edwin

2006-11-13

As the semiconductor industry continues to scale devices of smaller dimensions and improved performance, many ion implantation processes require lower energy and higher doses. Achieving these high doses (in some cases {approx}1x1016 ions/cm2) at low energies (<3 keV) while maintaining throughput is increasingly challenging for traditional beamline implant tools because of space-charge effects that limit achievable beam density at low energies. Plasma doping is recognized as a technology which can overcome this problem. In this paper, we highlight the technology available to achieve process control for all implant parameters associated with modem semiconductor manufacturing.

Radiation evaluation study of LSI RAM technologies

NASA Astrophysics Data System (ADS)

Dinger, G. L.; Knoll, M. G.

1980-01-01

Five commercial LSI static random access memory technologies having a 1 kilobit capacity were radiation characterized. Arrays from the transistor-transistor-logic (TTL), Schottky TTL, n-channel metal oxide semiconductor, complementary metal oxide semiconductor (CMOS), and CMOS/silicon on sapphire families were evaluated. Radiation failure thresholds for gamma doserate logic upset, total gamma dose survivability, and neutron fluence survivability were determined. A brief analysis of the radiation failure mechanism for each of the logic families tested is included.

Native gallium adatoms discovered on atomically-smooth gallium nitride surfaces at low temperature.

PubMed

Alam, Khan; Foley, Andrew; Smith, Arthur R

2015-03-11

In advanced compound semiconductor devices, such as in quantum dot and quantum well systems, detailed atomic configurations at the growth surfaces are vital in determining the structural and electronic properties. Therefore, it is important to investigate the surface reconstructions in order to make further technological advancements. Usually, conventional semiconductor surfaces (e.g., arsenides, phosphides, and antimonides) are highly reactive due to the existence of a high density of group V (anion) surface dangling bonds. However, in the case of nitrides, group III rich growth conditions in molecular beam epitaxy are usually preferred leading to group III (Ga)-rich surfaces. Here, we use low-temperature scanning tunneling microscopy to reveal a uniform distribution of native gallium adatoms with a density of 0.3%-0.5% of a monolayer on the clean, as-grown surface of nitrogen polar GaN(0001̅) having the centered 6 × 12 reconstruction. Unseen at room temperature, these Ga adatoms are strongly bound to the surface but move with an extremely low surface diffusion barrier and a high density saturation coverage in thermodynamic equilibrium with Ga droplets. Furthermore, the Ga adatoms reveal an intrinsic surface chirality and an asymmetric site occupation. These observations can have important impacts in the understanding of gallium nitride surfaces.

Optimization of 248nm bottom anti-reflective coatings with thin film and high etch rate on real device

NASA Astrophysics Data System (ADS)

Kim, MyoungSoo; Kim, HakJoon; Shim, KewChan; Jeon, JeHa; Gil, MyungGoon; Song, YongWook; Enomoto, Tomoyuki; Sakaguchi, Takahiro; Nakajima, Yasuyuki

2005-05-01

A frequent problem encountered by photoresists during the manufacturing of semiconductor device is that activating radiation is reflected back into the photoresist by the substrate. So, it is necessary that the light reflection is reduced from the substrate. One approach to reduce the light reflection is the use of bottom anti-reflective coating (BARC) applied to the substrate beneath the photoresist layer. The BARC technology has been utilized for a few years to minimize the reflectivity. As the chip size is reduced to sub 100nm, the photoresist thickness has to decrease with the aspect ratio being less than 3.0. Therefore, new Organic BARC is strongly required which has the minimum reflectivity with thinner BARC thickness and higher etch selectivity toward resists. Hynix Semiconductor Inc., Nissan Chemical Industries, Ltd., and Brewer Science, Inc. have developed the advanced Organic BARC for achieving the above purpose. As a result, the suitable high performance 248nm Organic BARCs, NCA series, were achieved. Using CF4 gas as etchant, the plasma etch rate of NCA series is about 1.4 times higher than that of conventional 248nm resists. NCA series can be minimizing the substrate reflectivity at below 45nm BARC thickness. NCA series show the excellent litho performance and coating property on real device.

Rapid, all dry microfabrication of three-dimensional Co3O4/Pt nanonetworks for high-performance microsupercapacitors.

PubMed

Ma, Xinyu; Feng, Shuxuan; He, Liang; Yan, Mengyu; Tian, Xiaocong; Li, Yanxi; Tang, Chunjuan; Hong, Xufeng; Mai, Liqiang

2017-08-17

On-chip electrochemical energy storage devices have attracted growing attention due to the decreasing size of electronic devices. Various approaches have been applied for constructing the microsupercapacitors. However, the microfabrication of high-performance microsupercapacitors by conventional and fully compatible semiconductor microfabrication technologies is still a critical challenge. Herein, unique three-dimensional (3D) Co 3 O 4 nanonetwork microelectrodes formed by the interconnection of Co 3 O 4 nanosheets are constructed by controllable physical vapor deposition combined with rapid thermal annealing. This construction process is an all dry and rapid (≤5 minutes) procedure. Afterward, by sputtering highly electrically conductive Pt nanoparticles on the microelectrodes, the 3D Co 3 O 4 /Pt nanonetworks based microsupercapacitor is fabricated, showing a high volume capacitance (35.7 F cm -3 ) at a scan rate of 20 mV s -1 due to the unique interconnected structures, high electrical conductivity and high surface area of the microelectrodes. This microfabrication process is also used to construct high-performance flexible microsupercapacitors, and it can be applied in the construction of wearable devices. The proposed strategy is completely compatible with the current semiconductor microfabrication and shows great potential in the applications of the large-scale integration of micro/nano and wearable devices.

Real time in vivo imaging and measurement of serine protease activity in the mouse hippocampus using a dedicated complementary metal-oxide semiconductor imaging device.

PubMed

Ng, David C; Tamura, Hideki; Tokuda, Takashi; Yamamoto, Akio; Matsuo, Masamichi; Nunoshita, Masahiro; Ishikawa, Yasuyuki; Shiosaka, Sadao; Ohta, Jun

2006-09-30

The aim of the present study is to demonstrate the application of complementary metal-oxide semiconductor (CMOS) imaging technology for studying the mouse brain. By using a dedicated CMOS image sensor, we have successfully imaged and measured brain serine protease activity in vivo, in real-time, and for an extended period of time. We have developed a biofluorescence imaging device by packaging the CMOS image sensor which enabled on-chip imaging configuration. In this configuration, no optics are required whereby an excitation filter is applied onto the sensor to replace the filter cube block found in conventional fluorescence microscopes. The fully packaged device measures 350 microm thick x 2.7 mm wide, consists of an array of 176 x 144 pixels, and is small enough for measurement inside a single hemisphere of the mouse brain, while still providing sufficient imaging resolution. In the experiment, intraperitoneally injected kainic acid induced upregulation of serine protease activity in the brain. These events were captured in real time by imaging and measuring the fluorescence from a fluorogenic substrate that detected this activity. The entire device, which weighs less than 1% of the body weight of the mouse, holds promise for studying freely moving animals.

A system approach for reducing the environmental impact of manufacturing and sustainability improvement of nano-scale manufacturing

NASA Astrophysics Data System (ADS)

Yuan, Yingchun

This dissertation develops an effective and economical system approach to reduce the environmental impact of manufacturing. The system approach is developed by using a process-based holistic method for upstream analysis and source reduction of the environmental impact of manufacturing. The system approach developed consists of three components of a manufacturing system: technology, energy and material, and is useful for sustainable manufacturing as it establishes a clear link between manufacturing system components and its overall sustainability performance, and provides a framework for environmental impact reductions. In this dissertation, the system approach developed is applied for environmental impact reduction of a semiconductor nano-scale manufacturing system, with three case scenarios analyzed in depth on manufacturing process improvement, clean energy supply, and toxic chemical material selection. The analysis on manufacturing process improvement is conducted on Atomic Layer Deposition of Al2O3 dielectric gate on semiconductor microelectronics devices. Sustainability performance and scale-up impact of the ALD technology in terms of environmental emissions, energy consumption, nano-waste generation and manufacturing productivity are systematically investigated and the ways to improve the sustainability of the ALD technology are successfully developed. The clean energy supply is studied using solar photovoltaic, wind, and fuel cells systems for electricity generation. Environmental savings from each clean energy supply over grid power are quantitatively analyzed, and costs for greenhouse gas reductions on each clean energy supply are comparatively studied. For toxic chemical material selection, an innovative schematic method is developed as a visual decision tool for characterizing and benchmarking the human health impact of toxic chemicals, with a case study conducted on six chemicals commonly used as solvents in semiconductor manufacturing. Reliability of the schematic method is validated by comparing its benchmark results on 104 chemicals with that from the conventional Human Toxicity Potential (HTP) method. This dissertation concludes with discussions on environmental impact assessment of nanotechnologies and sustainability management of nano-particles. As nano-manufacturing is emerging for wide industrial applications, improvement and expansion of the system approach would be valuable for use in the environmental management of nano-manufacturing and in the risk control of nano-particles in the interests of public health and the environment.

Structural, electrical and optical characterization of high brightness phosphor-free white light emitting diodes

NASA Astrophysics Data System (ADS)

Omiya, Hiromasa

Much interest currently exists in GaN and related materials for applications such as light-emitting devices operating in the amber to ultraviolet range. Solid-state lighting (SSL) using these materials is widely being investigated worldwide, especially due to their high-energy efficiency and its impact on environmental issues. A new approach for solid-state lighting uses phosphor-free white light emitting diodes (LEDs) that consist of blue, green, and red quantum wells (QW), all in a single device. This approach leads to improved color rendering, and directionality, compared to the conventional white LEDs that use yellow phosphor on blue or ultraviolet emitters. Improving the brightness of these phosphor-free white LEDs should enhance and accelerate the development of SSL technology. The main objective of the research reported in this dissertation is to provide a comprehensive understanding of the nature of the multiple quantum wells used in phosphor-free white LEDs. This dissertation starts with an introduction to lighting history, the fundamental concepts of nitride semiconductors, and the evolution of LED technology. Two important challenges in LED technology today are metal-semiconductor contacts and internal piezoelectric fields present in quantum well structures. Thus, the main portion of this dissertation consists of three parts dealing with metal-semiconductor interfaces, single quantum well structures, and multiple quantum well devices. Gold-nickel alloys are widely used as contacts to the p-region of LEDs. We have performed a detailed study for its evolution under standard annealing steps. The atomic arrangement of gold at its interface with GaN gives a clear explanation for the improved ohmic contact performance. We next focus on the nature of InGaN QWs. The dynamic response of the QWs was studied with electron holography and time-resolved cathodoluminescence. Establishing the correlation between energy band structure and the light emission spectra elucidated the nature of light emission. Finally, we studied a more complex device, consisting of two red, one green, and two blue emitting quantum wells. A correlation between structural, electrical and optical measurements allows us to understand the dynamic performance of this device. The collective results of this dissertation lead to an improved understanding of the performance of high-brightness, phosphor-free, white LEDs.

Linear and passive silicon diodes, isolators, and logic gates

NASA Astrophysics Data System (ADS)

Li, Zhi-Yuan

2013-12-01

Silicon photonic integrated devices and circuits have offered a promising means to revolutionalize information processing and computing technologies. One important reason is that these devices are compatible with conventional complementary metal oxide semiconductor (CMOS) processing technology that overwhelms current microelectronics industry. Yet, the dream to build optical computers has yet to come without the breakthrough of several key elements including optical diodes, isolators, and logic gates with low power, high signal contrast, and large bandwidth. Photonic crystal has a great power to mold the flow of light in micrometer/nanometer scale and is a promising platform for optical integration. In this paper we present our recent efforts of design, fabrication, and characterization of ultracompact, linear, passive on-chip optical diodes, isolators and logic gates based on silicon two-dimensional photonic crystal slabs. Both simulation and experiment results show high performance of these novel designed devices. These linear and passive silicon devices have the unique properties of small fingerprint, low power request, large bandwidth, fast response speed, easy for fabrication, and being compatible with COMS technology. Further improving their performance would open up a road towards photonic logics and optical computing and help to construct nanophotonic on-chip processor architectures for future optical computers.

Nanowire Photovoltaic Devices

NASA Technical Reports Server (NTRS)

Forbes, David

2015-01-01

Firefly Technologies, in collaboration with the Rochester Institute of Technology and the University of Wisconsin-Madison, developed synthesis methods for highly strained nanowires. Two synthesis routes resulted in successful nanowire epitaxy: direct nucleation and growth on the substrate and a novel selective-epitaxy route based on nanolithography using diblock copolymers. The indium-arsenide (InAs) nanowires are implemented in situ within the epitaxy environment-a significant innovation relative to conventional semiconductor nanowire generation using ex situ gold nanoparticles. The introduction of these nanoscale features may enable an intermediate band solar cell while simultaneously increasing the effective absorption volume that can otherwise limit short-circuit current generated by thin quantized layers. The use of nanowires for photovoltaics decouples the absorption process from the current extraction process by virtue of the high aspect ratio. While no functional solar cells resulted from this effort, considerable fundamental understanding of the nanowire epitaxy kinetics and nanopatterning process was developed. This approach could, in principle, be an enabling technology for heterointegration of dissimilar materials. The technology also is applicable to virtual substrates. Incorporating nanowires onto a recrystallized germanium/metal foil substrate would potentially solve the problem of grain boundary shunting of generated carriers by restricting the cross-sectional area of the nanowire (tens of nanometers in diameter) to sizes smaller than the recrystallized grains (0.5 to 1 micron(exp 2).

Room-temperature semiconductor heterostructure refrigeration

NASA Astrophysics Data System (ADS)

Chao, K. A.; Larsson, Magnus; Mal'shukov, A. G.

2005-07-01

With the proper design of semiconductor tunneling barrier structures, we can inject low-energy electrons via resonant tunneling, and take out high-energy electrons via a thermionic process. This is the operation principle of our semiconductor heterostructure refrigerator (SHR) without the need of applying a temperature gradient across the device. Even for the bad thermoelectric material AlGaAs, our calculation shows that at room temperature, the SHR can easily lower the temperature by 5-7K. Such devices can be fabricated with the present semiconductor technology. Besides its use as a kitchen refrigerator, the SHR can efficiently cool microelectronic devices.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nurmikko, Arto V

Synthesis of semiconductor nanomaterials by low-cost, solution-based methods is shown to lead to new classes of thin film light emitting materials. These materials have been integrated to demonstrative compact laser device testbeds to illustrate their potential for coherent emitters across the visible spectrum to disrupt established photonics technologies, particularly semiconductor lasers?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moghadam, Reza M.; Xiao, Zhiyong; Ahmadi-Majlan, Kamyar

The epitaxial growth of multifunctional oxides on semiconductors has opened a pathway to introduce new functionalities to semiconductor device technologies. In particular, ferroelectric materials integrated on semiconductors could lead to low-power field-effect devices that can be used for logic or memory. Essential to realizing such field-effect devices is the development of ferroelectric metal-oxide-semiconductor (MOS) capacitors, in which the polarization of a ferroelectric gate is coupled to the surface potential of a semiconducting channel. Here we demonstrate that ferroelectric MOS capacitors can be realized using single crystalline SrZrxTi1-xO3 (x= 0.7) that has been epitaxially grown on Ge. We find that themore » ferroelectric properties of SrZrxTi1-xO3 are exceptionally robust, as gate layers as thin as 5 nm give rise to hysteretic capacitance-voltage characteristics that are 2 V in width. The development of ferroelectric MOS capacitors with gate thicknesses that are technologically relevant opens a pathway to realize scalable ferroelectric field-effect devices.« less

Growth of Wide Band Gap II-VI Compound Semiconductors by Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Sha, Yi-Gao

1995-01-01

The studies on the crystal growth and characterization of II-VI wide band gap compound semiconductors, such as ZnTe, CdS, ZnSe and ZnS, have been conducted over the past three decades. The research was not quite as extensive as that on Si, III-V, or even narrow band gap II-VI semiconductors because of the high melting temperatures as well as the specialized applications associated with these wide band gap semiconductors. In the past several years, major advances in the thin film technology such as Molecular Beam Epitaxy (MBE) and Metal Organic Chemical Vapor Deposition (MOCVD) have demonstrated the applications of these materials for the important devices such as light-emitting diode, laser and ultraviolet detectors and the tunability of energy band gap by employing ternary or even quaternary systems of these compounds. At the same time, the development in the crystal growth of bulk materials has not advanced far enough to provide low price, high quality substrates needed for the thin film growth technology.

A Fully Implemented 12 × 12 Data Vortex Optical Packet Switching Interconnection Network

NASA Astrophysics Data System (ADS)

Shacham, Assaf; Small, Benjamin A.; Liboiron-Ladouceur, Odile; Bergman, Keren

2005-10-01

A fully functional optical packet switching (OPS) interconnection network based on the data vortex architecture is presented. The photonic switching fabric uniquely capitalizes on the enormous bandwidth advantage of wavelength division multiplexing (WDM) wavelength parallelism while delivering minimal packet transit latency. Utilizing semiconductor optical amplifier (SOA)-based switching nodes and conventional fiber-optic technology, the 12-port system exhibits a capacity of nearly 1 Tb/s. Optical packets containing an eight-wavelength WDM payload with 10 Gb/s per wavelength are routed successfully to all 12 ports while maintaining a bit error rate (BER) of 10-12 or better. Median port-to-port latencies of 110 ns are achieved with a distributed deflection routing network that resolves packet contention on-the-fly without the use of optical buffers and maintains the entire payload path in the optical domain.

Subwavelength core/shell cylindrical nanostructures for novel plasmonic and metamaterial devices

NASA Astrophysics Data System (ADS)

Kim, Kyoung-Ho; No, You-Shin

2017-12-01

In this review, we introduce novel plasmonic and metamaterial devices based on one-dimensional subwavelength nanostructures with cylindrical symmetry. Individual single devices with semiconductor/metal core/shell or dielectric/metal core/multi-shell structures experience strong light-matter interaction and yield unique optical properties with a variety of functions, e.g., invisibility cloaking, super-scattering/super-absorption, enhanced luminescence and nonlinear optical activities, and deep subwavelength-scale optical waveguiding. We describe the rational design of core/shell cylindrical nanostructures and the proper choice of appropriate constituent materials, which allow the efficient manipulation of electromagnetic waves and help to overcome the limitations of conventional homogeneous nanostructures. The recent developments of bottom-up synthesis combined with the top-down fabrication technologies for the practical applications and the experimental realizations of 1D subwavelength core/shell nanostructure devices are briefly discussed.

Uncertain behaviours of integrated circuits improve computational performance.

PubMed

Yoshimura, Chihiro; Yamaoka, Masanao; Hayashi, Masato; Okuyama, Takuya; Aoki, Hidetaka; Kawarabayashi, Ken-ichi; Mizuno, Hiroyuki

2015-11-20

Improvements to the performance of conventional computers have mainly been achieved through semiconductor scaling; however, scaling is reaching its limitations. Natural phenomena, such as quantum superposition and stochastic resonance, have been introduced into new computing paradigms to improve performance beyond these limitations. Here, we explain that the uncertain behaviours of devices due to semiconductor scaling can improve the performance of computers. We prototyped an integrated circuit by performing a ground-state search of the Ising model. The bit errors of memory cell devices holding the current state of search occur probabilistically by inserting fluctuations into dynamic device characteristics, which will be actualised in the future to the chip. As a result, we observed more improvements in solution accuracy than that without fluctuations. Although the uncertain behaviours of devices had been intended to be eliminated in conventional devices, we demonstrate that uncertain behaviours has become the key to improving computational performance.

THz semiconductor-based front-end receiver technology for space applications

NASA Technical Reports Server (NTRS)

Mehdi, Imran; Siegel, Peter

2004-01-01

Advances in the design and fabrication of very low capacitance planar Schottky diodes and millimeter-wave power amplifiers, more accurate device and circuit models for commercial 3-D electromagnetic simulators, and the availability of both MEMS and high precision metal machining, have enabled RF engineers to extend traditional waveguide-based sensor and source technologies well into the TI-Iz frequency regime. This short paper will highlight recent progress in realizing THz space-qualified receiver front-ends based on room temperature semiconductor devices.

Hydrogen Sensors Using Nitride-Based Semiconductor Diodes: The Role of Metal/Semiconductor Interfaces

PubMed Central

Irokawa, Yoshihiro

2011-01-01

In this paper, I review my recent results in investigating hydrogen sensors using nitride-based semiconductor diodes, focusing on the interaction mechanism of hydrogen with the devices. Firstly, effects of interfacial modification in the devices on hydrogen detection sensitivity are discussed. Surface defects of GaN under Schottky electrodes do not play a critical role in hydrogen sensing characteristics. However, dielectric layers inserted in metal/semiconductor interfaces are found to cause dramatic changes in hydrogen sensing performance, implying that chemical selectivity to hydrogen could be realized. The capacitance-voltage (C–V) characteristics reveal that the work function change in the Schottky metal is not responsible mechanism for hydrogen sensitivity. The interface between the metal and the semiconductor plays a critical role in the interaction of hydrogen with semiconductor devises. Secondly, low-frequency C–V characterization is employed to investigate the interaction mechanism of hydrogen with diodes. As a result, it is suggested that the formation of a metal/semiconductor interfacial polarization could be attributed to hydrogen-related dipoles. In addition, using low-frequency C–V characterization leads to clear detection of 100 ppm hydrogen even at room temperature where it is hard to detect hydrogen by using conventional current-voltage (I–V) characterization, suggesting that low-frequency C–V method would be effective in detecting very low hydrogen concentrations. PMID:22346597

Narrow-band double-pass superluminescent diodes emitting at 1060 nm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lobintsov, A A; Perevozchikov, M V; Shramenko, M V

2009-09-30

Experimental data are presented which show that double-pass superluminescent diodes (SLDs) with fibre Bragg grating (FBG) based spectrally selective external reflectors offer emission linewidths in the range 0.1-1.0 nm, i.e., one to two orders of magnitude narrower in comparison with conventional SLDs and considerably broader in comparison with single-frequency semiconductor lasers. Their optical power at the single-mode fibre output reaches 5.0-8.0 mW, and can be raised to 50 mW using a semiconductor optical amplifier. (lasers)

Analysis of signal to noise enhancement using a highly selective modulation tracking filter

NASA Technical Reports Server (NTRS)

Haden, C. R.; Alworth, C. W.

1972-01-01

Experiments are reported which utilize photodielectric effects in semiconductor loaded superconducting resonant circuits for suppressing noise in RF communication systems. The superconducting tunable cavity acts as a narrow band tracking filter for detecting conventional RF signals. Analytical techniques were developed which lead to prediction of signal-to-noise improvements. Progress is reported in optimization of the experimental variables. These include improved Q, new semiconductors, improved optics, and simplification of the electronics. Information bearing signals were passed through the system, and noise was introduced into the computer model.

32nd International Conference on the Physics of Semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chelikowsky, James

The International Conference on the Physics of Semiconductors (ICPS) continues a series of biennial conferences that began in the 1950's. ICPS is the premier meeting for reporting all aspects of semiconductor physics including electronic, structural, optical, magnetic and transport properties with an emphasis on new materials and their applications. The meeting will reflect the state of art in the semiconductor physics field and will serve as a forum where scholars, researchers, and specialists can interact to discuss future research directions and technological advancements. The conference typically draws 1,000 international physicists, scientists, and students. This is one of the largest sciencemore » meetings on semiconductors and related materials to be held in the United States.« less

MSM-Metal Semiconductor Metal Photo-detector Using Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Detection

DTIC Science & Technology

2012-09-01

MSM) photodectors fabricated using black silicon-germanium on silicon substrate (Si1–xGex//Si) for I-V, optical response, external quantum ...material for Si for many applications in low-power and high-speed semiconductor device technologies (4, 5). It is a promising material for quantum well ...MSM-Metal Semiconductor Metal Photo-detector Using Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Detection by Fred

Integrating Asynchronous Digital Design Into the Computer Engineering Curriculum

ERIC Educational Resources Information Center

Smith, S. C.; Al-Assadi, W. K.; Di, J.

2010-01-01

As demand increases for circuits with higher performance, higher complexity, and decreased feature size, asynchronous (clockless) paradigms will become more widely used in the semiconductor industry, as evidenced by the International Technology Roadmap for Semiconductors' (ITRS) prediction of a likely shift from synchronous to asynchronous design…

Calibration-free absolute frequency response measurement of directly modulated lasers based on additional modulation.

PubMed

Zhang, Shangjian; Zou, Xinhai; Wang, Heng; Zhang, Yali; Lu, Rongguo; Liu, Yong

2015-10-15

A calibration-free electrical method is proposed for measuring the absolute frequency response of directly modulated semiconductor lasers based on additional modulation. The method achieves the electrical domain measurement of the modulation index of directly modulated lasers without the need for correcting the responsivity fluctuation in the photodetection. Moreover, it doubles measuring frequency range by setting a specific frequency relationship between the direct and additional modulation. Both the absolute and relative frequency response of semiconductor lasers are experimentally measured from the electrical spectrum of the twice-modulated optical signal, and the measured results are compared to those obtained with conventional methods to check the consistency. The proposed method provides calibration-free and accurate measurement for high-speed semiconductor lasers with high-resolution electrical spectrum analysis.

Technology Development of Miniaturized Far-Infrared Sources for Biomolecular Spectroscopy

NASA Technical Reports Server (NTRS)

Kono, Junichiro

2003-01-01

The objective of this project was to develop a purely solid-state based, thus miniaturized, far-infrared (FIR) (also known as terahertz (THz)) wave source using III-V semiconductor nanostructures for biomolecular detection and sensing. Many biomolecules, such as DNA and proteins, have distinct spectroscopic features in the FIR wavelength range as a result of vibration-rotation-tunneling motions and various inter- and intra-molecule collective motions. Spectroscopic characterization of such molecules requires narrow linewidth, sufficiently high power, tunable (in wavelength), and coherent FIR sources. Unfortunately, the FIR frequency is one of the least technologically developed ranges in the electromagnetic spectrum. Currently available FIR sources based on non-solid state technology are bulky, inefficient, and very often incoherent. In this project we investigated antimonide based compound semiconductor (ABCS) nanostructures as the active medium to generate FIR radiation. The final goal of this project was to demonstrate a semiconductor THz source integrated with a pumping diode laser module to achieve a compact system for biomolecular applications.

The FinFET Breakthrough and Networks of Innovation in the Semiconductor Industry, 1980-2005: Applying Digital Tools to the History of Technology.

PubMed

O'Reagan, Douglas; Fleming, Lee

2018-01-01

The "FinFET" design for transistors, developed at the University of California, Berkeley, in the 1990s, represented a major leap forward in the semiconductor industry. Understanding its origins and importance requires deep knowledge of local factors, such as the relationships among the lab's principal investigators, students, staff, and the institution. It also requires understanding this lab within the broader network of relationships that comprise the semiconductor industry-a much more difficult task using traditional historical methods, due to the paucity of sources on industrial research. This article is simultaneously 1) a history of an impactful technology and its social context, 2) an experiment in using data tools and visualizations as a complement to archival and oral history sources, to clarify and explore these "big picture" dimensions, and 3) an introduction to specific data visualization tools that we hope will be useful to historians of technology more generally.

A review of the semiconductor storage of television signals. Part 2: Applications 1975-1986

NASA Astrophysics Data System (ADS)

Riley, J. L.

1987-08-01

This is the second of two reports. In the first, the emerging semiconductor memory technology over the last two decades and some of the important operational characteristics of each ensuing generation of device are described together with the design philosophy for forming the devices into useful tools for the storage of television signals. The second of these reports describes some of the applications. These include improved television synchronizers, high quality PAL decoders, television noise reducers, film dirt concealment equipment and buffer storage for television picture processing equipment such as stills stores. The continuing developments in the technology promise still further increases of memory capacity and there is a proposal to build a mass semiconductor television picture sequence store, initially as a research tool.

The electronic band structures of gadolinium chalcogenides: a first-principles prediction for neutron detecting

NASA Astrophysics Data System (ADS)

Li, Kexue; Liu, Lei; Yu, Peter Y.; Chen, Xiaobo; Shen, D. Z.

2016-05-01

By converting the energy of nuclear radiation to excited electrons and holes, semiconductor detectors have provided a highly efficient way for detecting them, such as photons or charged particles. However, for detecting the radiated neutrons, those conventional semiconductors hardly behave well, as few of them possess enough capability for capturing these neutral particles. While the element Gd has the highest nuclear cross section, here for searching proper neutron-detecting semiconductors, we investigate theoretically the Gd chalcogenides whose electronic band structures have never been characterized clearly. Among them, we identify that γ-phase Gd2Se3 should be the best candidate for neutron detecting since it possesses not only the right bandgap of 1.76 eV for devices working under room temperature but also the desired indirect gap nature for charge carriers surviving longer. We propose further that semiconductor neutron detectors with single-neutron sensitivity can be realized with such a Gd-chalcogenide on the condition that their crystals can be grown with good quality.

The electronic band structures of gadolinium chalcogenides: a first-principles prediction for neutron detecting.

PubMed

Li, Kexue; Liu, Lei; Yu, Peter Y; Chen, Xiaobo; Shen, D Z

2016-05-11

By converting the energy of nuclear radiation to excited electrons and holes, semiconductor detectors have provided a highly efficient way for detecting them, such as photons or charged particles. However, for detecting the radiated neutrons, those conventional semiconductors hardly behave well, as few of them possess enough capability for capturing these neutral particles. While the element Gd has the highest nuclear cross section, here for searching proper neutron-detecting semiconductors, we investigate theoretically the Gd chalcogenides whose electronic band structures have never been characterized clearly. Among them, we identify that γ-phase Gd2Se3 should be the best candidate for neutron detecting since it possesses not only the right bandgap of 1.76 eV for devices working under room temperature but also the desired indirect gap nature for charge carriers surviving longer. We propose further that semiconductor neutron detectors with single-neutron sensitivity can be realized with such a Gd-chalcogenide on the condition that their crystals can be grown with good quality.

Barrier height enhancement of metal/semiconductor contact by an enzyme biofilm interlayer

NASA Astrophysics Data System (ADS)

Ocak, Yusuf Selim; Gul Guven, Reyhan; Tombak, Ahmet; Kilicoglu, Tahsin; Guven, Kemal; Dogru, Mehmet

2013-06-01

A metal/interlayer/semiconductor (Al/enzyme/p-Si) MIS device was fabricated using α-amylase enzyme as a thin biofilm interlayer. It was observed that the device showed an excellent rectifying behavior and the barrier height value of 0.78 eV for Al/α-amylase/p-Si was meaningfully larger than the one of 0.58 eV for conventional Al/p-Si metal/semiconductor (MS) contact. Enhancement of the interfacial potential barrier of Al/p-Si MS diode was realized using enzyme interlayer by influencing the space charge region of Si semiconductor. The electrical properties of the structure were executed by the help of current-voltage and capacitance-voltage measurements. The photovoltaic properties of the structure were executed under a solar simulator with AM1.5 global filter between 40 and 100 mW/cm2 illumination conditions. It was also reported that the α-amylase enzyme produced from Bacillus licheniformis had a 3.65 eV band gap value obtained from optical method.

Noncontact, Electrode-free Capacitance/Voltage Measurement Based on General Theory of Metal-Oxide-Semiconductor (MOS) Structure

NASA Astrophysics Data System (ADS)

Sakai, Takamasa; Kohno, Motohiro; Hirae, Sadao; Nakatani, Ikuyoshi; Kusuda, Tatsufumi

1993-09-01

In this paper, we discussed a novel approach to semiconductor surface inspection, which is analysis using the C--V curve measured in a noncontact method by the metal-air-semiconductor (MAIS) technique. A new gap sensing method using the so-called Goos-Haenchen effect was developed to achieve the noncontact C--V measurement. The MAIS technique exhibited comparable sensitivity and repeatability to those of conventional C--V measurement, and hence, good reproducibility and resolution for quantifying the electrically active impurity on the order of 1× 109/cm2, which is better than most spectrometric techniques, such as secondary ion mass spectroscopy (SIMS), electron spectroscopy for chemical analysis (ESCA) and Auger electron spectrocopy (AES) which are time-consuming and destructive. This measurement without preparation of any electrical contact metal electrode suggested, for the first time, the possibility of measuring an intrinsic characteristic of the semiconductor surface, using the examples of a concrete examination.

Electron counting and a large family of two-dimensional semiconductors

NASA Astrophysics Data System (ADS)

Miao, Maosheng; Botana, Jorge; Zurek, Eva; Liu, Jingyao; Yang, Wen

Two-dimensional semiconductors (2DSC) are currently the focus of many studies, thanks to their novel and superior transport properties that may greatly influence future electronic devices. The potential applications of 2DSCs range from low-dimensional electronics, topological insulators and vallytronics all the way to novel photolysis. However, compared with the conventional semiconductors that are comprised of main group elements and cover a large range of band gaps and lattice constants, the choice of 2D materials is very limited. In this work, we propose and demonstrate a large family of 2DSCs, all adopting the same structure and consisting of only main group elements. Using advanced density functional calculations, we demonstrate the attainability of these materials, and show that they cover a large range of lattice constants, band gaps and band edge states, making them good candidate materials for heterojunctions. This family of two dimensional materials may be instrumental in the fabrication of 2DSC devices that may rival the currently employed 3D semiconductors.

Nanopatterned organic semiconductors for visible light communications

NASA Astrophysics Data System (ADS)

Yang, Xilu; Dong, Yurong; Zeng, Pan; Yu, Yan; Xie, Yujun; Gong, Junyi; Shi, Meng; Liang, Rongqing; Ou, Qiongrong; Chi, Nan; Zhang, Shuyu

2018-03-01

Visible light communication (VLC) is becoming an important and promising supplement to the existing Wi-Fi network for the coming 5G communications. Organic light-emitting semiconductors present much fast fluorescent decay rates compared to those of conventional colour-converting phosphors, therefore capable of achieving much higher bandwidths. Here we explore how nanopatterned organic semiconductors can further enhance the data rates of VLC links by improving bandwidths and signal-to-noise ratios (SNRs) and by supporting spatial multiplexing. We first demonstrate a colour-converting VLC system based on nanopatterned hyperbolic metamaterials (HMM), the bandwidth of which is enhanced by 50%. With regard to enhancing SNRs, we achieve a tripling of optical gain by integrating a nanopatterned luminescent concentrator to a signal receiver. In addition, we demonstrate highly directional fluorescent VLC antennas based on nanoimprinted polymer films, paving the way to achieving parallel VLC communications via spatialmultiplexing. These results indicate nanopatterned organic semiconductors provide a promising route to high speed VLC links.

Self-assembled molecular magnets on patterned silicon substrates: bridging bio-molecules with nanoelectronics.

PubMed

Chang, Chia-Ching; Sun, Kien Wen; Lee, Shang-Fan; Kan, Lou-Sing

2007-04-01

The paper reports the methods of preparing molecular magnets and patterning of the molecules on a semiconductor surface. A highly magnetically aligned metallothionein containing Mn and Cd (Mn,Cd-MT-2) is first synthesized, and the molecules are then placed into nanopores prepared on silicon (001) surfaces using electron beam lithography and reactive ion-etching techniques. We have observed the self-assemble growth of the MT molecules on the patterned Si surface such that the MT molecules have grown into rod or ring type three-dimensional nanostructures, depending on the patterned nanostructures on the surface. We also provide scanning electron microscopy, atomic force microscopy, and magnetic force microscope studies of the molecular nanostructures. This engineered molecule shows molecular magnetization and is biocompatible with conventional semiconductors. These features make Mn,Cd-MT-2 a good candidate for biological applications and sensing sources of new nanodevices. Using molecular self-assembly and topographical patterning of the semiconductor substrate, we can close the gap between bio-molecules and nanoelectronics built into the semiconductor chip.

Clinical application of the OneDose™ Patient Dosimetry System for total body irradiation

NASA Astrophysics Data System (ADS)

Best, S.; Ralston, A.; Suchowerska, N.

2005-12-01

The OneDose™ Patient Dosimetry System (Sicel Technologies) is a new dosimeter based on metal oxide semiconductor field-effect transistor technology and designed for the in vivo measurement of patient dose during radiotherapy. In vivo dosimetry for total body irradiation (TBI) is challenging due to the extended treatment distance, low dose rates and beam spoilers. Phantom results confirm the suitability of the dosimeter for TBI in terms of inherent build-up, post-irradiation fading, accuracy, reproducibility, linearity and temperature dependence. Directional dependence is significant and should be taken into account. The OneDose™ dosimeters were also trialed in vivo for two TBI patients and the dose measured compared to conventional dosimeter measurements using an ionization chamber and thermoluminescent dosimeters (TLD), with agreement to within 2.2% and 3.9%, respectively. Phantom and patient results confirm that the OneDose™ patient dosimetry system is a practical and convenient alternative to TLDs for TBI in vivo dosimetry. For increased confidence in results with this dosimeter, we recommend that two dosimeters be used for each site of interest.

Clinical application of the OneDose Patient Dosimetry System for total body irradiation.

PubMed

Best, S; Ralston, A; Suchowerska, N

2005-12-21

The OneDose Patient Dosimetry System (Sicel Technologies) is a new dosimeter based on metal oxide semiconductor field-effect transistor technology and designed for the in vivo measurement of patient dose during radiotherapy. In vivo dosimetry for total body irradiation (TBI) is challenging due to the extended treatment distance, low dose rates and beam spoilers. Phantom results confirm the suitability of the dosimeter for TBI in terms of inherent build-up, post-irradiation fading, accuracy, reproducibility, linearity and temperature dependence. Directional dependence is significant and should be taken into account. The OneDose dosimeters were also trialed in vivo for two TBI patients and the dose measured compared to conventional dosimeter measurements using an ionization chamber and thermoluminescent dosimeters (TLD), with agreement to within 2.2% and 3.9%, respectively. Phantom and patient results confirm that the OneDose patient dosimetry system is a practical and convenient alternative to TLDs for TBI in vivo dosimetry. For increased confidence in results with this dosimeter, we recommend that two dosimeters be used for each site of interest.

An HDR imaging method with DTDI technology for push-broom cameras

NASA Astrophysics Data System (ADS)

Sun, Wu; Han, Chengshan; Xue, Xucheng; Lv, Hengyi; Shi, Junxia; Hu, Changhong; Li, Xiangzhi; Fu, Yao; Jiang, Xiaonan; Huang, Liang; Han, Hongyin

2018-03-01

Conventionally, high dynamic-range (HDR) imaging is based on taking two or more pictures of the same scene with different exposure. However, due to a high-speed relative motion between the camera and the scene, it is hard for this technique to be applied to push-broom remote sensing cameras. For the sake of HDR imaging in push-broom remote sensing applications, the present paper proposes an innovative method which can generate HDR images without redundant image sensors or optical components. Specifically, this paper adopts an area array CMOS (complementary metal oxide semiconductor) with the digital domain time-delay-integration (DTDI) technology for imaging, instead of adopting more than one row of image sensors, thereby taking more than one picture with different exposure. And then a new HDR image by fusing two original images with a simple algorithm can be achieved. By conducting the experiment, the dynamic range (DR) of the image increases by 26.02 dB. The proposed method is proved to be effective and has potential in other imaging applications where there is a relative motion between the cameras and scenes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Weihuan; France, David M.; Yu, Wenhua

At present, single-phase liquid, forced convection cooled heat sinks with fins are used to cool power electronics in hybrid electric vehicles (HEVs). Although use of fins in the cooling channels increases heat transfer rates considerably, a second low-temperature radiator and associated pumping system are still required in HEVs. This additional cooling system adds weight and cost while decreasing the efficiency of HEVs. With the objective of eliminating this additional low-temperature radiator and pumping system in HEVs, an alternative cooling technology, subcooled boiling in the cooling channels, was investigated in the present study. Numerical heat transfer simulations were performed using subcooledmore » boiling in the power electronics cooling channels with the coolant supplied from the existing main engine cooling system. Results show that this subcooled boiling system is capable of removing 25% more heat from the power electronics than the conventional forced convection cooling technology, or it can reduce the junction temperature of the power electronics at the current heat removal rate. With the 25% increased heat transfer option, high heat fluxes up to 250 W/cm(2) (typical for wideband-gap semiconductor applications) are possible by using the subcooled boiling system.« less

Consideration of correlativity between litho and etching shape

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Shinoda, Shinichi; Toyoda, Yasutaka

2012-03-01

We developed an effective method for evaluating the correlation of shape of Litho and Etching pattern. The purpose of this method, makes the relations of the shape after that is the etching pattern an index in wafer same as a pattern shape on wafer made by a lithography process. Therefore, this method measures the characteristic of the shape of the wafer pattern by the lithography process and can predict the hotspot pattern shape by the etching process. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used wafer CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and lithography management, and this has a big impact on the semiconductor market that centers on the semiconductor business. 2-dimensional shape of wafer quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. In this study, we conducted experiments for correlation method of the pattern (Measurement Based Contouring) as two-dimensional litho and etch evaluation technique. That is, observation of the identical position of a litho and etch was considered. It is possible to analyze variability of the edge of the same position with high precision.

Semiconductor laser technology for remote sensing experiments

NASA Technical Reports Server (NTRS)

Katz, Joseph

1988-01-01

Semiconductor injection lasers are required for implementing virtually all spaceborne remote sensing systems. Their main advantages are high reliability and efficiency, and their main roles are envisioned in pumping and injection locking of solid state lasers. In some shorter range applications they may even be utilized directly as the sources.

Topological Quantum Buses: Coherent Quantum Information Transfer between Topological and Conventional Qubits

NASA Astrophysics Data System (ADS)

Bonderson, Parsa; Lutchyn, Roman M.

2011-04-01

We propose computing bus devices that enable quantum information to be coherently transferred between topological and conventional qubits. We describe a concrete realization of such a topological quantum bus acting between a topological qubit in a Majorana wire network and a conventional semiconductor double quantum dot qubit. Specifically, this device measures the joint (fermion) parity of these two different qubits by using the Aharonov-Casher effect in conjunction with an ancilliary superconducting flux qubit that facilitates the measurement. Such a parity measurement, together with the ability to apply Hadamard gates to the two qubits, allows one to produce states in which the topological and conventional qubits are maximally entangled and to teleport quantum states between the topological and conventional quantum systems.

Editorial

NASA Astrophysics Data System (ADS)

Bruzzi, Mara; Cartiglia, Nicolo; Pace, Emanuele; Talamonti, Cinzia

2015-10-01

The 10th edition of the International Conference on Radiation Effects on Semiconductor Materials, Detectors and Devices (RESMDD) was held in Florence, at Dipartimento di Fisica ed Astronomia on October 8-10, 2014. It has been aimed at discussing frontier research activities in several application fields as nuclear and particle physics, astrophysics, medical and solid-state physics. Main topics discussed in this conference concern performance of heavily irradiated silicon detectors, developments required for the luminosity upgrade of the Large Hadron Collider (HL-LHC), ultra-fast silicon detectors design and manufacturing, high-band gap semiconductor detectors, novel semiconductor-based devices for medical applications, radiation damage issues in semiconductors and related radiation-hardening technologies.

Negative Differential Conductance & Hot-Carrier Avalanching in Monolayer WS2 FETs

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, G.; Nathawat, J.; Kwan, C. -P.

The high field phenomena of inter-valley transfer and avalanching breakdown have long been exploited in devices based on conventional semiconductors. In this Article, we demonstrate the manifestation of these effects in atomically-thin WS 2 field-effect transistors. The negative differential conductance exhibits all of the features familiar from discussions of this phenomenon in bulk semiconductors, including hysteresis in the transistor characteristics and increased noise that is indicative of travelling high-field domains. It is also found to be sensitive to thermal annealing, a result that we attribute to the influence of strain on the energy separation of the different valleys involved inmore » hot-electron transfer. This idea is supported by the results of ensemble Monte Carlo simulations, which highlight the sensitivity of the negative differential conductance to the equilibrium populations of the different valleys. At high drain currents (>10 μA/μm) avalanching breakdown is also observed, and is attributed to trap-assisted inverse Auger scattering. This mechanism is not normally relevant in conventional semiconductors, but is possible in WS 2 due to the narrow width of its energy bands. The various results presented here suggest that WS 2 exhibits strong potential for use in hot-electron devices, including compact high-frequency sources and photonic detectors.« less

Negative Differential Conductance & Hot-Carrier Avalanching in Monolayer WS2 FETs

DOE PAGES

He, G.; Nathawat, J.; Kwan, C. -P.; ...

2017-09-12

The high field phenomena of inter-valley transfer and avalanching breakdown have long been exploited in devices based on conventional semiconductors. In this Article, we demonstrate the manifestation of these effects in atomically-thin WS 2 field-effect transistors. The negative differential conductance exhibits all of the features familiar from discussions of this phenomenon in bulk semiconductors, including hysteresis in the transistor characteristics and increased noise that is indicative of travelling high-field domains. It is also found to be sensitive to thermal annealing, a result that we attribute to the influence of strain on the energy separation of the different valleys involved inmore » hot-electron transfer. This idea is supported by the results of ensemble Monte Carlo simulations, which highlight the sensitivity of the negative differential conductance to the equilibrium populations of the different valleys. At high drain currents (>10 μA/μm) avalanching breakdown is also observed, and is attributed to trap-assisted inverse Auger scattering. This mechanism is not normally relevant in conventional semiconductors, but is possible in WS 2 due to the narrow width of its energy bands. The various results presented here suggest that WS 2 exhibits strong potential for use in hot-electron devices, including compact high-frequency sources and photonic detectors.« less

Semiconductor lasers for versatile applications from global communications to on-chip interconnects

NASA Astrophysics Data System (ADS)

Arai, Shigehisa

2015-01-01

Since semiconductor lasers were realized in 1962, various efforts have been made to enrich human life thorough novel equipments and services. Among them optical fiber communications in global communications have brought out marvelous information technology age represented by the internet. In this paper, emerging topics made on GaInAsP/InP based long-wavelength lasers toward ultra-low power consumption semiconductor lasers for optical interconnects in supercomputers as well as in future LSIs are presented.

From Vacuum Tubes to a Semiconductor Triode

NASA Astrophysics Data System (ADS)

Mil'shtein, S.

2005-06-01

Current study presents a brief review of an electronic technology evolution: from vacuum tubes, to transistors, to a novel, recently developed semiconductor triode, where electrons travel vertically about 600 angstroms from the filament to the anode. We plotted I-V and transfer curves for the semiconductor triodes. The very first prototypes proved to carry a maximum gain of about 15db and fT=8GHz. Filaments of variable length were produced to study mutual electrostatic interaction of the electrodes in the triode.

Transparent Large-Area MoS2 Phototransistors with Inkjet-Printed Components on Flexible Platforms.

PubMed

Kim, Tae-Young; Ha, Jewook; Cho, Kyungjune; Pak, Jinsu; Seo, Jiseok; Park, Jongjang; Kim, Jae-Keun; Chung, Seungjun; Hong, Yongtaek; Lee, Takhee

2017-10-24

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have gained considerable attention as an emerging semiconductor due to their promising atomically thin film characteristics with good field-effect mobility and a tunable band gap energy. However, their electronic applications have been generally realized with conventional inorganic electrodes and dielectrics implemented using conventional photolithography or transferring processes that are not compatible with large-area and flexible device applications. To facilitate the advantages of 2D TMDCs in practical applications, strategies for realizing flexible and transparent 2D electronics using low-temperature, large-area, and low-cost processes should be developed. Motivated by this challenge, we report fully printed transparent chemical vapor deposition (CVD)-synthesized monolayer molybdenum disulfide (MoS 2 ) phototransistor arrays on flexible polymer substrates. All the electronic components, including dielectric and electrodes, were directly deposited with mechanically tolerable organic materials by inkjet-printing technology onto transferred monolayer MoS 2 , and their annealing temperature of <180 °C allows the direct fabrication on commercial flexible substrates without additional assisted-structures. By integrating the soft organic components with ultrathin MoS 2 , the fully printed MoS 2 phototransistors exhibit excellent transparency and mechanically stable operation.

Silicon material technology status. [assessment for electronic and photovoltaic applications

NASA Technical Reports Server (NTRS)

Lutwack, R.

1983-01-01

Silicon has been the basic element for the electronic and photovoltaic industries. The use of silicon as the primary element for terrestrial photovoltaic solar arrays is projected to continue. The reasons for this projection are related to the maturity of silicon technology, the ready availability of extremely pure silicon, the performance of silicon solar cells, and the considerable present investment in technology and manufacturing facilities. The technologies for producing semiconductor grade silicon and, to a lesser extent, refined metallurgical grade silicon are considered. It is pointed out that nearly all of the semiconductor grade silicon is produced by processes based on the Siemens deposition reactor, a technology developed 26 years ago. The state-of-the-art for producing silicon by this process is discussed. It is expected that efforts to reduce polysilicon process costs will continue.

Novel gallium nitride based microwave noise and power heterostructure field effect transistors

NASA Astrophysics Data System (ADS)

Chumbes, Eduardo Martin

With the pioneering efforts of Isamu Akasaki of Meiji University and Shuji Nakamura of Nichia Chemical Industries in the late 1980's and early 1990's, the first long-lived candela-class blue and ultraviolet light emitting devices have finally come to fruition. Their success in conquering this Holy Grail in opto-electronics is due to their development of a new technology based remarkably on a class of semiconductor materials that has been practically ignored and overlooked by almost everyone for the past twenty years---the nitrides of Al, Ga and In and their alloys. The breakthroughs made from this new technology in the last decade of the 20th century has revolutionized and revitalized worldwide research and development efforts to the point where it is feasible for other important technologies such as high-density information storage, high-resolution full-color displays and efficient white light lamps and UV sensors to come much closer to realization. Equally important is the potential that this new technology can bring toward the development of efficient ultra-high power and high-temperature electronics that will revolutionize the aerospace and high-speed communication industries. Specifically, the large bandgap and strong polar properties of the group III-nitrides has at present allowed for the realization of simple doped and remarkably undoped AlGaN/GaN transistor structures on sapphire and SiC substrates with two-dimensional electron gas sheet densities significantly greater than that of conventional transistor structures based on GaAs and InP. This dissertation will look specifically at extending undoped AlGaN/GaN heterostructure field-effect transistors or HFETs towards more advanced system applications involving the integration of these devices onto a more advanced Si technology and looking at the feasibility of this integration. It will also address important issues similar devices on semi-insulating SiC substrates have in robust microwave low noise and linear amplification. Finally, it will look at incorporating high-temperature silicon nitride passivation as a key ingredient to developing a unique class of devices: metal-insulator-semiconductor field effect transistors or MISFETs as a means for providing efficient high power amplification without compromising performance associated with surface- and process-related dispersion. This dissertation will finally close with a brief outlook on the future outlook of these technologies.

Wafer-scale, massively parallel carbon nanotube arrays for realizing field effect transistors with current density exceeding silicon and gallium arsenide

NASA Astrophysics Data System (ADS)

Arnold, Michael

Calculations have indicated that aligned arrays of semiconducting carbon nanotubes (CNTs) promise to outperform conventional semiconducting materials in short-channel, aggressively scaled field effect transistors (FETs) like those used in semiconductor logic and high frequency amplifier technologies. These calculations have been based on extrapolation of measurements of FETs based on one CNT, in which ballistic transport approaching the quantum conductance limit of 2Go = 4e2/h has been achieved. However, constraints in CNT sorting, processing, alignment, and contacts give rise to non-idealities when CNTs are implemented in densely-packed parallel arrays, which has resulted in a conductance per CNT far from 2Go. The consequence has been that it has been very difficult to create high performance CNT array FETs, and CNT array FETs have not outperformed but rather underperformed channel materials such as Si by 6 x or more. Here, we report nearly ballistic CNT array FETs at a density of 50 CNTs um-1, created via CNT sorting, wafer-scale alignment and assembly, and treatment. The on-state conductance in the arrays is as high as 0.46 Go per CNT, and the conductance of the arrays reaches 1.7 mS um-1, which is 7 x higher than previous state-of-the-art CNT array FETs made by other methods. The saturated on-state current density reaches 900 uA um-1 and is similar to or exceeds that of Si FETs when compared at equivalent gate oxide thickness, off-state current density, and channel length. The on-state current density exceeds that of GaAs FETs, as well. This leap in CNT FET array performance is a significant advance towards the exploitation of CNTs in high-performance semiconductor electronics technologies.

Toward Realization of 2.4 GHz Balunless Narrowband Receiver Front-End for Short Range Wireless Applications.

PubMed

El-Desouki, Munir M; Qasim, Syed Manzoor; BenSaleh, Mohammed S; Deen, M Jamal

2015-05-07

The demand for radio frequency (RF) transceivers operating at 2.4 GHz band has attracted considerable research interest due to the advancement in short range wireless technologies. The performance of RF transceivers depends heavily on the transmitter and receiver front-ends. The receiver front-end is comprised of a low-noise amplifier (LNA) and a downconversion mixer. There are very few designs that focus on connecting the single-ended output LNA to a double-balanced mixer without the use of on-chip transformer, also known as a balun. The objective of designing such a receiver front-end is to achieve high integration and low power consumption. To meet these requirements, we present the design of fully-integrated 2.4 GHz receiver front-end, consisting of a narrow-band LNA and a double balanced mixer without using a balun. Here, the single-ended RF output signal of the LNA is translated into differential signal using an NMOS-PMOS (n-channel metal-oxide-semiconductor, p-channel metal-oxide-semiconductor) transistor differential pair instead of the conventional NMOS-NMOS transistor configuration, for the RF amplification stage of the double-balanced mixer. The proposed receiver circuit fabricated using TSMC 0.18 µm CMOS technology operates at 2.4 GHz and produces an output signal at 300 MHz. The fabricated receiver achieves a gain of 16.3 dB and consumes only 6.74 mW operating at 1.5 V, while utilizing 2.08 mm2 of chip area. Measurement results demonstrate the effectiveness and suitability of the proposed receiver for short-range wireless applications, such as in wireless sensor network (WSN).

Bacteria inside semiconductors as potential sensor elements: biochip progress.

PubMed

Sah, Vasu R; Baier, Robert E

2014-06-24

It was discovered at the beginning of this Century that living bacteria-and specifically the extremophile Pseudomonas syzgii-could be captured inside growing crystals of pure water-corroding semiconductors-specifically germanium-and thereby initiated pursuit of truly functional "biochip-based" biosensors. This observation was first made at the inside ultraviolet-illuminated walls of ultrapure water-flowing semiconductor fabrication facilities (fabs) and has since been, not as perfectly, replicated in simpler flow cell systems for chip manufacture, described here. Recognizing the potential importance of these adducts as optical switches, for example, or probes of metabolic events, the influences of the fabs and their components on the crystal nucleation and growth phenomena now identified are reviewed and discussed with regard to further research needs. For example, optical beams of current photonic circuits can be more easily modulated by integral embedded cells into electrical signals on semiconductors. Such research responds to a recently published Grand Challenge in ceramic science, designing and synthesizing oxide electronics, surfaces, interfaces and nanoscale structures that can be tuned by biological stimuli, to reveal phenomena not otherwise possible with conventional semiconductor electronics. This short review addresses only the fabrication facilities' features at the time of first production of these potential biochips.

SONOS technology for commercial and military nonvolatile memory applications

NASA Astrophysics Data System (ADS)

Adams, D.; Farrell, P.; Jacunski, M.; Williams, D.; Jakubczak, J.; Knoll, M.; Murray, J.

Silicon Oxide Nitride Oxide Semiconductor (SONOS) technology is well suited for military and commercial nonvolatile memory applications. Excellent long term memory retention, radiation hardness, and endurance has been demonstrated with this technology. This paper summarizes our data in these areas for SONOS technology.

Holograms for laser diode: Single mode optical fiber coupling

NASA Technical Reports Server (NTRS)

Fuhr, P. L.

1982-01-01

The low coupling efficiency of semiconductor laser emissions into a single mode optical fibers place a severe restriction on their use. Associated with these conventional optical coupling techniques are stringent alignment sensitivities. Using holographic elements, the coupling efficiency may be increased and the alignment sensitivity greatly reduced. Both conventional and computer methods used in the generation of the holographic couplers are described and diagrammed. The reconstruction geometries used are shown to be somewhat restrictive but substantially less rigid than their conventional optical counterparts. Single and double hologram techniques are examined concerning their respective ease of fabrication and relative merits.

Computer Technology: State of the Art.

ERIC Educational Resources Information Center

Withington, Frederic G.

1981-01-01

Describes the nature of modern general-purpose computer systems, including hardware, semiconductor electronics, microprocessors, computer architecture, input output technology, and system control programs. Seven suggested readings are cited. (FM)

Trends in solid state electronics, part 2

NASA Technical Reports Server (NTRS)

Gassaway, J. D.

1972-01-01

Developments in the fields of semiconductors and magnetics are surveyed. Materials, devices, theory, and fabrication technology are discussed. Important events up until the present time are reported, and events are interpreted through historical perspective. A brief analysis of forces which have driven the development of today's electronic technology and some projections of present trends are given. More detailed discussions are presented for four areas of contemporary interest: amorphous semiconductors, bubble domain devices, charge-coupled devices, and electron and ion beam techniques. Beam addressed magnetic memories are reviewed to a lesser extent.

Semiconductor technology program. Progress briefs

NASA Technical Reports Server (NTRS)

Bullis, W. M. (Editor)

1979-01-01

The current status of NBS work on measurement technology for semiconductor materials, process control, and devices is reported. Results of both in-house and contract research are covered. Highlighted activities include modeling of diffusion processes, analysis of model spreading resistance data, and studies of resonance ionization spectroscopy, resistivity-dopant density relationships in p-type silicon, deep level measurements, photoresist sensitometry, random fault measurements, power MOSFET thermal characteristics, power transistor switching characteristics, and gross leak testing. New and selected on-going projects are described. Compilations of recent publications and publications in press are included.

Semiconductor Cubing

NASA Technical Reports Server (NTRS)

1996-01-01

Through Goddard Space Flight Center and Jet Propulsion Laboratory Small Business Innovation Research contracts, Irvine Sensors developed a three-dimensional memory system for a spaceborne data recorder and other applications for NASA. From these contracts, the company created the Memory Short Stack product, a patented technology for stacking integrated circuits that offers higher processing speeds and levels of integration, and lower power requirements. The product is a three-dimensional semiconductor package in which dozens of integrated circuits are stacked upon each other to form a cube. The technology is being used in various computer and telecommunications applications.

Computers and Employment.

ERIC Educational Resources Information Center

McConnell, Sheila; And Others

1996-01-01

Includes "Role of Computers in Reshaping the Work Force" (McConnell); "Semiconductors" (Moris); "Computer Manufacturing" (Warnke); "Commercial Banking Transformed by Computer Technology" (Morisi); "Software, Engineering Industries: Threatened by Technological Change?" (Goodman); "Job Creation…

Semiconductor Laser Diode Arrays by MOCVD (Metalorganic Chemical Vapor Deposition)

DTIC Science & Technology

1987-09-01

laser diode arrays are intended to be used as an optical pump for solid state yttrium aluminum garnet (YAG) lasers. In particular, linear uniform...corresponds to about . , 8080A. Such thin layer structures, while difficult to grow by such conventional growth methods as liquid phase epitaxy ( LPE ...lower yet than for DH lasers grown by LPE . , - Conventional self-aligned stripe laser This structure is formed by growing (on an n-type GaAs substrate

Fundamentals handbook of electrical and computer engineering. Volume 1 Circuits fields and electronics

NASA Astrophysics Data System (ADS)

Chang, S. S. L.

State of the art technology in circuits, fields, and electronics is discussed. The principles and applications of these technologies to industry, digital processing, microwave semiconductors, and computer-aided design are explained. Important concepts and methodologies in mathematics and physics are reviewed, and basic engineering sciences and associated design methods are dealt with, including: circuit theory and the design of magnetic circuits and active filter synthesis; digital signal processing, including FIR and IIR digital filter design; transmission lines, electromagnetic wave propagation and surface acoustic wave devices. Also considered are: electronics technologies, including power electronics, microwave semiconductors, GaAs devices, and magnetic bubble memories; digital circuits and logic design.

High-Performance WSe2 Complementary Metal Oxide Semiconductor Technology and Integrated Circuits.

PubMed

Yu, Lili; Zubair, Ahmad; Santos, Elton J G; Zhang, Xu; Lin, Yuxuan; Zhang, Yuhao; Palacios, Tomás

2015-08-12

Because of their extraordinary structural and electrical properties, two-dimensional materials are currently being pursued for applications such as thin-film transistors and integrated circuit. One of the main challenges that still needs to be overcome for these applications is the fabrication of air-stable transistors with industry-compatible complementary metal oxide semiconductor (CMOS) technology. In this work, we experimentally demonstrate a novel high performance air-stable WSe2 CMOS technology with almost ideal voltage transfer characteristic, full logic swing and high noise margin with different supply voltages. More importantly, the inverter shows large voltage gain (∼38) and small static power (picowatts), paving the way for low power electronic system in 2D materials.

Atomic Layer Deposition of Gallium Oxide Films as Gate Dielectrics in AlGaN/GaN Metal-Oxide-Semiconductor High-Electron-Mobility Transistors

NASA Astrophysics Data System (ADS)

Shih, Huan-Yu; Chu, Fu-Chuan; Das, Atanu; Lee, Chia-Yu; Chen, Ming-Jang; Lin, Ray-Ming

2016-04-01

In this study, films of gallium oxide (Ga2O3) were prepared through remote plasma atomic layer deposition (RP-ALD) using triethylgallium and oxygen plasma. The chemical composition and optical properties of the Ga2O3 thin films were investigated; the saturation growth displayed a linear dependence with respect to the number of ALD cycles. These uniform ALD films exhibited excellent uniformity and smooth Ga2O3-GaN interfaces. An ALD Ga2O3 film was then used as the gate dielectric and surface passivation layer in a metal-oxide-semiconductor high-electron-mobility transistor (MOS-HEMT), which exhibited device performance superior to that of a corresponding conventional Schottky gate HEMT. Under similar bias conditions, the gate leakage currents of the MOS-HEMT were two orders of magnitude lower than those of the conventional HEMT, with the power-added efficiency enhanced by up to 9 %. The subthreshold swing and effective interfacial state density of the MOS-HEMT were 78 mV decade-1 and 3.62 × 1011 eV-1 cm-2, respectively. The direct-current and radio-frequency performances of the MOS-HEMT device were greater than those of the conventional HEMT. In addition, the flicker noise of the MOS-HEMT was lower than that of the conventional HEMT.

Biaxial stress driven tetragonal symmetry breaking and high-temperature ferromagnetic semiconductor from half-metallic CrO2

NASA Astrophysics Data System (ADS)

Xiao, Xiang-Bo; Liu, Bang-Gui

2018-03-01

It is highly desirable to combine the full spin polarization of carriers with modern semiconductor technology for spintronic applications. For this purpose, one needs good crystalline ferromagnetic (or ferrimagnetic) semiconductors with high Curie temperatures. Rutile CrO2 is a half-metallic spintronic material with Curie temperature 394 K and can have nearly full spin polarization at room temperature. Here, we find through first-principles investigation that when a biaxial compressive stress is applied on rutile CrO2, the density of states at the Fermi level decreases with the in-plane compressive strain, there is a structural phase transition to an orthorhombic phase at the strain of -5.6 % , and then appears an electronic phase transition to a semiconductor phase at -6.1 % . Further analysis shows that this structural transition, accompanying the tetragonal symmetry breaking, is induced by the stress-driven distortion and rotation of the oxygen octahedron of Cr, and the half-metal-semiconductor transition originates from the enhancement of the crystal field splitting due to the structural change. Importantly, our systematic total-energy comparison indicates the ferromagnetic Curie temperature remains almost independent of the strain, near 400 K. This biaxial stress can be realized by applying biaxial pressure or growing the CrO2 epitaxially on appropriate substrates. These results should be useful for realizing full (100%) spin polarization of controllable carriers as one uses in modern semiconductor technology.

Electronics

DTIC Science & Technology

2001-01-01

International Acer Incorporated, Hsin Chu, Taiwan Aerospace Industrial Development Corporation, Taichung, Taiwan American Institute of Taiwan, Taipei, Taiwan...Singapore and Malaysia .5 - 4 - The largest market for semiconductor products is the high technology consumer electronics industry that consumes up...Singapore, and Malaysia . A new semiconductor facility costs around $3 billion to build and takes about two years to become operational

78 FR 33859 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-DIE Products...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-05

... Technologies, AG, Munich, Germany; Freescale Semiconductor, Inc., Austin, TX; Philips Semiconductors, Inc., San... DEPARTMENT OF JUSTICE Antitrust Division Notice Pursuant to the National Cooperative Research and... Section 6(a) of the National Cooperative Research and Production Act of 1993, 15 U.S.C. 4301 et seq...

Methods to Account for Accelerated Semi-Conductor Device Wearout in Longlife Aerospace Applications

DTIC Science & Technology

2003-01-01

Vasi, “Device scalling effects on hot-carrier induced interface and oxide-trappoing charge distributions in MOSFETs,” IEEE Transactions on Electron...Symposium Proceedings, pp. 248–254, 2002. [104] S. I. A. ( SIA ), “International technology roadmap for semiconductors.” <www.semichips.org>, 1999. 113

Optical temperature sensor using thermochromic semiconductors

DOEpatents

Kronberg, J.W.

1994-01-01

Optical thermometry is a growing technological field which exploits the ability of certain materials to change their optical properties with temperature. A subclass of such materials are those which change their color as a reversible and reproducible function of temperature. These materials are thermochromic. This invention is a composition to measure temperature utilizing thermochromic semiconductors.

A Brief History of ... Semiconductors

ERIC Educational Resources Information Center

Jenkins, Tudor

2005-01-01

The development of studies in semiconductor materials is traced from its beginnings with Michael Faraday in 1833 to the production of the first silicon transistor in 1954, which heralded the age of silicon electronics and microelectronics. Prior to the advent of band theory, work was patchy and driven by needs of technology. However, the arrival…

An integrated semiconductor device enabling non-optical genome sequencing.

PubMed

Rothberg, Jonathan M; Hinz, Wolfgang; Rearick, Todd M; Schultz, Jonathan; Mileski, William; Davey, Mel; Leamon, John H; Johnson, Kim; Milgrew, Mark J; Edwards, Matthew; Hoon, Jeremy; Simons, Jan F; Marran, David; Myers, Jason W; Davidson, John F; Branting, Annika; Nobile, John R; Puc, Bernard P; Light, David; Clark, Travis A; Huber, Martin; Branciforte, Jeffrey T; Stoner, Isaac B; Cawley, Simon E; Lyons, Michael; Fu, Yutao; Homer, Nils; Sedova, Marina; Miao, Xin; Reed, Brian; Sabina, Jeffrey; Feierstein, Erika; Schorn, Michelle; Alanjary, Mohammad; Dimalanta, Eileen; Dressman, Devin; Kasinskas, Rachel; Sokolsky, Tanya; Fidanza, Jacqueline A; Namsaraev, Eugeni; McKernan, Kevin J; Williams, Alan; Roth, G Thomas; Bustillo, James

2011-07-20

The seminal importance of DNA sequencing to the life sciences, biotechnology and medicine has driven the search for more scalable and lower-cost solutions. Here we describe a DNA sequencing technology in which scalable, low-cost semiconductor manufacturing techniques are used to make an integrated circuit able to directly perform non-optical DNA sequencing of genomes. Sequence data are obtained by directly sensing the ions produced by template-directed DNA polymerase synthesis using all-natural nucleotides on this massively parallel semiconductor-sensing device or ion chip. The ion chip contains ion-sensitive, field-effect transistor-based sensors in perfect register with 1.2 million wells, which provide confinement and allow parallel, simultaneous detection of independent sequencing reactions. Use of the most widely used technology for constructing integrated circuits, the complementary metal-oxide semiconductor (CMOS) process, allows for low-cost, large-scale production and scaling of the device to higher densities and larger array sizes. We show the performance of the system by sequencing three bacterial genomes, its robustness and scalability by producing ion chips with up to 10 times as many sensors and sequencing a human genome.

Observation of quantum oscillation of work function in ultrathin-metal/semiconductor junctions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takhar, Kuldeep; Meer, Mudassar; Khachariya, Dolar

2015-09-15

Quantization in energy level due to confinement is generally observed for semiconductors. This property is used for various quantum devices, and it helps to improve the characteristics of conventional devices. Here, the authors have demonstrated the quantum size effects in ultrathin metal (Ni) layers sandwiched between two large band-gap materials. The metal work function is found to oscillate as a function of its thickness. The thermionic emission current bears the signature of the oscillating work function, which has a linear relationship with barrier heights. This methodology allows direct observation of quantum oscillations in metals at room temperature using a Schottkymore » diode and electrical measurements using source-measure-units. The observed phenomena can provide additional mechanism to tune the barrier height of metal/semiconductor junctions, which are used for various electronic devices.« less

Decreased oscillation threshold of a continuous-wave OPO using a semiconductor gain mirror.

PubMed

Siltanen, Mikael; Leinonen, Tomi; Halonen, Lauri

2011-09-26

We have constructed a singly resonant, continuous-wave optical parametric oscillator, where the signal beam resonates and is amplified by a semiconductor gain mirror. The gain mirror can significantly decrease the oscillation threshold compared to an identical system with conventional mirrors. The largest idler beam tuning range reached by changing the pump laser wavelength alone is from 3.6 to 4.7 µm. The single mode output power is limited but can be continuously scanned for at least 220 GHz by adding optical components in the oscillator cavity for increased stability. © 2011 Optical Society of America

Contactless measurement of electrical conductivity of semiconductor wafers using the reflection of millimeter waves

NASA Astrophysics Data System (ADS)

Ju, Yang; Inoue, Kojiro; Saka, Masumi; Abe, Hiroyuki

2002-11-01

We present a method for quantitative measurement of electrical conductivity of semiconductor wafers in a contactless fashion by using millimeter waves. A focusing sensor was developed to focus a 110 GHz millimeter wave beam on the surface of a silicon wafer. The amplitude and the phase of the reflection coefficient of the millimeter wave signal were measured by which electrical conductivity of the wafer was determined quantitatively, independent of the permittivity and thickness of the wafers. The conductivity obtained by this method agrees well with that measured by the conventional four-point-probe method.

Improved method of preparing p-i-n junctions in amorphous silicon semiconductors

DOEpatents

Madan, A.

1984-12-10

A method of preparing p/sup +/-i-n/sup +/ junctions for amorphous silicon semiconductors includes depositing amorphous silicon on a thin layer of trivalent material, such as aluminum, indium, or gallium at a temperature in the range of 200/sup 0/C to 250/sup 0/C. At this temperature, the layer of trivalent material diffuses into the amorphous silicon to form a graded p/sup +/-i junction. A layer of n-type doped material is then deposited onto the intrinsic amorphous silicon layer in a conventional manner to finish forming the p/sup +/-i-n/sup +/ junction.

Coloration of tyrosine by organic-semiconductor interfacial charge-transfer transitions

NASA Astrophysics Data System (ADS)

Fujisawa, Jun-ichi; Kikuchi, Natsumi; Hanaya, Minoru

2016-11-01

L-tyrosine (Tyr) plays a crucial role as a proteinogenic amino acid and also as a precursor to several neurotransmitters and hormones. Here we demonstrate coloration of Tyr based on organic-semiconductor interfacial charge-transfer (ICT) transitions. The ICT transitions from Tyr to TiO2 are induced by the chemisorption of Tyr on TiO2 surfaces via the hydroxy group of the phenol moiety. Because other amino acids possess no chemical group to induce ICT transitions, this coloration method enables to detect Tyr selectively without drastic structural change in contrast to the conventional coloration methods.

Thermally Generated Spin Signals in a Nondegenerate Silicon Spin Valve

NASA Astrophysics Data System (ADS)

Yamashita, Naoto; Ando, Yuichiro; Koike, Hayato; Miwa, Shinji; Suzuki, Yoshishige; Shiraishi, Masashi

2018-05-01

Thermally generated spin signals are observed in a nondegenerate Si spin valve. The spin-dependent Seebeck effect is used for thermal spin-signal generation. A thermal gradient of about 200 mK at the interface of Fe and Si enables the generation of a spin voltage of 8 μ V at room temperature. A simple expansion of the conventional spin-drift-diffusion model that takes into account the spin-dependent Seebeck effect shows that semiconductor materials are more promising for thermal spin-signal generation comparing than metallic materials, and thus enable efficient heat recycling in semiconductor spin devices.

Metal oxide semiconductor thin-film transistors for flexible electronics

NASA Astrophysics Data System (ADS)

Petti, Luisa; Münzenrieder, Niko; Vogt, Christian; Faber, Hendrik; Büthe, Lars; Cantarella, Giuseppe; Bottacchi, Francesca; Anthopoulos, Thomas D.; Tröster, Gerhard

2016-06-01

The field of flexible electronics has rapidly expanded over the last decades, pioneering novel applications, such as wearable and textile integrated devices, seamless and embedded patch-like systems, soft electronic skins, as well as imperceptible and transient implants. The possibility to revolutionize our daily life with such disruptive appliances has fueled the quest for electronic devices which yield good electrical and mechanical performance and are at the same time light-weight, transparent, conformable, stretchable, and even biodegradable. Flexible metal oxide semiconductor thin-film transistors (TFTs) can fulfill all these requirements and are therefore considered the most promising technology for tomorrow's electronics. This review reflects the establishment of flexible metal oxide semiconductor TFTs, from the development of single devices, large-area circuits, up to entirely integrated systems. First, an introduction on metal oxide semiconductor TFTs is given, where the history of the field is revisited, the TFT configurations and operating principles are presented, and the main issues and technological challenges faced in the area are analyzed. Then, the recent advances achieved for flexible n-type metal oxide semiconductor TFTs manufactured by physical vapor deposition methods and solution-processing techniques are summarized. In particular, the ability of flexible metal oxide semiconductor TFTs to combine low temperature fabrication, high carrier mobility, large frequency operation, extreme mechanical bendability, together with transparency, conformability, stretchability, and water dissolubility is shown. Afterward, a detailed analysis of the most promising metal oxide semiconducting materials developed to realize the state-of-the-art flexible p-type TFTs is given. Next, the recent progresses obtained for flexible metal oxide semiconductor-based electronic circuits, realized with both unipolar and complementary technology, are reported. In particular, the realization of large-area digital circuitry like flexible near field communication tags and analog integrated circuits such as bendable operational amplifiers is presented. The last topic of this review is devoted for emerging flexible electronic systems, from foldable displays, power transmission elements to integrated systems for large-area sensing and data storage and transmission. Finally, the conclusions are drawn and an outlook over the field with a prediction for the future is provided.

Metal oxide semiconductor thin-film transistors for flexible electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petti, Luisa; Vogt, Christian; Büthe, Lars

The field of flexible electronics has rapidly expanded over the last decades, pioneering novel applications, such as wearable and textile integrated devices, seamless and embedded patch-like systems, soft electronic skins, as well as imperceptible and transient implants. The possibility to revolutionize our daily life with such disruptive appliances has fueled the quest for electronic devices which yield good electrical and mechanical performance and are at the same time light-weight, transparent, conformable, stretchable, and even biodegradable. Flexible metal oxide semiconductor thin-film transistors (TFTs) can fulfill all these requirements and are therefore considered the most promising technology for tomorrow's electronics. This reviewmore » reflects the establishment of flexible metal oxide semiconductor TFTs, from the development of single devices, large-area circuits, up to entirely integrated systems. First, an introduction on metal oxide semiconductor TFTs is given, where the history of the field is revisited, the TFT configurations and operating principles are presented, and the main issues and technological challenges faced in the area are analyzed. Then, the recent advances achieved for flexible n-type metal oxide semiconductor TFTs manufactured by physical vapor deposition methods and solution-processing techniques are summarized. In particular, the ability of flexible metal oxide semiconductor TFTs to combine low temperature fabrication, high carrier mobility, large frequency operation, extreme mechanical bendability, together with transparency, conformability, stretchability, and water dissolubility is shown. Afterward, a detailed analysis of the most promising metal oxide semiconducting materials developed to realize the state-of-the-art flexible p-type TFTs is given. Next, the recent progresses obtained for flexible metal oxide semiconductor-based electronic circuits, realized with both unipolar and complementary technology, are reported. In particular, the realization of large-area digital circuitry like flexible near field communication tags and analog integrated circuits such as bendable operational amplifiers is presented. The last topic of this review is devoted for emerging flexible electronic systems, from foldable displays, power transmission elements to integrated systems for large-area sensing and data storage and transmission. Finally, the conclusions are drawn and an outlook over the field with a prediction for the future is provided.« less

Materials for multifunctional balloon catheters with capabilities in cardiac electrophysiological mapping and ablation therapy

NASA Astrophysics Data System (ADS)

Kim, Dae-Hyeong; Lu, Nanshu; Ghaffari, Roozbeh; Kim, Yun-Soung; Lee, Stephen P.; Xu, Lizhi; Wu, Jian; Kim, Rak-Hwan; Song, Jizhou; Liu, Zhuangjian; Viventi, Jonathan; de Graff, Bassel; Elolampi, Brian; Mansour, Moussa; Slepian, Marvin J.; Hwang, Sukwon; Moss, Joshua D.; Won, Sang-Min; Huang, Younggang; Litt, Brian; Rogers, John A.

2011-04-01

Developing advanced surgical tools for minimally invasive procedures represents an activity of central importance to improving human health. A key challenge is in establishing biocompatible interfaces between the classes of semiconductor device and sensor technologies that might be most useful in this context and the soft, curvilinear surfaces of the body. This paper describes a solution based on materials that integrate directly with the thin elastic membranes of otherwise conventional balloon catheters, to provide diverse, multimodal functionality suitable for clinical use. As examples, we present sensors for measuring temperature, flow, tactile, optical and electrophysiological data, together with radiofrequency electrodes for controlled, local ablation of tissue. Use of such ‘instrumented’ balloon catheters in live animal models illustrates their operation, as well as their specific utility in cardiac ablation therapy. The same concepts can be applied to other substrates of interest, such as surgical gloves.

Nanoionic devices: Interface nanoarchitechtonics for physical property tuning and enhancement

NASA Astrophysics Data System (ADS)

Tsuchiya, Takashi; Terabe, Kazuya; Yang, Rui; Aono, Masakazu

2016-11-01

Nanoionic devices have been developed to generate novel functions overcoming limitations of conventional materials synthesis and semiconductor technology. Various physical properties can be tuned and enhanced by local ion transport near the solid/solid interface. Two electronic carrier doping methods can be used to achieve extremely high-density electronic carriers: one is electrostatic carrier doping using an electric double layer (EDL); the other is electrochemical carrier doping using a redox reaction. Atomistic restructuring near the solid/solid interface driven by a DC voltage, namely, interface nanoarchitechtonics, has huge potential. For instance, the use of EDL enables high-density carrier doping in potential superconductors, which can hardly accept chemical doping, in order to achieve room-temperature superconductivity. Optical bandgap and photoluminescence can be controlled for various applications including smart windows and biosensors. In situ tuning of magnetic properties is promising for low-power-consumption spintronics. Synaptic plasticity in the human brain is achieved in neuromorphic devices.

Mcare 2017

NASA Astrophysics Data System (ADS)

Kim, Do-Heyoung; Yong, Kijung; Im, Yeonho; Kim, Woojae; Lee, Doh Chang

2018-01-01

The Materials Challenges in Alternative and Renewable Energy Conference (MCARE 2017) was aimed at providing a forum for closely interactive communication and collaboration between leading experts from various fields related with materials in alternative and renewable energy. MCARE 2017 was held on Jeju Island, Korea on February 20-24, 2017. At this beautiful site, about 450 participants joined the conference and 459 papers were presented. About 110 foreign participants from all over the world particpated. MCARE 2017 was hosted by the Korea Institute of Chemical Engineers (KIChE) and was organized by the Materials Division of KIChE and the American Ceramic Society. Financial support was given by Lotte Chemical, LG Hausys, Jeju Convention & Visitors Bureau, and Korea Tourism Organization, Flexible Thermoelectric Semiconductor Device Technology Center, Super Ultra Low Energy and Emission Vehicle Center, Korea Institute of Materials Science, Jeju Techno Park, Center for Future Energy Materials and Devices and Korea Institute for Rare Metals.

Scrubbers with a level head

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pedersen, G.C.; Bhattachararjee, P.K.

1997-11-01

The available methods for removing pollutants from a gas stream are numerous, to say the least. A popular method, scrubbers allow users to separate gases and solids by allowing the gas to come into contact with a liquid stream. In the end, the pollutants are washed away in the effluent, and the gas exits the system to be used in later processes or to be released into the atmosphere. For many years, counter-flow scrubber methods have been used for the lion`s share of the work in industries such as phosphate fertilizer and semiconductor chemicals manufacturing. Now these industries are exploringmore » the use of cross-flow scrubber design, which offers consistently high efficiency and low operating costs. In addition, the unit`s horizontal orientation makes maintenance easier than typical tower scrubbers. For certain classes of unit operations, cross-flow is now being recognized as a strong alternative to conventional counterflow technology.« less

Resonant tunnelling in a quantum oxide superlattice

DOE PAGES

Choi, Woo Seok; Lee, Sang A.; You, Jeong Ho; ...

2015-06-24

Resonant tunneling is a quantum mechanical process that has long been attracting both scientific and technological attention owing to its intriguing underlying physics and unique applications for high-speed electronics. The materials system exhibiting resonant tunneling, however, has been largely limited to the conventional semiconductors, partially due to their excellent crystalline quality. Here we show that a deliberately designed transition metal oxide superlattice exhibits a resonant tunneling behaviour with a clear negative differential resistance. The tunneling occurred through an atomically thin, lanthanum δ- doped SrTiO 3 layer, and the negative differential resistance was realized on top of the bi-polar resistance switchingmore » typically observed for perovskite oxide junctions. This combined process resulted in an extremely large resistance ratio (~10 5) between the high and low resistance states. Lastly, the unprecedentedly large control found in atomically thin δ-doped oxide superlattices can open a door to novel oxide-based high-frequency logic devices.« less

MEMS reliability: coming of age

NASA Astrophysics Data System (ADS)

Douglass, Michael R.

2008-02-01

In today's high-volume semiconductor world, one could easily take reliability for granted. As the MOEMS/MEMS industry continues to establish itself as a viable alternative to conventional manufacturing in the macro world, reliability can be of high concern. Currently, there are several emerging market opportunities in which MOEMS/MEMS is gaining a foothold. Markets such as mobile media, consumer electronics, biomedical devices, and homeland security are all showing great interest in microfabricated products. At the same time, these markets are among the most demanding when it comes to reliability assurance. To be successful, each company developing a MOEMS/MEMS device must consider reliability on an equal footing with cost, performance and manufacturability. What can this maturing industry learn from the successful development of DLP technology, air bag accelerometers and inkjet printheads? This paper discusses some basic reliability principles which any MOEMS/MEMS device development must use. Examples from the commercially successful and highly reliable Digital Micromirror Device complement the discussion.

Origami silicon optoelectronics for hemispherical electronic eye systems.

PubMed

Zhang, Kan; Jung, Yei Hwan; Mikael, Solomon; Seo, Jung-Hun; Kim, Munho; Mi, Hongyi; Zhou, Han; Xia, Zhenyang; Zhou, Weidong; Gong, Shaoqin; Ma, Zhenqiang

2017-11-24

Digital image sensors in hemispherical geometries offer unique imaging advantages over their planar counterparts, such as wide field of view and low aberrations. Deforming miniature semiconductor-based sensors with high-spatial resolution into such format is challenging. Here we report a simple origami approach for fabricating single-crystalline silicon-based focal plane arrays and artificial compound eyes that have hemisphere-like structures. Convex isogonal polyhedral concepts allow certain combinations of polygons to fold into spherical formats. Using each polygon block as a sensor pixel, the silicon-based devices are shaped into maps of truncated icosahedron and fabricated on flexible sheets and further folded either into a concave or convex hemisphere. These two electronic eye prototypes represent simple and low-cost methods as well as flexible optimization parameters in terms of pixel density and design. Results demonstrated in this work combined with miniature size and simplicity of the design establish practical technology for integration with conventional electronic devices.

Computational predictions of the new Gallium nitride nanoporous structures

NASA Astrophysics Data System (ADS)

Lien, Le Thi Hong; Tuoc, Vu Ngoc; Duong, Do Thi; Thu Huyen, Nguyen

2018-05-01

Nanoporous structural prediction is emerging area of research because of their advantages for a wide range of materials science and technology applications in opto-electronics, environment, sensors, shape-selective and bio-catalysis, to name just a few. We propose a computationally and technically feasible approach for predicting Gallium nitride nanoporous structures with hollows at the nano scale. The designed porous structures are studied with computations using the density functional tight binding (DFTB) and conventional density functional theory methods, revealing a variety of promising mechanical and electronic properties, which can potentially find future realistic applications. Their stability is discussed by means of the free energy computed within the lattice-dynamics approach. Our calculations also indicate that all the reported hollow structures are wide band gap semiconductors in the same fashion with their parent’s bulk stable phase. The electronic band structures of these nanoporous structures are finally examined in detail.

Old and new ideas in ferroelectric liquid crystal technology

NASA Astrophysics Data System (ADS)

Lagerwall, Sven T.; Matuszczyk, M.; Matuszczyk, T.

1998-02-01

Ferroelectric liquid crystals (FLC) are to conventional liquid crystal what Gallium Arsenide is to Silicon in the semiconductor area. The first generation of FLC displays in now present on the market and has some outstanding features based on the symmetric bistability which may be achieved in these materials. One of the greatest challenges for the next generation is to achieve an analog grey scale out of an essentially digital principle. We will analyze in some detail which major problems had to be solved to reach the present state and show how the final steps could be taken toward a new state-of-the-art level in liquid crystal devices. In the last decade university research and industrial R and D have almost equally contributed to treat the very serious complications caused by the so-called chevron structures We will review this important topic in particular detail.

Raster Scan Computer Image Generation (CIG) System Based On Refresh Memory

NASA Astrophysics Data System (ADS)

Dichter, W.; Doris, K.; Conkling, C.

1982-06-01

A full color, Computer Image Generation (CIG) raster visual system has been developed which provides a high level of training sophistication by utilizing advanced semiconductor technology and innovative hardware and firmware techniques. Double buffered refresh memory and efficient algorithms eliminate the problem of conventional raster line ordering by allowing the generated image to be stored in a random fashion. Modular design techniques and simplified architecture provide significant advantages in reduced system cost, standardization of parts, and high reliability. The major system components are a general purpose computer to perform interfacing and data base functions; a geometric processor to define the instantaneous scene image; a display generator to convert the image to a video signal; an illumination control unit which provides final image processing; and a CRT monitor for display of the completed image. Additional optional enhancements include texture generators, increased edge and occultation capability, curved surface shading, and data base extensions.

Integrated logic circuits using single-atom transistors

PubMed Central

Mol, J. A.; Verduijn, J.; Levine, R. D.; Remacle, F.

2011-01-01

Scaling down the size of computing circuits is about to reach the limitations imposed by the discrete atomic structure of matter. Reducing the power requirements and thereby dissipation of integrated circuits is also essential. New paradigms are needed to sustain the rate of progress that society has become used to. Single-atom transistors, SATs, cascaded in a circuit are proposed as a promising route that is compatible with existing technology. We demonstrate the use of quantum degrees of freedom to perform logic operations in a complementary-metal–oxide–semiconductor device. Each SAT performs multilevel logic by electrically addressing the electronic states of a dopant atom. A single electron transistor decodes the physical multivalued output into the conventional binary output. A robust scalable circuit of two concatenated full adders is reported, where by utilizing charge and quantum degrees of freedom, the functionality of the transistor is pushed far beyond that of a simple switch. PMID:21808050

78 FR 23472 - Amendments to Existing Validated End-User Authorizations: CSMC Technologies Corporation in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-19

... of Wuxi CR Semiconductor Wafers & Chips Co., Ltd. and CSMC Technologies Fab 1 Co., Ltd., which is... Validated End-User: CSMC Technologies Corporation. Eligible Destinations: CSMC Technologies Fab 1 Co., Ltd., 14 Liangxi Road, Wuxi, Jiangsu 214061, China. CSMC Technologies Fab 2 Co., Ltd., 8 Xinzhou Rd., Wuxi...

Topological quantum buses: coherent quantum information transfer between topological and conventional qubits.

PubMed

Bonderson, Parsa; Lutchyn, Roman M

2011-04-01

We propose computing bus devices that enable quantum information to be coherently transferred between topological and conventional qubits. We describe a concrete realization of such a topological quantum bus acting between a topological qubit in a Majorana wire network and a conventional semiconductor double quantum dot qubit. Specifically, this device measures the joint (fermion) parity of these two different qubits by using the Aharonov-Casher effect in conjunction with an ancilliary superconducting flux qubit that facilitates the measurement. Such a parity measurement, together with the ability to apply Hadamard gates to the two qubits, allows one to produce states in which the topological and conventional qubits are maximally entangled and to teleport quantum states between the topological and conventional quantum systems. © 2011 American Physical Society

Electrostatic modification of novel materials

NASA Astrophysics Data System (ADS)

Ahn, C. H.; Bhattacharya, A.; di Ventra, M.; Eckstein, J. N.; Frisbie, C. Daniel; Gershenson, M. E.; Goldman, A. M.; Inoue, I. H.; Mannhart, J.; Millis, Andrew J.; Morpurgo, Alberto F.; Natelson, Douglas; Triscone, Jean-Marc

2006-10-01

Application of the field-effect transistor principle to novel materials to achieve electrostatic doping is a relatively new research area. It may provide the opportunity to bring about modifications of the electronic and magnetic properties of materials through controlled and reversible changes of the carrier concentration without modifying the level of disorder, as occurs when chemical composition is altered. As well as providing a basis for new devices, electrostatic doping can in principle serve as a tool for studying quantum critical behavior, by permitting the ground state of a system to be tuned in a controlled fashion. In this paper progress in electrostatic doping of a number of materials systems is reviewed. These include structures containing complex oxides, such as cuprate superconductors and colossal magnetoresistive compounds, organic semiconductors, in the form of both single crystals and thin films, inorganic layered compounds, single molecules, and magnetic semiconductors. Recent progress in the field is discussed, including enabling experiments and technologies, open scientific issues and challenges, and future research opportunities. For many of the materials considered, some of the results can be anticipated by combining knowledge of macroscopic or bulk properties and the understanding of the field-effect configuration developed during the course of the evolution of conventional microelectronics. However, because electrostatic doping is an interfacial phenomenon, which is largely an unexplored field, real progress will depend on the development of a better understanding of lattice distortion and charge transfer at interfaces in these systems.

Room temperature electrical spin injection into GaAs by an oxide spin injector

PubMed Central

Bhat, Shwetha G.; Kumar, P. S. Anil

2014-01-01

Spin injection, manipulation and detection are the integral parts of spintronics devices and have attracted tremendous attention in the last decade. It is necessary to judiciously choose the right combination of materials to have compatibility with the existing semiconductor technology. Conventional metallic magnets were the first choice for injecting spins into semiconductors in the past. So far there is no success in using a magnetic oxide material for spin injection, which is very important for the development of oxide based spintronics devices. Here we demonstrate the electrical spin injection from an oxide magnetic material Fe3O4, into GaAs with the help of tunnel barrier MgO at room temperature using 3-terminal Hanle measurement technique. A spin relaxation time τ ~ 0.9 ns for n-GaAs at 300 K is observed along with expected temperature dependence of τ. Spin injection using Fe3O4/MgO system is further established by injecting spins into p-GaAs and a τ of ~0.32 ns is obtained at 300 K. Enhancement of spin injection efficiency is seen with barrier thickness. In the field of spin injection and detection, our work using an oxide magnetic material establishes a good platform for the development of room temperature oxide based spintronics devices. PMID:24998440

New Technology CZT Detectors for High-Energy Flare Spectroscopy: The Room Temperature Semiconductor Spectrometer for JAWSAT

NASA Technical Reports Server (NTRS)

Vestrand, W. Thomas

1999-01-01

The goal of our Room Temperature Semiconductor Spectrometer (RTeSS) project is to develop a small high-energy solar flare spectrometer employing semiconductor detectors that do not require significant cooling when used as high-energy solar flare spectrometers. Specifically, the goal is to test Cadmium Zinc Telluride (CZT) detectors with coplanar grid electrodes as x-ray and gamma-ray spectrometers and to design an experiment that can be flown as a "piggy-back" payload on a satellite mission during the next solar maximum.

PUBLISHER'S ANNOUNCEMENT: Important changes for 2008

NASA Astrophysics Data System (ADS)

Bedrock, Claire

2008-01-01

Having reviewed several aspects of IOP journal content, both in print and online, we have made some changes for 2008, some of which affect Semiconductor Science and Technology. Article numbering In common with many other IOP journals, Semiconductor Science and Technology has moved from sequential page numbering to an article numbering system. Articles will continue to be published on the web in advance of the print edition. The bibliographic citation will change slightly. Articles should be referenced using the six-digit article number in place of a page number, and this number must include any leading zeros. For instance: Surname X and Surname Y 2008 Semicond. Sci. Technol. 18 015003 A new look and feel Semiconductor Science and Technology has changed from European A4 format to a slightly smaller size, closer to US Letter format, and we have taken the opportunity to refresh the cover, in order to modernise the typography, and create a consistent look and feel across our range of publications. If you have any questions or comments about any of these changes, please contact us at sst@iop.org

Multidimensional Anodized Titanium Foam Photoelectrode for Efficient Utilization of Photons in Mesoscopic Solar Cells.

PubMed

Kang, Jin Soo; Choi, Hyelim; Kim, Jin; Park, Hyeji; Kim, Jae-Yup; Choi, Jung-Woo; Yu, Seung-Ho; Lee, Kyung Jae; Kang, Yun Sik; Park, Sun Ha; Cho, Yong-Hun; Yum, Jun-Ho; Dunand, David C; Choe, Heeman; Sung, Yung-Eun

2017-09-01

Mesoscopic solar cells based on nanostructured oxide semiconductors are considered as a promising candidates to replace conventional photovoltaics employing costly materials. However, their overall performances are below the sufficient level required for practical usages. Herein, this study proposes an anodized Ti foam (ATF) with multidimensional and hierarchical architecture as a highly efficient photoelectrode for the generation of a large photocurrent. ATF photoelectrodes prepared by electrochemical anodization of freeze-cast Ti foams have three favorable characteristics: (i) large surface area for enhanced light harvesting, (ii) 1D semiconductor structure for facilitated charge collection, and (iii) 3D highly conductive metallic current collector that enables exclusion of transparent conducting oxide substrate. Based on these advantages, when ATF is utilized in dye-sensitized solar cells, short-circuit photocurrent density up to 22.0 mA cm -2 is achieved in the conventional N719 dye-I 3 - /I - redox electrolyte system even with an intrinsically inferior quasi-solid electrolyte. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Single Phase 7-Level Cascade Inverter Topology with Reduced Number of Switches on Resistive Load by Using PWM

NASA Astrophysics Data System (ADS)

Hamzah, H. H.; Ponniran, A.; Kasiran, A. N.; Harimon, M. A.; Gendum, D. A.; Yatim, M. H.

2018-04-01

This paper discussing design principles of inverter structure with reduced number of semiconductor devices of seven levels symmetric H-bridge multilevel inverter (MLI) topology. The aim of this paper is to design an inverter circuit with reduction of semiconductor losses, converter size and development cost. The H-bridge and auxiliary structures were considered in order to achieve seven levels output voltage. The performance of design circuit is compared with conventional seven levels structure in terms of voltage output. The circuit development consists of seven switches and three diode. A basic modulation technique is used to confirm the designed circuit. The results show that the designed circuit is able to convert seven level output voltage with low total harmonics distortion (THD) in voltage fundamental output. According to the results, fundamental output voltage is increased up to 8.314%, and the THD is decreased up to 0.81% compared to the conventional seven level inverter.

The Semiconductor Industry and Emerging Technologies: A Study Using a Modified Delphi Method

ERIC Educational Resources Information Center

Jordan, Edgar A.

2010-01-01

The purpose of this qualitative descriptive study was to determine what leaders in the semiconductor industry thought the future of computing would look like and what emerging materials showed the most promise to overcome the current theoretical limit of 10 nanometers for silicon dioxide. The researcher used a modified Delphi technique in two…

SEMICONDUCTOR TECHNOLOGY Supercritical carbon dioxide process for releasing stuck cantilever beams

NASA Astrophysics Data System (ADS)

Yu, Hui; Chaoqun, Gao; Lei, Wang; Yupeng, Jing

2010-10-01

The multi-SCCO2 (supercritical carbon dioxide) release and dry process based on our specialized SCCO2 semiconductor process equipment is investigated and the releasing mechanism is discussed. The experiment results show that stuck cantilever beams were held up again under SCCO2 high pressure treatment and the repeatability of this process is nearly 100%.

Apparatus and method for fabricating a microbattery

DOEpatents

Shul, Randy J.; Kravitz, Stanley H.; Christenson, Todd R.; Zipperian, Thomas E.; Ingersoll, David

2002-01-01

An apparatus and method for fabricating a microbattery that uses silicon as the structural component, packaging component, and semiconductor to reduce the weight, size, and cost of thin film battery technology is described. When combined with advanced semiconductor packaging techniques, such a silicon-based microbattery enables the fabrication of autonomous, highly functional, integrated microsystems having broad applicability.

Organizational Growth: Linking Founding Team, Strategy, Environment, and Growth among U.S. Semiconductor Ventures, 1978-1988.

ERIC Educational Resources Information Center

Eisenhardt, Kathleen M.; Schoonhoven, Claudia Bird

1990-01-01

Summarizes a study exploring organizational growth in technology-based ventures. Characteristics of the founding top-management team, strategy, and environment are matched to the sales growth of newly founded semiconductor firms. Results show that the effects of the founding team and environment grew instead of fading with time. Includes 54…

A stable solution-processed polymer semiconductor with record high-mobility for printed transistors

PubMed Central

Li, Jun; Zhao, Yan; Tan, Huei Shuan; Guo, Yunlong; Di, Chong-An; Yu, Gui; Liu, Yunqi; Lin, Ming; Lim, Suo Hon; Zhou, Yuhua; Su, Haibin; Ong, Beng S.

2012-01-01

Microelectronic circuits/arrays produced via high-speed printing instead of traditional photolithographic processes offer an appealing approach to creating the long-sought after, low-cost, large-area flexible electronics. Foremost among critical enablers to propel this paradigm shift in manufacturing is a stable, solution-processable, high-performance semiconductor for printing functionally capable thin-film transistors — fundamental building blocks of microelectronics. We report herein the processing and optimisation of solution-processable polymer semiconductors for thin-film transistors, demonstrating very high field-effect mobility, high on/off ratio, and excellent shelf-life and operating stabilities under ambient conditions. Exceptionally high-gain inverters and functional ring oscillator devices on flexible substrates have been demonstrated. This optimised polymer semiconductor represents a significant progress in semiconductor development, dispelling prevalent skepticism surrounding practical usability of organic semiconductors for high-performance microelectronic devices, opening up application opportunities hitherto functionally or economically inaccessible with silicon technologies, and providing an excellent structural framework for fundamental studies of charge transport in organic systems. PMID:23082244

High-energy side-peak emission of exciton-polariton condensates in high density regime

PubMed Central

Horikiri, Tomoyuki; Yamaguchi, Makoto; Kamide, Kenji; Matsuo, Yasuhiro; Byrnes, Tim; Ishida, Natsuko; Löffler, Andreas; Höfling, Sven; Shikano, Yutaka; Ogawa, Tetsuo; Forchel, Alfred; Yamamoto, Yoshihisa

2016-01-01

In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates–sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity–have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics. PMID:27193700

Nanometals for Solar-to-Chemical Energy Conversion: From Semiconductor-Based Photocatalysis to Plasmon-Mediated Photocatalysis and Photo-Thermocatalysis.

PubMed

Meng, Xianguang; Liu, Lequan; Ouyang, Shuxin; Xu, Hua; Wang, Defa; Zhao, Naiqin; Ye, Jinhua

2016-08-01

Nanometal materials play very important roles in solar-to-chemical energy conversion due to their unique catalytic and optical characteristics. They have found wide applications from semiconductor photocatalysis to rapidly growing surface plasmon-mediated heterogeneous catalysis. The recent research achievements of nanometals are reviewed here, with regard to applications in semiconductor photocatalysis, plasmonic photocatalysis, and plasmonic photo-thermocatalysis. As the first important topic discussed here, the latest progress in the design of nanometal cocatalysts and their applications in semiconductor photocatalysis are introduced. Then, plasmonic photocatalysis and plasmonic photo-thermocatalysis are discussed. A better understanding of electron-driven and temperature-driven catalytic behaviors over plasmonic nanometals is helpful to bridge the present gap between the communities of photocatalysis and conventional catalysis controlled by temperature. The objective here is to provide instructive information on how to take the advantages of the unique functions of nanometals in different types of catalytic processes to improve the efficiency of solar-energy utilization for more practical artificial photosynthesis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interface designed MoS2/GaAs heterostructure solar cell with sandwich stacked hexagonal boron nitride

PubMed Central

Lin, Shisheng; Li, Xiaoqiang; Wang, Peng; Xu, Zhijuan; Zhang, Shengjiao; Zhong, Huikai; Wu, Zhiqian; Xu, Wenli; Chen, Hongsheng

2015-01-01

MoS2 is a layered two-dimensional semiconductor with a direct band gap of 1.8 eV. The MoS2/bulk semiconductor system offers a new platform for solar cell device design. Different from the conventional bulk p-n junctions, in the MoS2/bulk semiconductor heterostructure, static charge transfer shifts the Fermi level of MoS2 toward that of bulk semiconductor, lowering the barrier height of the formed junction. Herein, we introduce hexagonal boron nitride (h-BN) into MoS2/GaAs heterostructure to suppress the static charge transfer, and the obtained MoS2/h-BN/GaAs solar cell exhibits an improved power conversion efficiency of 5.42%. More importantly, the sandwiched h-BN makes the Fermi level tuning of MoS2 more effective. By employing chemical doping and electrical gating into the solar cell device, PCE of 9.03% is achieved, which is the highest among all the reported monolayer transition metal dichalcogenide based solar cells. PMID:26458358

A General Strategy to Achieve Colossal Permittivity and Low Dielectric Loss Through Constructing Insulator/Semiconductor/Insulator Multilayer Structures

NASA Astrophysics Data System (ADS)

Liu, Kai; Sun, Yalong; Zheng, Fengang; Tse, Mei-Yan; Sun, Qingbo; Liu, Yun; Hao, Jianhua

2018-06-01

In this work, we propose a route to realize high-performance colossal permittivity (CP) by creating multilayer structures of insulator/semiconductor/insulator. To prove the new concept, we made heavily reduced rutile TiO2 via annealing route in Ar/H2 atmosphere. Dielectric studies show that the maximum dielectric permittivity ( 3.0 × 104) of our prepared samples is about 100 times higher than that ( 300) of conventional TiO2. The minimum dielectric loss is 0.03 (at 104-105 Hz). Furthermore, CP is almost independent of the frequency (100-106 Hz) and the temperature (20-350 K). We suggest that the colossal permittivity is attributed to the high carrier concentration of the inner TiO2 semiconductor, while the low dielectric loss is due to the presentation of the insulator layer on the surface of TiO2. The method proposed here can be expanded to other material systems, such as semiconductor Si sandwiched by top and bottom insulator layers of Ga2O3.

Electrical characterization of organic thin film transistors and alternative device architectures

NASA Astrophysics Data System (ADS)

Newman, Christopher R.

In the last 10--15 years, organic semiconductors have evolved from experimental curiosities into viable alternatives for practical applications involving large-area and low-cost electronics such as display backplanes, electronic paper, radio frequency identification (RFID) tags, and solar cells. Many of the initially-stated goals in this field have been achieved; organic semconductors have demonstrated performance comparable to or greater than amorphous silicon (a-Si), the entrenched technology for most of the applications listed above. At present, the major obstacles remaining to commercialization of devices based on organic semiconductors involve material stability, processing considerations and optimization of the other device components (e.g. metal contacts and dielectric materials). Despite these technical achievements, significant gaps remain in our understanding of the underlying transport physics in these devices. This thesis summarizes experiments performed on organic field-effect transistors (OFETs) in an attempt to address some of these knowledge gaps. The FET, in addition to being a very useful device for practical applications (such as the driving elements in pixel backplanes), is also a very flexible architecture from an experimental standpoint. The presence of a capacitively-coupled gate electrode allows the investigation of transport physics as a function of carrier concentration. For devices in which non-idealities (i.e. carrier traps) largely dictate the observed characteristics, this is a very useful feature. Although practical OFETs are fabricated as conventional single-gate structures on an organic thin film (OTFTs), more exotic structures can often provide insights that standard OTFTs cannot. Specifically, single-crystal OFETs allow the investigation of carrier transport in the absence of grain boundaries, and double-gated OTFTs facilitate the investigation and comparison of properties across two discrete interfaces. One of the remaining challenges in terms of achieving stability inorganic semiconductors involves understanding, and hopefully minimizing, the bias stress effect of operating OTFTs. Largely ignored during the years in which research groups sought to optimize the standard device metrics of field-effect mobility, current on/off ratio, and threshold voltage, operational stability is emerging as a dominant consideration in these materials. Experiments performed with the goal of quantifying and understanding the bias-stress effect in organic semiconductors are described at the end of this thesis.

Imaging detectors and electronics—a view of the future

NASA Astrophysics Data System (ADS)

Spieler, Helmuth

2004-09-01

Imaging sensors and readout electronics have made tremendous strides in the past two decades. The application of modern semiconductor fabrication techniques and the introduction of customized monolithic integrated circuits have made large-scale imaging systems routine in high-energy physics. This technology is now finding its way into other areas, such as space missions, synchrotron light sources, and medical imaging. I review current developments and discuss the promise and limits of new technologies. Several detector systems are described as examples of future trends. The discussion emphasizes semiconductor detector systems, but I also include recent developments for large-scale superconducting detector arrays.

Economics of polysilicon processes

NASA Technical Reports Server (NTRS)

Yaws, C. L.; Li, K. Y.; Chou, S. M.

1986-01-01

Techniques are being developed to provide lower cost polysilicon material for solar cells. Existing technology which normally provides semiconductor industry polysilicon material is undergoing changes and also being used to provide polysilicon material for solar cells. Economics of new and existing technologies are presented for producing polysilicon. The economics are primarily based on the preliminary process design of a plant producing 1,000 metric tons/year of silicon. The polysilicon processes include: Siemen's process (hydrogen reduction of trichlorosilane); Union Carbide process (silane decomposition); and Hemlock Semiconductor process (hydrogen reduction of dichlorosilane). The economics include cost estimates of capital investment and product cost to produce polysilicon via the technology. Sensitivity analysis results are also presented to disclose the effect of major paramentes such as utilities, labor, raw materials and capital investment.

Computing technology in the 1980's. [computers

NASA Technical Reports Server (NTRS)

Stone, H. S.

1978-01-01

Advances in computing technology have been led by consistently improving semiconductor technology. The semiconductor industry has turned out ever faster, smaller, and less expensive devices since transistorized computers were first introduced 20 years ago. For the next decade, there appear to be new advances possible, with the rate of introduction of improved devices at least equal to the historic trends. The implication of these projections is that computers will enter new markets and will truly be pervasive in business, home, and factory as their cost diminishes and their computational power expands to new levels. The computer industry as we know it today will be greatly altered in the next decade, primarily because the raw computer system will give way to computer-based turn-key information and control systems.

Advanced 3-V semiconductor technology assessment

NASA Technical Reports Server (NTRS)

Nowogrodzki, M.

1983-01-01

Components required for extensions of currently planned space communications systems are discussed for large antennas, crosslink systems, single sideband systems, Aerostat systems, and digital signal processing. Systems using advanced modulation concepts and new concepts in communications satellites are included. The current status and trends in materials technology are examined with emphasis on bulk growth of semi-insulating GaAs and InP, epitaxial growth, and ion implantation. Microwave solid state discrete active devices, multigigabit rate GaAs digital integrated circuits, microwave integrated circuits, and the exploratory development of GaInAs devices, heterojunction devices, and quasi-ballistic devices is considered. Competing technologies such as RF power generation, filter structures, and microwave circuit fabrication are discussed. The fundamental limits of semiconductor devices and problems in implementation are explored.

Limits on silicon nanoelectronics for terascale integration.

PubMed

Meindl, J D; Chen, Q; Davis, J A

2001-09-14

Throughout the past four decades, silicon semiconductor technology has advanced at exponential rates in both performance and productivity. Concerns have been raised, however, that the limits of silicon technology may soon be reached. Analysis of fundamental, material, device, circuit, and system limits reveals that silicon technology has an enormous remaining potential to achieve terascale integration (TSI) of more than 1 trillion transistors per chip. Such massive-scale integration is feasible assuming the development and economical mass production of double-gate metal-oxide-semiconductor field effect transistors with gate oxide thickness of about 1 nanometer, silicon channel thickness of about 3 nanometers, and channel length of about 10 nanometers. The development of interconnecting wires for these transistors presents a major challenge to the achievement of nanoelectronics for TSI.

New semiconductor laser technology for gas sensing applications in the 1650nm range

NASA Astrophysics Data System (ADS)

Morrison, Gordon B.; Sherman, Jes; Estrella, Steven; Moreira, Renan L.; Leisher, Paul O.; Mashanovitch, Milan L.; Stephen, Mark; Numata, Kenji; Wu, Stewart; Riris, Haris

2017-08-01

Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. CH4 also contributes to pollution in the lower atmosphere through chemical reactions leading to ozone production. Recent developments of LIDAR measurement technology for CH4 have been previously reported by Goddard Space Flight Center (GSFC). In this paper, we report on a novel, high-performance tunable semiconductor laser technology developed by Freedom Photonics for the 1650nm wavelength range operation, and for LIDAR detection of CH4. Devices described are monolithic, with simple control, and compatible with low-cost fabrication techniques. We present 3 different types of tunable lasers implemented for this application.

Riding the Technology Wave.

ERIC Educational Resources Information Center

Malan, Pierre

This paper presents an overview of information technology development. The first section sets the scene, comparing the first WAN (Wide Area Network) and Intel processor to current technology. The birth of the microcomputer is described in the second section, including historical background on semiconductors, microprocessors, and the microcomputer.…

16th Russian Youth Conference on Physics of Semiconductors and Nanostructures, Opto- and Nanoelectronics

NASA Astrophysics Data System (ADS)

Suris, Robert A.; Vorobjev, Leonid E.; Firsov, Dmitry A.

2015-01-01

The 16th Russian Youth Conference on Physics of Semiconductors and Nanostructures, Opto- and Nanoelectronics was held on November 24 - 28 at St. Petersburg Polytechnic University. The program of the Conference included semiconductor technology, heterostructures with quantum wells and quantum dots, opto- and nanoelectronic devices, and new materials. A large number of participants with about 200 attendees from many regions of Russia provided a perfect platform for the valuable discussions between students and experienced scientists. The Conference included two invited talks given by a corresponding member of RAS P.S. Kopyev ("Nitrides: the 4th Nobel Prize on semiconductor heterostructures") and Dr. A.V. Ivanchik ("XXI century is the era of precision cosmology"). Students, graduate and postgraduate students presented their results on plenary and poster sessions. The total number of accepted papers published in Russian (the official conference language) was 92. Here we publish 18 of them in English. Like previous years, the participants were involved in the competition for the best report. Certificates and cash prizes were awarded to a number of participants for the presentations selected by the Program Committee. Two special E.F. Gross Prizes were given for the best presentations in semiconductor optics. Works with potential applications were recommended for participation in the following competition for support from the Russian Foundation for Assistance to Small Innovative Enterprises in Science and Technology. The Conference was supported by the Russian Foundation for Basic Research, the "Dynasty" foundation and the innovation company "ATC - Semiconductor Devices", St. Petersburg. The official Conference website is http://www.semicond.spbstu.ru/conf2014-eng.html

Photochemical Construction of Carbonitride Structures for Red-Light Redox Catalysis.

PubMed

Yang, Pengju; Wang, Ruirui; Zhou, Min; Wang, Xinchen

2018-05-22

Metal-free carbonitride(CN) semiconductors are appealing light-transducers for photocatalytic redox reactions owing to the unique band gap and stability. To harness solar energy efficiently, CN catalysts that are active over a wider range of the visible spectrum are desired. Now a photochemical approach has been used to prepare a new-type triazine-based CN structure. The obtained CN shows extraordinary light-harvesting characteristics, with suitable semiconductor-redox potentials. The light absorption edge of the CN reaches up to 735 nm, which is significantly longer than that of the conventional CN semiconductor at about 460 nm. As expected, the CN can efficiently catalyze oxidation of alcohols and reduction of CO 2 with visible light, even under red-light irradiation. The results represent an important step toward the development of red-light-responsive triazine-based structures for solar applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pseudo 2-transistor active pixel sensor using an n-well/gate-tied p-channel metal oxide semiconductor field eeffect transistor-type photodetector with built-in transfer gate

NASA Astrophysics Data System (ADS)

Seo, Sang-Ho; Seo, Min-Woong; Kong, Jae-Sung; Shin, Jang-Kyoo; Choi, Pyung

2008-11-01

In this paper, a pseudo 2-transistor active pixel sensor (APS) has been designed and fabricated by using an n-well/gate-tied p-channel metal oxide semiconductor field effect transistor (PMOSFET)-type photodetector with built-in transfer gate. The proposed sensor has been fabricated using a 0.35 μm 2-poly 4-metal standard complementary metal oxide semiconductor (CMOS) logic process. The pseudo 2-transistor APS consists of two NMOSFETs and one photodetector which can amplify the generated photocurrent. The area of the pseudo 2-transistor APS is 7.1 × 6.2 μm2. The sensitivity of the proposed pixel is 49 lux/(V·s). By using this pixel, a smaller pixel area and a higher level of sensitivity can be realized when compared with a conventional 3-transistor APS which uses a pn junction photodiode.

Manipulation of charge transfer and transport in plasmonic-ferroelectric hybrids for photoelectrochemical applications

PubMed Central

Wang, Zhijie; Cao, Dawei; Wen, Liaoyong; Xu, Rui; Obergfell, Manuel; Mi, Yan; Zhan, Zhibing; Nasori, Nasori; Demsar, Jure; Lei, Yong

2016-01-01

Utilizing plasmonic nanostructures for efficient and flexible conversion of solar energy into electricity or fuel presents a new paradigm in photovoltaics and photoelectrochemistry research. In a conventional photoelectrochemical cell, consisting of a plasmonic structure in contact with a semiconductor, the type of photoelectrochemical reaction is determined by the band bending at the semiconductor/electrolyte interface. The nature of the reaction is thus hard to tune. Here instead of using a semiconductor, we employed a ferroelectric material, Pb(Zr,Ti)O3 (PZT). By depositing gold nanoparticle arrays and PZT films on ITO substrates, and studying the photocurrent as well as the femtosecond transient absorbance in different configurations, we demonstrate an effective charge transfer between the nanoparticle array and PZT. Most importantly, we show that the photocurrent can be tuned by nearly an order of magnitude when changing the ferroelectric polarization in PZT, demonstrating a versatile and tunable system for energy harvesting. PMID:26753764

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John; Nuzzo, Ralph; Meitl, Matthew; Menard, Etienne; Baca, Alfred J; Motala, Michael; Ahn, Jong-Hyun; Park, Sang-Il; Yu, Chang-Jae; Ko, Heung Cho; Stoykovich, Mark; Yoon, Jongseung

2014-05-13

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John [Champaign, IL; Nuzzo, Ralph [Champaign, IL; Meitl, Matthew [Durham, NC; Menard, Etienne [Durham, NC; Baca, Alfred J [Urbana, IL; Motala, Michael [Champaign, IL; Ahn, Jong-Hyun [Suwon, KR; Park, Sang-II [Savoy, IL; Yu,; Chang-Jae, [Urbana, IL; Ko, Heung-Cho [Gwangju, KR; Stoykovich,; Mark, [Dover, NH; Yoon, Jongseung [Urbana, IL

2011-07-05

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Nanoscale doping of compound semiconductors by solid phase dopant diffusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, Jaehyun, E-mail: jaehyun.ahn@utexas.edu; Koh, Donghyi; Roy, Anupam

2016-03-21

Achieving damage-free, uniform, abrupt, ultra-shallow junctions while simultaneously controlling the doping concentration on the nanoscale is an ongoing challenge to the scaling down of electronic device dimensions. Here, we demonstrate a simple method of effectively doping ΙΙΙ-V compound semiconductors, specifically InGaAs, by a solid phase doping source. This method is based on the in-diffusion of oxygen and/or silicon from a deposited non-stoichiometric silicon dioxide (SiO{sub x}) film on InGaAs, which then acts as donors upon activation by annealing. The dopant profile and concentration can be controlled by the deposited film thickness and thermal annealing parameters, giving active carrier concentration ofmore » 1.4 × 10{sup 18 }cm{sup −3}. Our results also indicate that conventional silicon based processes must be carefully reviewed for compound semiconductor device fabrication to prevent unintended doping.« less

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John; Nuzzo, Ralph; Meitl, Matthew; Menard, Etienne; Baca, Alfred; Motala, Michael; Ahn, Jong -Hyun; Park, Sang -Il; Yu, Chang -Jae; Ko, Heung Cho; Stoykovich, Mark; Yoon, Jongseung

2015-08-25

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John; Nuzzo, Ralph; Meitl, Matthew; Menard, Etienne; Baca, Alfred; Motala, Michael; Ahn, Jong-Hyun; Park, Sang-Il; Yu, Chang-Jae; Ko, Heung Cho; Stoykovich, Mark; Yoon, Jongseung

2017-03-21

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Semiconductor optoelectronic devices for free-space optical communications

NASA Technical Reports Server (NTRS)

Katz, J.

1983-01-01

The properties of individual injection lasers are reviewed, and devices of greater complexity are described. These either include or are relevant to monolithic integration configurations of the lasers with their electronic driving circuitry, power combining methods of semiconductor lasers, and electronic methods of steering the radiation patterns of semiconductor lasers and laser arrays. The potential of AlGaAs laser technology for free-space optical communications systems is demonstrated. These solid-state components, which can generate and modulate light, combine the power of a number of sources and perform at least part of the beam pointing functions. Methods are proposed for overcoming the main drawback of semiconductor lasers, that is, their inability to emit the needed amount of optical power in a single-mode operation.

Semiconductor systems utilizing materials that form rectifying junctions in both N and P-type doping regions, whether metallurgically or field induced, and methods of use

DOEpatents

Welch, James D.

2000-01-01

Disclosed are semiconductor systems, such as integrated circuits utilizing Schotky barrier and/or diffused junction technology, which semiconductor systems incorporate material(s) that form rectifying junctions in both metallurgically and/or field induced N and P-type doping regions, and methods of their use. Disclosed are Schottky barrier based inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to multiple device CMOS systems and which can be operated as modulators, N and P-channel MOSFETS and CMOS formed therefrom, and (MOS) gate voltage controlled rectification direction and gate voltage controlled switching devices, and use of such material(s) to block parasitic current flow pathways. Simple demonstrative five mask fabrication procedures for inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to multiple device CMOS systems are also presented.

Semiconductor Nonlinear Dynamics Study by Broadband Terahertz Spectroscopy

NASA Astrophysics Data System (ADS)

Ho, I.-Chen

Semiconductor nonlinearity in the terahertz (THz) frequency range has been attracting considerable attention due to the recent development of high-power semiconductor-based nanodevices. However, the underlying physics concerning carrier dynamics in the presence of high-field THz transients is still obscure. This thesis introduces an ultrafast, time-resolved THz pump/THz probe approach to the study of semiconductor properties in the nonlinear regime. The carrier dynamics regarding two mechanisms, intervalley scattering and impact ionization, is observed for doped InAs on a sub-picosecond time scale. In addition, polaron modulation driven by intense THz pulses is experimentally and theoretically investigated. The observed polaron dynamics verifies the interaction between energetic electrons and a phonon field. In contrast to previous work which reports optical phonon responses, acoustic phonon modulations are addressed in this study. A further understanding of the intense field interacting with solid materials will accelerate the development of semiconductor devices. This thesis starts with the design and performance of a table-top THz spectrometer which has the advantages of ultra-broad bandwidth (one order higher bandwidth compared to a conventional ZnTe sensor) and high electric field strength (>100 kV/cm). Unlike the conventional THz time-domain spectroscopy, the spectrometer integrates a novel THz air-biased-coherent-detection (THz-ABCD) technique and utilizes selected gases as THz emitters and sensors. In comparison with commonly used electro-optic (EO) crystals or photoconductive (PC) dipole antennas, the gases have the benefits of no phonon absorption as existing in EO crystals and no carrier life time limitation as observed in PC dipole antennas. The newly development THz-ABCD spectrometer with a strong THz field strength capability provides a platform for various research topics especially on the nonlinear carrier dynamics of semiconductors. Two mechanisms, electron intervalley scattering and impact ionization of InAs crystals, are observed under the excitation of intense THz field on a sub-picosecond time scale. These two competing mechanisms are demonstrated by changing the impurity doping type of the semiconductors and varying the strength of the THz field. Another investigation of nonlinear carrier dynamics is the observation of coherent polaron oscillation in n-doped semiconductors excited by intense THz pulses. Through modulations of surface reflection with a THz pump/THz probe technique, this work experimentally verifies the interaction between energetic electrons and a phonon field, which has been theoretically predicted by previous publications, and shows that this interaction applies for the acoustic phonon modes. Usually, two transverse acoustic (2TA) phonon responses are inactive in infrared measurement, while they are detectable in second-order Raman spectroscopy. The study of polaron dynamics, with nonlinear THz spectroscopy (in the far-infrared range), provides a unique method to diagnose the overtones of 2TA phonon responses of semiconductors, and therefore incorporates the abilities of both infrared and Raman spectroscopy. This work presents a new milestone in wave-matter interaction and seeks to benefit the industrial applications in high power, small scale devices.

Mechanics and thermal management of stretchable inorganic electronics.

PubMed

Song, Jizhou; Feng, Xue; Huang, Yonggang

2016-03-01

Stretchable electronics enables lots of novel applications ranging from wearable electronics, curvilinear electronics to bio-integrated therapeutic devices that are not possible through conventional electronics that is rigid and flat in nature. One effective strategy to realize stretchable electronics exploits the design of inorganic semiconductor material in a stretchable format on an elastomeric substrate. In this review, we summarize the advances in mechanics and thermal management of stretchable electronics based on inorganic semiconductor materials. The mechanics and thermal models are very helpful in understanding the underlying physics associated with these systems, and they also provide design guidelines for the development of stretchable inorganic electronics.

Resonant polarization transfer from electron spins to nuclear spins-or to muon spins-in semiconductors

NASA Astrophysics Data System (ADS)

Henstra, A.; Wenckebach, W. Th.

1991-02-01

A review is given of newly developed pulsed Electron Spin Resonance (ESR) methods for dynamic polarization of nuclear spins. The application of two of these methods, Nuclear Orientation Via Electron spin Locking (NOVEL) and the Integrated Solid Effect (ISE), for the polarization of nuclear spins in semiconductors is discussed in more detail. It is proposed to use these methods to study the ESR spectrum of unpaired electrons in the vicinity of muons that are bound in a solid. Thus, ESR would be observed with a sensitivity which is enhanced by about ten orders of magnitude compared to conventional ESR.

Reproducible Growth of High-Quality Cubic-SiC Layers

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Powell, J. Anthony

2004-01-01

Semiconductor electronic devices and circuits based on silicon carbide (SiC) are being developed for use in high-temperature, high-power, and/or high-radiation conditions under which devices made from conventional semiconductors cannot adequately perform. The ability of SiC-based devices to function under such extreme conditions is expected to enable significant improvements in a variety of applications and systems. These include greatly improved high-voltage switching for saving energy in public electric power distribution and electric motor drives; more powerful microwave electronic circuits for radar and communications; and sensors and controls for cleaner-burning, more fuel-efficient jet aircraft and automobile engines.

Wide-band-gap, alkaline-earth-oxide semiconductor and devices utilizing same

DOEpatents

Abraham, Marvin M.; Chen, Yok; Kernohan, Robert H.

1981-01-01

This invention relates to novel and comparatively inexpensive semiconductor devices utilizing semiconducting alkaline-earth-oxide crystals doped with alkali metal. The semiconducting crystals are produced by a simple and relatively inexpensive process. As a specific example, a high-purity lithium-doped MgO crystal is grown by conventional techniques. The crystal then is heated in an oxygen-containing atmosphere to form many [Li].degree. defects therein, and the resulting defect-rich hot crystal is promptly quenched to render the defects stable at room temperature and temperatures well above the same. Quenching can be effected conveniently by contacting the hot crystal with room-temperature air.

Mechanics and thermal management of stretchable inorganic electronics

PubMed Central

Song, Jizhou; Feng, Xue; Huang, Yonggang

2016-01-01

Stretchable electronics enables lots of novel applications ranging from wearable electronics, curvilinear electronics to bio-integrated therapeutic devices that are not possible through conventional electronics that is rigid and flat in nature. One effective strategy to realize stretchable electronics exploits the design of inorganic semiconductor material in a stretchable format on an elastomeric substrate. In this review, we summarize the advances in mechanics and thermal management of stretchable electronics based on inorganic semiconductor materials. The mechanics and thermal models are very helpful in understanding the underlying physics associated with these systems, and they also provide design guidelines for the development of stretchable inorganic electronics. PMID:27547485

Silicon carbide novel optical sensor for combustion systems and nuclear reactors

NASA Astrophysics Data System (ADS)

Lim, Geunsik; Kar, Aravinda

2014-09-01

Crystalline silicon carbide is a wide bandgap semiconductor material with excellent optical properties, chemical inertness, radiation hardness and high mechanical strength at high temperatures. It is an excellent material platform for sensor applications in harsh environments such as combustion systems and nuclear reactors. A laser doping technique is used to fabricate SiC sensors for different combustion gases such as CO2, CO, NO and NO2. The sensor operates based on the principle of semiconductor optics, producing optical signal in contrast to conventional electrical sensors that produces electrical signal. The sensor response is measured with a low power He-Ne or diode laser.

Energy-Efficient Neuromorphic Classifiers.

PubMed

Martí, Daniel; Rigotti, Mattia; Seok, Mingoo; Fusi, Stefano

2016-10-01

Neuromorphic engineering combines the architectural and computational principles of systems neuroscience with semiconductor electronics, with the aim of building efficient and compact devices that mimic the synaptic and neural machinery of the brain. The energy consumptions promised by neuromorphic engineering are extremely low, comparable to those of the nervous system. Until now, however, the neuromorphic approach has been restricted to relatively simple circuits and specialized functions, thereby obfuscating a direct comparison of their energy consumption to that used by conventional von Neumann digital machines solving real-world tasks. Here we show that a recent technology developed by IBM can be leveraged to realize neuromorphic circuits that operate as classifiers of complex real-world stimuli. Specifically, we provide a set of general prescriptions to enable the practical implementation of neural architectures that compete with state-of-the-art classifiers. We also show that the energy consumption of these architectures, realized on the IBM chip, is typically two or more orders of magnitude lower than that of conventional digital machines implementing classifiers with comparable performance. Moreover, the spike-based dynamics display a trade-off between integration time and accuracy, which naturally translates into algorithms that can be flexibly deployed for either fast and approximate classifications, or more accurate classifications at the mere expense of longer running times and higher energy costs. This work finally proves that the neuromorphic approach can be efficiently used in real-world applications and has significant advantages over conventional digital devices when energy consumption is considered.

Extending green technology innovations to enable greener fabs

NASA Astrophysics Data System (ADS)

Takahisa, Kenji; Yoo, Young Sun; Fukuda, Hitomi; Minegishi, Yuji; Enami, Tatsuo

2015-03-01

Semiconductor manufacturing industry has growing concerns over future environmental impacts as fabs expand and new generations of equipment become more powerful. Especially rare gases supply and price are one of prime concerns for operation of high volume manufacturing (HVM) fabs. Over the past year it has come to our attention that Helium and Neon gas supplies could be unstable and become a threat to HVM fabs. To address these concerns, Gigaphoton has implemented various green technologies under its EcoPhoton program. One of the initiatives is GigaTwin deep ultraviolet (DUV) lithography laser design which enables highly efficient and stable operation. Under this design laser systems run with 50% less electric energy and gas consumption compared to conventional laser designs. In 2014 we have developed two technologies to further reduce electric energy and gas efficiency. The electric energy reduction technology is called eGRYCOS (enhanced Gigaphoton Recycled Chamber Operation System), and it reduces electric energy by 15% without compromising any of laser performances. eGRYCOS system has a sophisticated gas flow design so that we can reduce cross-flow-fan rotation speed. The gas reduction technology is called eTGM (enhanced Total gas Manager) and it improves gas management system optimizing the gas injection and exhaust amount based on laser performances, resulting in 50% gas savings. The next steps in our roadmap technologies are indicated and we call for potential partners to work with us based on OPEN INNOVATION concept to successfully develop faster and better solutions in all possible areas where green innovation may exist.

Information Technology and the Third Industrial Revolution.

ERIC Educational Resources Information Center

Fitzsimmons, Joe

1994-01-01

Discusses the so-called third industrial revolution, or the information revolution. Topics addressed include the progression of the revolution in the U.S. economy, in Europe, and in Third World countries; the empowering technologies, including digital switches, optical fiber, semiconductors, CD-ROM, networks, and combining technologies; and future…

Ferroelectrics for semiconductor devices

NASA Astrophysics Data System (ADS)

Sayer, M.; Wu, Z.; Vasant Kumar, C. V. R.; Amm, D. T.; Griswold, E. M.

1992-11-01

The technology for the implementation of the integration of thin film ferroelectrics with silicon processing for various devices is described, and factors affecting the integration of ferroelectric films with semiconductor processing are discussed. Consideration is also given to film properties, the properties of electrode materials and structures, and the phenomena of ferroelectric fatigue and aging. Particular attention is given to the nonmemory device application of ferroelectrics.

Photonic Arbitrary Waveform Generation Technology

DTIC Science & Technology

2006-06-01

locked external- cavity semiconductor diode ring laser “, Optics Letters, Vol. 27, No. 9 , 719-721, (2002). [22] S. Gee, F. Quinlan, S. Ozharar... optical pulses that one is accustomed to. Modelocked semiconductor lasers are used to generate a set of phase locked optical frequencies on a periodic...The corresponding optical spectrum of the laser consists of a comb of periodically spaced, phase - locked

Improvement of screening methods for silicon planar semiconductor devices

NASA Technical Reports Server (NTRS)

Berger, W. M.

1972-01-01

The results of the program for the development of a more sensitive method for selecting silicon planar semiconductor devices for long life applications are reported. The manufacturing technologies (MOS and Bipolar) are discussed along with the screening procedures developed as a result of the tests and evaluations, and the effectiveness of the MOS and Bilayer screening procedures are evaluated.

Metrology-based control and profitability in the semiconductor industry

NASA Astrophysics Data System (ADS)

Weber, Charles

2001-06-01

This paper summarizes three studies of the semiconductor industry conducted at SEMATECH and MIT's Sloan School of Management. In conjunction they lead to the conclusion that rapid problem solving is an essential component of profitability in the semiconductor industry, and that metrology-based control is instrumental to rapid problem solving. The studies also identify the need for defect attribution. Once a source of a defect has been identified, the appropriate resources--human and technological--need to be brought into the physically optimal location for corrective action. The Internet is likely to enable effective defect attribution by inducing collaboration between different companies.

Ring resonator based narrow-linewidth semiconductor lasers

NASA Technical Reports Server (NTRS)

Ksendzov, Alexander (Inventor)

2005-01-01

The present invention is a method and apparatus for using ring resonators to produce narrow linewidth hybrid semiconductor lasers. According to one embodiment of the present invention, the narrow linewidths are produced by combining the semiconductor gain chip with a narrow pass band external feedback element. The semi conductor laser is produced using a ring resonator which, combined with a Bragg grating, acts as the external feedback element. According to another embodiment of the present invention, the proposed integrated optics ring resonator is based on plasma enhanced chemical vapor deposition (PECVD) SiO.sub.2 /SiON/SiO.sub.2 waveguide technology.

Semiconductor Ion Implanters

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacKinnon, Barry A.; Ruffell, John P.

In 1953 the Raytheon CK722 transistor was priced at $7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at $6.2 billion. Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intelmore » product to disposable items containing 'only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around $2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.« less

Band alignments in Fe/graphene/Si(001) junctions studied by x-ray photoemission spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Breton, J.-C., E-mail: jean-christophe.lebreton@univ-rennes1.fr; Tricot, S.; Delhaye, G.

2016-08-01

The control of tunnel contact resistance is of primary importance for semiconductor-based spintronic devices. This control is hardly achieved with conventional oxide-based tunnel barriers due to deposition-induced interface states. Manipulation of single 2D atomic crystals (such as graphene sheets) weakly interacting with their substrate might represent an alternative and efficient way to design new heterostructures for a variety of different purposes including spin injection into semiconductors. In the present paper, we study by x-ray photoemission spectroscopy the band alignments and interface chemistry of iron–graphene-hydrogenated passivated silicon (001) surfaces for a low and a high n-doping concentration. We find that themore » hydrogen passivation of the Si(001) surface remains efficient even with a graphene sheet on the Si(001) surface. For both doping concentrations, the semiconductor is close to flat-band conditions which indicates that the Fermi level is unpinned on the semiconductor side of the Graphene/Si(001):H interface. When iron is deposited on the graphene/Si(001):H structures, the Schottky barrier height remains mainly unaffected by the metallic overlayer with a very low barrier height for electrons, a sought-after property in semiconductor based spintronic devices. Finally, we demonstrate that the graphene layer intercalated between the metal and semiconductor also serves as a protection against iron-silicide formation even at elevated temperatures preventing from the formation of a Si-based magnetic dead layer.« less

Band alignments in Fe/graphene/Si(001) junctions studied by x-ray photoemission spectroscopy

NASA Astrophysics Data System (ADS)

Le Breton, J.-C.; Tricot, S.; Delhaye, G.; Lépine, B.; Turban, P.; Schieffer, P.

2016-08-01

The control of tunnel contact resistance is of primary importance for semiconductor-based spintronic devices. This control is hardly achieved with conventional oxide-based tunnel barriers due to deposition-induced interface states. Manipulation of single 2D atomic crystals (such as graphene sheets) weakly interacting with their substrate might represent an alternative and efficient way to design new heterostructures for a variety of different purposes including spin injection into semiconductors. In the present paper, we study by x-ray photoemission spectroscopy the band alignments and interface chemistry of iron-graphene-hydrogenated passivated silicon (001) surfaces for a low and a high n-doping concentration. We find that the hydrogen passivation of the Si(001) surface remains efficient even with a graphene sheet on the Si(001) surface. For both doping concentrations, the semiconductor is close to flat-band conditions which indicates that the Fermi level is unpinned on the semiconductor side of the Graphene/Si(001):H interface. When iron is deposited on the graphene/Si(001):H structures, the Schottky barrier height remains mainly unaffected by the metallic overlayer with a very low barrier height for electrons, a sought-after property in semiconductor based spintronic devices. Finally, we demonstrate that the graphene layer intercalated between the metal and semiconductor also serves as a protection against iron-silicide formation even at elevated temperatures preventing from the formation of a Si-based magnetic dead layer.

THE SILICON OLFACTORY BULB: A NEUROMORPHIC APPROACH TO MOLECULAR SENSING WITH CHEMORECEPTIVE NEURON MOS TRANSISTORS (CNMOS)

EPA Science Inventory

Within the 3 -year effort, we have established several major findings:

• Chemical sensor in fluid environment with inorganic and polymer sensing surfaces (1,5): Conventional metal oxide semiconductor field effect transistor (MOSFET)-based chemical sensing su...

• The performances of different overlay mark types at 65nm node on 300-mm wafers

  NASA Astrophysics Data System (ADS)

  Tseng, H. T.; Lin, Ling-Chieh; Huang, I. H.; Lin, Benjamin S.; Huang, Chin-Chou K.; Huang, Chien-Jen

  2005-05-01

  The integrated circuit (IC) manufacturing factories have measured overlay with conventional "box-in-box" (BiB) or "frame-in-frame" (FiF) structures for many years. Since UMC played as a roll of world class IC foundry service provider, tighter and tighter alignment accuracy specs need to be achieved from generation to generation to meet any kind of customers' requirement, especially according to International Technology Roadmap for Semiconductors (ITRS) 2003 METROLOGY section1. The process noises resulting from dishing, overlay mark damaging by chemical mechanism polishing (CMP), and the variation of film thickness during deposition are factors which can be very problematic in mark alignment. For example, the conventional "box-in-box" overlay marks could be damaged easily by CMP, because the less local pattern density and wide feature width of the box induce either dishing or asymmetric damages for the measurement targets, which will make the overlay measurement varied and difficult. After Advanced Imaging Metrology (AIM) overlay targets was introduced by KLA-Tencor, studies in the past shown AIM was more robust in overlay metrology than conventional FiF or BiB targets. In this study, the applications of AIM overlay marks under different process conditions will be discussed and compared with the conventional overlay targets. To evaluate the overlay mark performance against process variation on 65nm technology node in 300-mm wafer, three critical layers were chosen in this study. These three layers were Poly, Contact, and Cu-Metal. The overlay targets used for performance comparison were BiB and Non-Segmented AIM (NS AIM) marks. We compared the overlay mark performance on two main areas. The first one was total measurement uncertainty (TMU)3 related items that include Tool Induced Shift (TIS) variability, precision, and matching. The other area is the target robustness against process variations. Based on the present study AIM mark demonstrated an equal or better performance in the TMU related items under our process conditions. However, when non-optimized tungsten CMP was introduced in the tungsten contact process, due to the dense grating line structure design, we found that AIM mark was much more robust than BiB overlay target.

• Piezoresistive silicon nanowire resonators as embedded building blocks in thick SOI

  NASA Astrophysics Data System (ADS)

  Nasr Esfahani, Mohammad; Kilinc, Yasin; Çagatay Karakan, M.; Orhan, Ezgi; Hanay, M. Selim; Leblebici, Yusuf; Erdem Alaca, B.

  2018-04-01

  The use of silicon nanowire resonators in nanoelectromechanical systems for new-generation sensing and communication devices faces integration challenges with higher-order structures. Monolithic and deterministic integration of such nanowires with the surrounding microscale architecture within the same thick crystal is a critical aspect for the improvement of throughput, reliability and device functionality. A monolithic and IC-compatible technology based on a tuned combination of etching and protection processes was recently introduced yielding silicon nanowires within a 10 μ m-thick device layer. Motivated by its success, the implications of the technology regarding the electromechanical resonance are studied within a particular setting, where the resonator is co-fabricated with all terminals and tuning electrodes. Frequency response is measured via piezoresistive readout with frequency down-mixing. Measurements indicate mechanical resonance with frequencies as high as 100 MHz exhibiting a Lorentzian behavior with proper transition to nonlinearity, while Allan deviation on the order of 3-8 ppm is achieved. Enabling the fabrication of silicon nanowires in thick silicon crystals using conventional semiconductor manufacturing, the present study thus demonstrates an alternative pathway to bottom-up and thin silicon-on-insulator approaches for silicon nanowire resonators.

• New trend in electron holography

  NASA Astrophysics Data System (ADS)

  Tanigaki, Toshiaki; Harada, Ken; Murakami, Yasukazu; Niitsu, Kodai; Akashi, Tetsuya; Takahashi, Yoshio; Sugawara, Akira; Shindo, Daisuke

  2016-06-01

  Electron holography using a coherent electron wave is a promising technique for high-resolution visualization of electromagnetic fields in and around objects. The capability of electron holography has been enhanced by the development of new technologies and has thus become an even more powerful tool for exploring scientific frontiers. This review introduces these technologies including split-illumination electron holography and vector-field electron tomography. Split-illumination electron holography, which uses separated coherent waves, overcomes the limits imposed by the lateral coherence requirement for electron waves in electron holography. Areas that are difficult to observe using conventional electron holography are now observable. Exemplified applications include observing a singular magnetic domain wall in electrical steel sheets, local magnetizations at anti-phase boundaries, and electrostatic potentials in metal-oxide-semiconductor field-effect transistors. Vector-field electron tomography can be used to visualize magnetic vectors in three dimensions. Two components of the vectors are reconstructed using dual-axis tomography, and the remaining one is calculated using div B   =  0. A high-voltage electron microscope can be used to achieve precise magnetic reconstruction. For example, magnetic vortices have been visualized using a 1 MV holography electron microscope.

• Dramatic Changes in Thermoelectric Power of Germanium under Pressure: Printing n–p Junctions by Applied Stress

  PubMed Central

  Korobeinikov, Igor V.; Morozova, Natalia V.; Shchennikov, Vladimir V.; Ovsyannikov, Sergey V.

  2017-01-01

  Controlled tuning the electrical, optical, magnetic, mechanical and other characteristics of the leading semiconducting materials is one of the primary technological challenges. Here, we demonstrate that the electronic transport properties of conventional single-crystalline wafers of germanium may be dramatically tuned by application of moderate pressures. We investigated the thermoelectric power (Seebeck coefficient) of p– and n–type germanium under high pressure to 20 GPa. We established that an applied pressure of several GPa drastically shifts the electrical conduction to p–type. The p–type conduction is conserved across the semiconductor-metal phase transition at near 10 GPa. Upon pressure releasing, germanium transformed to a metastable st12 phase (Ge-III) with n–type semiconducting conductivity. We proposed that the unusual electronic properties of germanium in the original cubic-diamond-structured phase could result from a splitting of the “heavy” and “light” holes bands, and a related charge transfer between them. We suggested new innovative applications of germanium, e.g., in technologies of printing of n–p and n–p–n junctions by applied stress. Thus, our work has uncovered a new face of germanium as a ‘smart’ material. PMID:28290495

• Deep sub-micron low-Tc Josephson technology - The opportunities and the challenges

  NASA Astrophysics Data System (ADS)

  Ketchen, M. B.

  1993-03-01

  It is suggested that the possibility now exists of highly leveraging existing semiconductor technology to explore submicrometer Josephson technology. Some of the opportunities and challenges of such an undertaking are discussed in the context of SQUIDs and digital applications. In the area of digital Josephson, a 50-100-ps cycle-time 64-b reduced instruction set computer (RISC) microprocessor is proposed as a long-term goal. While it is unlikely that one will see a sub-100-ps system like this in the near term, research results supporting its feasibility may ultimately help build the case for the resources needed to produce it. Fabrication has been and will probably continue to be an impediment to the exploration of sub- and deep sub-micrometer Josephson technology. Coupling to existing semiconductor fabrication capability should help considerably in this area and should help to lay the groundwork for eventual manufacturing of sub-micrometer Josephson products.

• Compact, High Power, Multi-Spectral Mid-Infrared Semiconductor Laser Package

  NASA Astrophysics Data System (ADS)

  Guo, Bujin; Hwang, Wen-Yen; Lin, Chich-Hsiang

  2001-10-01

  Through a vertically integrated effort involving atomic level material engineering, advanced device processing development, state-of-the-art optomechanical packaging, and thermal management, Applied Optoelectronics, Inc. (AOI), University of Houston (U H), and Physical Science, Inc. (PSI) have made progress in both Sb-based type-II semiconductor material and in P-based type-I laser device development. We have achieved record performance on inP based quantum cascade continuous wave (CW) laser (with more than 5 mW CW power at 210 K). Grating-coupled external-cavity quantum cascade lasers were studied for temperatures from 20 to 230 K. A tuning range of 88 nm has been obtained at 80 K. The technology can be made commercially available and represents a significant milestone with regard to the Dual Use Science and Technology (DUST) intention of fostering dual use commercial technology for defense need. AOI is the first commercial company to ship products of this licensed technology.

• Nano-scale measurement of biomolecules by optical microscopy and semiconductor nanoparticles

  PubMed Central

  Ichimura, Taro; Jin, Takashi; Fujita, Hideaki; Higuchi, Hideo; Watanabe, Tomonobu M.

  2014-01-01

  Over the past decade, great developments in optical microscopy have made this technology increasingly compatible with biological studies. Fluorescence microscopy has especially contributed to investigating the dynamic behaviors of live specimens and can now resolve objects with nanometer precision and resolution due to super-resolution imaging. Additionally, single particle tracking provides information on the dynamics of individual proteins at the nanometer scale both in vitro and in cells. Complementing advances in microscopy technologies has been the development of fluorescent probes. The quantum dot, a semi-conductor fluorescent nanoparticle, is particularly suitable for single particle tracking and super-resolution imaging. This article overviews the principles of single particle tracking and super resolution along with describing their application to the nanometer measurement/observation of biological systems when combined with quantum dot technologies. PMID:25120488

EDITORIAL: Semiconductor lasers: the first fifty years Semiconductor lasers: the first fifty years

NASA Astrophysics Data System (ADS)

Calvez, S.; Adams, M. J.

2012-09-01

Anniversaries call for celebrations. Since it is now fifty years since the first semiconductor lasers were reported, it is highly appropriate to celebrate this anniversary with a Special Issue dedicated to the topic. The semiconductor laser now has a major effect on our daily lives since it has been a key enabler in the development of optical fibre communications (and hence the internet and e-mail), optical storage (CDs, DVDs, etc) and barcode scanners. In the early 1960s it was impossible for most people (with the exception of very few visionaries) to foresee any of these future developments, and the first applications identified were for military purposes (range-finders, target markers, etc). Of course, many of the subsequent laser applications were made possible by developments in semiconductor materials, in the associated growth and fabrication technology, and in the increased understanding of the underlying fundamental physics. These developments continue today, so that the subject of semiconductor lasers, although mature, is in good health and continues to grow. Hence, we can be confident that the pervasive influence of semiconductor lasers will continue to develop as optoelectronics technology makes further advances into other sectors such as healthcare, security and a whole host of applications based on the global imperatives to reduce energy consumption, minimise environmental impact and conserve resources. The papers in this Special Issue are intended to tell some of the story of the last fifty years of laser development as well as to provide evidence of the current state of semiconductor laser research. Hence, there are a number of papers where the early developments are recalled by authors who played prominent parts in the story, followed by a selection of papers from authors who are active in today's exciting research. The twenty-fifth anniversary of the semiconductor laser was celebrated by the publication of a number of papers dealing with the early achievements in the June 1987 Special Issue of IEEE Journal of Quantum Electronics. The Millennium Issue of IEEE Journal of Selected Topics in Quantum Electronics presented a further set of articles on historical aspects of the subject as well as a 'snapshot' of current research in June 2000. It is not the intention here to duplicate any of this historical material that is already available, but rather to complement it with personal recollections from researchers who were involved in laser development in the USA, France, Russia and the UK. Hence, in addition to fascinating accounts of the discovery of the theoretical condition for stimulated emission from semiconductors and of the pioneering work at IBM, there are two complementary views of the laser research at the Lebedev Institute, and personal insights into the developments at STL and at Bell Laboratories. These are followed by an account of the scientific and technological connections between the early pioneering breakthroughs and the commercialisation of semiconductor laser products. Turning to the papers from today's researchers, there is coverage of many of the current 'hot' topics including quantum cascade lasers, mid-infrared lasers, high-power lasers, the exciting developments in understanding and exploiting the nonlinear dynamics of lasers, and photonic integrated circuits with extremely high communication data capacity, as well as reports of recent progress on laser materials such as dilute nitrides and bismides, photonic crystals, quantum dots and organic semiconductors. Thanks are due to Jarlath McKenna for sterling support from IOP Publishing and to Peter Blood for instigating this Special Issue and inviting us to serve as Guest Editors.

Cavity-Mediated Coherent Coupling between Distant Quantum Dots

NASA Astrophysics Data System (ADS)

Nicolí, Giorgio; Ferguson, Michael Sven; Rössler, Clemens; Wolfertz, Alexander; Blatter, Gianni; Ihn, Thomas; Ensslin, Klaus; Reichl, Christian; Wegscheider, Werner; Zilberberg, Oded

2018-06-01

Scalable architectures for quantum information technologies require one to selectively couple long-distance qubits while suppressing environmental noise and cross talk. In semiconductor materials, the coherent coupling of a single spin on a quantum dot to a cavity hosting fermionic modes offers a new solution to this technological challenge. Here, we demonstrate coherent coupling between two spatially separated quantum dots using an electronic cavity design that takes advantage of whispering-gallery modes in a two-dimensional electron gas. The cavity-mediated, long-distance coupling effectively minimizes undesirable direct cross talk between the dots and defines a scalable architecture for all-electronic semiconductor-based quantum information processing.

The Fundamentals of Using the Digital Micromirror Device (DMD(TM)) for Projection Display

NASA Technical Reports Server (NTRS)

Yoder, Lars A.

1995-01-01

Developed by Texas Instruments (TI) the digital micromirror device (DMD(tm)) is a quickly emerging and highly useful micro-electro-mechanical structures (MEMS) device. Using standard semiconductor fabrication technology, the DMD's simplicity in concept and design will provide advantageous solutions for many different applications. At the rudimentary level, the DMD is a precision, semiconductor light switch. In the initial commercial development of DMD technology, TI has concentrated on projection display and hardcopy. This paper will focus on how the DMD is used for projection display. Other application areas are being explored and evaluated to find appropriate and beneficial uses for the DMD.

Polycrystalline silicon study: Low-cost silicon refining technology prospects and semiconductor-grade polycrystalline silicon availability through 1988

NASA Technical Reports Server (NTRS)

Costogue, E. N.; Ferber, R.; Lutwack, R.; Lorenz, J. H.; Pellin, R.

1984-01-01

Photovoltaic arrays that convert solar energy into electrical energy can become a cost effective bulk energy generation alternative, provided that an adequate supply of low cost materials is available. One of the key requirements for economic photovoltaic cells is reasonably priced silicon. At present, the photovoltaic industry is dependent upon polycrystalline silicon refined by the Siemens process primarily for integrated circuits, power devices, and discrete semiconductor devices. This dependency is expected to continue until the DOE sponsored low cost silicon refining technology developments have matured to the point where they are in commercial use. The photovoltaic industry can then develop its own source of supply. Silicon material availability and market pricing projections through 1988 are updated based on data collected early in 1984. The silicon refining industry plans to meet the increasing demands of the semiconductor device and photovoltaic product industries are overviewed. In addition, the DOE sponsored technology research for producing low cost polycrystalline silicon, probabilistic cost analysis for the two most promising production processes for achieving the DOE cost goals, and the impacts of the DOE photovoltaics program silicon refining research upon the commercial polycrystalline silicon refining industry are addressed.

Solution-Processed Donor-Acceptor Polymer Nanowire Network Semiconductors For High-Performance Field-Effect Transistors

PubMed Central

Lei, Yanlian; Deng, Ping; Li, Jun; Lin, Ming; Zhu, Furong; Ng, Tsz-Wai; Lee, Chun-Sing; Ong, Beng S.

2016-01-01

Organic field-effect transistors (OFETs) represent a low-cost transistor technology for creating next-generation large-area, flexible and ultra-low-cost electronics. Conjugated electron donor-acceptor (D-A) polymers have surfaced as ideal channel semiconductor candidates for OFETs. However, high-molecular weight (MW) D-A polymer semiconductors, which offer high field-effect mobility, generally suffer from processing complications due to limited solubility. Conversely, the readily soluble, low-MW D-A polymers give low mobility. We report herein a facile solution process which transformed a lower-MW, low-mobility diketopyrrolopyrrole-dithienylthieno[3,2-b]thiophene (I) into a high crystalline order and high-mobility semiconductor for OFETs applications. The process involved solution fabrication of a channel semiconductor film from a lower-MW (I) and polystyrene blends. With the help of cooperative shifting motion of polystyrene chain segments, (I) readily self-assembled and crystallized out in the polystyrene matrix as an interpenetrating, nanowire semiconductor network, providing significantly enhanced mobility (over 8 cm2V−1s−1), on/off ratio (107), and other desirable field-effect properties that meet impactful OFET application requirements. PMID:27091315

Metal-optic and Plasmonic Semiconductor-based Nanolasers

DTIC Science & Technology

2012-05-07

provides a means to integrate laser sources for silicon photonics technology. Using wafer bonding techniques, the metal- clad nanocavity can be integrated...SUPPLEMENTARY NOTES 14. ABSTRACT Over the past few decades, semiconductor lasers have relentlessly followed the path towards miniaturization...Smaller lasers are more energy e cient, are cheaper to make, and open up new applications in sensing and displays, among many other things. Yet, up until

MEDEA+ project 2T302 MUSCLE: masks through user's supply chain: leadership by excellence

NASA Astrophysics Data System (ADS)

Torsy, Andreas

2008-04-01

The rapid evolution of our information society depends on the continuous developments and innovations of semiconductor products. The cost per chip functionality keeps reducing by a factor of 2 every 18 month. However, this performance and success of the semiconductor industry critically depends on the quality of the lithographic photomasks. The need for the high quality of photomask drives lithography costs sensitively, which is a key factor in the manufacture of microelectronics devices. Therefore, the aim is to reduce production costs while overcoming challenges in terms of feature sizes, complexity and cycle times. Consequently, lithography processes must provide highest possible quality at reasonable prices. This way, the leadership in the lithographic area can be maintained and European chipmakers can stay competitive with manufacturers in the Far East and the USA. Under the umbrella of MEDEA+, a project called MUSCLE (<< Masks through User's Supply Chain: Leadership by Excellence >>) has been started among leading semiconductor companies in Europe: ALTIS Semiconductor (Project Leader), ALCATEL Vacuum, ATMEL, CEA/LETI, Entegris, NXP Semiconductors, TOPPAN Photomasks, AMTC, Carl ZEISS SMS, DMS, Infineon Technologies, VISTEC Semiconductor, NIKON Precision, SCHOTT Lithotec, ASML, PHOTRONICS, IMEC, DCE, DNP Photomask, STMicroelectronics, XYALIS and iCADA. MUSCLE focuses particularly on mask data flow, photomask carrier, photomask defect characterization and photomask data handling. In this paper, we will discuss potential solutions like standardization and automation of the photomask data flow based on SEMI P10, the performance and the impact of the supply chain parameter within the photomask process, the standardization of photomask defect characterization and a discussion of the impact of new Reticle Enhancement Technologies (RET) such as mask process correction and finally a generic model to describe the photomasks key performance indicators for prototype photomasks.

Rare resource supply crisis and solution technology for semiconductor manufacturing

NASA Astrophysics Data System (ADS)

Fukuda, Hitomi; Hu, Sophia; Yoo, Youngsun; Takahisa, Kenji; Enami, Tatsuo

2016-03-01

There are growing concerns over future environmental impact and earth resource shortage throughout the world and in many industries. Our semiconductor industry is not excluded. "Green" has become an important topic as production volume become larger and more powerful. Especially, the rare gases are widely used in semiconductor manufacturing because of its inertness and extreme chemical stability. One major component of an Excimer laser system is Neon. It is used as a buffer gas for Argon (Ar) and Krypton (Kr) gases used in deep ultraviolet (DUV) lithography laser systems. Since Neon gas accounting for more than 96% of the laser gas mixture, a fairly large amount of neon gas is consumed to run these DUV lasers. However, due to country's instability both in politics and economics in Ukraine, the main producer of neon gas today, supply reduction has become an issue and is causing increasing concern. This concern is not only based on price increases, but has escalated to the point of supply shortages in 2015. This poses a critical situation for the semiconductor industry, which represents the leading consumer of neon gas in the world. Helium is another noble gas used for Excimer laser operation. It is used as a purge gas for optical component modules to prevent from being damaged by active gases and impurities. Helium has been used in various industries, including for medical equipment, linear motor cars, and semiconductors, and is indispensable for modern life. But consumption of helium in manufacturing has been increased dramatically, and its unstable supply and price rise has been a serious issue today. In this article, recent global supply issue of rare resources, especially Neon gas and Helium gas, and its solution technology to support semiconductor industry will be discussed.

Spin Coherence at the Nanoscale: Polymer Surfaces and Interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Epstein, Arthur J.

2013-09-10

Breakthrough results were achieved during the reporting period in the areas of organic spintronics. (A) For the first time the giant magnetic resistance (GMR) was observed in spin valve with an organic spacer. Thus we demonstrated the ability of organic semiconductors to transport spin in GMR devices using rubrene as a prototype for organic semiconductors. (B) We discovered the electrical bistability and spin valve effect in a ferromagnet /organic semiconductor/ ferromagnet heterojunction. The mechanism of switching between conducting phases and its potential applications were suggested. (C) The ability of V(TCNE)x to inject spin into organic semiconductors such as rubrene wasmore » demonstrated for the first time. The mechanisms of spin injection and transport from and into organic magnets as well through organic semiconductors were elucidated. (D) In collaboration with the group of OSU Prof. Johnston-Halperin we reported the successful extraction of spin polarized current from a thin film of the organic-based room temperature ferrimagnetic semiconductor V[TCNE]x and its subsequent injection into a GaAs/AlGaAs light-emitting diode (LED). Thus all basic steps for fabrication of room temperature, light weight, flexible all organic spintronic devices were successfully performed. (E) A new synthesis/processing route for preparation of V(TCNE)x enabling control of interface and film thicknesses at the nanoscale was developed at OSU. Preliminary results show these films are higher quality and what is extremely important they are substantially more air stable than earlier prepared V(TCNE)x. In sum the breakthrough results we achieved in the past two years form the basis of a promising new technology, Multifunctional Flexible Organic-based Spintronics (MFOBS). MFOBS technology enables us fabrication of full function flexible spintronic devices that operate at room temperature.« less

Memory technology survey

NASA Technical Reports Server (NTRS)

1981-01-01

The current status of semiconductor, magnetic, and optical memory technologies is described. Projections based on these research activities planned for the shot term are presented. Conceptual designs of specific memory buffer pplications employing bipola, CMOS, GaAs, and Magnetic Bubble devices are discussed.

Employment Lessons from the Electronics Industry.

ERIC Educational Resources Information Center

Alic, John A.; Harris, Martha Caldwell

1986-01-01

Semiskilled and "unskilled" workers in semiconductors, computer manufacturing, and consumer electronics industries are more likely than other workers to lose jobs because of technology, imports, and offshore production. However, advances in technology do tend to create jobs for skilled workers. (CT)

Novel Material Integration for Reliable and Energy-Efficient NEM Relay Technology

NASA Astrophysics Data System (ADS)

Chen, I.-Ru

Energy-efficient switching devices have become ever more important with the emergence of ubiquitous computing. NEM relays are promising to complement CMOS transistors as circuit building blocks for future ultra-low-power information processing, and as such have recently attracted significant attention from the semiconductor industry and researchers. Relay technology potentially can overcome the energy efficiency limit for conventional CMOS technology due to several key characteristics, including zero OFF-state leakage, abrupt switching behavior, and potentially very low active energy consumption. However, two key issues must be addressed for relay technology to reach its full potential: surface oxide formation at the contacting surfaces leading to increased ON-state resistance after switching, and high switching voltages due to strain gradient present within the relay structure. This dissertation advances NEM relay technology by investigating solutions to both of these pressing issues. Ruthenium, whose native oxide is conductive, is proposed as the contacting material to improve relay ON-state resistance stability. Ruthenium-contact relays are fabricated after overcoming several process integration challenges, and show superior ON-state resistance stability in electrical measurements and extended device lifetime. The relay structural film is optimized via stress matching among all layers within the structure, to provide lower strain gradient (below 10E-3/microm -1) and hence lower switching voltage. These advancements in relay technology, along with the integration of a metallic interconnect layer, enable complex relay-based circuit demonstration. In addition to the experimental efforts, this dissertation theoretically analyzes the energy efficiency limit of a NEM switch, which is generally believed to be limited by the surface adhesion energy. New compact (<1 microm2 footprint), low-voltage (<0.1 V) switch designs are proposed to overcome this limit. The results pave a pathway to scaled energy-efficient electronic device technology.

Technology and characterization of Thin-Film Transistors (TFTs) with a-IGZO semiconductor and high-k dielectric layer

NASA Astrophysics Data System (ADS)

Mroczyński, R.; Wachnicki, Ł.; Gierałtowska, S.

2016-12-01

In this work, we present the design of the technology and fabrication of TFTs with amorphous IGZO semiconductor and high-k gate dielectric layer in the form of hafnium oxide (HfOx). In the course of this work, the IGZO fabrication was optimized by means of Taguchi orthogonal tables approach in order to obtain an active semiconductor with reasonable high concentration of charge carriers, low roughness and relatively high mobility. The obtained Thin-Film Transistors can be characterized by very good electrical parameters, i.e., the effective mobility (μeff ≍ 12.8 cm2V-1s-1) significantly higher than that for a-Si TFTs (μeff ≍ 1 cm2V-1s-1). However, the value of sub-threshold swing (i.e., 640 mV/dec) points that the interfacial properties of IGZO/HfOx stack is characterized by high value of interface states density (Dit) which, in turn, demands further optimization for future applications of the demonstrated TFT structures.

Department of Defense statement on the X-ray Lithography Program to the Research and Development Subcommittee of the House Armed Services Committee of 100th Congress, second session

NASA Astrophysics Data System (ADS)

Maynard, E. D., Jr.

1988-03-01

The Department has a broad and necessarily diverse program in semiconductor science and technology. The three principal goals of that effort are: Reduce the gap between commercial integrated circuit usage and its deployment in military systems, assure a healthy on-shore industrial base to support our defense needs, enhance the producibility of specialized military semiconductor products. The major effort to achieve the first of these objectives is the Very High Speed Integrated Circuits (VHSIC) Program which is nearing completion. The Microwave/millimeter wave Monolithic Integrated Circuit (MIMIC) program has just completed a study program to define the product mix needed to meet military system requirements for radar, electronic warfare, smart weapons and telecommunications. We are bringing together the system requirements of all DoD with the device fabrication and product delivery capabilities of industry in an Infrared Focal Plane Array (IRFPA) program. The goal of the Software Initiative is to enhance our warfighting capability through development of efficient software generation technology and products plus the creation of a technology infusion infrastructure to couple the technology and products to system applications. The X-Ray Lithography Program will begin to establish the industrial base which will be required to sustain U.S. leadership in the semiconductor industry for the late 1990s.

SEMATECH, A Case Study: Analysis of a Government-Industry Partnership

DTIC Science & Technology

1993-09-23

profit potential in the private market. Often, public sector technologies do not. Commercial technologies must be technically and economically...and Private Spending .................. 80 ix I. INTRODUCTION AND BACKGROUND Critics proclaim the Semiconductor Manufacturing Technology Initiative...in the R&D market and in the product market." (Katz and Ordover, 1990, p. 150) Technological spillovers result primarily from private R&D investment

Impact of surface chemistry

PubMed Central

Somorjai, Gabor A.; Li, Yimin

2011-01-01

The applications of molecular surface chemistry in heterogeneous catalyst technology, semiconductor-based technology, medical technology, anticorrosion and lubricant technology, and nanotechnology are highlighted in this perspective. The evolution of surface chemistry at the molecular level is reviewed, and the key roles of surface instrumentation developments for in situ studies of the gas–solid, liquid–solid, and solid–solid interfaces under reaction conditions are emphasized. PMID:20880833

Overcoming Limitations in Semiconductor Alloy Design

NASA Astrophysics Data System (ADS)

Christian, Theresa Marie

Inorganic semiconductors provide an astonishingly versatile, robust, and efficient platform for optoelectronic energy conversion devices. However, conventional alloys and growth regimes face materials challenges that restrict the full potential of these devices. Novel alloy designs based on isoelectronic co-doping, metamorphic growth and controllable atomic ordering offer new pathways to practical and ultra-high-efficiency optoelectronic devices including solar cells and light-emitting diodes. Abnormal isoelectronic alloys of GaP1-xBix, GaP 1-x-yBixNy, and GaAs1-xBix with unprecedented bismuth incorporation fractions and crystalline quality are explored in this thesis research. Comparative studies of several GaP1-xBix and GaP1-x-yBixNy alloys demonstrate that the site-specific incorporation of bismuth during epitaxial growth is sensitive to growth temperature and has dramatic effects on carrier transfer processes in these alloys. Additionally, distinctive bismuth-related localized states are spectrally identified for the first time in samples of GaAs1-xBix grown by laser-assisted epitaxial growth. These results address fundamental questions about the nature of bismuth-bismuth inter-impurity interactions. Finally, a metamorphic growth strategy for a novel light-emitting diode (LED) design is also discussed. This work utilized direct-bandgap AlxIn1-xP active layers with atomic ordering-based electron confinement to improve emission in the yellow and green spectral regions, where incumbent technologies are least effective, and demonstrated the feasibility of non-lattice-matched LED active materials for visible light emission.

High performance printed oxide field-effect transistors processed using photonic curing.

PubMed

Garlapati, Suresh Kumar; Marques, Gabriel Cadilha; Gebauer, Julia Susanne; Dehm, Simone; Bruns, Michael; Winterer, Markus; Tahoori, Mehdi Baradaran; Aghassi-Hagmann, Jasmin; Hahn, Horst; Dasgupta, Subho

2018-06-08

Oxide semiconductors are highly promising candidates for the most awaited, next-generation electronics, namely, printed electronics. As a fabrication route for the solution-processed/printed oxide semiconductors, photonic curing is becoming increasingly popular, as compared to the conventional thermal curing method; the former offers numerous advantages over the latter, such as low process temperatures and short exposure time and thereby, high throughput compatibility. Here, using dissimilar photonic curing concepts (UV-visible light and UV-laser), we demonstrate facile fabrication of high performance In 2 O 3 field-effect transistors (FETs). Beside the processing related issues (temperature, time etc.), the other known limitation of oxide electronics is the lack of high performance p-type semiconductors, which can be bypassed using unipolar logics from high mobility n-type semiconductors alone. Interestingly, here we have found that our chosen distinct photonic curing methods can offer a large variation in threshold voltage, when they are fabricated from the same precursor ink. Consequently, both depletion and enhancement-mode devices have been achieved which can be used as the pull-up and pull-down transistors in unipolar inverters. The present device fabrication recipe demonstrates fast processing of low operation voltage, high performance FETs with large threshold voltage tunability.

Graphene-based hybrid structures combined with functional materials of ferroelectrics and semiconductors.

PubMed

Jie, Wenjing; Hao, Jianhua

2014-06-21

Fundamental studies and applications of 2-dimensional (2D) graphene may be deepened and broadened via combining graphene sheets with various functional materials, which have been extended from the traditional insulator of SiO2 to a versatile range of dielectrics, semiconductors and metals, as well as organic compounds. Among them, ferroelectric materials have received much attention due to their unique ferroelectric polarization. As a result, many attractive characteristics can be shown in graphene/ferroelectric hybrid systems. On the other hand, graphene can be integrated with conventional semiconductors and some newly-discovered 2D layered materials to form distinct Schottky junctions, yielding fascinating behaviours and exhibiting the potential for various applications in future functional devices. This review article is an attempt to illustrate the most recent progress in the fabrication, operation principle, characterization, and promising applications of graphene-based hybrid structures combined with various functional materials, ranging from ferroelectrics to semiconductors. We focus on mechanically exfoliated and chemical-vapor-deposited graphene sheets integrated in numerous advanced devices. Some typical hybrid structures have been highlighted, aiming at potential applications in non-volatile memories, transparent flexible electrodes, solar cells, photodetectors, and so on.

Thick layered semiconductor devices with water top-gates: High on-off ratio field-effect transistors and aqueous sensors.

PubMed

Huang, Yuan; Sutter, Eli; Wu, Liangmei; Xu, Hong; Bao, Lihong; Gao, Hong-Jun; Zhou, Xingjiang; Sutter, Peter

2018-06-21

Layered semiconductors show promise as channel materials for field-effect transistors (FETs). Usually, such devices incorporate solid back or top gate dielectrics. Here, we explore de-ionized (DI) water as a solution top gate for field-effect switching of layered semiconductors including SnS2, MoS2, and black phosphorus. The DI water gate is easily fabricated, can sustain rapid bias changes, and its efficient coupling to layered materials provides high on-off current ratios, near-ideal sub-threshold swing, and enhanced short-channel behavior even for FETs with thick, bulk-like channels where such control is difficult to realize with conventional back-gating. Screening by the high-k solution gate eliminates hysteresis due to surface and interface trap states and substantially enhances the field-effect mobility. The onset of water electrolysis sets the ultimate limit to DI water gating at large negative gate bias. Measurements in this regime show promise for aqueous sensing, demonstrated here by the amperometric detection of glucose in aqueous solution. DI water gating of layered semiconductors can be harnessed in research on novel materials and devices, and it may with further development find broad applications in microelectronics and sensing.

Graphene-based hybrid structures combined with functional materials of ferroelectrics and semiconductors

NASA Astrophysics Data System (ADS)

Jie, Wenjing; Hao, Jianhua

2014-05-01

Fundamental studies and applications of 2-dimensional (2D) graphene may be deepened and broadened via combining graphene sheets with various functional materials, which have been extended from the traditional insulator of SiO2 to a versatile range of dielectrics, semiconductors and metals, as well as organic compounds. Among them, ferroelectric materials have received much attention due to their unique ferroelectric polarization. As a result, many attractive characteristics can be shown in graphene/ferroelectric hybrid systems. On the other hand, graphene can be integrated with conventional semiconductors and some newly-discovered 2D layered materials to form distinct Schottky junctions, yielding fascinating behaviours and exhibiting the potential for various applications in future functional devices. This review article is an attempt to illustrate the most recent progress in the fabrication, operation principle, characterization, and promising applications of graphene-based hybrid structures combined with various functional materials, ranging from ferroelectrics to semiconductors. We focus on mechanically exfoliated and chemical-vapor-deposited graphene sheets integrated in numerous advanced devices. Some typical hybrid structures have been highlighted, aiming at potential applications in non-volatile memories, transparent flexible electrodes, solar cells, photodetectors, and so on.

More Efficient Power Conversion for EVs: Gallium-Nitride Advanced Power Semiconductor and Packaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-02-01

Broad Funding Opportunity Announcement Project: Delphi is developing power converters that are smaller and more energy efficient, reliable, and cost-effective than current power converters. Power converters rely on power transistors which act like a very precisely controlled on-off switch, controlling the electrical energy flowing through an electrical circuit. Most power transistors today use silicon (Si) semiconductors. However, Delphi is using semiconductors made with a thin layer of gallium-nitride (GaN) applied on top of the more conventional Si material. The GaN layer increases the energy efficiency of the power transistor and also enables the transistor to operate at much higher temperatures,more » voltages, and power-density levels compared to its Si counterpart. Delphi is packaging these high-performance GaN semiconductors with advanced electrical connections and a cooling system that extracts waste heat from both sides of the device to further increase the device’s efficiency and allow more electrical current to flow through it. When combined with other electronic components on a circuit board, Delphi’s GaN power transistor package will help improve the overall performance and cost-effectiveness of HEVs and EVs.« less

3D Band Diagram and Photoexcitation of 2D-3D Semiconductor Heterojunctions.

PubMed

Li, Bo; Shi, Gang; Lei, Sidong; He, Yongmin; Gao, Weilu; Gong, Yongji; Ye, Gonglan; Zhou, Wu; Keyshar, Kunttal; Hao, Ji; Dong, Pei; Ge, Liehui; Lou, Jun; Kono, Junichiro; Vajtai, Robert; Ajayan, Pulickel M

2015-09-09

The emergence of a rich variety of two-dimensional (2D) layered semiconductor materials has enabled the creation of atomically thin heterojunction devices. Junctions between atomically thin 2D layers and 3D bulk semiconductors can lead to junctions that are fundamentally electronically different from the covalently bonded conventional semiconductor junctions. Here we propose a new 3D band diagram for the heterojunction formed between n-type monolayer MoS2 and p-type Si, in which the conduction and valence band-edges of the MoS2 monolayer are drawn for both stacked and in-plane directions. This new band diagram helps visualize the flow of charge carriers inside the device in a 3D manner. Our detailed wavelength-dependent photocurrent measurements fully support the diagrams and unambiguously show that the band alignment is type I for this 2D-3D heterojunction. Photogenerated electron-hole pairs in the atomically thin monolayer are separated and driven by an external bias and control the "on/off" states of the junction photodetector device. Two photoresponse regimes with fast and slow relaxation are also revealed in time-resolved photocurrent measurements, suggesting the important role played by charge trap states.

Bacteria Inside Semiconductors as Potential Sensor Elements: Biochip Progress

PubMed Central

Sah, Vasu R.; Baier, Robert E.

2014-01-01

It was discovered at the beginning of this Century that living bacteria—and specifically the extremophile Pseudomonas syzgii—could be captured inside growing crystals of pure water-corroding semiconductors—specifically germanium—and thereby initiated pursuit of truly functional “biochip-based” biosensors. This observation was first made at the inside ultraviolet-illuminated walls of ultrapure water-flowing semiconductor fabrication facilities (fabs) and has since been, not as perfectly, replicated in simpler flow cell systems for chip manufacture, described here. Recognizing the potential importance of these adducts as optical switches, for example, or probes of metabolic events, the influences of the fabs and their components on the crystal nucleation and growth phenomena now identified are reviewed and discussed with regard to further research needs. For example, optical beams of current photonic circuits can be more easily modulated by integral embedded cells into electrical signals on semiconductors. Such research responds to a recently published Grand Challenge in ceramic science, designing and synthesizing oxide electronics, surfaces, interfaces and nanoscale structures that can be tuned by biological stimuli, to reveal phenomena not otherwise possible with conventional semiconductor electronics. This short review addresses only the fabrication facilities' features at the time of first production of these potential biochips. PMID:24961215

Emerging Hierarchical Aerogels: Self-Assembly of Metal and Semiconductor Nanocrystals.

PubMed

Cai, Bin; Sayevich, Vladimir; Gaponik, Nikolai; Eychmüller, Alexander

2018-06-19

Aerogels assembled from colloidal metal or semiconductor nanocrystals (NCs) feature large surface area, ultralow density, and high porosity, thus rendering them attractive in various applications, such as catalysis, sensors, energy storage, and electronic devices. Morphological and structural modification of the aerogel backbones while maintaining the aerogel properties enables a second stage of the aerogel research, which is defined as hierarchical aerogels. Different from the conventional aerogels with nanowire-like backbones, those hierarchical aerogels are generally comprised of at least two levels of architectures, i.e., an interconnected porous structure on the macroscale and a specially designed configuration at local backbones at the nanoscale. This combination "locks in" the inherent properties of the NCs, so that the beneficial genes obtained by nanoengineering are retained in the resulting monolithic hierarchical aerogels. Herein, groundbreaking advances in the design, synthesis, and physicochemical properties of the hierarchical aerogels are reviewed and organized in three sections: i) pure metallic hierarchical aerogels, ii) semiconductor hierarchical aerogels, and iii) metal/semiconductor hybrid hierarchical aerogels. This report aims to define and demonstrate the concept, potential, and challenges of the hierarchical aerogels, thereby providing a perspective on the further development of these materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High performance printed oxide field-effect transistors processed using photonic curing

NASA Astrophysics Data System (ADS)

Garlapati, Suresh Kumar; Cadilha Marques, Gabriel; Gebauer, Julia Susanne; Dehm, Simone; Bruns, Michael; Winterer, Markus; Baradaran Tahoori, Mehdi; Aghassi-Hagmann, Jasmin; Hahn, Horst; Dasgupta, Subho

2018-06-01

Oxide semiconductors are highly promising candidates for the most awaited, next-generation electronics, namely, printed electronics. As a fabrication route for the solution-processed/printed oxide semiconductors, photonic curing is becoming increasingly popular, as compared to the conventional thermal curing method; the former offers numerous advantages over the latter, such as low process temperatures and short exposure time and thereby, high throughput compatibility. Here, using dissimilar photonic curing concepts (UV–visible light and UV-laser), we demonstrate facile fabrication of high performance In2O3 field-effect transistors (FETs). Beside the processing related issues (temperature, time etc.), the other known limitation of oxide electronics is the lack of high performance p-type semiconductors, which can be bypassed using unipolar logics from high mobility n-type semiconductors alone. Interestingly, here we have found that our chosen distinct photonic curing methods can offer a large variation in threshold voltage, when they are fabricated from the same precursor ink. Consequently, both depletion and enhancement-mode devices have been achieved which can be used as the pull-up and pull-down transistors in unipolar inverters. The present device fabrication recipe demonstrates fast processing of low operation voltage, high performance FETs with large threshold voltage tunability.

Electrostatic analysis of n-doped SrTiO{sub 3} metal-insulator-semiconductor systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamerbeek, A. M., E-mail: a.m.kamerbeek@rug.nl; Banerjee, T.; Hueting, R. J. E.

2015-12-14

Electron doped SrTiO{sub 3}, a complex-oxide semiconductor, possesses novel electronic properties due to its strong temperature and electric-field dependent permittivity. Due to the high permittivity, metal/n-SrTiO{sub 3} systems show reasonably strong rectification even when SrTiO{sub 3} is degenerately doped. Our experiments show that the insertion of a sub nanometer layer of AlO{sub x} in between the metal and n-SrTiO{sub 3} interface leads to a dramatic reduction of the Schottky barrier height (from around 0.90 V to 0.25 V). This reduces the interface resistivity by 4 orders of magnitude. The derived electrostatic analysis of the metal-insulator-semiconductor (n-SrTiO{sub 3}) system is consistent with thismore » trend. When compared with a Si based MIS system, the change is much larger and mainly governed by the high permittivity of SrTiO{sub 3}. The non-linear permittivity of n-SrTiO{sub 3} leads to unconventional properties such as a temperature dependent surface potential non-existent for semiconductors with linear permittivity such as Si. This allows tuning of the interfacial band alignment, and consequently the Schottky barrier height, in a much more drastic way than in conventional semiconductors.« less

New materials and structures for photovoltaics

NASA Astrophysics Data System (ADS)

Zunger, Alex; Wagner, S.; Petroff, P. M.

1993-01-01

Despite the fact that over the years crystal chemists have discovered numerous semiconducting substances, and that modern epitaxial growth techniques are able to produce many novel atomic-scale architectures, current electronic and opto-electronic technologies are based but on a handful of ˜10 traditional semiconductor core materials. This paper surveys a number of yet-unexploited classes of semiconductors, pointing to the much-needed research in screening, growing, and characterizing promising members of these classes. In light of the unmanageably large number of a-priori possibilities, we emphasize the role that structural chemistry and modern computer-aided design must play in screening potentially important candidates. The basic classes of materials discussed here include nontraditional alloys, such as non-isovalent and heterostructural semiconductors, materials at reduced dimensionality, including superlattices, zeolite-caged nanostructures and organic semiconductors, spontaneously ordered alloys, interstitial semiconductors, filled tetrahedral structures, ordered vacancy compounds, and compounds based on d and f electron elements. A collaborative effort among material predictor, material grower, and material characterizer holds the promise for a successful identification of new and exciting systems.

Efficient light emission from inorganic and organic semiconductor hybrid structures by energy-level tuning

PubMed Central

Schlesinger, R.; Bianchi, F.; Blumstengel, S.; Christodoulou, C.; Ovsyannikov, R.; Kobin, B.; Moudgil, K.; Barlow, S.; Hecht, S.; Marder, S.R.; Henneberger, F.; Koch, N.

2015-01-01

The fundamental limits of inorganic semiconductors for light emitting applications, such as holographic displays, biomedical imaging and ultrafast data processing and communication, might be overcome by hybridization with their organic counterparts, which feature enhanced frequency response and colour range. Innovative hybrid inorganic/organic structures exploit efficient electrical injection and high excitation density of inorganic semiconductors and subsequent energy transfer to the organic semiconductor, provided that the radiative emission yield is high. An inherent obstacle to that end is the unfavourable energy level offset at hybrid inorganic/organic structures, which rather facilitates charge transfer that quenches light emission. Here, we introduce a technologically relevant method to optimize the hybrid structure's energy levels, here comprising ZnO and a tailored ladder-type oligophenylene. The ZnO work function is substantially lowered with an organometallic donor monolayer, aligning the frontier levels of the inorganic and organic semiconductors. This increases the hybrid structure's radiative emission yield sevenfold, validating the relevance of our approach. PMID:25872919

Determination of diffusion coefficient in disordered organic semiconductors

NASA Astrophysics Data System (ADS)

Rani, Varsha; Sharma, Akanksha; Ghosh, Subhasis

2016-05-01

Charge carrier transport in organic semiconductors is dominated by positional and energetic disorder in Gaussian density of states (GDOS) and is characterized by hopping through localized states. Due to the immobilization of charge carriers in these localized states, significant non-uniform carrier distribution exists, resulting diffusive transport. A simple, nevertheless powerful technique to determine diffusion coefficient D in disordered organic semiconductors has been presented. Diffusion coefficients of charge carriers in two technologically important organic molecular semiconductors, Pentacene and copper phthalocyanine (CuPc) have been measured from current-voltage (J-V) characteristics of Al/Pentacene/Au and Al/CuPc/Au based Schottky diodes. Ideality factor g and carrier mobility μ have been calculated from the exponential and space charge limited region respectively of J-V characteristics. Classical Einstein relation is not valid in organic semiconductors due to energetic disorders in DOS. Using generalized Einstein relation, diffusion coefficients have been obtained to be 1.31×10-6 and 1.73×10-7 cm2/s for Pentacene and CuPc respectively.

Efficient light emission from inorganic and organic semiconductor hybrid structures by energy-level tuning.

PubMed

Schlesinger, R; Bianchi, F; Blumstengel, S; Christodoulou, C; Ovsyannikov, R; Kobin, B; Moudgil, K; Barlow, S; Hecht, S; Marder, S R; Henneberger, F; Koch, N

2015-04-15

The fundamental limits of inorganic semiconductors for light emitting applications, such as holographic displays, biomedical imaging and ultrafast data processing and communication, might be overcome by hybridization with their organic counterparts, which feature enhanced frequency response and colour range. Innovative hybrid inorganic/organic structures exploit efficient electrical injection and high excitation density of inorganic semiconductors and subsequent energy transfer to the organic semiconductor, provided that the radiative emission yield is high. An inherent obstacle to that end is the unfavourable energy level offset at hybrid inorganic/organic structures, which rather facilitates charge transfer that quenches light emission. Here, we introduce a technologically relevant method to optimize the hybrid structure's energy levels, here comprising ZnO and a tailored ladder-type oligophenylene. The ZnO work function is substantially lowered with an organometallic donor monolayer, aligning the frontier levels of the inorganic and organic semiconductors. This increases the hybrid structure's radiative emission yield sevenfold, validating the relevance of our approach.

Water as probe molecule for midgap states in nanocrystalline strontium titanate by conventional and synchronous luminescence spectroscopy under ambient conditions

NASA Astrophysics Data System (ADS)

Taylor, Sean; Samokhvalov, Alexander

2017-03-01

Alkaline earth metal titanates are broad bandgap semiconductors with applications in electronic devices, as catalysts, photocatalysts, sorbents, and sensors. Strontium titanate SrTiO3 is of interest in electronic devices, sensors, in the photocatalytic hydrogen generation, as catalyst and sorbent. Both photocatalysis and operation of electronic devices rely upon the pathways of relaxation of excited charge in the semiconductor, including relaxation through the midgap states. We report characterization of nanocrystalline SrTiO3 at room temperature by "conventional" vs. synchronous luminescence spectroscopy and complementary methods. We determined energies of radiative transitions in the visible range through the two midgap states in the nanocrystalline SrTiO3. Further, adsorption and desorption of vapor of water as "probe molecule" for midgap states in the nanocrystalline SrTiO3 was studied, for the first time, by luminescence spectroscopy under ambient conditions. Emission of visible light from the nanocrystalline SrTiO3 is significantly increased upon desorption of water and decreased (quenched) upon adsorption of water vapor, due to interactions with the surface midgap states.

Tunable room-temperature spin-selective optical Stark effect in solution-processed layered halide perovskites.

PubMed

Giovanni, David; Chong, Wee Kiang; Dewi, Herlina Arianita; Thirumal, Krishnamoorthy; Neogi, Ishita; Ramesh, Ramamoorthy; Mhaisalkar, Subodh; Mathews, Nripan; Sum, Tze Chien

2016-06-01

Ultrafast spin manipulation for opto-spin logic applications requires material systems that have strong spin-selective light-matter interaction. Conventional inorganic semiconductor nanostructures [for example, epitaxial II to VI quantum dots and III to V multiple quantum wells (MQWs)] are considered forerunners but encounter challenges such as lattice matching and cryogenic cooling requirements. Two-dimensional halide perovskite semiconductors, combining intrinsic tunable MQW structures and large oscillator strengths with facile solution processability, can offer breakthroughs in this area. We demonstrate novel room-temperature, strong ultrafast spin-selective optical Stark effect in solution-processed (C6H4FC2H4NH3)2PbI4 perovskite thin films. Exciton spin states are selectively tuned by ~6.3 meV using circularly polarized optical pulses without any external photonic cavity (that is, corresponding to a Rabi energy of ~55 meV and equivalent to applying a 70 T magnetic field), which is much larger than any conventional system. The facile halide and organic replacement in these perovskites affords control of the dielectric confinement and thus presents a straightforward strategy for tuning light-matter coupling strength.

Damage-Free Smooth-Sidewall InGaAs Nanopillar Array by Metal-Assisted Chemical Etching.

PubMed

Kong, Lingyu; Song, Yi; Kim, Jeong Dong; Yu, Lan; Wasserman, Daniel; Chim, Wai Kin; Chiam, Sing Yang; Li, Xiuling

2017-10-24

Producing densely packed high aspect ratio In 0.53 Ga 0.47 As nanostructures without surface damage is critical for beyond Si-CMOS nanoelectronic and optoelectronic devices. However, conventional dry etching methods are known to produce irreversible damage to III-V compound semiconductors because of the inherent high-energy ion-driven process. In this work, we demonstrate the realization of ordered, uniform, array-based In 0.53 Ga 0.47 As pillars with diameters as small as 200 nm using the damage-free metal-assisted chemical etching (MacEtch) technology combined with the post-MacEtch digital etching smoothing. The etching mechanism of In x Ga 1-x As is explored through the characterization of pillar morphology and porosity as a function of etching condition and indium composition. The etching behavior of In 0.53 Ga 0.47 As, in contrast to higher bandgap semiconductors (e.g., Si or GaAs), can be interpreted by a Schottky barrier height model that dictates the etching mechanism constantly in the mass transport limited regime because of the low barrier height. A broader impact of this work relates to the complete elimination of surface roughness or porosity related defects, which can be prevalent byproducts of MacEtch, by post-MacEtch digital etching. Side-by-side comparison of the midgap interface state density and flat-band capacitance hysteresis of both the unprocessed planar and MacEtched pillar In 0.53 Ga 0.47 As metal-oxide-semiconductor capacitors further confirms that the surface of the resultant pillars is as smooth and defect-free as before etching. MacEtch combined with digital etching offers a simple, room-temperature, and low-cost method for the formation of high-quality In 0.53 Ga 0.47 As nanostructures that will potentially enable large-volume production of In 0.53 Ga 0.47 As-based devices including three-dimensional transistors and high-efficiency infrared photodetectors.

Delay-Line Three-Dimensional Position Sensitive Radiation Detection

NASA Astrophysics Data System (ADS)

Jeong, Manhee

High-resistivity silicon(Si) in large volumes and with good charge carrier transport properties has been produced and achieved success as a radiation detector material over the past few years due to its relatively low cost as well as the availability of well-established processing technologies. One application of that technology is in the fabrication of various position-sensing topologies from which the incident radiation's direction can be determined. We have succeeded in developing the modeling tools for investigating different position-sensing schemes and used those tools to examine both amplitude-based and time-based methods, an assessment that indicates that fine position-sensing can be achieved with simpler readout designs than are conventionally deployed. This realization can make ubiquitous and inexpensive deployment of special nuclear materials (SNM) detecting technology becomes more feasible because if one can deploy position-sensitive semiconductor detectors with only one or two contacts per side. For this purpose, we have described the delay-line radiation detector and its optimized fabrication. The semiconductor physics were simulated, the results from which guided the fabrication of the guard ring structure and the detector electrode, both of which included metal-field-plates. The measured improvement in the leakage current was confirmed with the fabricated devices, and the structures successfully suppressed soft-breakdown. We also demonstrated that fabricating an asymmetric strip-line structure successfully minimizing the pulse shaping and increases the distance through which one can propagate the information of the deposited charge distribution. With fabricated delay-line detectors we can acquire alpha spectra (Am-241) and gamma spectra (Ba-133, Co-57 and Cd-109). The delay-line detectors can therefore be used to extract the charge information from both ion and gamma-ray interactions. Furthermore, standard charge-sensitive circuits yield high SNR pulses. The detectors and existing electronics can therefore be used to yield imaging instruments for neutron and gamma-rays, in the case of silicon. For CZT, we would prefer to utilize current sensing to be able to clearly isolate the effects of the various charge-transport non-idealities, the full realization of which awaits the fabrication of the custom-designed TIA chip.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Switching Characteristics of Phase Change Memory Cell Integrated with Metal-Oxide Semiconductor Field Effect Transistor

NASA Astrophysics Data System (ADS)

Xu, Cheng; Liu, Bo; Chen, Yi-Feng; Liang, Shuang; Song, Zhi-Tang; Feng, Song-Lin; Wan, Xu-Dong; Yang, Zuo-Ya; Xie, Joseph; Chen, Bomy

2008-05-01

A Ge2Sb2Te5 based phase change memory device cell integrated with metal-oxide semiconductor field effect transistor (MOSFET) is fabricated using standard 0. 18 μm complementary metal-oxide semiconductor process technology. It shows steady switching characteristics in the dc current-voltage measurement. The phase changing phenomenon from crystalline state to amorphous state with a voltage pulse altitude of 2.0 V and pulse width of 50 ns is also obtained. These results show the feasibility of integrating phase change memory cell with MOSFET.

Effect of the depolarization field on coherent optical properties in semiconductor quantum dots

NASA Astrophysics Data System (ADS)

Mitsumori, Yasuyoshi; Watanabe, Shunta; Asakura, Kenta; Seki, Keisuke; Edamatsu, Keiichi; Akahane, Kouichi; Yamamoto, Naokatsu

2018-06-01

We study the photon echo spectrum of self-assembled semiconductor quantum dots using femtosecond light pulses. The spectrum shape changes from a single-peaked to a double-peaked structure as the time delay between the two excitation pulses is increased. The spectrum change is reproduced by numerical calculations, which include the depolarization field induced by the biexciton-exciton transition as well as the conventional local-field effect for the exciton-ground-state transition in a quantum dot. Our findings suggest that various optical transitions in tightly localized systems generate a depolarization field, which renormalizes the resonant frequency with a change in the polarization itself, leading to unique optical properties.

The Beginning of Semiconductor Research in Cuba

NASA Astrophysics Data System (ADS)

Veltfort, Theodore

I was invited to Cuba in 1962 to initiate some efforts in semiconductor development. I had been a physicist and senior research engineer with various electronic companies of the "Silicon Valley" of California, south of San Francisco. I had heard of the efforts made by the new revolutionary government of Cuba to advance the level of science and technology, and I was anxious to see what I could do to help.

Synthesis of a Nano-Silver Metal Ink for Use in Thick Conductive Film Fabrication Applied on a Semiconductor Package

PubMed Central

Yung, Lai Chin; Fei, Cheong Choke; Mandeep, JS; Binti Abdullah, Huda; Wee, Lai Khin

2014-01-01

The success of printing technology in the electronics industry primarily depends on the availability of metal printing ink. Various types of commercially available metal ink are widely used in different industries such as the solar cell, radio frequency identification (RFID) and light emitting diode (LED) industries, with limited usage in semiconductor packaging. The use of printed ink in semiconductor IC packaging is limited by several factors such as poor electrical performance and mechanical strength. Poor adhesion of the printed metal track to the epoxy molding compound is another critical factor that has caused a decline in interest in the application of printing technology to the semiconductor industry. In this study, two different groups of adhesion promoters, based on metal and polymer groups, were used to promote adhesion between the printed ink and the epoxy molding substrate. The experimental data show that silver ink with a metal oxide adhesion promoter adheres better than silver ink with a polymer adhesion promoter. This result can be explained by the hydroxyl bonding between the metal oxide promoter and the silane grouping agent on the epoxy substrate, which contributes a greater adhesion strength compared to the polymer adhesion promoter. Hypotheses of the physical and chemical functions of both adhesion promoters are described in detail. PMID:24830317

Preparation methodologies and nano/microstructural evaluation of metal/semiconductor thin films.

PubMed

Chen, Zhiwen; Jiao, Zheng; Wu, Minghong; Shek, Chan-Hung; Wu, C M Lawrence; Lai, Joseph K L

2012-01-01

Metal/semiconductor thin films are a class of unique materials that are widespread technological applications, particularly in the field of microelectronic devices. Assessment strategies of fractal and tures are of fundamental importance in the development of nano/microdevices. This review presents the preparation methodologies and nano/microstructural evaluation of metal/semiconductor thin films including Au/Ge bilayer films and Pd-Ge alloy thin films, which show in the form of fractals and nanocrystals. Firstly, the extended version of Au/Ge thin films for the fractal crystallization of amorphous Ge and the formation of nanocrystals developed with improved micro- and nanostructured features are described in Section 2. Secondly, the nano/microstructural characteristics of Pd/Ge alloy thin films during annealing have been investigated in detail and described in Section 3. Finally, we will draw the conclusions from the present work as shown in Section 4. It is expected that the preparation methodologies developed and the knowledge of nano/microstructural evolution gained in metal/semiconductor thin films, including Au/Ge bilayer films and Pd-Ge alloy thin films, will provide an important fundamental basis underpinning further interdisciplinary research in these fields such as physics, chemistry, materials science, and nanoscience and nanotechnology, leading to promising exciting opportunities for future technological applications involving these thin films.

Real-time two-dimensional imaging of potassium ion distribution using an ion semiconductor sensor with charged coupled device technology.

PubMed

Hattori, Toshiaki; Masaki, Yoshitomo; Atsumi, Kazuya; Kato, Ryo; Sawada, Kazuaki

2010-01-01

Two-dimensional real-time observation of potassium ion distributions was achieved using an ion imaging device based on charge-coupled device (CCD) and metal-oxide semiconductor technologies, and an ion selective membrane. The CCD potassium ion image sensor was equipped with an array of 32 × 32 pixels (1024 pixels). It could record five frames per second with an area of 4.16 × 4.16 mm(2). Potassium ion images were produced instantly. The leaching of potassium ion from a 3.3 M KCl Ag/AgCl reference electrode was dynamically monitored in aqueous solution. The potassium ion selective membrane on the semiconductor consisted of plasticized poly(vinyl chloride) (PVC) with bis(benzo-15-crown-5). The addition of a polyhedral oligomeric silsesquioxane to the plasticized PVC membrane greatly improved adhesion of the membrane onto Si(3)N(4) of the semiconductor surface, and the potential response was stabilized. The potential response was linear from 10(-2) to 10(-5) M logarithmic concentration of potassium ion. The selectivity coefficients were K(K(+),Li(+))(pot) = 10(-2.85), K(K(+),Na(+))(pot) = 10(-2.30), K(K(+),Rb(+))(pot) =10(-1.16), and K(K(+),Cs(+))(pot) = 10(-2.05).

Synthesis of a nano-silver metal ink for use in thick conductive film fabrication applied on a semiconductor package.

PubMed

Yung, Lai Chin; Fei, Cheong Choke; Mandeep, Js; Binti Abdullah, Huda; Wee, Lai Khin

2014-01-01

The success of printing technology in the electronics industry primarily depends on the availability of metal printing ink. Various types of commercially available metal ink are widely used in different industries such as the solar cell, radio frequency identification (RFID) and light emitting diode (LED) industries, with limited usage in semiconductor packaging. The use of printed ink in semiconductor IC packaging is limited by several factors such as poor electrical performance and mechanical strength. Poor adhesion of the printed metal track to the epoxy molding compound is another critical factor that has caused a decline in interest in the application of printing technology to the semiconductor industry. In this study, two different groups of adhesion promoters, based on metal and polymer groups, were used to promote adhesion between the printed ink and the epoxy molding substrate. The experimental data show that silver ink with a metal oxide adhesion promoter adheres better than silver ink with a polymer adhesion promoter. This result can be explained by the hydroxyl bonding between the metal oxide promoter and the silane grouping agent on the epoxy substrate, which contributes a greater adhesion strength compared to the polymer adhesion promoter. Hypotheses of the physical and chemical functions of both adhesion promoters are described in detail.

Review on the dynamics of semiconductor nanowire lasers

NASA Astrophysics Data System (ADS)

Röder, Robert; Ronning, Carsten

2018-03-01

Semiconductor optoelectronic devices have contributed tremendously to the technological progress in the past 50-60 years. Today, they also play a key role in nanophotonics stimulated by the inherent limitations of electronic integrated circuits and the growing demand for faster communications on chip. In particular, the field of ‘nanowire photonics’ has emerged including the search for coherent light sources with a nano-scaled footprint. The past decade has been dedicated to find suitable semiconductor nanowire (NW) materials for such nanolasers. Nowadays, such NW lasers consistently work at room temperature covering a huge spectral range from the ultraviolet down to the mid-infrared depending on the band gap of the NW material. Furthermore, first approaches towards the modification and optimization of such NW laser devices have been demonstrated. The underlying dynamics of the electronic and photonic NW systems have also been studied very recently, as they need to be understood in order to push the technological relevance of nano-scaled coherent light sources. Therefore, this review will first present novel measurement approaches in order to study the ultrafast temporal and optical mode dynamics of individual NW laser devices. Furthermore, these fundamental new insights are reviewed and deeply discussed towards the efficient control and adjustment of the dynamics in semiconductor NW lasers.

Metrology needs for the semiconductor industry over the next decade

NASA Astrophysics Data System (ADS)

Melliar-Smith, Mark; Diebold, Alain C.

1998-11-01

Metrology will continue to be a key enabler for the development and manufacture of future generations of integrated circuits. During 1997, the Semiconductor Industry Association renewed the National Technology Roadmap for Semiconductors (NTRS) through the 50 nm technology generation and for the first time included a Metrology Roadmap (1). Meeting the needs described in the Metrology Roadmap will be both a technological and financial challenge. In an ideal world, metrology capability would be available at the start of process and tool development, and silicon suppliers would have 450 mm wafer capable metrology tools in time for development of that wafer size. Unfortunately, a majority of the metrology suppliers are small companies that typically can't afford the additional two to three year wait for return on R&D investment. Therefore, the success of the semiconductor industry demands that we expand cooperation between NIST, SEMATECH, the National Labs, SRC, and the entire community. In this paper, we will discuss several critical metrology topics including the role of sensor-based process control, in-line microscopy, focused measurements for transistor and interconnect fabrication, and development needs. Improvements in in-line microscopy must extend existing critical dimension measurements up to 100 nm generations and new methods may be required for sub 100 nm generations. Through development, existing metrology dielectric thickness and dopant dose and junction methods can be extended to 100 nm, but new and possibly in-situ methods are needed beyond 100 nm. Interconnect process control will undergo change before 100 nm due to the introduction of copper metallization, low dielectric constant interlevel dielectrics, and Damascene process flows.

Modeling and simulation of floating gate nanocrystal FET devices and circuits

NASA Astrophysics Data System (ADS)

Hasaneen, El-Sayed A. M.

The nonvolatile memory market has been growing very fast during the last decade, especially for mobile communication systems. The Semiconductor Industry Association International Technology Roadmap for Semiconductors states that the difficult challenge for nonvolatile semiconductor memories is to achieve reliable, low power, low voltage performance and high-speed write/erase. This can be achieved by aggressive scaling of the nonvolatile memory cells. Unfortunately, scaling down of conventional nonvolatile memory will further degrade the retention time due to the charge loss between the floating gate and drain/source contacts and substrate which makes conventional nonvolatile memory unattractive. Using nanocrystals as charge storage sites reduces dramatically the charge leakage through oxide defects and drain/source contacts. Floating gate nanocrystal nonvolatile memory, FG-NCNVM, is a candidate for future memory because it is advantageous in terms of high-speed write/erase, small size, good scalability, low-voltage, low-power applications, and the capability to store multiple bits per cell. Many studies regarding FG-NCNVMs have been published. Most of them have dealt with fabrication improvements of the devices and device characterizations. Due to the promising FG-NCNVM applications in integrated circuits, there is a need for circuit a simulation model to simulate the electrical characteristics of the floating gate devices. In this thesis, a FG-NCNVM circuit simulation model has been proposed. It is based on the SPICE BSIM simulation model. This model simulates the cell behavior during normal operation. Model validation results have been presented. The SPICE model shows good agreement with experimental results. Current-voltage characteristics, transconductance and unity gain frequency (fT) have been studied showing the effect of the threshold voltage shift (DeltaVth) due to nanocrystal charge on the device characteristics. The threshold voltage shift due to nanocrystal charge has a strong effect on the memory characteristics. Also, the programming operation of the memory cell has been investigated. The tunneling rate from quantum well channel to quantum dot (nanocrystal) gate is calculated. The calculations include various memory parameters, wavefunctions, and energies of quantum well channel and quantum dot gate. The use of floating gate nanocrystal memory as a transistor with a programmable threshold voltage has been demonstrated. The incorporation of FG-NCFETs to design programmable integrated circuit building blocks has been discussed. This includes the design of programmable current and voltage reference circuits. Finally, we demonstrated the design of tunable gain op-amp incorporating FG-NCFETs. Programmable integrated circuit building blocks can be used in intelligent analog and digital systems.

The effect of body bias of the metal-oxide-semiconductor field-effect transistor in the resistive network on spatial current distribution in a bio-inspired complementary metal-oxide-semiconductor vision chip

NASA Astrophysics Data System (ADS)

Kong, Jae-Sung; Hyun, Hyo-Young; Seo, Sang-Ho; Shin, Jang-Kyoo

2008-11-01

Complementary metal-oxide-semiconductor (CMOS) vision chips for edge detection based on a resistive circuit have recently been developed. These chips help in the creation of neuromorphic systems of a compact size, high speed of operation, and low power dissipation. The output of the vision chip depends predominantly upon the electrical characteristics of the resistive network which consists of a resistive circuit. In this paper, the body effect of the metal-oxide-semiconductor field-effect transistor for current distribution in a resistive circuit is discussed with a simple model. In order to evaluate the model, two 160 × 120 CMOS vision chips have been fabricated using a standard CMOS technology. The experimental results nicely match our prediction.

Rocksalt nitride metal/semiconductor superlattices: A new class of artificially structured materials

NASA Astrophysics Data System (ADS)

Saha, Bivas; Shakouri, Ali; Sands, Timothy D.

2018-06-01

Artificially structured materials in the form of superlattice heterostructures enable the search for exotic new physics and novel device functionalities, and serve as tools to push the fundamentals of scientific and engineering knowledge. Semiconductor heterostructures are the most celebrated and widely studied artificially structured materials, having led to the development of quantum well lasers, quantum cascade lasers, measurements of the fractional quantum Hall effect, and numerous other scientific concepts and practical device technologies. However, combining metals with semiconductors at the atomic scale to develop metal/semiconductor superlattices and heterostructures has remained a profoundly difficult scientific and engineering challenge. Though the potential applications of metal/semiconductor heterostructures could range from energy conversion to photonic computing to high-temperature electronics, materials challenges primarily had severely limited progress in this pursuit until very recently. In this article, we detail the progress that has taken place over the last decade to overcome the materials engineering challenges to grow high quality epitaxial, nominally single crystalline metal/semiconductor superlattices based on transition metal nitrides (TMN). The epitaxial rocksalt TiN/(Al,Sc)N metamaterials are the first pseudomorphic metal/semiconductor superlattices to the best of our knowledge, and their physical properties promise a new era in superlattice physics and device engineering.

PREFACE: E-MRS 2012 Spring Meeting, Symposium M: More than Moore: Novel materials approaches for functionalized Silicon based Microelectronics

NASA Astrophysics Data System (ADS)

Wenger, Christian; Fompeyrine, Jean; Vallée, Christophe; Locquet, Jean-Pierre

2012-12-01

More than Moore explores a new area of Silicon based microelectronics, which reaches beyond the boundaries of conventional semiconductor applications. Creating new functionality to semiconductor circuits, More than Moore focuses on motivating new technological possibilities. In the past decades, the main stream of microelectronics progresses was mainly powered by Moore's law, with two focused development arenas, namely, IC miniaturization down to nano scale, and SoC based system integration. While the microelectronics community continues to invent new solutions around the world to keep Moore's law alive, there is increasing momentum for the development of 'More than Moore' technologies which are based on silicon technologies but do not simply scale with Moore's law. Typical examples are RF, Power/HV, Passives, Sensor/Actuator/MEMS or Bio-chips. The More than Moore strategy is driven by the increasing social needs for high level heterogeneous system integration including non-digital functions, the necessity to speed up innovative product creation and to broaden the product portfolio of wafer fabs, and the limiting cost and time factors of advanced SoC development. It is believed that More than Moore will add value to society on top of and beyond advanced CMOS with fast increasing marketing potentials. Important key challenges for the realization of the 'More than Moore' strategy are: perspective materials for future THz devices materials systems for embedded sensors and actuators perspective materials for epitaxial approaches material systems for embedded innovative memory technologies development of new materials with customized characteristics The Hot topics covered by the symposium M (More than Moore: Novel materials approaches for functionalized Silicon based Microelectronics) at E-MRS 2012 Spring Meeting, 14-18 May 2012 have been: development of functional ceramics thin films New dielectric materials for advanced microelectronics bio- and CMOS compatible material systems piezoelectric films and nanostructures Atomic Layer Deposition (ALD) of oxides and nitrides characterization and metrology of very thin oxide layers We would like to take this opportunity to thank the Scientific Committee and Local Committee for bringing together a coherent and high quality Symposium at E-MRS 2012 Spring Meeting. Christian Wenger, Jean Fompeyrine, Christophe Vallée and Jean-Pierre Locquet Organizing Committee of Symposium M September 2012

Method and apparatus for thermal processing of semiconductor substrates

DOEpatents

Griffiths, Stewart K.; Nilson, Robert H.; Mattson, Brad S.; Savas, Stephen E.

2002-01-01

An improved apparatus and method for thermal processing of semiconductor wafers. The apparatus and method provide the temperature stability and uniformity of a conventional batch furnace as well as the processing speed and reduced time-at-temperature of a lamp-heated rapid thermal processor (RTP). Individual wafers are rapidly inserted into and withdrawn from a furnace cavity held at a nearly constant and isothermal temperature. The speeds of insertion and withdrawal are sufficiently large to limit thermal stresses and thereby reduce or prevent plastic deformation of the wafer as it enters and leaves the furnace. By processing the semiconductor wafer in a substantially isothermal cavity, the wafer temperature and spatial uniformity of the wafer temperature can be ensured by measuring and controlling only temperatures of the cavity walls. Further, peak power requirements are very small compared to lamp-heated RTPs because the cavity temperature is not cycled and the thermal mass of the cavity is relatively large. Increased speeds of insertion and/or removal may also be used with non-isothermal furnaces.

Method and apparatus for thermal processing of semiconductor substrates

DOEpatents

Griffiths, Stewart K.; Nilson, Robert H.; Mattson, Brad S.; Savas, Stephen E.

2000-01-01

An improved apparatus and method for thermal processing of semiconductor wafers. The apparatus and method provide the temperature stability and uniformity of a conventional batch furnace as well as the processing speed and reduced time-at-temperature of a lamp-heated rapid thermal processor (RTP). Individual wafers are rapidly inserted into and withdrawn from a furnace cavity held at a nearly constant and isothermal temperature. The speeds of insertion and withdrawal are sufficiently large to limit thermal stresses and thereby reduce or prevent plastic deformation of the wafer as it enters and leaves the furnace. By processing the semiconductor wafer in a substantially isothermal cavity, the wafer temperature and spatial uniformity of the wafer temperature can be ensured by measuring and controlling only temperatures of the cavity walls. Further, peak power requirements are very small compared to lamp-heated RTPs because the cavity temperature is not cycled and the thermal mass of the cavity is relatively large. Increased speeds of insertion and/or removal may also be used with non-isothermal furnaces.

Heterostructured TiO2/NiTiO3 Nanorod Arrays for Inorganic Sensitized Solar Cells with Significantly Enhanced Photovoltaic Performance and Stability.

PubMed

Li, Yue-Ying; Wang, Jian-Gan; Sun, Huan-Huan; Wei, Bingqing

2018-04-11

Organic dyes used in the conventional dye-sensitized solar cells (DSSCs) suffer from poor light stability and high cost. In this work, we demonstrate a new inorganic sensitized solar cell based on ordered one-dimensional semiconductor nanorod arrays of TiO 2 /NiTiO 3 (NTO) heterostructures prepared via a facile two-step hydrothermal approach. The semiconductor heterostructure arrays are highly desirable and promising for DSSCs because of their direct charge transport capability and slow charge recombination rate. The low-cost NTO inorganic semiconductor possesses an appropriate band gap that matches well with TiO 2 , which behaves like a "dye" to enable efficient light harvesting and fast electron-hole separation. The solar cells constructed by the ordered TiO 2 /NTO heterostructure photoanodes show a significantly improved power conversion efficiency, high fill factor, and more promising, outstanding life stability. The present work will open up an avenue to design heterostructured inorganics for high-performance solar cells.

Analysis of electric field distribution in GaAs metal-semiconductor field effect transistor with a field-modulating plate

NASA Astrophysics Data System (ADS)

Hori, Yasuko; Kuzuhara, Masaaki; Ando, Yuji; Mizuta, Masashi

2000-04-01

Electric field distribution in the channel of a field effect transistor (FET) with a field-modulating plate (FP) has been theoretically investigated using a two-dimensional ensemble Monte Carlo simulation. This analysis revealed that the introduction of FP is effective in canceling the influence of surface traps under forward bias conditions and in reducing the electric field intensity at the drain side of the gate edge under pinch-off bias conditions. This study also found that a partial overlap of the high-field region under the gate and that at the FP electrode is important for reducing the electric field intensity. The optimized metal-semiconductor FET with FP (FPFET) (LGF˜0.2 μm) exhibited a much lower peak electric field intensity than a conventional metal-semiconductor FET. Based on these numerically calculated results, we have proposed a design procedure to optimize the power FPFET structure with extremely high breakdown voltages while maintaining reasonable gain performance.

High-performance III-V MOSFET with nano-stacked high-k gate dielectric and 3D fin-shaped structure.

PubMed

Chen, Szu-Hung; Liao, Wen-Shiang; Yang, Hsin-Chia; Wang, Shea-Jue; Liaw, Yue-Gie; Wang, Hao; Gu, Haoshuang; Wang, Mu-Chun

2012-08-01

A three-dimensional (3D) fin-shaped field-effect transistor structure based on III-V metal-oxide-semiconductor field-effect transistor (MOSFET) fabrication has been demonstrated using a submicron GaAs fin as the high-mobility channel. The fin-shaped channel has a thickness-to-width ratio (TFin/WFin) equal to 1. The nano-stacked high-k Al2O3 dielectric was adopted as a gate insulator in forming a metal-oxide-semiconductor structure to suppress gate leakage. The 3D III-V MOSFET exhibits outstanding gate controllability and shows a high Ion/Ioff ratio > 105 and a low subthreshold swing of 80 mV/decade. Compared to a conventional Schottky gate metal-semiconductor field-effect transistor or planar III-V MOSFETs, the III-V MOSFET in this work exhibits a significant performance improvement and is promising for future development of high-performance n-channel devices based on III-V materials.

High-performance III-V MOSFET with nano-stacked high-k gate dielectric and 3D fin-shaped structure

PubMed Central

2012-01-01

A three-dimensional (3D) fin-shaped field-effect transistor structure based on III-V metal-oxide-semiconductor field-effect transistor (MOSFET) fabrication has been demonstrated using a submicron GaAs fin as the high-mobility channel. The fin-shaped channel has a thickness-to-width ratio (TFin/WFin) equal to 1. The nano-stacked high-k Al2O3 dielectric was adopted as a gate insulator in forming a metal-oxide-semiconductor structure to suppress gate leakage. The 3D III-V MOSFET exhibits outstanding gate controllability and shows a high Ion/Ioff ratio > 105 and a low subthreshold swing of 80 mV/decade. Compared to a conventional Schottky gate metal–semiconductor field-effect transistor or planar III-V MOSFETs, the III-V MOSFET in this work exhibits a significant performance improvement and is promising for future development of high-performance n-channel devices based on III-V materials. PMID:22853458

Solvent-Free Toner Printing of Organic Semiconductor Layer in Flexible Thin-Film Transistors

NASA Astrophysics Data System (ADS)

Sakai, Masatoshi; Koh, Tokuyuki; Toyoshima, Kenji; Nakamori, Kouta; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Shinamura, Shoji; Kudo, Kazuhiro

2017-07-01

A solvent-free printing process for printed electronics is successfully developed using toner-type patterning of organic semiconductor toner particles and the subsequent thin-film formation. These processes use the same principle as that used for laser printing. The organic thin-film transistors are prepared by electrically distributing the charged toner onto a Au electrode on a substrate film, followed by thermal lamination. The thermal lamination is effective for obtaining an oriented and crystalline thin film. Toner printing is environmentally friendly compared with other printing technologies because it is solvent free, saves materials, and enables easy recycling. In addition, this technology simultaneously enables both wide-area and high-resolution printing.

Visible light laser voltage probing on thinned substrates

DOEpatents

Beutler, Joshua; Clement, John Joseph; Miller, Mary A.; Stevens, Jeffrey; Cole, Jr., Edward I.

2017-03-21

The various technologies presented herein relate to utilizing visible light in conjunction with a thinned structure to enable characterization of operation of one or more features included in an integrated circuit (IC). Short wavelength illumination (e.g., visible light) is applied to thinned samples (e.g., ultra-thinned samples) to achieve a spatial resolution for laser voltage probing (LVP) analysis to be performed on smaller technology node silicon-on-insulator (SOI) and bulk devices. Thinning of a semiconductor material included in the IC (e.g., backside material) can be controlled such that the thinned semiconductor material has sufficient thickness to enable operation of one or more features comprising the IC during LVP investigation.

Science& Technology Review November 2003

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMahon, D

2003-11-01

This issue of Science & Technology Review covers the following topics: (1) We Will Always Need Basic Science--Commentary by Tomas Diaz de la Rubia; (2) When Semiconductors Go Nano--experiments and computer simulations reveal some surprising behavior of semiconductors at the nanoscale; (3) Retinal Prosthesis Provides Hope for Restoring Sight--A microelectrode array is being developed for a retinal prosthesis; (4) Maglev on the Development Track for Urban Transportation--Inductrack, a Livermore concept to levitate train cars using permanent magnets, will be demonstrated on a 120-meter-long test track; and (5) Power Plant on a Chip Moves Closer to Reality--Laboratory-designed fuel processor gives powermore » boost to dime-size fuel cell.« less

“Playing around” with Field-Effect Sensors on the Basis of EIS Structures, LAPS and ISFETs

PubMed Central

Schöning, Michael J.

2005-01-01

Microfabricated semiconductor devices are becoming increasingly relevant, also for the detection of biological and chemical quantities. Especially, the “marriage” of biomolecules and silicon technology often yields successful new sensor concepts. The fabrication techniques of such silicon-based chemical sensors and biosensors, respectively, will have a distinct impact in different fields of application such as medicine, food technology, environment, chemistry and biotechnology as well as information processing. Moreover, scientists and engineers are interested in the analytical benefits of miniaturised and microfabricated sensor devices. This paper gives a survey on different types of semiconductor-based field-effect structures that have been recently developed in our laboratory.

HTMT-class Latency Tolerant Parallel Architecture for Petaflops Scale Computation

NASA Technical Reports Server (NTRS)

Sterling, Thomas; Bergman, Larry

2000-01-01

Computational Aero Sciences and other numeric intensive computation disciplines demand computing throughputs substantially greater than the Teraflops scale systems only now becoming available. The related fields of fluids, structures, thermal, combustion, and dynamic controls are among the interdisciplinary areas that in combination with sufficient resolution and advanced adaptive techniques may force performance requirements towards Petaflops. This will be especially true for compute intensive models such as Navier-Stokes are or when such system models are only part of a larger design optimization computation involving many design points. Yet recent experience with conventional MPP configurations comprising commodity processing and memory components has shown that larger scale frequently results in higher programming difficulty and lower system efficiency. While important advances in system software and algorithms techniques have had some impact on efficiency and programmability for certain classes of problems, in general it is unlikely that software alone will resolve the challenges to higher scalability. As in the past, future generations of high-end computers may require a combination of hardware architecture and system software advances to enable efficient operation at a Petaflops level. The NASA led HTMT project has engaged the talents of a broad interdisciplinary team to develop a new strategy in high-end system architecture to deliver petaflops scale computing in the 2004/5 timeframe. The Hybrid-Technology, MultiThreaded parallel computer architecture incorporates several advanced technologies in combination with an innovative dynamic adaptive scheduling mechanism to provide unprecedented performance and efficiency within practical constraints of cost, complexity, and power consumption. The emerging superconductor Rapid Single Flux Quantum electronics can operate at 100 GHz (the record is 770 GHz) and one percent of the power required by convention semiconductor logic. Wave Division Multiplexing optical communications can approach a peak per fiber bandwidth of 1 Tbps and the new Data Vortex network topology employing this technology can connect tens of thousands of ports providing a bi-section bandwidth on the order of a Petabyte per second with latencies well below 100 nanoseconds, even under heavy loads. Processor-in-Memory (PIM) technology combines logic and memory on the same chip exposing the internal bandwidth of the memory row buffers at low latency. And holographic storage photorefractive storage technologies provide high-density memory with access a thousand times faster than conventional disk technologies. Together these technologies enable a new class of shared memory system architecture with a peak performance in the range of a Petaflops but size and power requirements comparable to today's largest Teraflops scale systems. To achieve high-sustained performance, HTMT combines an advanced multithreading processor architecture with a memory-driven coarse-grained latency management strategy called "percolation", yielding high efficiency while reducing the much of the parallel programming burden. This paper will present the basic system architecture characteristics made possible through this series of advanced technologies and then give a detailed description of the new percolation approach to runtime latency management.

Junction-less poly-Ge FinFET and charge-trap NVM fabricated by laser-enabled low thermal budget processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Wen-Hsien; Shen, Chang-Hong; Wang, Hsing-Hsiang

2016-06-13

A doping-free poly-Ge film as channel material was implemented by CVD-deposited nano-crystalline Ge and visible-light laser crystallization, which behaves as a p-type semiconductor, exhibiting holes concentration of 1.8 × 10{sup 18 }cm{sup −3} and high crystallinity (Raman FWHM ∼ 4.54 cm{sup −1}). The fabricated junctionless 7 nm-poly-Ge FinFET performs at an I{sub on}/I{sub off} ratio over 10{sup 5} and drain-induced barrier lowering of 168 mV/V. Moreover, the fast programming speed of 100 μs–1 ms and reliable retention can be obtained from the junctionless poly-Ge nonvolatile-memory. Such junctionless poly-Ge devices with low thermal budget are compatible with the conventional CMOS technology and are favorable for 3D sequential-layer integrationmore » and flexible electronics.« less

Spray-combustion synthesis: Efficient solution route to high-performance oxide transistors

PubMed Central

Yu, Xinge; Smith, Jeremy; Zhou, Nanjia; Zeng, Li; Guo, Peijun; Xia, Yu; Alvarez, Ana; Aghion, Stefano; Lin, Hui; Yu, Junsheng; Chang, Robert P. H.; Bedzyk, Michael J.; Ferragut, Rafael; Marks, Tobin J.; Facchetti, Antonio

2015-01-01

Metal-oxide (MO) semiconductors have emerged as enabling materials for next generation thin-film electronics owing to their high carrier mobilities, even in the amorphous state, large-area uniformity, low cost, and optical transparency, which are applicable to flat-panel displays, flexible circuitry, and photovoltaic cells. Impressive progress in solution-processed MO electronics has been achieved using methodologies such as sol gel, deep-UV irradiation, preformed nanostructures, and combustion synthesis. Nevertheless, because of incomplete lattice condensation and film densification, high-quality solution-processed MO films having technologically relevant thicknesses achievable in a single step have yet to be shown. Here, we report a low-temperature, thickness-controlled coating process to create high-performance, solution-processed MO electronics: spray-combustion synthesis (SCS). We also report for the first time, to our knowledge, indium-gallium-zinc-oxide (IGZO) transistors having densification, nanoporosity, electron mobility, trap densities, bias stability, and film transport approaching those of sputtered films and compatible with conventional fabrication (FAB) operations. PMID:25733848

Spray-combustion synthesis: efficient solution route to high-performance oxide transistors.

PubMed

Yu, Xinge; Smith, Jeremy; Zhou, Nanjia; Zeng, Li; Guo, Peijun; Xia, Yu; Alvarez, Ana; Aghion, Stefano; Lin, Hui; Yu, Junsheng; Chang, Robert P H; Bedzyk, Michael J; Ferragut, Rafael; Marks, Tobin J; Facchetti, Antonio

2015-03-17

Metal-oxide (MO) semiconductors have emerged as enabling materials for next generation thin-film electronics owing to their high carrier mobilities, even in the amorphous state, large-area uniformity, low cost, and optical transparency, which are applicable to flat-panel displays, flexible circuitry, and photovoltaic cells. Impressive progress in solution-processed MO electronics has been achieved using methodologies such as sol gel, deep-UV irradiation, preformed nanostructures, and combustion synthesis. Nevertheless, because of incomplete lattice condensation and film densification, high-quality solution-processed MO films having technologically relevant thicknesses achievable in a single step have yet to be shown. Here, we report a low-temperature, thickness-controlled coating process to create high-performance, solution-processed MO electronics: spray-combustion synthesis (SCS). We also report for the first time, to our knowledge, indium-gallium-zinc-oxide (IGZO) transistors having densification, nanoporosity, electron mobility, trap densities, bias stability, and film transport approaching those of sputtered films and compatible with conventional fabrication (FAB) operations.

Photo-excited charge carriers suppress sub-terahertz phonon mode in silicon at room temperature

DOE PAGES

Liao, Bolin; Maznev, A. A.; Nelson, Keith A.; ...

2016-10-12

There is a growing interest in the mode-by-mode understanding of electron and phonon transport for improving energy conversion technologies, such as thermoelectrics and photovoltaics. Whereas remarkable progress has been made in probing phonon–phonon interactions, it has been a challenge to directly measure electron–phonon interactions at the single-mode level, especially their effect on phonon transport above cryogenic temperatures. Here in this paper, we use three-pulse photoacoustic spectroscopy to investigate the damping of a single sub-terahertz coherent phonon mode by free charge carriers in silicon at room temperature. Building on conventional pump–probe photoacoustic spectroscopy, we introduce an additional laser pulse to opticallymore » generate charge carriers, and carefully design temporal sequence of the three pulses to unambiguously quantify the scattering rate of a single-phonon mode due to the electron–phonon interaction. Our results confirm predictions from first-principles simulations and indicate the importance of the often-neglected effect of electron–phonon interaction on phonon transport in doped semiconductors.« less

Modeling and fabrication of 4H-SiC Schottky junction

NASA Astrophysics Data System (ADS)

Martychowiec, A.; Pedryc, A.; Kociubiński, A.

2017-08-01

The rapidly growing demand for electronic devices requires using of alternative semiconductor materials, which could replace conventional silicon. Silicon carbide has been proposed for these harsh environment applications (high temperature, high voltage, high power conditions) because of its wide bandgap, its high temperature operation ability, its excellent thermal and chemical stability, and its high breakdown electric field strength. The Schottky barrier diode (SBD) is known as one of the best refined SiC devices. This paper presents prepared model, simulations and description of technology of 4H-SiC Schottky junction as well as characterization of fabricated structures. The future aim of the application of the structures is an optical detection of an ultraviolet radiation. The model section contains a comparison of two different solutions of SBD's construction. Simulations - as a crucial process of designing electronic devices - have been performed using the ATLAS device of Silvaco TCAD software. As a final result the paper shows I-V characteristics of fabricated diodes.

Intercorrelated In-Plane and Out-of-Plane Ferroelectricity in Ultrathin Two-Dimensional Layered Semiconductor In2Se3.

PubMed

Cui, Chaojie; Hu, Wei-Jin; Yan, Xingxu; Addiego, Christopher; Gao, Wenpei; Wang, Yao; Wang, Zhe; Li, Linze; Cheng, Yingchun; Li, Peng; Zhang, Xixiang; Alshareef, Husam N; Wu, Tom; Zhu, Wenguang; Pan, Xiaoqing; Li, Lain-Jong

2018-02-14

Enriching the functionality of ferroelectric materials with visible-light sensitivity and multiaxial switching capability would open up new opportunities for their applications in advanced information storage with diverse signal manipulation functions. We report experimental observations of robust intralayer ferroelectricity in two-dimensional (2D) van der Waals layered α-In 2 Se 3 ultrathin flakes at room temperature. Distinct from other 2D and conventional ferroelectrics, In 2 Se 3 exhibits intrinsically intercorrelated out-of-plane and in-plane polarization, where the reversal of the out-of-plane polarization by a vertical electric field also induces the rotation of the in-plane polarization. On the basis of the in-plane switchable diode effect and the narrow bandgap (∼1.3 eV) of ferroelectric In 2 Se 3 , a prototypical nonvolatile memory device, which can be manipulated both by electric field and visible light illumination, is demonstrated for advancing data storage technologies.

Conformable amplified lead zirconate titanate sensors with enhanced piezoelectric response for cutaneous pressure monitoring.

PubMed

Dagdeviren, Canan; Su, Yewang; Joe, Pauline; Yona, Raissa; Liu, Yuhao; Kim, Yun-Soung; Huang, YongAn; Damadoran, Anoop R; Xia, Jing; Martin, Lane W; Huang, Yonggang; Rogers, John A

2014-08-05

The ability to measure subtle changes in arterial pressure using devices mounted on the skin can be valuable for monitoring vital signs in emergency care, detecting the early onset of cardiovascular disease and continuously assessing health status. Conventional technologies are well suited for use in traditional clinical settings, but cannot be easily adapted for sustained use during daily activities. Here we introduce a conformal device that avoids these limitations. Ultrathin inorganic piezoelectric and semiconductor materials on elastomer substrates enable amplified, low hysteresis measurements of pressure on the skin, with high levels of sensitivity (~0.005 Pa) and fast response times (~0.1 ms). Experimental and theoretical studies reveal enhanced piezoelectric responses in lead zirconate titanate that follow from integration on soft supports as well as engineering behaviours of the associated devices. Calibrated measurements of pressure variations of blood flow in near-surface arteries demonstrate capabilities for measuring radial artery augmentation index and pulse pressure velocity.

Energy harvesting of non-emissive triplet excitons in tetracene by emissive PbS nanocrystals

NASA Astrophysics Data System (ADS)

Thompson, Nicholas J.; Wilson, Mark W. B.; Congreve, Daniel N.; Brown, Patrick R.; Scherer, Jennifer M.; Bischof, Thomas S.; Wu, Mengfei; Geva, Nadav; Welborn, Matthew; Voorhis, Troy Van; Bulović, Vladimir; Bawendi, Moungi G.; Baldo, Marc A.

2014-11-01

Triplet excitons are ubiquitous in organic optoelectronics, but they are often an undesirable energy sink because they are spin-forbidden from emitting light and their high binding energy hinders the generation of free electron-hole pairs. Harvesting their energy is consequently an important technological challenge. Here, we demonstrate direct excitonic energy transfer from ‘dark’ triplets in the organic semiconductor tetracene to colloidal PbS nanocrystals, thereby successfully harnessing molecular triplet excitons in the near infrared. Steady-state excitation spectra, supported by transient photoluminescence studies, demonstrate that the transfer efficiency is at least (90 ± 13)%. The mechanism is a Dexter hopping process consisting of the simultaneous exchange of two electrons. Triplet exciton transfer to nanocrystals is expected to be broadly applicable in solar and near-infrared light-emitting applications, where effective molecular phosphors are lacking at present. In particular, this route to ‘brighten’ low-energy molecular triplet excitons may permit singlet exciton fission sensitization of conventional silicon solar cells.

Pinpoint and bulk electrochemical reduction of insulating silicon dioxide to silicon.

PubMed

Nohira, Toshiyuki; Yasuda, Kouji; Ito, Yasuhiko

2003-06-01

Silicon dioxide (SiO(2)) is conventionally reduced to silicon by carbothermal reduction, in which the oxygen is removed by a heterogeneous-homogeneous reaction sequence at approximately 1,700 degrees C. Here we report pinpoint and bulk electrochemical methods for removing oxygen from solid SiO(2) in a molten CaCl(2) electrolyte at 850 degrees C. This approach involves a 'contacting electrode', in which a metal wire supplies electrons to a selected region of the insulating SiO(2). Bulk reduction of SiO(2) is possible by increasing the number of contacting points. The same method was also demonstrated with molten LiCl-KCl-CaCl(2) at 500 degrees C. The novelty and relative simplicity of this method might lead to new processes in silicon semiconductor technology, as well as in high-purity silicon production. The methodology may be applicable to electrochemical processing of a wide variety of insulating materials, provided that the electrolyte dissolves the appropriate constituent ion(s) of the material.

Design of an Inductive Adder for the FCC injection kicker pulse generator

NASA Astrophysics Data System (ADS)

Woog, D.; Barnes, M. J.; Ducimetière, L.; Holma, J.; Kramer, T.

2017-07-01

The injection system for a 100 TeV centre-of-mass collider is an important part of the Future Circular Collider (FCC) study. Due to issues with conventional kicker systems, such as self-triggering and long term availability of thyratrons and limitations of HV-cables, innovative design changes are planned for the FCC injection kicker pulse generator. An inductive adder (IA) based on semiconductor (SC) switches is a promising technology for kicker systems. Its modular design, and the possibility of an active ripple suppression are significant advantages. Since the IA is a complex device, with multiple components whose characteristics are important, a detailed design study and construction of a prototype is necessary. This paper summarizes the system requirements and constraints, and describes the main components and design challenges of the prototype IA. It outlines the results from simulations and measurements on different magnetic core materials as well as on SC switches. The paper concludes on the design choices and progress for the prototype to be built at CERN.

Localized Charges Control Exciton Energetics and Energy Dissipation in Doped Carbon Nanotubes.

PubMed

Eckstein, Klaus H; Hartleb, Holger; Achsnich, Melanie M; Schöppler, Friedrich; Hertel, Tobias

2017-10-24

Doping by chemical or physical means is key for the development of future semiconductor technologies. Ideally, charge carriers should be able to move freely in a homogeneous environment. Here, we report on evidence suggesting that excess carriers in electrochemically p-doped semiconducting single-wall carbon nanotubes (s-SWNTs) become localized, most likely due to poorly screened Coulomb interactions with counterions in the Helmholtz layer. A quantitative analysis of blue-shift, broadening, and asymmetry of the first exciton absorption band also reveals that doping leads to hard segmentation of s-SWNTs with intrinsic undoped segments being separated by randomly distributed charge puddles approximately 4 nm in width. Light absorption in these doped segments is associated with the formation of trions, spatially separated from neutral excitons. Acceleration of exciton decay in doped samples is governed by diffusive exciton transport to, and nonradiative decay at charge puddles within 3.2 ps in moderately doped s-SWNTs. The results suggest that conventional band-filling in s-SWNTs breaks down due to inhomogeneous electrochemical doping.

Electrothermal Feedback and Absorption-Induced Open-Circuit-Voltage Turnover in Solar Cells

NASA Astrophysics Data System (ADS)

Ullbrich, Sascha; Fischer, Axel; Tang, Zheng; Ávila, Jorge; Bolink, Henk J.; Reineke, Sebastian; Vandewal, Koen

2018-05-01

Solar panels easily heat up upon intense solar radiation due to excess energy dissipation of the absorbed photons or by nonradiative recombination of charge carriers. Still, photoinduced self-heating is often ignored when characterizing lab-sized samples. For light-intensity-dependent measurements of the open-circuit voltage (Suns-VO C ), allowing us to characterize the recombination mechanism, sample heating is often not considered, although almost 100% of the absorbed energy is converted into heat. Here, we show that the frequently observed stagnation or even decrease in VOC at increasingly high light intensities can be explained by considering an effective electrothermal feedback between the recombination current and the open-circuit voltage. Our analytical model fully explains the experimental data for various solar-cell technologies, comprising conventional inorganic semiconductors as well as organic and perovskite materials. Furthermore, the model can be exploited to determine the ideality factor, the effective gap, and the temperature rise from a single Suns-VOC measurement at ambient conditions.

Modulation Doping of Silicon using Aluminium-induced Acceptor States in Silicon Dioxide

PubMed Central

König, Dirk; Hiller, Daniel; Gutsch, Sebastian; Zacharias, Margit; Smith, Sean

2017-01-01

All electronic, optoelectronic or photovoltaic applications of silicon depend on controlling majority charge carriers via doping with impurity atoms. Nanoscale silicon is omnipresent in fundamental research (quantum dots, nanowires) but also approached in future technology nodes of the microelectronics industry. In general, silicon nanovolumes, irrespective of their intended purpose, suffer from effects that impede conventional doping due to fundamental physical principles such as out-diffusion, statistics of small numbers, quantum- or dielectric confinement. In analogy to the concept of modulation doping, originally invented for III-V semiconductors, we demonstrate a heterostructure modulation doping method for silicon. Our approach utilizes a specific acceptor state of aluminium atoms in silicon dioxide to generate holes as majority carriers in adjacent silicon. By relocating the dopants from silicon to silicon dioxide, Si nanoscale doping problems are circumvented. In addition, the concept of aluminium-induced acceptor states for passivating hole selective tunnelling contacts as required for high-efficiency photovoltaics is presented and corroborated by first carrier lifetime and tunnelling current measurements. PMID:28425460

78 FR 18370 - Investigations Regarding Eligibility To Apply for Worker Adjustment Assistance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-26

... (State/One-Stop) 82538 Zebra Technologies (Company) Lincoln, RI 03/08/13 03/07/13 82539 Elster Solutions... Semiconductor, Clarksville, TN....... 03/08/13 03/07/13 L.L.C. (Company) 82543 Zebra Technologies (Company... NewPage Duluth Paper Mill Duluth, MN 03/04/13 03/01/13 (State/One-Stop) 82522 United Technologies...

Construction of vesicle CdSe nano-semiconductors photocatalysts with improved photocatalytic activity: Enhanced photo induced carriers separation efficiency and mechanism insight.

PubMed

Wen, Jiangsu; Ma, Changchang; Huo, Pengwei; Liu, Xinlin; Wei, Maobin; Liu, Yang; Yao, Xin; Ma, Zhongfei; Yan, Yongsheng

2017-10-01

Visible-light-driven photocatalysis as a green technology has attracted a lot of attention due to its potential applications in environmental remediation. Vesicle CdSe nano-semiconductor photocatalyst are successfully prepared by a gas template method and characterized by a variety of methods. The vesicle CdSe nano-semiconductors display enhanced photocatalytic performance for the degradation of tetracycline hydrochloride, the photodegradation rate of 78.824% was achieved by vesicle CdSe, which exhibited an increase of 31.779% compared to granular CdSe. Such an exceptional photocatalytic capability can be attributed to the unique structure of the vesicle CdSe nano-semiconductor with enhanced light absorption ability and excellent carrier transport capability. Meanwhile, the large surface area of the vesicle CdSe nano-semiconductor can increase the contact probability between catalyst and target and provide more surface-active centers. The photocatalytic mechanisms are analyzed by active species quenching. It indicates that h + and O 2 - are the main active species which play a major role in catalyzing environmental toxic pollutants. Simultaneously, the vesicle CdSe nano-semiconductor had high efficiency and stability. Copyright © 2017. Published by Elsevier B.V.

Crystalline silicon photovoltaics via low-temperature TiO 2/Si and PEDOT/Si heterojunctions

NASA Astrophysics Data System (ADS)

Nagamatsu, Ken Alfred

The most important goals in developing solar cell technology are to achieve high power conversion efficiencies and lower costs of manufacturing. Solar cells based on crystalline silicon currently dominate the market because they can achieve high efficiency. However, conventional p-n junction solar cells require high-temperature diffusions of dopants, and conventional heterojunction cells based on amorphous silicon require plasma-enhanced deposition, both of which can add manufacturing costs. This dissertation investigates an alternative approach, which is to form crystalline-silicon-based solar cells using heterojunctions with materials that are easily deposited at low temperatures and without plasma enhancement, such as organic semiconductors and metal oxides. We demonstrate a heterojunction between the organic polymer, poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT), and crystalline silicon, which acts as a hole-selective contact and an alternative to a diffused p-n junction. We also present the use of a heterojunction between titanium dioxide and crystalline silicon as a passivating electron-selective contact. The Si/TiO2 heterojunction is demonstrated for the first time as a back-surface field in a crystalline silicon solar cell, and is incorporated into a PEDOT/Si device. The resulting PEDOT/Si/TiO2 solar cell represents an alternative to conventional silicon solar cells that rely on thermally-diffused junctions or plasma-deposited heterojunctions. Finally, we investigate the merits of using conductive networks of silver nanowires to enhance the photovoltaic performance of PEDOT/Si solar cells. The investigation of these materials and devices contributes to the growing body of work regarding crystalline silicon solar cells made with selective contacts.

Three fundamental devices in one: a reconfigurable multifunctional device in two-dimensional WSe2

NASA Astrophysics Data System (ADS)

Dhakras, Prathamesh; Agnihotri, Pratik; Lee, Ji Ung

2017-06-01

The three pillars of semiconductor device technologies are (1) the p-n diode, (2) the metal-oxide-semiconductor field-effect transistor and (3) the bipolar junction transistor. They have enabled the unprecedented growth in the field of information technology that we see today. Until recently, the technological revolution for better, faster and more efficient devices has been governed by scaling down the device dimensions following Moore’s Law. With the slowing of Moore’s law, there is a need for alternative materials and computing technologies that can continue the advancement in functionality. Here, we describe a single, dynamically reconfigurable device that implements these three fundamental device functions. The device uses buried gates to achieve n- and p-channels and fits into a larger effort to develop devices with enhanced functionalities, including logic functions, over device scaling. As they are all surface conducting devices, we use one material parameter, the interface trap density of states, to describe the key figure-of-merit of each device.

High-Temperature, Wirebondless, Ultracompact Wide Bandgap Power Semiconductor Modules

NASA Technical Reports Server (NTRS)

Elmes, John

2015-01-01

Silicon carbide (SiC) and other wide bandgap semiconductors offer great promise of high power rating, high operating temperature, simple thermal management, and ultrahigh power density for both space and commercial power electronic systems. However, this great potential is seriously limited by the lack of reliable high-temperature device packaging technology. This Phase II project developed an ultracompact hybrid power module packaging technology based on the use of double lead frames and direct lead frame-to-chip transient liquid phase (TLP) bonding that allows device operation up to 450 degC. The new power module will have a very small form factor with 3-5X reduction in size and weight from the prior art, and it will be capable of operating from 450 degC to -125 degC. This technology will have a profound impact on power electronics and energy conversion technologies and help to conserve energy and the environment as well as reduce the nation's dependence on fossil fuels.

Applications of Optical Coherent Transient Technology to Pulse Shaping, Spectral Filtering, Arbitrary Waveform Generation and RF Beamforming

DTIC Science & Technology

2006-04-15

was amplified by injection locking of a high power diode laser and further amplified to -300 mW with a semiconductor optical amplifier. This light...amplifiers at 793nm, cascaded injection locked amplifiers at 793nm, and frequency chirped lasers at 793nm. 15. SUBJECT TERMS Optical Coherent Transients...injection- locking for broadband optical signal amplification ................. 34 2.10. Tapered semiconductor optical amplifier

A 94GHz Temperature Compensated Low Noise Amplifier in 45nm Silicon-on-Insulator Complementary Metal-Oxide Semiconductor (SOI CMOS)

DTIC Science & Technology

2014-01-01

ring oscillator based temperature sensor will be designed to compensate for gain variations over temperature. For comparison to a competing solution...Simulated (Green) Capacitance of the GSG Pads ........................ 9 Figure 6: Die Picture and Schematic of the L-2L Coplanar Waveguides...complementary metal-oxide-semiconductor (CMOS) technology. A ring oscillator based temperature sensor was designed to compensate for gain variations

Nanoscale wide-band semiconductors for photocatalytic remediation of aquatic pollution.

PubMed

Sarkar, Biplab; Daware, Akshay Vishnu; Gupta, Priya; Krishnani, Kishore Kumar; Baruah, Sunandan; Bhattacharjee, Surajit

2017-11-01

Water pollution is a serious challenge to the public health. Among different forms of aquatic pollutants, chemical and biological agents create paramount threat to water quality when the safety standards are surpassed. There are many conventional remediatory strategies that are practiced such as resin-based exchanger and activated charcoal/carbon andreverse osmosis. Newer technologies using plants, microorganisms, genetic engineering, and enzyme-based approaches are also proposed for aquatic pollution management. However, the conventional technologies have shown impending inadequacies. On the other hand, new bio-based techniques have failed to exhibit reproducibility, wide specificity, and fidelity in field conditions. Hence, to solve these shortcomings, nanotechnology ushered a ray of hope by applying nanoscale zinc oxide (ZnO), titanium dioxide (TiO 2 ), and tungsten oxide (WO 3 ) particles for the remediation of water pollution. These nanophotocatalysts are active, cost-effective, quicker in action, and can be implemented at a larger scale. These nanoparticles are climate-independent, assist in complete mineralization of pollutants, and can act non-specifically against chemically and biologically based aquatic pollutants. Photocatalysis for environmental remediation depends on the availability of solar light. The mechanism of photocatalysis involves the formation of electron-hole pairs upon light irradiations at intensities higher than their band gap energies. In the present review, different methods of synthesis of nanoscale ZnO, TiO 2 , and WO 3 as well as their structural characterizations have been discussed. Photodegradation of organic pollutants through mentioned nanoparticles has been reviewed with recent advancements. Enhancing the efficacy of photocatalysis through doping of TiO 2 and ZnO nanoparticles with non-metals, metals, and metal ions has also been documented in this report.

A Compact Soft X-Ray Microscope using an Electrode-less Z-Pinch Source.

PubMed

Horne, S F; Silterra, J; Holber, W

2009-01-01

Soft X-rays (< 1Kev) are of medical interest both for imaging and microdosimetry applications. X-ray sources at this low energy present a technological challenge. Synchrotrons, while very powerful and flexible, are enormously expensive national research facilities. Conventional X-ray sources based on electron bombardment can be compact and inexpensive, but low x-ray production efficiencies at low electron energies restrict this approach to very low power applications. Laser-based sources tend to be expensive and unreliable. Energetiq Technology, Inc. (Woburn, MA, USA) markets a 92 eV, 10W(2pi sr) electrode-less Z-pinch source developed for advanced semiconductor lithography. A modified version of this commercial product has produced 400 mW at 430 eV (2pi sr), appropriate for water window soft X-ray microscopy. The US NIH has funded Energetiq to design and construct a demonstration microscope using this source, coupled to a condenser optic, as the illumination system. The design of the condenser optic matches the unique characteristics of the source to the illumination requirements of the microscope, which is otherwise a conventional design. A separate program is underway to develop a microbeam system, in conjunction with the RARAF facility at Columbia University, NY, USA. The objective is to develop a focused, sub-micron beam capable of delivering > 1 Gy/second to the nucleus of a living cell. While most facilities of this type are coupled to a large and expensive particle accelerator, the Z-pinch X-ray source enables a compact, stand-alone design suitable to a small laboratory. The major technical issues in this system involve development of suitable focusing X-ray optics. Current status of these programs will be reported.

A Compact Soft X-Ray Microscope using an Electrode-less Z-Pinch Source

PubMed Central

Silterra, J; Holber, W

2009-01-01

Soft X-rays (< 1Kev) are of medical interest both for imaging and microdosimetry applications. X-ray sources at this low energy present a technological challenge. Synchrotrons, while very powerful and flexible, are enormously expensive national research facilities. Conventional X-ray sources based on electron bombardment can be compact and inexpensive, but low x-ray production efficiencies at low electron energies restrict this approach to very low power applications. Laser-based sources tend to be expensive and unreliable. Energetiq Technology, Inc. (Woburn, MA, USA) markets a 92 eV, 10W(2pi sr) electrode-less Z-pinch source developed for advanced semiconductor lithography. A modified version of this commercial product has produced 400 mW at 430 eV (2pi sr), appropriate for water window soft X-ray microscopy. The US NIH has funded Energetiq to design and construct a demonstration microscope using this source, coupled to a condenser optic, as the illumination system. The design of the condenser optic matches the unique characteristics of the source to the illumination requirements of the microscope, which is otherwise a conventional design. A separate program is underway to develop a microbeam system, in conjunction with the RARAF facility at Columbia University, NY, USA. The objective is to develop a focused, sub-micron beam capable of delivering > 1 Gy/second to the nucleus of a living cell. While most facilities of this type are coupled to a large and expensive particle accelerator, the Z-pinch X-ray source enables a compact, stand-alone design suitable to a small laboratory. The major technical issues in this system involve development of suitable focusing X-ray optics. Current status of these programs will be reported. PMID:20198115

Cucumber Power

ERIC Educational Resources Information Center

Wibig, Tadeusz

2010-01-01

The flow of electricity from one body to another has been known by man since we first learned how to gather an electric charge. In contrast to conventional wisdom, the process in the general case is not easy to explain. It is different in plasma in the Sun or in your colour TV display, in semiconductors inside your computer or TV set circuits, or…

Technology-design-manufacturing co-optimization for advanced mobile SoCs

NASA Astrophysics Data System (ADS)

Yang, Da; Gan, Chock; Chidambaram, P. R.; Nallapadi, Giri; Zhu, John; Song, S. C.; Xu, Jeff; Yeap, Geoffrey

2014-03-01

How to maintain the Moore's Law scaling beyond the 193 immersion resolution limit is the key question semiconductor industry needs to answer in the near future. Process complexity will undoubtfully increase for 14nm node and beyond, which brings both challenges and opportunities for technology development. A vertically integrated design-technologymanufacturing co-optimization flow is desired to better address the complicated issues new process changes bring. In recent years smart mobile wireless devices have been the fastest growing consumer electronics market. Advanced mobile devices such as smartphones are complex systems with the overriding objective of providing the best userexperience value by harnessing all the technology innovations. Most critical system drivers are better system performance/power efficiency, cost effectiveness, and smaller form factors, which, in turns, drive the need of system design and solution with More-than-Moore innovations. Mobile system-on-chips (SoCs) has become the leading driver for semiconductor technology definition and manufacturing. Here we highlight how the co-optimization strategy influenced architecture, device/circuit, process technology and package, in the face of growing process cost/complexity and variability as well as design rule restrictions.

Challenges to Scaling CIGS Photovoltaics

NASA Astrophysics Data System (ADS)

Stanbery, B. J.

2011-03-01

The challenges of scaling any photovoltaic technology to terawatts of global capacity are arguably more economic than technological or resource constraints. All commercial thin-film PV technologies are based on direct bandgap semiconductors whose absorption coefficient and bandgap alignment with the solar spectrum enable micron-thick coatings in lieu to hundreds of microns required using indirect-bandgap c-Si. Although thin-film PV reduces semiconductor materials cost, its manufacture is more capital intensive than c-Si production, and proportional to deposition rate. Only when combined with sufficient efficiency and cost of capital does this tradeoff yield lower manufacturing cost. CIGS has the potential to become the first thin film technology to achieve the terawatt benchmark because of its superior conversion efficiency, making it the only commercial thin film technology which demonstrably delivers performance comparable to the dominant incumbent, c-Si. Since module performance leverages total systems cost, this competitive advantage bears directly on CIGS' potential to displace c-Si and attract the requisite capital to finance the tens of gigawatts of annual production capacity needed to manufacture terawatts of PV modules apace with global demand growth.

Enabling iron pyrite (FeS2) and related ternary pyrite compounds for high-performance solar energy applications

NASA Astrophysics Data System (ADS)

Caban Acevedo, Miguel

The success of solar energy technologies depends not only on highly efficient solar-to-electrical energy conversion, charge storage or chemical fuel production, but also on dramatically reduced cost, to meet the future terawatt energy challenges we face. The enormous scale involved in the development of impactful solar energy technologies demand abundant and inexpensive materials, as well as energy-efficient and cost-effective processes. As a result, the investigation of semiconductor, catalyst and electrode materials made of earth-abundant and sustainable elements may prove to be of significant importance for the long-term adaptation of solar energy technologies on a larger scale. Among earth-abundant semiconductors, iron pyrite (cubic FeS2) has been considered the most promising solar energy absorber with the potential to achieve terawatt energy-scale deployment. Despite extensive synthetic progress and device efforts, the solar conversion efficiency of iron pyrite has remained below 3% since the 1990s, primarily due to a low open circuit voltage (V oc). The low photovoltage (Voc) of iron pyrite has puzzled scientists for decades and limited the development of cost-effective solar energy technologies based on this otherwise promising semiconductor. Here I report a comprehensive investigation of the syntheses and properties of iron pyrite materials, which reveals that the Voc of iron pyrite is limited by the ionization of a high density of intrinsic bulk defect states despite high density surface states and strong surface Fermi level pinning. Contrary to popular belief, bulk defects most-likely caused by intrinsic sulfur vacancies in iron pyrite must be controlled in order to enable this earth-abundant semiconductor for cost-effective and sustainable solar energy conversion. Lastly, the investigation of iron pyrite presented here lead to the discovery of ternary pyrite-type cobalt phosphosulfide (CoPS) as a highly-efficient earth-abundant catalyst material for electrochemical and solar energy driven hydrogen production.

Carbon Nanotube based Nanotechnolgy

NASA Astrophysics Data System (ADS)

Meyyappan, M.

2000-10-01

Carbon nanotube(CNT) was discovered in the early 1990s and is an off-spring of C60(the fullerene or buckyball). CNT, depending on chirality and diameter, can be metallic or semiconductor and thus allows formation of metal-semiconductor and semiconductor-semiconductor junctions. CNT exhibits extraordinary electrical and mechanical properties and offers remarkable potential for revolutionary applications in electronics devices, computing and data storage technology, sensors, composites, storage of hydrogen or lithium for battery development, nanoelectromechanical systems(NEMS), and as tip in scanning probe microscopy(SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization and applications touch upon all disciplines of science and engineering. A common growth method now is based on CVD though surface catalysis is key to synthesis, in contrast to many CVD applications common in microelectronics. A plasma based variation is gaining some attention. This talk will provide an overview of CNT properties, growth methods, applications, and research challenges and opportunities ahead.

Quantum information density scaling and qubit operation time constraints of CMOS silicon-based quantum computer architectures

NASA Astrophysics Data System (ADS)

Rotta, Davide; Sebastiano, Fabio; Charbon, Edoardo; Prati, Enrico

2017-06-01

Even the quantum simulation of an apparently simple molecule such as Fe2S2 requires a considerable number of qubits of the order of 106, while more complex molecules such as alanine (C3H7NO2) require about a hundred times more. In order to assess such a multimillion scale of identical qubits and control lines, the silicon platform seems to be one of the most indicated routes as it naturally provides, together with qubit functionalities, the capability of nanometric, serial, and industrial-quality fabrication. The scaling trend of microelectronic devices predicting that computing power would double every 2 years, known as Moore's law, according to the new slope set after the 32-nm node of 2009, suggests that the technology roadmap will achieve the 3-nm manufacturability limit proposed by Kelly around 2020. Today, circuital quantum information processing architectures are predicted to take advantage from the scalability ensured by silicon technology. However, the maximum amount of quantum information per unit surface that can be stored in silicon-based qubits and the consequent space constraints on qubit operations have never been addressed so far. This represents one of the key parameters toward the implementation of quantum error correction for fault-tolerant quantum information processing and its dependence on the features of the technology node. The maximum quantum information per unit surface virtually storable and controllable in the compact exchange-only silicon double quantum dot qubit architecture is expressed as a function of the complementary metal-oxide-semiconductor technology node, so the size scale optimizing both physical qubit operation time and quantum error correction requirements is assessed by reviewing the physical and technological constraints. According to the requirements imposed by the quantum error correction method and the constraints given by the typical strength of the exchange coupling, we determine the workable operation frequency range of a silicon complementary metal-oxide-semiconductor quantum processor to be within 1 and 100 GHz. Such constraint limits the feasibility of fault-tolerant quantum information processing with complementary metal-oxide-semiconductor technology only to the most advanced nodes. The compatibility with classical complementary metal-oxide-semiconductor control circuitry is discussed, focusing on the cryogenic complementary metal-oxide-semiconductor operation required to bring the classical controller as close as possible to the quantum processor and to enable interfacing thousands of qubits on the same chip via time-division, frequency-division, and space-division multiplexing. The operation time range prospected for cryogenic control electronics is found to be compatible with the operation time expected for qubits. By combining the forecast of the development of scaled technology nodes with operation time and classical circuitry constraints, we derive a maximum quantum information density for logical qubits of 2.8 and 4 Mqb/cm2 for the 10 and 7-nm technology nodes, respectively, for the Steane code. The density is one and two orders of magnitude less for surface codes and for concatenated codes, respectively. Such values provide a benchmark for the development of fault-tolerant quantum algorithms by circuital quantum information based on silicon platforms and a guideline for other technologies in general.

Solar energy harvesting by magnetic-semiconductor nanoheterostructure in water treatment technology.

PubMed

Mahmoodi, Vahid; Bastami, Tahereh Rohani; Ahmadpour, Ali

2018-03-01

Photocatalytic degradation of toxic organic pollutants in the wastewater using dispersed semiconductor nanophotocatalysts has a number of advantages such as high activity, cost effectiveness, and utilization of free solar energy. However, it is difficult to recover and recycle nanophotocatalysts since the fine dispersed nanoparticles are easily suspended in waters. Furthermore, a large amount of photocatalysts will lead to color contamination. Thus, it is necessary to prepare photocatalysts with easy separation for the reusable application. To take advantage of high photocatalysis activity and reusability, magnetic photocatalysts with separation function were utilized. In this review, the photocatalytic principle, structure, and application of the magnetic-semiconductor nanoheterostructure photocatalysts under solar light are evaluated. Graphical abstract ᅟ.

Composition-matched molecular “solders” for semiconductors

NASA Astrophysics Data System (ADS)

Dolzhnikov, Dmitriy S.; Zhang, Hao; Jang, Jaeyoung; Son, Jae Sung; Panthani, Matthew G.; Shibata, Tomohiro; Chattopadhyay, Soma; Talapin, Dmitri V.

2015-01-01

We propose a general strategy to synthesize largely unexplored soluble chalcogenidometallates of cadmium, lead, and bismuth. These compounds can be used as “solders” for semiconductors widely used in photovoltaics and thermoelectrics. The addition of solder helped to bond crystal surfaces and link nano- or mesoscale particles together. For example, CdSe nanocrystals with Na2Cd2Se3 solder was used as a soluble precursor for CdSe films with electron mobilities exceeding 300 square centimeters per volt-second. CdTe, PbTe, and Bi2Te3 powders were molded into various shapes in the presence of a small additive of composition-matched chalcogenidometallate or chalcogel, thus opening new design spaces for semiconductor technologies.

Cadmium Telluride Semiconductor Detector for Improved Spatial and Energy Resolution Radioisotopic Imaging

PubMed Central

Abbaspour, Samira; Mahmoudian, Babak; Islamian, Jalil Pirayesh

2017-01-01

The detector in single-photon emission computed tomography has played a key role in the quality of the images. Over the past few decades, developments in semiconductor detector technology provided an appropriate substitution for scintillation detectors in terms of high sensitivity, better energy resolution, and also high spatial resolution. One of the considered detectors is cadmium telluride (CdTe). The purpose of this paper is to review the CdTe semiconductor detector used in preclinical studies, small organ and small animal imaging, also research in nuclear medicine and other medical imaging modalities by a complete inspect on the material characteristics, irradiation principles, applications, and epitaxial growth method. PMID:28553175

Advanced Microelectronics Technologies for Future Small Satellite Systems

NASA Technical Reports Server (NTRS)

Alkalai, Leon

1999-01-01

Future small satellite systems for both Earth observation as well as deep-space exploration are greatly enabled by the technological advances in deep sub-micron microelectronics technologies. Whereas these technological advances are being fueled by the commercial (non-space) industries, more recently there has been an exciting new synergism evolving between the two otherwise disjointed markets. In other words, both the commercial and space industries are enabled by advances in low-power, highly integrated, miniaturized (low-volume), lightweight, and reliable real-time embedded systems. Recent announcements by commercial semiconductor manufacturers to introduce Silicon On Insulator (SOI) technology into their commercial product lines is driven by the need for high-performance low-power integrated devices. Moreover, SOI has been the technology of choice for many space semiconductor manufacturers where radiation requirements are critical. This technology has inherent radiation latch-up immunity built into the process, which makes it very attractive to space applications. In this paper, we describe the advanced microelectronics and avionics technologies under development by NASA's Deep Space Systems Technology Program (also known as X2000). These technologies are of significant benefit to both the commercial satellite as well as the deep-space and Earth orbiting science missions. Such a synergistic technology roadmap may truly enable quick turn-around, low-cost, and highly capable small satellite systems for both Earth observation as well as deep-space missions.

Efficient Solar Energy Conversion Systems for Hydrogen Production from Water using Semiconductor Photoelectrodes and Photocatalysts

NASA Astrophysics Data System (ADS)

Sayama, K.; Arai, T.

2008-02-01

Efficient solar energy conversion system for hydrogen production from water, solar-hydrogen system, is one of most important technologies for genuinely sustainable development of the society in the world wide scale. However, there are many problems to breakthrough such as low solar-to-H2 efficiency (STH), high cost, low stability, etc in order to realize the system practically and economically. The solar-hydrogen systems using semiconductors are mainly classified as follows; solar cell-electrolysis system, semiconductor photoelectrode system, and photocatalyst system. There are various merits and demerits in each system. The solar cell-electrolysis system is very efficient but is very high cost. The photocatalyst system is very simple and relatively low cost, but the efficiency is still very low. On the other hand, various semiconductor systems with high efficiency have been investigated. A high STH more than 10% was reported using non-oxide semiconductor photoelectrodes such as InGaP, while the preparation methods were costly. In a European project, some simple oxide semiconductor photoelectrodes such as Fe2O3 and WO3 are mainly studied. Here, we investigated various photoelectrodes using mixed metal oxide especially on BiVO4 semiconductor, and a high throughput screening system of new visible light responsible semiconductors for photoelectrode and photocatalyst. Moreover, photocatalysis-electrolysis hybrid system for economical H2 production is studied to overcome the demerit of photocatalyst system on the gas separation and low efficiency.

Nanoscience and Nanotechnology: From Energy Applications to Advanced Medical Therapies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tijana Rajh

2009-10-14

Dr. Rajh will present a general talk on nanotechnology – an overview of why nanotechnology is important and how it is useful in various fields. The specific focus will be on Solar energy conversion, environmental applications and advanced medical therapies. She has broad expertise in synthesis and characterization of nanomaterials that are used in nanotechnology including novel hybrid systems connecting semiconductors to biological molecules like DNA and antibodies. This technology could lead to new gene therapy procedures, cancer treatments and other medical applications. She will also discuss technologies made possible by organizing small semiconductor particles called quantum dots, materials thatmore » exhibit a rich variety of phenomena that are size and shape dependent. Development of these new materials that harnesses the unique properties of materials at the 1-100 nanometer scale resulted in the new field of nanotechnology that currently affects many applications in technological and medical fields.« less

An overview of silicon carbide device technology

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Matus, Lawrence G.

1992-01-01

Recent progress in the development of silicon carbide (SiC) as a semiconductor is briefly reviewed. This material shows great promise towards providing electronic devices that can operate under the high-temperature, high-radiation, and/or high-power conditions where current semiconductor technologies fail. High quality single crystal wafers have become available, and techniques for growing high quality epilayers have been refined to the point where experimental SiC devices and circuits can be developed. The prototype diodes and transistors that have been produced to date show encouraging characteristics, but by the same token they also exhibit some device-related problems that are not unlike those faced in the early days of silicon technology development. Although these problems will not prevent the implementation of some useful circuits, the performance and operating regime of SiC electronics will be limited until these device-related issues are solved.

Picosecond UV single photon detectors with lateral drift field: Concept and technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yakimov, M.; Oktyabrsky, S.; Murat, P.

2015-09-01

Group III–V semiconductor materials are being considered as a Si replacement for advanced logic devices for quite some time. Advances in III–V processing technologies, such as interface and surface passivation, large area deep submicron lithography with high-aspect ratio etching primarily driven by the metal-oxide-semiconductor field-effect transistor development can also be used for other applications. In this paper we will focus on photodetectors with the drift field parallel to the surface. We compare the proposed concept to the state-of-the-art Si-based technology and discuss requirements which need to be satisfied for such detectors to be used in a single photon counting modemore » in blue and ultraviolet spectral region with about 10 ps photon timing resolution essential for numerous applications ranging from high-energy physics to medical imaging.« less

Nanoscience and Nanotechnology: From Energy Applications to Advanced Medical Therapies

ScienceCinema

Tijana Rajh

2017-12-09

Dr. Rajh will present a general talk on nanotechnology – an overview of why nanotechnology is important and how it is useful in various fields. The specific focus will be on Solar energy conversion, environmental applications and advanced medical therapies. She has broad expertise in synthesis and characterization of nanomaterials that are used in nanotechnology including novel hybrid systems connecting semiconductors to biological molecules like DNA and antibodies. This technology could lead to new gene therapy procedures, cancer treatments and other medical applications. She will also discuss technologies made possible by organizing small semiconductor particles called quantum dots, materials that exhibit a rich variety of phenomena that are size and shape dependent. Development of these new materials that harnesses the unique properties of materials at the 1-100 nanometer scale resulted in the new field of nanotechnology that currently affects many applications in technological and medical fields.

Effect of nickel silicide gettering on metal-induced crystallized polycrystalline-silicon thin-film transistors

NASA Astrophysics Data System (ADS)

Kim, Hyung Yoon; Seok, Ki Hwan; Chae, Hee Jae; Lee, Sol Kyu; Lee, Yong Hee; Joo, Seung Ki

2017-06-01

Low-temperature polycrystalline-silicon (poly-Si) thin-film transistors (TFTs) fabricated via metal-induced crystallization (MIC) are attractive candidates for use in active-matrix flat-panel displays. However, these exhibit a large leakage current due to the nickel silicide being trapped at the grain boundaries of the poly-Si. We reduced the leakage current of the MIC poly-Si TFTs by developing a gettering method to remove the Ni impurities using a Si getter layer and natively-formed SiO2 as the etch stop interlayer. The Ni trap state density (Nt) in the MIC poly-Si film decreased after the Ni silicide gettering, and as a result, the leakage current of the MIC poly-Si TFTs decreased. Furthermore, the leakage current of MIC poly-Si TFTs gradually decreased with additional gettering. To explain the gettering effect on MIC poly-Si TFTs, we suggest an appropriate model. He received the B.S. degree in School of Advanced Materials Engineering from Kookmin University, Seoul, South Korea in 2012, and the M.S. degree in Department of Materials Science and Engineering from Seoul National University, Seoul, South Korea in 2014. He is currently pursuing the Ph.D. degree with the Department of Materials Science and Engineering, Seoul National University, Seoul. He is involved in semiconductor device fabrication technology and top-gate polycrystalline-silicon thin-film transistors. He received the M.S. degree in innovation technology from Ecol Polytechnique, Palaiseau, France in 2013. He is currently pursuing the Ph.D. degree with the Department of Materials Science and Engineering, Seoul National University, Seoul. He is involved in semiconductor device fabrication technology and bottom-gate polycrystalline-silicon thin-film transistors. He is currently pursuing the integrated M.S and Ph.D course with the Department of Materials Science and Engineering, Seoul National University, Seoul. He is involved in semiconductor device fabrication technology and copper-gate polycrystalline-silicon thin-film transistors. He is currently pursuing the integrated M.S and Ph.D course with the Department of Materials Science and Engineering, Seoul National University, Seoul. He is involved in semiconductor device fabrication technology and bottom-gate polycrystalline-silicon thin-film transistors. He is currently pursuing the integrated M.S and Ph.D course with the Department of Materials Science and Engineering, Seoul National University, Seoul. He is involved in semiconductor device fabrication technology and bottom-gate polycrystalline-silicon thin-film transistors. He received the B.S. degree in metallurgical engineering from Seoul National University, Seoul, South Korea, in 1974, and the M.S. and Ph.D. degrees in material science and engineering from Stanford University, Stanford, CA, USA, in 1980 and 1983, respectively. He is currently a Professor with the Department of Materials Science and Engineering, Seoul National University, Seoul.

Electronics Troubleshooting. High-Technology Training Module.

ERIC Educational Resources Information Center

Lodahl, Dan

This learning module for a postsecondary electronics course in solid state circuits is designed to help teachers lead students through electronics troubleshooting. The module is intended to be used for a second-semester technical college course for electromechanical technology majors. The module introduces students to semiconductor devices and…

High Definition Television: A New Challenge for Telecommunication Policy.

ERIC Educational Resources Information Center

Hongcharu, Boonchai

The telecommunications industry has now entered the most critical period of evolution in television technology since the introduction of color television. The transition to high definition television (HDTV), with related technologies such as semiconductors and computers, would mean a multi-billion dollar business for the telecommunications…