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Sample records for crystal diamond devices

  1. Thermal neutron dosimeter by synthetic single crystal diamond devices.

    PubMed

    Almaviva, S; Marinelli, Marco; Milani, E; Prestopino, G; Tucciarone, A; Verona, C; Verona-Rinati, G; Angelone, M; Pillon, M

    2009-07-01

    We report on a new solid state dosimeter based on chemical vapor deposition (CVD) single crystal diamond fabricated at Roma "Tor Vergata" University laboratories. The dosimeter has been specifically designed for direct neutron dose measurements in boron neutron capture therapy (BNCT). The response to thermal neutrons of the proposed diamond dosimeter is directly due to (10)B and, therefore, the dosimeter response is directly proportional to the boron absorbed doses in BNCT. Two single crystal diamond detectors are fabricated in a p-type/intrinsic/metal configuration and are sandwiched together with a boron containing layer in between the metallic contacts (see Fig.1). Neutron irradiations were performed at the Frascati Neutron Generator (FNG) using the 2.5 MeV neutrons produced through the D(d,n)(3)He fusion reaction. Thermal neutrons were then produced by slowing down the 2.5 MeV neutrons using a cylindrical polymethylmethacrylate (PMMA) moderator. The diamond dosimeter was placed in the center of the moderator. The products of (10)B(n,alpha)Li nuclear reaction were collected simultaneously giving rise to a single peak. Stable performance, high reproducibility, high efficiency and good linearity were observed.

  2. Single crystal diamond boron 'delta doped' nanometric layers for 2D electronic devices (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Butler, James

    2016-10-01

    Use of diamond as a semiconductor material suffers from the high activation energy of all known impurity dopants (0.37 eV for Boron, 0.6 eV for Phosphorous). To achieve the simultaneous carrier concentration and mobility desired for devices operating at room temperature, growth of a nanometric thick `delta' layer doped to above the metal insulator transition adjacent to high mobility intrinsic material can provide a 2D high mobility conduction layer. Critical to obtaining the enhanced mobility of the carriers in the layer next to the `delta' doped layer is the abruptness of the doping interface. Single and multiple nanometer thick epitaxial layers of heavily boron `delta' doped diamond have been grown on high quality, intrinsic lab grown diamond single crystals. These layers were grown in a custom microwave plasma activated chemical vapor deposition reactor based on a rapid reactant switching technique. Characterization of the `delta' layers by various analytical techniques will be presented. Electrical measurements demonstrating enhanced hole mobility (100 to 800 cm2/V sec) as well as other electrical characterizations will be presented.

  3. Diamond drumhead crystals (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kolodziej, Tomasz; Vodnala, Preeti; Terentyev, Sergey A.; Blank, Vladimir D.; Shvyd'ko, Yuri V.

    2016-09-01

    Ultra-thin (< 100 um) diamond single crystals are essential for the realization of numerous next generation x-ray optical devices. Fabrication and handling of such ultra-thin crystal components without introducing damage and strain is a challenge. Drumhead crystals, monolithic crystal structures comprised of a thin membrane furnished with a surrounding solid collar would be a solution for the proper handling ensuring mechanically stable and strain-free mount of the membranes with efficient thermal transport. However, diamond being one of the hardest and chemically inert materials poses insurmountable difficulties in the fabrication. Here we report on a successful manufacturing of the diamond drumhead crystals using picosecond laser milling. Subsequent temperature treatment appears to be crucial for the membranes to become defect-free and unstrained, as revealed by x-ray double-crystal topography on an example of drumhead crystals with 1-mm in diameter and 28 um to 47 um-thick membranes in the (100) orientation.

  4. Synchrotron Bragg diffraction imaging characterization of synthetic diamond crystals for optical and electronic power device applications1 1

    PubMed Central

    Tran Thi, Thu Nhi; Morse, J.; Caliste, D.; Fernandez, B.; Eon, D.; Härtwig, J.; Mer-Calfati, C.; Tranchant, N.; Arnault, J. C.; Lafford, T. A.; Baruchel, J.

    2017-01-01

    Bragg diffraction imaging enables the quality of synthetic single-crystal diamond substrates and their overgrown, mostly doped, diamond layers to be characterized. This is very important for improving diamond-based devices produced for X-ray optics and power electronics applications. The usual first step for this characterization is white-beam X-ray diffraction topography, which is a simple and fast method to identify the extended defects (dislocations, growth sectors, boundaries, stacking faults, overall curvature etc.) within the crystal. This allows easy and quick comparison of the crystal quality of diamond plates available from various commercial suppliers. When needed, rocking curve imaging (RCI) is also employed, which is the quantitative counterpart of monochromatic Bragg diffraction imaging. RCI enables the local determination of both the effective misorientation, which results from lattice parameter variation and the local lattice tilt, and the local Bragg position. Maps derived from these parameters are used to measure the magnitude of the distortions associated with polishing damage and the depth of this damage within the volume of the crystal. For overgrown layers, these maps also reveal the distortion induced by the incorporation of impurities such as boron, or the lattice parameter variations associated with the presence of growth-incorporated nitrogen. These techniques are described, and their capabilities for studying the quality of diamond substrates and overgrown layers, and the surface damage caused by mechanical polishing, are illustrated by examples. PMID:28381981

  5. Diamond Electronic Devices

    NASA Astrophysics Data System (ADS)

    Isberg, J.

    2010-11-01

    For high-power and high-voltage applications, silicon is by far the dominant semiconductor material. However, silicon has many limitations, e.g. a relatively low thermal conductivity, electric breakdown occurs at relatively low fields and the bandgap is 1.1 eV which effectively limits operation to temperatures below 175° C. Wide-bandgap materials, such as silicon carbide (SiC), gallium nitride (GaN) and diamond offer the potential to overcome both the temperature and power handling limitations of silicon. Diamond is the most extreme in this class of materials. By the fundamental material properties alone, diamond offers the largest benefits as a semiconductor material for power electronic applications. On the other hand, diamond has a problem with a large carrier activation energy of available dopants which necessitates specialised device concepts to allow room temperature (RT) operation. In addition, the role of common defects on the charge transport properties of diamond is poorly understood. Notwithstanding this, many proof-of-principle two-terminal and three-terminal devices have been made and tested. Two-terminal electronic diamond devices described in the literature include: p-n diodes, p-i-n diodes, various types of radiation detectors, Schottky diodes and photoconductive or electron beam triggered switches. Three terminal devices include e.g. MISFETs and JFETs. However, the development of diamond devices poses great challenges for the future. A particularly interesting way to overcome the doping problem, for which there has been some recent progress, is to make so-called delta doped (or pulse-doped) devices. Such devices utilise very thin (˜1 nm) doped layers in order to achieve high RT activation.

  6. A novel synthetic single crystal diamond device for in vivo dosimetry

    SciTech Connect

    Marinelli, Marco; Prestopino, G. Tonnetti, A.; Verona, C.; Verona-Rinati, G.; Falco, M. D.; Bagalà, P.; Pimpinella, M.; Guerra, A. S.; De Coste, V.

    2015-08-15

    Purpose: Aim of the present work is to evaluate the synthetic single crystal diamond Schottky photodiode developed at the laboratories of “Tor Vergata” University in Rome in a new dosimeter configuration specifically designed for offline wireless in vivo dosimetry (IVD) applications. Methods: The new diamond based dosimeter, single crystal diamond detector (SCDD-iv), consists of a small unwired detector and a small external reading unit that can be connected to commercial electrometers for getting the detector readout after irradiation. Two nominally identical SCDD-iv dosimeter prototypes were fabricated and tested. A basic dosimetric characterization of detector performances relevant for IVD application was performed under irradiation with {sup 60}Co and 6 MV photon beams. Preirradiation procedure, response stability, short and long term reproducibility, leakage charge, fading effect, linearity with dose, dose rate dependence, temperature dependence, and angular response were investigated. Results: The SCDD-iv is simple, with no cables linked to the patient and the readout is immediate. The range of response with dose has been tested from 1 up to 12 Gy; the reading is independent of the accumulated dose and dose rate independent in the range between about 0.5 and 5 Gy/min; its temperature dependence is within 0.5% between 25 and 38 °C, and its directional dependence is within 2% from 0° to 90°. The combined relative standard uncertainty of absorbed dose to water measurements is estimated lower than the tolerance and action level of 5%. Conclusions: The reported results indicate the proposed novel offline dosimeter based on a synthetic single crystal diamond Schottky photodiode as a promising candidate for in vivo dosimetry applications with photon beams.

  7. Dynamic Actuation of Single-Crystal Diamond Nanobeams

    DTIC Science & Technology

    2014-08-25

    ar X iv :1 40 8. 58 22 v1 [ co nd -m at .m es -h al l] 2 5 A ug 2 01 4 Dynamic Actuation of Single-Crystal Diamond Nanobeams Young-Ik Sohn...United States E-mail: loncar@seas.harvard.edu KEYWORDS: Single-crystal diamond , nanoelectromechanical systems (NEMS), nanofabrica- tion...dielectrophoresis Abstract We show the dielectrophoretic actuation of single-crystal diamond nanomechanical devices using gradient radio-frequency electromagnetic

  8. A procedure for diamond turning KDP crystals

    SciTech Connect

    Montesanti, R.C.; Thompson, S.L.

    1995-07-07

    A procedure and the equipment necessary for single-point diamond flycutting (loosely referred to as diamond turning) potassium di-hydrogen phosphate (KDP) crystals are described. It is based on current KDP diamond turning activities at the Lawrence Livermore National Laboratory (LLNL), drawing upon knowledge from the Nova crystal finishing development during the 1980`s and incorporating refinements from our efforts during 1995. In addition to describing a step-by-step process for diamond turning KDP, specific discussions are included on the necessary diamond tool geometry and edge sharpness, cutting fluid, and crystal preparation, handling, cleaning, and inspection. The authors presuppose that the reader is already familiar with diamond turning practices.

  9. Prospects of bipolar diamond devices

    NASA Astrophysics Data System (ADS)

    Aleksov, A.; Denisenko, A.; Kohn, E.

    2000-02-01

    The prospects of diamond bipolar devices are analysed theoretically and experimentally in respect to the problem of deep doping, especially the deep donor in diamond. For this purpose a set of p- n- p bipolar junction transistors (BJTs) is fabricated on p-type diamond substrates by epitaxial growth using boron ( EA=0.4 eV) and nitrogen ( ED=1.7 eV) as the p- and n-type dopants respectively. It is shown that at the boron/nitrogen junction a p- n junction is formed. The built-in potential of the junction is determined by the ionised boron/nitrogen impurities. The specific features of the fabricated devices are the high resistivity of the nitrogen doped base (10 GΩ·cm at 20°C) and a significant leakage current of the reverse biased p- n junctions. These factors limit the transistor action to d.c.-operation in the nA-current range and to temperatures below 200°C where leakage starts to dominate. The values of the static current gain IC/ IB are measured in the common base mode 200 and in the common emitter mode 1.1. The theoretical section of the paper deals with the calculation of the static current gain of diamond pnp transistor structures in dependence of the donor energy level, temperature and frequency. Both the theoretical and the experimental results indicate that diamond bipolar transistors with a nitrogen doped n-type base can exhibit a current gain β of up to 30,000 in the d.c.-regime provided the leakage of the p- n junctions is sufficiently low. High-gain diamond transistors operating in GHz-frequency can be expected as soon as n-doping by shallow donor like phosphorous ( ED<0.5 eV) becomes available.

  10. Ultratough single crystal boron-doped diamond

    DOEpatents

    Hemley, Russell J [Carnegie Inst. for Science, Washington, DC ; Mao, Ho-Kwang [Carnegie Inst. for Science, Washington, DC ; Yan, Chih-Shiue [Carnegie Inst. for Science, Washington, DC ; Liang, Qi [Carnegie Inst. for Science, Washington, DC

    2015-05-05

    The invention relates to a single crystal boron doped CVD diamond that has a toughness of at least about 22 MPa m.sup.1/2. The invention further relates to a method of manufacturing single crystal boron doped CVD diamond. The growth rate of the diamond can be from about 20-100 .mu.m/h.

  11. Diamond MEMS: wafer scale processing, devices, and technology insertion

    NASA Astrophysics Data System (ADS)

    Carlisle, J. A.

    2009-05-01

    Diamond has long held the promise of revolutionary new devices: impervious chemical barriers, smooth and reliable microscopic machines, and tough mechanical tools. Yet it's been an outsider. Laboratories have been effectively growing diamond crystals for at least 25 years, but the jump to market viability has always been blocked by the expense of diamond production and inability to integrate with other materials. Advances in chemical vapor deposition (CVD) processes have given rise to a hierarchy of carbon films ranging from diamond-like carbon (DLC) to vapor-deposited diamond coatings, however. All have pros and cons based on structure and cost, but they all share some of diamond's heralded attributes. The best performer, in theory, is the purest form of diamond film possible, one absent of graphitic phases. Such a material would capture the extreme hardness, high Young's modulus and chemical inertness of natural diamond. Advanced Diamond Technologies Inc., Romeoville, Ill., is the first company to develop a distinct chemical process to create a marketable phase-pure diamond film. The material, called UNCD® (for ultrananocrystalline diamond), features grain sizes from 3 to 300 nm in size, and layers just 1 to 2 microns thick. With significant advantages over other thin films, UNCD is designed to be inexpensive enough for use in atomic force microscopy (AFM) probes, microelectromechanical machines (MEMS), cell phone circuitry, radio frequency devices, and even biosensors.

  12. Growth, Characterization and Device Development in Monocrystalline Diamond Films

    DTIC Science & Technology

    1992-09-01

    AD-A256 283 Quarterly Letter Report Growth, Characterization and Device Development in Monocrystalline Diamond Films DT C * F LEC EGOT 2 1992L... Characterization and Device Development in s400003srrO8 Monocrystalline Diamond Films 1114SS 6. AUTHOR(S) N00179N66005 Robert F. Davis 4B855 7. PERFORMING...deposited on single crystal Si(100) substrates via in-situ carburization followed by bias-enhanced nucleation. Photoluminescence and Raman spectroscopy

  13. Diamond Pixel Detectors and 3D Diamond Devices

    NASA Astrophysics Data System (ADS)

    Venturi, N.

    2016-12-01

    Results from detectors of poly-crystalline chemical vapour deposited (pCVD) diamond are presented. These include the first analysis of data of the ATLAS Diamond Beam Monitor (DBM). The DBM module consists of pCVD diamond sensors instrumented with pixellated FE-I4 front-end electronics. Six diamond telescopes, each with three modules, are placed symmetrically around the ATLAS interaction point. The DBM tracking capabilities allow it to discriminate between particles coming from the interaction point and background particles passing through the ATLAS detector. Also, analysis of test beam data of pCVD DBM modules are presented. A new low threshold tuning algorithm based on noise occupancy was developed which increases the DBM module signal to noise ratio significantly. Finally first results from prototypes of a novel detector using pCVD diamond and resistive electrodes in the bulk, forming a 3D diamond device, are discussed. 3D devices based on pCVD diamond were successfully tested with test beams at CERN. The measured charge is compared to that of a strip detector mounted on the same pCVD diamond showing that the 3D device collects significantly more charge than the planar device.

  14. Microplasma device architectures with various diamond nanostructures

    NASA Astrophysics Data System (ADS)

    Kunuku, Srinivasu; Jothiramalingam Sankaran, Kamatchi; Leou, Keh-Chyang; Lin, I.-Nan

    2017-02-01

    Diamond nanostructures (DNSs) were fabricated from three different morphological diamonds, microcrystalline diamond (MCD), nanocrystalline diamond (NCD), and ultrananocrystalline diamond (UNCD) films, using a reactive ion etching method. The plasma illumination (PI) behavior of microplasma devices using the DNSs and the diamond films as cathode were investigated. The Paschen curve approach revealed that the secondary electron emission coefficient (γ value) of diamond materials is similar irrespective of the microstructure (MCD, NCD, and UNCD) and geometry of the materials (DNSs and diamond films). The diamond materials show markedly larger γ-coefficient than conventional metallic cathode materials such as Mo that resulted in markedly better PI behavior for the corresponding microplasma devices. Moreover, the PI behavior, i.e. the voltage dependence of plasma current density (J pl‑V), plasma density (n e‑V), and the robustness of the devices, varied markedly with the microstructure and geometry of the cathode materials that was closely correlated to the electron field emission (EFE) properties of the cathode materials. The UNCD nanopillars, possessing good EFE properties, resulted in superior PI behavior, whereas the MCD diamond films with insufficient EFE properties led to inferior PI behavior. Consequently, enhancement of plasma characteristics is the collective effects of EFE behavior and secondary electron emission characteristics of diamond-based cathode materials.

  15. Dynamic actuation of single-crystal diamond nanobeams

    SciTech Connect

    Sohn, Young-Ik; Burek, Michael J.; Lončar, Marko; Kara, Vural; Kearns, Ryan

    2015-12-14

    We show the dielectrophoretic actuation of single-crystal diamond nanomechanical devices. Gradient radio-frequency electromagnetic forces are used to achieve actuation of both cantilever and doubly clamped beam structures, with operation frequencies ranging from a few MHz to ∼50 MHz. Frequency tuning and parametric actuation are also studied.

  16. Liquid Crystal Devices.

    ERIC Educational Resources Information Center

    Bradshaw, Madeline J.

    1983-01-01

    The nature of liquid crystals and several important liquid crystal devices are described. Ideas for practical experiments to illustrate the properties of liquid crystals and their operation in devices are also described. (Author/JN)

  17. Single crystal diamond detector for radiotherapy

    NASA Astrophysics Data System (ADS)

    Schirru, F.; Kisielewicz, K.; Nowak, T.; Marczewska, B.

    2010-07-01

    The new generation of synthetic diamonds grown as a CVD single crystal on a high pressure high temperature substrate offers a wide range of applications. In particular, because of the near tissue equivalence and its small size (good spatial resolution), CVD single crystal diamond finds applicability in radiotherapy as a dosemeter of ionizing radiation. In this paper we report the electrical and dosimetric properties of a new diamond detector which was fabricated at IFJ based on a single crystal detector-grade CVD diamond provided with a novel contact metallization. Diamond properties were assessed at IFJ using a Theratron 680E therapeutic 60Co gamma rays unit and at COOK with 6 and 18 MV x-rays Varian Clinac CL2300 C/D accelerator. The new dosemeter showed high electric and dosimetric performances: low value of dark current, high current at the level of some nanoamperes during irradiation, very fast dynamic response with a rise time amounting to parts of a second, good stability and repeatability of the current and linearity of the detector signal at different dose and dose rate levels typically applied in radiotherapy. The results confirm the potential applicability of diamond material as a dosemeter for applications in radiotherapy.

  18. Ultratough CVD single crystal diamond and three dimensional growth thereof

    DOEpatents

    Hemley, Russell J.; Mao, Ho-kwang; Yan, Chih-shiue

    2009-09-29

    The invention relates to a single-crystal diamond grown by microwave plasma chemical vapor deposition that has a toughness of at least about 30 MPa m.sup.1/2. The invention also relates to a method of producing a single-crystal diamond with a toughness of at least about 30 MPa m.sup.1/2. The invention further relates to a process for producing a single crystal CVD diamond in three dimensions on a single crystal diamond substrate.

  19. Phononic crystal devices

    DOEpatents

    El-Kady, Ihab F [Albuquerque, NM; Olsson, Roy H [Albuquerque, NM

    2012-01-10

    Phononic crystals that have the ability to modify and control the thermal black body phonon distribution and the phonon component of heat transport in a solid. In particular, the thermal conductivity and heat capacity can be modified by altering the phonon density of states in a phononic crystal. The present invention is directed to phononic crystal devices and materials such as radio frequency (RF) tags powered from ambient heat, dielectrics with extremely low thermal conductivity, thermoelectric materials with a higher ratio of electrical-to-thermal conductivity, materials with phononically engineered heat capacity, phononic crystal waveguides that enable accelerated cooling, and a variety of low temperature application devices.

  20. Single crystal CVD diamond membranes for betavoltaic cells

    NASA Astrophysics Data System (ADS)

    Delfaure, C.; Pomorski, M.; de Sanoit, J.; Bergonzo, P.; Saada, S.

    2016-06-01

    A single crystal diamond large area thin membrane was assembled as a p-doped/Intrinsic/Metal (PIM) structure and used in a betavoltaic configuration. When tested with a 20 keV electron beam from a high resolution scanning electron microscope, we measured an open circuit voltage (Voc) of 1.85 V, a charge collection efficiency (CCE) of 98%, a fill-factor of 80%, and a total conversion efficiency of 9.4%. These parameters are inherently linked to the diamond membrane PIM structure that allows full device depletion even at 0 V and are among the highest reported up to now for any other material tested for betavoltaic devices. It enables to drive a high short-circuit current Isc up to 7.12 μA, to reach a maximum power Pmax of 10.48 μW, a remarkable value demonstrating the high-benefit of diamond for the realization of long-life radioisotope based micro-batteries.

  1. Thermal diffusion boron doping of single-crystal natural diamond

    NASA Astrophysics Data System (ADS)

    Seo, Jung-Hun; Wu, Henry; Mikael, Solomon; Mi, Hongyi; Blanchard, James P.; Venkataramanan, Giri; Zhou, Weidong; Gong, Shaoqin; Morgan, Dane; Ma, Zhenqiang

    2016-05-01

    With the best overall electronic and thermal properties, single crystal diamond (SCD) is the extreme wide bandgap material that is expected to revolutionize power electronics and radio-frequency electronics in the future. However, turning SCD into useful semiconductors requires overcoming doping challenges, as conventional substitutional doping techniques, such as thermal diffusion and ion implantation, are not easily applicable to SCD. Here we report a simple and easily accessible doping strategy demonstrating that electrically activated, substitutional doping in SCD without inducing graphitization transition or lattice damage can be readily realized with thermal diffusion at relatively low temperatures by using heavily doped Si nanomembranes as a unique dopant carrying medium. Atomistic simulations elucidate a vacancy exchange boron doping mechanism that occurs at the bonded interface between Si and diamond. We further demonstrate selectively doped high voltage diodes and half-wave rectifier circuits using such doped SCD. Our new doping strategy has established a reachable path toward using SCDs for future high voltage power conversion systems and for other novel diamond based electronic devices. The novel doping mechanism may find its critical use in other wide bandgap semiconductors.

  2. Enhancing the Mechanical Properties of Single-Crystal CVD Diamond

    SciTech Connect

    Liang, Q.; Yan, C; Meng, Y; Lai, J; Krasnicki, S; Mao, H; Hemley, R

    2009-01-01

    Approaches for enhancing the strength and toughness of single-crystal diamond produced by chemical vapor deposition (CVD) at high growth rates are described. CVD processes used to grow single-crystal diamond in high density plasmas were modified to incorporate boron and nitrogen. Semi-quantitative studies of mechanical properties were carried out using Vickers indentation techniques. The introduction of boron in single-crystal CVD diamond can significantly enhance the fracture toughness of this material without sacrificing its high hardness ({approx}78 GPa). Growth conditions were varied to investigate its effect on boron incorporation and optical properties by means of photoluminescence, infrared, and ultraviolet-visible absorption spectroscopy. Boron can be readily incorporated into single-crystal diamond by the methods used, but with nitrogen addition, the incorporation of boron was hindered. The spectroscopic measurements indicate that nitrogen and boron coexist in the diamond structure, which helps explain the origin of the enhanced fracture toughness of this material. Further, low pressure/high temperature annealing can enhance the intrinsic hardness of single-crystal CVD diamond by a factor of two without appreciable loss in fracture toughness. This doping and post-growth treatment of diamond may lead to new technological applications that require enhanced mechanical properties of diamond.

  3. Synthetic single crystal diamond diodes for radiotherapy dosimetry

    NASA Astrophysics Data System (ADS)

    Almaviva, S.; Marinelli, Marco; Milani, E.; Tucciarone, A.; Verona-Rinati, G.; Consorti, R.; Petrucci, A.; De Notaristefani, F.; Ciancaglioni, I.

    2008-09-01

    Synthetic single crystal diamonds in a p-type/intrinsic/metal structure were tested as dosimeters for radiotherapy. The devices have been analyzed by using 6 and 10 MV Bremsstrahlung X-ray beams and electron beams from 6 MeV up to 18 MeV from a CLINAC DHX Varian accelerator. All measurements have been performed in a water phantom and ionization chambers were used for calibration and comparison. The dosimeters were operated in photovoltaic regime with no external bias voltage applied. A few Gy pre-irradiation was performed in order to stabilize the device output, resulting in fluctuations sensitivity below ±0.5%. No dose rate dependence of the detector response was observed. Very good reproducibility and linearity were obtained as well.

  4. Ultrananocrystalline diamond contacts for electronic devices

    SciTech Connect

    Sumant, Anirudha V.; Smedley, John; Muller, Erik

    2016-11-01

    A method of forming electrical contacts on a diamond substrate comprises producing a plasma ball using a microwave plasma source in the presence of a mixture of gases. The mixture of gases include a source of a p-type or an n-type dopant. The plasma ball is disposed at a first distance from the diamond substrate. The diamond substrate is maintained at a first temperature. The plasma ball is maintained at the first distance from the diamond substrate for a first time, and a UNCD film, which is doped with at least one of a p-type dopant and an n-type dopant, is disposed on the diamond substrate. The doped UNCD film is patterned to define UNCD electrical contacts on the diamond substrate.

  5. Colloidal crystals with diamond symmetry at optical lengthscales.

    PubMed

    Wang, Yifan; Jenkins, Ian C; McGinley, James T; Sinno, Talid; Crocker, John C

    2017-02-13

    Future optical materials promise to do for photonics what semiconductors did for electronics, but the challenge has long been in creating the structure they require-a regular, three-dimensional array of transparent microspheres arranged like the atoms in a diamond crystal. Here we demonstrate a simple approach for spontaneously growing double-diamond (or B32) crystals that contain a suitable diamond structure, using DNA to direct the self-assembly process. While diamond symmetry crystals have been grown from much smaller nanoparticles, none of those previous methods suffice for the larger particles needed for photonic applications, whose size must be comparable to the wavelength of visible light. Intriguingly, the crystals we observe do not readily form in previously validated simulations; nor have they been predicted theoretically. This finding suggests that other unexpected microstructures may be accessible using this approach and bodes well for future efforts to inexpensively mass-produce metamaterials for an array of photonic applications.

  6. Colloidal crystals with diamond symmetry at optical lengthscales

    NASA Astrophysics Data System (ADS)

    Wang, Yifan; Jenkins, Ian C.; McGinley, James T.; Sinno, Talid; Crocker, John C.

    2017-02-01

    Future optical materials promise to do for photonics what semiconductors did for electronics, but the challenge has long been in creating the structure they require--a regular, three-dimensional array of transparent microspheres arranged like the atoms in a diamond crystal. Here we demonstrate a simple approach for spontaneously growing double-diamond (or B32) crystals that contain a suitable diamond structure, using DNA to direct the self-assembly process. While diamond symmetry crystals have been grown from much smaller nanoparticles, none of those previous methods suffice for the larger particles needed for photonic applications, whose size must be comparable to the wavelength of visible light. Intriguingly, the crystals we observe do not readily form in previously validated simulations; nor have they been predicted theoretically. This finding suggests that other unexpected microstructures may be accessible using this approach and bodes well for future efforts to inexpensively mass-produce metamaterials for an array of photonic applications.

  7. Colloidal crystals with diamond symmetry at optical lengthscales

    PubMed Central

    Wang, Yifan; Jenkins, Ian C.; McGinley, James T.; Sinno, Talid; Crocker, John C.

    2017-01-01

    Future optical materials promise to do for photonics what semiconductors did for electronics, but the challenge has long been in creating the structure they require—a regular, three-dimensional array of transparent microspheres arranged like the atoms in a diamond crystal. Here we demonstrate a simple approach for spontaneously growing double-diamond (or B32) crystals that contain a suitable diamond structure, using DNA to direct the self-assembly process. While diamond symmetry crystals have been grown from much smaller nanoparticles, none of those previous methods suffice for the larger particles needed for photonic applications, whose size must be comparable to the wavelength of visible light. Intriguingly, the crystals we observe do not readily form in previously validated simulations; nor have they been predicted theoretically. This finding suggests that other unexpected microstructures may be accessible using this approach and bodes well for future efforts to inexpensively mass-produce metamaterials for an array of photonic applications. PMID:28194025

  8. Nanostructured Diamond Device for Biomedical Applications.

    PubMed

    Fijalkowski, M; Karczemska, A; Lysko, J M; Zybala, R; KozaneckI, M; Filipczak, P; Ralchenko, V; Walock, M; Stanishevsky, A; Mitura, S

    2015-02-01

    Diamond is increasingly used in biomedical applications because of its unique properties such as the highest thermal conductivity, good optical properties, high electrical breakdown voltage as well as excellent biocompatibility and chemical resistance. Diamond has also been introduced as an excellent substrate to make the functional microchip structures for electrophoresis, which is the most popular separation technique for the determination of analytes. In this investigation, a diamond electrophoretic chip was manufactured by a replica method using a silicon mold. A polycrystalline 300 micron-thick diamond layer was grown by the microwave plasma-assisted CVD (MPCVD) technique onto a patterned silicon substrate followed by the removal of the substrate. The geometry of microstructure, chemical composition, thermal and optical properties of the resulting free-standing diamond electrophoretic microchip structure were examined by CLSM, SFE, UV-Vis, Raman, XRD and X-ray Photoelectron Spectroscopy, and by a modified laser flash method for thermal property measurements.

  9. Electronic devices from diamond-like carbon

    NASA Astrophysics Data System (ADS)

    Milne, W. I.

    2003-03-01

    This paper reviews the work carried out over the past few years on the application of diamond-like carbon (DLC) materials to electronic devices. The use of such materials is still in its infancy due to their high defect state density and associated low mobilities. To date, the major effort in the electronic field has been in their attempted use as cold cathode field emitters where their low threshold field has attracted much attention. However, attempts have also been made to produce metal semiconductor metal structures, diodes, a-C/c-Si heterostructures and thin film transistors with varying degrees of success. A brief review of work carried out on the use of DLCs in solar cell manufacture will also be presented but it seems at this early stage in their development that the most promising area for future development will be in the field of microelectromechanical structures where their friction, stiction and wear properties make them prime candidates for use in moving mechanical assemblies.

  10. Luminescent properties of diamond single crystals of pyramidal shape

    NASA Astrophysics Data System (ADS)

    Alekseev, A. M.; Tuyakova, F. T.; Obraztsova, E. A.; Korostylev, E. V.; Klinov, D. V.; Prusakov, K. A.; Malykhin, S. A.; Ismagilov, R. R.; Obraztsov, A. N.

    2016-11-01

    The luminescence properties of needle-like crystals of diamond, obtained by selective oxidation of textured polycrystalline diamond films, are studied. Diamond films were grown by chemical vapor deposition from a methane-hydrogen mixture activated by a DC discharge. The spectra of photo- and cathodoluminescence and the spatial distribution of the intensity of radiation at different wavelengths are obtained for individual needle-like crystals. Based on the spectral characteristics, conclusions are made about the presence of optically active defects containing nitrogen and silicon impurities in their structure, as well as the significant effect of structural defects on their luminescence spectra.

  11. X-ray beam monitor made by thin-film CVD single-crystal diamond.

    PubMed

    Marinelli, Marco; Milani, E; Prestopino, G; Verona, C; Verona-Rinati, G; Angelone, M; Pillon, M; Kachkanov, V; Tartoni, N; Benetti, M; Cannatà, D; Di Pietrantonio, F

    2012-11-01

    A novel beam position monitor, operated at zero bias voltage, based on high-quality chemical-vapor-deposition single-crystal Schottky diamond for use under intense synchrotron X-ray beams was fabricated and tested. The total thickness of the diamond thin-film beam monitor is about 60 µm. The diamond beam monitor was inserted in the B16 beamline of the Diamond Light Source synchrotron in Harwell (UK). The device was characterized under monochromatic high-flux X-ray beams from 6 to 20 keV and a micro-focused 10 keV beam with a spot size of approximately 2 µm × 3 µm square. Time response, linearity and position sensitivity were investigated. Device response uniformity was measured by a raster scan of the diamond surface with the micro-focused beam. Transmissivity and spectral responsivity versus beam energy were also measured, showing excellent performance of the new thin-film single-crystal diamond beam monitor.

  12. Some Properties Of Synthetic Single Crystal And Thin Film Diamonds

    NASA Astrophysics Data System (ADS)

    Yazu, Shuji; Sato, Shuichi; Fujimori, Naoji

    1989-01-01

    Large synthetic diamond single crystals, in sizes up to 1.4 ct, are produced on 4 commercial basis for some industrial application fields by Sumitomo Electric. The crystals are yellow colored type Ib stones which contain lower amounts of nitrogen (up to about 100 ppm) dispersed through the crystal structure in the form of singly substituting atoms. The impurity controlled type lb crystals have the highest thermal conductivity which is equivalent to that of pure type IIa crystals. Optical and thermal properties of diamond crystals are strongly affected by dispersed impurities. We studied the kinds of dispersed impurities and amounts of those impurity atoms in our synthesized crystals by SIMS. A relation of the thermal conductivities and the nitrogen concentrations of the crystals was examined. The state of nitrogen impurity in the crystals could be transformed by electron irradiation and subsequent high temperature annealing. The reaction rates for the transformation Ib nitrogen to type IaA aggregates and differences in crystal growth sectors have been studied. Vapor phase deposited diamond films are hopeful candidates for optical application of diamond. Preliminary spectroscopic analysis has been done for the free standing polycrystalline films.

  13. Single Crystal Diamond Needle as Point Electron Source

    PubMed Central

    Kleshch, Victor I.; Purcell, Stephen T.; Obraztsov, Alexander N.

    2016-01-01

    Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2–0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics. PMID:27731379

  14. Single Crystal Diamond Needle as Point Electron Source

    NASA Astrophysics Data System (ADS)

    Kleshch, Victor I.; Purcell, Stephen T.; Obraztsov, Alexander N.

    2016-10-01

    Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2–0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

  15. Metal films on the surfaces and within diamond crystals from Arkhangelskaya and Yakutian diamond provinces

    NASA Astrophysics Data System (ADS)

    Makeev, A. B.; Kriulina, G. Yu.

    2012-12-01

    Representative samples of diamonds from five kimberlite pipes (Lomonosovskaya, Archangel'sk, Snegurochka, XXIII Congress of the Communist Party of the Soviet Union (CPSU), and Internationalnaya) of the Arkhangelskaya and Yakutian diamond provinces in Russia have been studied. Thirty-three varieties of metal films have been identified as syngenetic associated minerals. The films consist of 15 chemical elements that occur in the form of native metals and their natural alloys. Remnants of metal films were detected within diamond crystals. The metal films coating diamonds are a worldwide phenomenon. To date, these films have been described from Europe, Asia, South America, and Africa. Native metals, their alloys, and intermetallides are actual companion minerals of diamond.

  16. Implanted contacts for diamond semiconductor devices

    NASA Astrophysics Data System (ADS)

    Tan, Soo-Hee; Beetz, C. P., Jr.

    1992-01-01

    The key to future diamond semiconductor development are ohmic and Schottky contacts that are stable at high temperatures. Wide bandgap materials, such as diamond (5.5 eV), pose special problems and demand ingenious solutions. Prior to our work, recent research into stable ohmic and Schottky contacts had been primarily limited to e-beam evaporation of carbide forming metals such as Ti, Ta, and Mo. These approaches have been relatively successful at decreasing the specific contact resistivity to as low as 10(exp -5) ohm sq cm on natural semiconducting diamond with about 10(exp 16) boron atoms/cubic cm. In our Phase 1 SBIR program we investigated metal systems coupled with a shallow Si implant that would form low resistivity, high temperature stable metal silicides. We showed in our Phase 1 results that the barrier height of metals such as Pt, Ti and Mo were reduced when deposited on shallow Si implants and given a heat treatment at 500 C. The barrier height of Pt on diamond was reduced from 1.89 to 0.97 eV by annealing of a sputtered Pt contact on a Si implanted dose of 10(exp 15) cm(exp -2) sq A into the diamond surface. Using the same approach, the barrier height of Ti on diamond was reduced from 2.00 to 1.29 eV.

  17. Structural peculiarities of single crystal diamond needles of nanometer thickness

    NASA Astrophysics Data System (ADS)

    Orekhov, Andrey S.; Tuyakova, Feruza T.; Obraztsova, Ekaterina A.; Loginov, Artem B.; Chuvilin, Andrey L.; Obraztsov, Alexander N.

    2016-11-01

    Diamond is attractive for various applications due to its unique mechanical and optical properties. In particular, single crystal diamond needles with high aspect ratios and sharp apexes of nanometer size are demanded for different types of optical sensors including optically sensing tip probes for scanning microscopy. This paper reports on electron microscopy and Raman spectroscopy characterization of the diamond needles having geometrically perfect pyramidal shapes with rectangular atomically flat bases with (001) crystallography orientation, 2-200 nm sharp apexes, and with lengths from about 10-160 μm. The needles were produced by selective oxidation of (001) textured polycrystalline diamond films grown by chemical vapor deposition. Here we study the types and distribution of defects inside and on the surface of the single crystal diamond needles. We show that sp3 type point defects are incorporated into the volume of the diamond crystal during growth, while the surface of the lateral facets is enriched by multiple extended defects. Nitrogen addition to the reaction mixture results in increase of the growth rate on {001} facets correlated with the rise in the concentration of sp3 type defects.

  18. Mechanism for diamond nucleation and growth on single crystal copper surfaces implanted with carbon

    NASA Technical Reports Server (NTRS)

    Ong, T. P.; Xiong, Fulin; Chang, R. P. H.; White, C. W.

    1992-01-01

    The nucleation and growth of diamond crystals on single-crystal copper surfaces implanted with carbon ions is studied. Microwave plasma-enhanced chemical-vapor deposition is used for diamond growth. The single-crystal copper substrates were implanted either at room or elevated temperature with carbon ions prior to diamond nucleation. This procedure leads to the formation of a graphite film on the copper surface which greatly enhances diamond crystallite nucleation. A simple lattice model is constructed for diamond growth on graphite as 111 line (diamond) parallel to 0001 line (graphite) and 110 line (diamond) parallel to 1 1 -2 0 (graphite).

  19. Free-standing nanomechanical and nanophotonic structures in single-crystal diamond

    NASA Astrophysics Data System (ADS)

    Burek, Michael John

    Realizing complex three-dimensional structures in a range of material systems is critical to a variety of emerging nanotechnologies. This is particularly true of nanomechanical and nanophotonic systems, both relying on free-standing small-scale components. In the case of nanomechanics, necessary mechanical degrees of freedom require physically isolated structures, such as suspended beams, cantilevers, and membranes. For nanophotonics, elements like waveguides and photonic crystal cavities rely on light confinement provided by total internal reflection or distributed Bragg reflection, both of which require refractive index contrast between the device and surrounding medium (often air). Such suspended nanostructures are typically fabricated in a heterolayer structure, comprising of device (top) and sacrificial (middle) layers supported by a substrate (bottom), using standard surface nanomachining techniques. A selective, isotropic etch is then used to remove the sacrificial layer, resulting in free-standing devices. While high-quality, crystalline, thin film heterolayer structures are readily available for silicon (as silicon-on-insulator (SOI)) or III-V semiconductors (i.e. GaAs/AlGaAs), there remains an extensive list of materials with attractive electro-optic, piezoelectric, quantum optical, and other properties for which high quality single-crystal thin film heterolayer structures are not available. These include complex metal oxides like lithium niobate (LiNbO3), silicon-based compounds such as silicon carbide (SiC), III-V nitrides including gallium nitride (GaN), and inert single-crystals such as diamond. Diamond is especially attractive for a variety of nanoscale technologies due to its exceptional physical and chemical properties, including high mechanical hardness, stiffness, and thermal conductivity. Optically, it is transparent over a wide wavelength range (from 220 nm to the far infrared), has a high refractive index (n ~ 2.4), and is host to a vast

  20. Self-assembling hybrid diamond-biological quantum devices

    NASA Astrophysics Data System (ADS)

    Albrecht, A.; Koplovitz, G.; Retzker, A.; Jelezko, F.; Yochelis, S.; Porath, D.; Nevo, Y.; Shoseyov, O.; Paltiel, Y.; Plenio, M. B.

    2014-09-01

    The realization of scalable arrangements of nitrogen vacancy (NV) centers in diamond remains a key challenge on the way towards efficient quantum information processing, quantum simulation and quantum sensing applications. Although technologies based on implanting NV-centers in bulk diamond crystals or hybrid device approaches have been developed, they are limited by the achievable spatial resolution and by the intricate technological complexities involved in achieving scalability. We propose and demonstrate a novel approach for creating an arrangement of NV-centers, based on the self-assembling capabilities of biological systems and their beneficial nanometer spatial resolution. Here, a self-assembled protein structure serves as a structural scaffold for surface functionalized nanodiamonds, in this way allowing for the controlled creation of NV-structures on the nanoscale and providing a new avenue towards bridging the bio-nano interface. One-, two- as well as three-dimensional structures are within the scope of biological structural assembling techniques. We realized experimentally the formation of regular structures by interconnecting nanodiamonds using biological protein scaffolds. Based on the achievable NV-center distances of 11 nm, we evaluate the expected dipolar coupling interaction with neighboring NV-centers as well as the expected decoherence time. Moreover, by exploiting these couplings, we provide a detailed theoretical analysis on the viability of multiqubit quantum operations, suggest the possibility of individual addressing based on the random distribution of the NV intrinsic symmetry axes and address the challenges posed by decoherence and imperfect couplings. We then demonstrate in the last part that our scheme allows for the high-fidelity creation of entanglement, cluster states and quantum simulation applications.

  1. Growth, Characterization and Device Development in Monocrystalline Diamond Films

    DTIC Science & Technology

    1990-09-30

    silicon substrate surfaces. The aspect ratio of diamond grown on single crystals of different substrate materials correlates with their surface free ...to check the feasibility of such considerations for the present research. The surface free energy of diamond is estimated to be 3387 ergs/cm 2, [Il...while the surface free energies of Si, Ni, Mo, Ta, and W are 1457 ergs/cm2 , 2072 ergs/cm 2, 2463 ergs/cm 2 , 2628 ergs/cm 2 and 3111 ergs/cm 2

  2. Radiation-induced diamond crystallization: Origin of carbonados and its implications on meteorite nano-diamonds

    USGS Publications Warehouse

    Ozima, M.; Tatsumoto, M.

    1997-01-01

    Ten carbonados from Central Africa were studied for U-Th-Pb systematics. To extract U, Th, and Pb from the samples, we developed a cold combustion technique wherein diamond was burnt in liquid oxygen. The technique gave low blanks; 25-50 pg for Pb, 3 pg for U, and 5 pg for Th. After very thorough acid treatments of the carbonados with hot HNO3, HF, and HCl over one week, most of U, Th, and Pb were removed from the samples. Lead in the acid-leached diamonds was highly radiogenic (206Pb/204Pb up to 470). However, the amounts of U and Th in the acid-leached diamonds are too low to account for the radiogenic Pb even if we assume 4.5 Ga for the age of the diamonds. Therefore, we conclude that the radiogenic Pb was implanted into the diamonds from surroundings by means of recoil energy of radioactive decays of U and Th. From the radiogenic lead isotopic composition, we estimate a minimum age of 2.6 Ga and a maximum age of 3.8 Ga for the formation of the carbonados. The above findings of the implantation of recoiled radiogenic Pb into carbonados is consistent with the process of radiation-induced crystallization which was proposed for carbonado by Kaminsky (1987). We show from some theoretical considerations that when highly energetic particles, such as those emitted from radioactive decay of U and Th, interact with carbonaceous materials, they give rise to cascades of atomic disturbance (over regions of about a few nanometer), and the disturbed atoms are likely to recrystallize to form micro-diamonds because of increasing surface energy due to small size. The radiation-induced diamond formation mechanism may be relevant to the origin of nano-diamonds in primitive meteorites. Copyright ?? 1997 Elsevier Science Ltd.

  3. Polycrystalline CVD diamond device level modeling for particle detection applications

    NASA Astrophysics Data System (ADS)

    Morozzi, A.; Passeri, D.; Kanxheri, K.; Servoli, L.; Lagomarsino, S.; Sciortino, S.

    2016-12-01

    Diamond is a promising material whose excellent physical properties foster its use for radiation detection applications, in particular in those hostile operating environments where the silicon-based detectors behavior is limited due to the high radiation fluence. Within this framework, the application of Technology Computer Aided Design (TCAD) simulation tools is highly envisaged for the study, the optimization and the predictive analysis of sensing devices. Since the novelty of using diamond in electronics, this material is not included in the library of commercial, state-of-the-art TCAD software tools. In this work, we propose the development, the application and the validation of numerical models to simulate the electrical behavior of polycrystalline (pc)CVD diamond conceived for diamond sensors for particle detection. The model focuses on the characterization of a physically-based pcCVD diamond bandgap taking into account deep-level defects acting as recombination centers and/or trap states. While a definite picture of the polycrystalline diamond band-gap is still debated, the effect of the main parameters (e.g. trap densities, capture cross-sections, etc.) can be deeply investigated thanks to the simulated approach. The charge collection efficiency due to β -particle irradiation of diamond materials provided by different vendors and with different electrode configurations has been selected as figure of merit for the model validation. The good agreement between measurements and simulation findings, keeping the traps density as the only one fitting parameter, assesses the suitability of the TCAD modeling approach as a predictive tool for the design and the optimization of diamond-based radiation detectors.

  4. Diamond and Carbon Nanotube Composites for Supercapacitor Devices

    NASA Astrophysics Data System (ADS)

    Moreira, João Vitor Silva; May, Paul William; Corat, Evaldo José; Peterlevitz, Alfredo Carlos; Pinheiro, Romário Araújo; Zanin, Hudson

    2017-02-01

    We report on the synthesis and electrochemical properties of diamond grown onto vertically aligned carbon nanotubes with high surface areas as a template, resulting in a composite material exhibiting high double-layer capacitance as well as low electrochemical impedance electrodes suitable for applications as supercapacitor devices. We contrast results from devices fabricated with samples which differ in both their initial substrates (Si and Ti) and their final diamond coatings, such as boron-doped diamond and diamond-like carbon (DLC). We present for first time a conducting model for non-doped DLC thin-films. All samples were characterized by scanning and transmission electron microscopy and Fourier transform infrared and Raman spectroscopy. Our results show specific capacitance as high as 8.25 F g-1 (˜1 F cm-2) and gravimetric specific energy and power as high as 0.7 W h kg-1 and 176.4 W kg-1, respectively, which suggest that these diamond/carbon nanotube composite electrodes are excellent candidates for supercapacitor fabrication.

  5. Single crystal diamond for infrared sensing applications

    SciTech Connect

    Majdi, S. Kovi, K. K.; Isberg, J.; Kolahdouz, M.; Moeen, M.; Radamson, H. H.; Balmer, R. S.

    2014-10-20

    The synthesis of new materials for thermal infrared (IR) detection has been an intensive research area in recent years. Among new semiconductor materials, synthetic diamond has the ability to function even under very high temperature and high radiation conditions. In the present work, diamond Schottky diodes with boron concentrations in the range of 10{sup 14 }< B < 10{sup 17 }cm{sup −3} are presented as candidates for IR thermal sensors with an excellent temperature coefficient of resistance (−8.42%/K) and very low noise levels around 6.6 × 10{sup −15} V{sup 2}/Hz. This enables huge performance enhancements for a wide variety of systems, e.g., automotive and space applications.

  6. Silica based polishing of {100} and {111} single crystal diamond

    PubMed Central

    Thomas, Evan L H; Mandal, Soumen; Brousseau, Emmanuel B; Williams, Oliver A

    2014-01-01

    Diamond is one of the hardest and most difficult to polish materials. In this paper, the polishing of {111} and {100} single crystal diamond surfaces by standard chemical mechanical polishing, as used in the silicon industry, is demonstrated. A Logitech Tribo Chemical Mechanical Polishing system with Logitech SF1 Syton and a polyurethane/polyester polishing pad was used. A reduction in roughness from 0.92 to 0.23 nm root mean square and 0.31 to 0.09 nm rms for {100} and {111} samples respectively was observed. PMID:27877689

  7. Diamond turning of Si and Ge single crystals

    SciTech Connect

    Blake, P.; Scattergood, R.O.

    1988-12-01

    Single-point diamond turning studies have been completed on Si and Ge crystals. A new process model was developed for diamond turning which is based on a critical depth of cut for plastic flow-to-brittle fracture transitions. This concept, when combined with the actual machining geometry for single-point turning, predicts that {open_quotes}ductile{close_quotes} machining is a combined action of plasticity and fracture. Interrupted cutting experiments also provide a meant to directly measure the critical depth parameter for given machining conditions.

  8. Spontaneous synthesis of diamond crystals from graphite irradiated by {gamma} rays

    SciTech Connect

    Dutov, A. G.; Azarko, I. I. Kozlova, E. I.; Komar, V. A.; Kurilovich, N. F.; Shipilo, V. B.; Shipilo, N. V.

    2006-01-15

    The model of martensite transition of graphite to diamond (specifically, the mechanism of inheritance of the properties of radiation-modified graphite by synthesized diamond crystals) is confirmed experimentally.

  9. Large-area low-temperature ultrananocrystaline diamond (UNCD) films and integration with CMOS devices for monolithically integrated diamond MEMD/NEMS-CMOS systems.

    SciTech Connect

    Sumant, A.V.; Auciello, O.; Yuan, H.-C; Ma, Z.; Carpick, R. W.; Mancini, D. C.; Univ. of Wisconsin; Univ. of Pennsylvania

    2009-05-01

    Because of exceptional mechanical, chemical, and tribological properties, diamond has a great potential to be used as a material for the development of high-performance MEMS and NEMS such as resonators and switches compatible with harsh environments, which involve mechanical motion and intermittent contact. Integration of such MEMS/NEMS devices with complementary metal oxide semiconductor (CMOS) microelectronics will provide a unique platform for CMOS-driven commercial MEMS/NEMS. The main hurdle to achieve diamond-CMOS integration is the relatively high substrate temperatures (600-800 C) required for depositing conventional diamond thin films, which are well above the CMOS operating thermal budget (400 C). Additionally, a materials integration strategy has to be developed to enable diamond-CMOS integration. Ultrananocrystalline diamond (UNCD), a novel material developed in thin film form at Argonne, is currently the only microwave plasma chemical vapor deposition (MPCVD) grown diamond film that can be grown at 400 C, and still retain exceptional mechanical, chemical, and tribological properties comparable to that of single crystal diamond. We have developed a process based on MPCVD to synthesize UNCD films on up to 200 mm in diameter CMOS wafers, which will open new avenues for the fabrication of monolithically integrated CMOS-driven MEMS/NEMS based on UNCD. UNCD films were grown successfully on individual Si-based CMOS chips and on 200 mm CMOS wafers at 400 C in a MPCVD system, using Ar-rich/CH4 gas mixture. The CMOS devices on the wafers were characterized before and after UNCD deposition. All devices were performing to specifications with very small degradation after UNCD deposition and processing. A threshold voltage degradation in the range of 0.08-0.44V and transconductance degradation in the range of 1.5-9% were observed.

  10. Analysis of synthetic diamond single crystals by X-ray topography and double-crystal diffractometry

    SciTech Connect

    Prokhorov, I. A.; Ralchenko, V. G.; Bolshakov, A. P.; Polskiy, A. V.; Vlasov, A. V.; Subbotin, I. A.; Podurets, K. M.; Pashaev, E. M.; Sozontov, E. A.

    2013-12-15

    Structural features of diamond single crystals synthesized under high pressure and homoepitaxial films grown by chemical vapor deposition (CVD) have been analyzed by double-crystal X-ray diffractometry and topography. The conditions of a diffraction analysis of diamond crystals using Ge monochromators have been optimized. The main structural defects (dislocations, stacking faults, growth striations, second-phase inclusions, etc.) formed during crystal growth have been revealed. The nitrogen concentration in high-pressure/high-temperature (HPHT) diamond substrates is estimated based on X-ray diffraction data. The formation of dislocation bundles at the film-substrate interface in the epitaxial structures has been revealed by plane-wave topography; these dislocations are likely due to the relaxation of elastic macroscopic stresses caused by the lattice mismatch between the substrate and film. The critical thicknesses of plastic relaxation onset in CVD diamond films are calculated. The experimental techniques for studying the real diamond structure in optimizing crystal-growth technology are proven to be highly efficient.

  11. Single Crystal Diamond Beam Position Monitors with Radiofrequency Electronic Readout

    SciTech Connect

    Solar, B.; Graafsma, H.; Potdevin, G.; Trunk, U.; Morse, J.; Salome, M.

    2010-06-23

    Over the energy range 5{approx}30 keV a suitably contacted, thin ({approx}100 {mu}m) diamond plate can be operated in situ as a continuous monitor of X-ray beam intensity and position as the diamond absorbs only a small percentage of the incident beam. Single crystal diamond is a completely homogeneous material showing fast (ns), spatially uniform signal response and negligible (diamond beam position monitors of simple quadrant electrode designs with metal contacts, operated using wideband electronic readout corresponding to the RF accelerator frequency. The instrumentation for these monitors must cover a large range of operating conditions: different beam sizes, fluxes, energies and time structure corresponding to the synchrotron fill patterns. Sophisticated new RF sampling electronics can satisfy most requirements: using a modified Libera Brilliance readout system, we measured the center of gravity position of a 25 {mu}m beam at the DORIS III F4 beam line at a rate of 130 Msample/s with narrowband filtering of a few MHz bandwidth. Digitally averaging the signal further provided a spatial resolution {approx}20 nm.

  12. Low propagation loss in a one-port SAW resonator fabricated on single-crystal diamond for super-high-frequency applications.

    PubMed

    Fujii, Satoshi; Odawara, Tatsuya; Yamada, Haruya; Omori, Tatsuya; Hashimoto, Ken-Ya; Torii, Hironori; Umezawa, Hitoshi; Shikata, Shinichi

    2013-05-01

    Diamond has the highest known SAW phase velocity, sufficient for applications in the gigahertz range. However, although numerous studies have demonstrated SAW devices on polycrystalline diamond thin films, all have had much larger propagation loss than single-crystal materials such as LiNbO3. Hence, in this study, we fabricated and characterized one-port SAW resonators on single-crystal diamond substrates synthesized using a high-pressure and high-temperature method to identify and minimize sources of propagation loss. A series of one-port resonators were fabricated with the interdigital transducer/ AlN/diamond structure and their characteristics were measured. The device with the best performance exhibited a resonance frequency f of 5.3 GHz, and the equivalent circuit model gave a quality factor Q of 5509. Thus, a large fQ product of approximately 2.9 × 10(13) was obtained, and the propagation loss was found to be only 0.006 dB/wavelength. These excellent properties are attributed mainly to the reduction of scattering loss in a substrate using a single-crystal diamond, which originated from the grain boundary of diamond and the surface roughness of the AlN thin film and the diamond substrate. These results show that single-crystal diamond SAW resonators have great potential for use in low-noise super-high-frequency oscillators.

  13. Scalable fabrication of high-quality, ultra-thin single crystal diamond membrane windows

    NASA Astrophysics Data System (ADS)

    Piracha, Afaq Habib; Ganesan, Kumaravelu; Lau, Desmond W. M.; Stacey, Alastair; McGuinness, Liam P.; Tomljenovic-Hanic, Snjezana; Prawer, Steven

    2016-03-01

    High quality, ultra-thin single crystal diamond (SCD) membranes that have a thickness in the sub-micron range are of extreme importance as a materials platform for photonics, quantum sensing, nano/micro electro-mechanical systems (N/MEMS) and other diverse applications. However, the scalable fabrication of such thin SCD membranes is a challenging process. In this paper, we demonstrate a new method which enables high quality, large size (~4 × 4 mm) and low surface roughness, low strain, ultra-thin SCD membranes which can be fabricated without deformations such as breakage, bowing or bending. These membranes are easy to handle making them particularly suitable for fabrication of optical and mechanical devices. We demonstrate arrays of single crystal diamond membrane windows (SCDMW), each up to 1 × 1 mm in dimension and as thin as ~300 nm, supported by a diamond frame as thick as ~150 μm. The fabrication method is robust, reproducible, scalable and cost effective. Microwave plasma chemical vapour deposition is used for in situ creation of single nitrogen-vacancy (NV) centers into the thin SCDMW. We have also developed SCD drum head mechanical resonator composed of our fully clamped and freely suspended membranes.High quality, ultra-thin single crystal diamond (SCD) membranes that have a thickness in the sub-micron range are of extreme importance as a materials platform for photonics, quantum sensing, nano/micro electro-mechanical systems (N/MEMS) and other diverse applications. However, the scalable fabrication of such thin SCD membranes is a challenging process. In this paper, we demonstrate a new method which enables high quality, large size (~4 × 4 mm) and low surface roughness, low strain, ultra-thin SCD membranes which can be fabricated without deformations such as breakage, bowing or bending. These membranes are easy to handle making them particularly suitable for fabrication of optical and mechanical devices. We demonstrate arrays of single crystal diamond

  14. Very High Efficiency, Miniaturized, Long-Lived Alpha Particle Power Source Using Diamond Devices for Extreme Space Environments

    NASA Technical Reports Server (NTRS)

    Kolawa, Elizabeth A. (Inventor); Patel, Jagdishbhai U. (Inventor); Fleurial, Jean-Pierre (Inventor)

    2004-01-01

    A power source that converts a-particle energy into electricity by coulomb collision in doped diamond films is described. Alpha particle decay from curium-244 creates electron-hole pairs by free- ing electrons and holes inside the crystal lattice in N- and P-doped diamond films. Ohmic contacts provide electrical connection to an electronic device. Due to the built-in electric field at the rectifying junction across the hT- and P-doped diamond films, the free electrons are constrained to traveling in generally one direction. This one direction then supplies electrons in a manner similar to that of a battery. The radioactive curium layer may be disposed on diamond films for even distribution of a-particle radiation. The resulting power source may be mounted on a diamond substrate that serves to insulate structures below the diamond substrate from a-particle emission. Additional insulation or isolation may be provided in order to prevent damage from a-particle collision. N-doped silicon may be used instead of N-doped diamond.

  15. Brilliant camouflage: photonic crystals in the diamond weevil, Entimus imperialis.

    PubMed

    Wilts, Bodo D; Michielsen, Kristel; Kuipers, Jeroen; De Raedt, Hans; Stavenga, Doekele G

    2012-07-07

    The neotropical diamond weevil, Entimus imperialis, is marked by rows of brilliant spots on the overall black elytra. The spots are concave pits with intricate patterns of structural-coloured scales, consisting of large domains of three-dimensional photonic crystals that have a diamond-type structure. Reflectance spectra measured from individual scale domains perfectly match model spectra, calculated with anatomical data and finite-difference time-domain methods. The reflections of single domains are extremely directional (observed with a point source less than 5°), but the special arrangement of the scales in the concave pits significantly broadens the angular distribution of the reflections. The resulting virtually angle-independent green coloration of the weevil closely approximates the colour of a foliaceous background. While the close-distance colourful shininess of E. imperialis may facilitate intersexual recognition, the diffuse green reflectance of the elytra when seen at long-distance provides cryptic camouflage.

  16. A neutron sensor based on synthetic single crystal diamond

    SciTech Connect

    Schmid, G J; Koch, J A; Lerche, R A; Moran, M J

    2003-10-17

    We report the first neutron data for a single crystal Chemical Vapor Deposition (CVD) diamond sensor. Results are presented for 2.5, 14.1, and 14.9 MeV incident neutrons. We show that the energy resolution for 14.1 MeV neutrons is at least 2.9% (as limited by the energy spread of the incident neutrons), and perhaps as good as 0.4% (as extrapolated from high resolution {alpha} particle data). This result could be relevant to fusion neutron spectroscopy at machines like the International Thermonuclear Experimental Reactor (ITER). We also show that our sensor has a high neutron linear attenuation coefficient, due to the high atomic density of diamond, and this could lead to applications in fission neutron detection.

  17. Surface structures of high-quality diamond crystals synthesized by the oxy-acetylene flame method

    NASA Astrophysics Data System (ADS)

    Hirabayashi, Keiji; Amanuma, Shuji; Hirose, Yoichi

    1992-02-01

    The microstructures of the {111} surfaces of high-quality diamond crystals deposited by the oxy-acetylene flame method have been studied using a high-resolution scanning electron microscope to clear the mechanism of the crystal growth. On the {111} surfaces of the high-quality diamond crystals, the two-dimensional nucleation rate is suppressed and the two-dimensional crystal growth rate is promoted. The suppression of the two-dimensional nucleation rate and the promotion of the two-dimensional crystal growth rate reduce the number of faults, dislocations, and defects and result in the formation of high-quality diamond crystals.

  18. Modeling liquid crystal polymeric devices

    NASA Astrophysics Data System (ADS)

    Gimenez Pinto, Vianney Karina

    The main focus of this work is the theoretical and numerical study of materials that combine liquid crystal and polymer. Liquid crystal elastomers are polymeric materials that exhibit both the ordered properties of the liquid crystals and the elastic properties of rubbers. Changing the order of the liquid crystal molecules within the polymer network can induce shape change. These materials are very valuable for applications such as actuators, sensors, artificial muscles, haptic displays, etc. In this work we apply finite element elastodynamics simulations to study the temperature induced shape deformation in nematic elastomers with complex director microstructure. In another topic, we propose a novel numerical method to model the director dynamics and microstructural evolution of three dimensional nematic and cholesteric liquid crystals. Numerical studies presented in this work are in agreement with experimental observations and provide insight into the design of application devices.

  19. Multistrip synthetic single-crystal-diamond photodiode based on a p-type/intrinsic/Schottky metal transverse configuration

    NASA Astrophysics Data System (ADS)

    Ciancaglioni, I.; Marinelli, Marco; Milani, E.; Prestopino, G.; Verona, C.; Verona-Rinati, G.; Angelone, M.; Pillon, M.; Dolbnya, I.; Sawhney, K.; Tartoni, N.

    2011-04-01

    A synthetic multistrip single-crystal-diamond detector based on a p-type/intrinsic diamond/Schottky metal transverse configuration, operating at zero-bias voltage, was developed. The device was characterized at the Diamond Light Source synchrotron in Harwell (UK) under monochromatic high-flux X-ray beams from 6 to 20 keV and a micro-focused 10 keV beam with a spot size of ~3 μm. No significant pixel-to-pixel variation of both spectral responsivity and time response, high spatial resolution and good signal uniformity along each strip were found, suggesting the tested device structure as a promising sensor for X-ray and UV radiation imaging.

  20. Application of a single crystal chemical vapor deposition diamond detector for deuteron plasma neutron measurement

    NASA Astrophysics Data System (ADS)

    Xie, Xufei; Yuan, Xi; Zhang, Xing; Chen, Zhongjing; Peng, Xingyu; Du, Tengfei; Li, Tao; Hu, Zhimeng; Cui, Zhiqiang; Chen, Jinxiang; Li, Xiangqing; Zhang, Guohui; Fan, Tieshuan; Yuan, Guoliang; Yang, Jinwei; Yang, Qingwei

    2014-10-01

    A single crystal chemical vapor deposition (scCVD) diamond detector has been characterized and employed for the neutron measurement at the HL-2A tokamak device. The scCVD diamond detector has been deposited with 5 μm of lithium fluoride (LiF) layer to enhance the sensitivity to thermal neutrons. Time stability of the detector has been studied with α-source and good performance has been found for more than 12 h. Neutron irradiations have been performed in four quasi-monoenergetic neutron fields in the energy range from 2.50 MeV to 16.03 MeV. The measured response function of the scCVD diamond detector to 14.13 MeV neutrons shows a narrow 12C (n, α)9Be reaction peak which is well isolated from other structures by about 1 MeV in energy, indicating the great potential as a fast neutron spectrometer. Neutron measurement of deuterium plasma discharge was established at the HL-2A tokamak device, and good consistence has been revealed among this detector signal and other related signals.

  1. Investigations of high mobility single crystal chemical vapor deposition diamond for radiotherapy photon beam monitoring

    SciTech Connect

    Tromson, D.; Descamps, C.; Tranchant, N.; Bergonzo, P.; Nesladek, M.; Isambert, A.

    2008-03-01

    The intrinsic properties of diamond make this material theoretically very suitable for applications in medical physics. Until now ionization chambers have been fabricated from natural stones and are commercialized by PTW, but their fairly high costs and long delivery times have often limited their use in hospital. The properties of commercialized intrinsic polycrystalline diamond were investigated in the past by many groups. The results were not completely satisfactory due to the nature of the polycrystalline material itself. In contrast, the recent progresses in the growth of high mobility single crystal synthetic diamonds prepared by chemical vapor deposition (CVD) technique offer new alternatives. In the framework of the MAESTRO project (Methods and Advanced Treatments and Simulations for Radio Oncology), the CEA-LIST is studying the potentialities of synthetic diamond for new techniques of irradiation such as intensity modulated radiation therapy. In this paper, we present the growth and characteristics of single crystal diamond prepared at CEA-LIST in the framework of the NoRHDia project (Novel Radiation Hard CVD Diamond Detector for Hadrons Physics), as well as the investigations of high mobility single crystal CVD diamond for radiotherapy photon beam monitoring: dosimetric analysis performed with the single crystal diamond detector in terms of stability and repeatability of the response signal, signal to noise ratio, response speed, linearity of the signal versus the absorbed dose, and dose rate. The measurements performed with photon beams using radiotherapy facilities demonstrate that single crystal CVD diamond is a good alternative for air ionization chambers for beam quality control.

  2. Find of anisotropic carbonic matter on a curve-faced diamond crystal

    NASA Astrophysics Data System (ADS)

    Brodskaya, R. L.; Golubev, E. A.; Isaenko, S. I.

    2016-12-01

    The study focuses on the identification and investigation of crystal-optical anisotropy phenomena observed on surfaces of a curve-faced diamond crystal found in alluvial sediments of the Lower Us'va River in Perm territory. Raman spectroscopy and atomic force microscopy show that interference of polarized light reflected from the tetrahexahedral faces of the diamond crystal is inspired by anisotropic carbonic matter, which appears as a film with graphene or nanographite structure and about 4 nm in thickness. The data allow us to suggest the formation conditions of curve-faced diamond crystals and origin of nanocrystalline carbonic matter on their faces.

  3. High-temperature Superconductivity in Diamond Films - from Fundamentals to Device Applications

    DTIC Science & Technology

    2014-12-20

    Final 3. DATES COVERED (From - To) 25 Mar 2013 to 24 Sep 2014 4. TITLE AND SUBTITLE High-temperature superconductivity in diamond films...as proposed in the original grant application) are: (i) to test the hypotheses that repeated implants of boron in diamond below the graphitization...superconductivity; (ii) the demonstration of superconductivity in a (repeatedly) boron-implanted and annealed diamond crystal in our dilution refrigerator

  4. Observations of growth process of chemically vapor deposited diamond single crystal

    NASA Astrophysics Data System (ADS)

    Itoh, Hideaki; Nakamura, Tadashi; Iwahara, Hiroyasu; Sakamoto, Hiromichi

    1991-02-01

    The growth process and morphological variations of diamond single crystals obtained by microwave plasma CVD of the CO-H 2 reactant system were observed using scanning electron microscopy. The optimum conditions for spontaneous nucleation and growth of diamond on a (100) Si wafer were microwave power of 550 W, total pressure of 30-60 Torr, total flow rate of 200 ml/min and CO concentration of 5-10 vol%. Cubo-octahedral single crystals of diamond composed of {111} and {100} planes were grown epitaxially for 50 h by treating the coarse seed crystals of natural diamonds under the above growth conditions. Concave and terrace parts of the growing crystal surface were preferentially grown, resulting in the formation of symmetric single crystals. Typical trigonal pit patterns were formed on {111} planes of the developing crystal surface, while pyramidal shaped growth steps were observed on the {100} planes.

  5. The stability of a crystal with diamond structure for patchy particles with tetrahedral symmetry

    NASA Astrophysics Data System (ADS)

    Noya, Eva G.; Vega, Carlos; Doye, Jonathan P. K.; Louis, Ard A.

    2010-06-01

    The phase diagram of model anisotropic particles with four attractive patches in a tetrahedral arrangement has been computed at two different values of the range of the potential, with the aim of investigating the conditions under which a diamond crystal can be formed. We find that the diamond phase is never stable for our longer-ranged potential. At low temperatures and pressures, the fluid freezes into a body-centered-cubic solid that can be viewed as two interpenetrating diamond lattices with a weak interaction between the two sublattices. Upon compression, an orientationally ordered face-centered-cubic crystal becomes more stable than the body-centered-cubic crystal, and at higher temperatures, a plastic face-centered-cubic phase is stabilized by the increased entropy due to orientational disorder. A similar phase diagram is found for the shorter-ranged potential, but at low temperatures and pressures, we also find a region over which the diamond phase is thermodynamically favored over the body-centered-cubic phase. The higher vibrational entropy of the diamond structure with respect to the body-centered-cubic solid explains why it is stable even though the enthalpy of the latter phase is lower. Some preliminary studies on the growth of the diamond structure starting from a crystal seed were performed. Even though the diamond phase is never thermodynamically stable for the longer-ranged model, direct coexistence simulations of the interface between the fluid and the body-centered-cubic crystal and between the fluid and the diamond crystal show that at sufficiently low pressures, it is quite probable that in both cases the solid grows into a diamond crystal, albeit involving some defects. These results highlight the importance of kinetic effects in the formation of diamond crystals in systems of patchy particles.

  6. The stability of a crystal with diamond structure for patchy particles with tetrahedral symmetry.

    PubMed

    Noya, Eva G; Vega, Carlos; Doye, Jonathan P K; Louis, Ard A

    2010-06-21

    The phase diagram of model anisotropic particles with four attractive patches in a tetrahedral arrangement has been computed at two different values of the range of the potential, with the aim of investigating the conditions under which a diamond crystal can be formed. We find that the diamond phase is never stable for our longer-ranged potential. At low temperatures and pressures, the fluid freezes into a body-centered-cubic solid that can be viewed as two interpenetrating diamond lattices with a weak interaction between the two sublattices. Upon compression, an orientationally ordered face-centered-cubic crystal becomes more stable than the body-centered-cubic crystal, and at higher temperatures, a plastic face-centered-cubic phase is stabilized by the increased entropy due to orientational disorder. A similar phase diagram is found for the shorter-ranged potential, but at low temperatures and pressures, we also find a region over which the diamond phase is thermodynamically favored over the body-centered-cubic phase. The higher vibrational entropy of the diamond structure with respect to the body-centered-cubic solid explains why it is stable even though the enthalpy of the latter phase is lower. Some preliminary studies on the growth of the diamond structure starting from a crystal seed were performed. Even though the diamond phase is never thermodynamically stable for the longer-ranged model, direct coexistence simulations of the interface between the fluid and the body-centered-cubic crystal and between the fluid and the diamond crystal show that at sufficiently low pressures, it is quite probable that in both cases the solid grows into a diamond crystal, albeit involving some defects. These results highlight the importance of kinetic effects in the formation of diamond crystals in systems of patchy particles.

  7. Diamond bio electronics.

    PubMed

    Linares, Robert; Doering, Patrick; Linares, Bryant

    2009-01-01

    The use of diamond for advanced applications has been the dream of mankind for centuries. Until recently this dream has been realized only in the use of diamond for gemstones and abrasive applications where tons of diamonds are used on an annual basis. Diamond is the material system of choice for many applications, but its use has historically been limited due to the small size, high cost, and inconsistent (and typically poor) quality of available diamond materials until recently. The recent development of high quality, single crystal diamond crystal growth via the Chemical Vapor Deposition (CVD) process has allowed physcists and increasingly scientists in the life science area to think beyond these limitations and envision how diamond may be used in advanced applications ranging from quantum computing, to power generation and molecular imaging, and eventually even diamond nano-bots. Because of diamond's unique properties as a bio-compatible material, better understanding of diamond's quantum effects and a convergence of mass production, semiconductor-like fabrication process, diamond now promises a unique and powerful key to the realization of the bio-electronic devices being envisioned for the new era of medical science. The combination of robust in-the-body diamond based sensors, coupled with smart bio-functionalized diamond devices may lead to diamond being the platform of choice for bio-electronics. This generation of diamond based bio-electronic devices would contribute substantially to ushering in a paradigm shift for medical science, leading to vastly improved patient diagnosis, decrease of drug development costs and risks, and improved effectiveness of drug delivery and gene therapy programs through better timed and more customized solutions.

  8. Stimulated Raman scattering-active isotopically pure 12C and 13C diamond crystals: A milestone in the development of diamond photonics

    NASA Astrophysics Data System (ADS)

    Kaminskii, A. A.; Ral'chenko, V. G.; Yoneda, H.; Bol'shakov, A. P.; Inyushkin, A. V.

    2016-09-01

    Isotopically pure 12C and 13C diamonds are synthesized by chemical vapor deposition and impulsive stimulated Raman scattering in these crystals is investigated. The thermal conductivity of 12C isotopically pure damond and natC diamond with natural isotopic composition is measured. Phonon-nondegenerate Stokes lasing based on the χ(3) nonlinearity in the 12C, 13C, and natC diamond "triad" is attained, which opens a new stage in the development of diamond photonics.

  9. Morphology of flattened diamond crystals synthesized by the oxy-acetylene flame method

    NASA Astrophysics Data System (ADS)

    Hirabayashi, Keiji; Kimura, Takeshi; Hirose, Yoichi

    1993-01-01

    Flattened diamond crystals were synthesized by the oxy-acetyle flame method under high O2/C2H2 gas ratio conditions (≥0.95). The morphology of the flattened diamond crystals is characterized as follows: the ratio of the size of the top face and the height is 5:1 or more and all the faces are {111} faces. The twin boundaries are formed many times parallel to the top face. Scanning electron microscopy observations indicate that the flattened diamond crystals exhibit a good crystalline morphology. The motive force of lateral growth is caused by a re-entrant corner effect which results from the formation of twin boundaries.

  10. Single-crystal CVD diamond detector for high-resolution particle spectrometry

    NASA Astrophysics Data System (ADS)

    Sato, Y.; Murakami, H.; Shimaoka, T.; Tsubota, M.; Kaneko, J. H.

    2014-11-01

    The performance of a single-crystal diamond detector, grown by chemical vapour deposition, as an energy spectrometer for charged particles was studied. The detector was able to identify four different energies of 241\\text{Am} α -particles (5.389, 5.443, 5.486, and 5.545 MeV) thanks to a superior intrinsic energy resolution of ˜0.4{%} (full width at half maximum). The electrode configuration, specifically the electric field configuration inside the diamond crystal, and the electrode materials, strongly affect the energy resolution for charged particles. The charge collection efficiency inside the diamond crystal was ˜97{%} for both electrons and holes.

  11. Recent Advances in High-Growth Rate Single-Crystal CVD Diamond

    SciTech Connect

    Liang, Q.; Yan, C; Meng, Y; Lai, J; Krasnicki, S; Mao, H; Hemley, R

    2009-01-01

    There have been important advances in microwave plasma chemical vapor deposition (MPCVD) of large single-crystal CVD diamond at high growth rates and applications of this diamond. The types of gas chemistry and growth conditions, including microwave power, pressure, and substrate surface temperatures, have been varied to optimize diamond quality and growth rates. The diamond has been characterized by a variety of spectroscopic and diffraction techniques. We have grown single-crystal CVD diamond over ten carats and above 1 cm in thickness at growth rates of 50-100 {micro}m/h. Colorless and near colorless single crystals up to two carats have been produced by further optimizing the process. The nominal Vickers fracture toughness of this high-growth rate diamond can be tuned to exceed 20 MPa m{sup 1/2} in comparison to 5-10 MPa m{sup 1/2} for conventional natural and CVD diamond. Post-growth high-pressure/high-temperature (HPHT) and low-pressure/high-temperature (LPHT) annealing have been carried out to alter the optical, mechanical, and electronic properties. Most recently, single-crystal CVD diamond has been successfully annealed by LPHT methods without graphitization up to 2200 C and < 300 Torr for periods of time ranging from a fraction of minute to a few hours. Significant changes observed in UV, visible, infrared, and photoluminescence spectra are attributed to changes in various vacancy centers and extended defects.

  12. HPHT synthesis of N-H co-doped diamond single crystals

    NASA Astrophysics Data System (ADS)

    Fang, Chao; Jia, Xiaopeng; Chen, Ning; Li, Yadong; Guo, Longsuo; Chen, Liangchao; Ma, Hong-an; Liu, Xiaobing

    2016-02-01

    In this paper, a series of nitrogen and hydrogen elements (N-H) co-doped diamond single crystals were synthesized in the NiMnCo-C system with melamine (C3N6H6) additive by temperature gradient growth (TGG) method under high-pressure and high-temperature (HPHT). High nitrogen and hydrogen growth environment obviously reduces the growth rate of the diamond. The synthetic diamond crystals are octahedral shape with a green or dark green color. This results indicate that the morphology of the synthetic N-H co-doped gem-diamond can be well-controlled by TGG method. Fourier transform infrared spectroscopy (FTIR) indicate that high-quality diamond single crystals with nitrogen concentrations up to 2100 ppm have been successfully synthesized and the hydrogen related peaks at 2850 cm-1 (sp3-CH3) and 2920 cm-1 (sp3-CH2-) are found in these synthetic diamond. Meanwhile, with the increasing of C-centers the nitrogen atoms aggregate and form into A-centers in these synthetic diamonds. This is the highest quality of N-H co-doped gem-diamond single crystal synthesized in high nitrogen and high hydrogen growth environment reported so far.

  13. A relation between a metallic film covering on diamond formed during growth and nanosized inclusions in HPHT as-grown diamond single crystals

    NASA Astrophysics Data System (ADS)

    Yin, L.-W.; Li, M.-S.; Gong, Z.-G.; Bai, Y.-J.; Li, F.-Z.; Hao, Z.-Y.

    One of the most important characteristics and basic phenomena during diamond growth from liquid metal catalyst solutions saturated with carbon at high temperature-high pressure (HPHT) is that there exists a thin metallic film covering on the growing diamond, through which carbon-atom clusters are delivered to the surface of the growing diamond by diffusion. A study of microstructures of such a metallic film and a relation between the thin metallic film and the inclusions trapped in HPHT as-grown diamond single crystals may be helpful to obtain high-purity diamond single crystals. It was found that both the metallic film and the HPHT as-grown diamond single crystals contain some nanostructured regions. Examination by transmission electron microscopy suggests that the microstructure of the thin metallic film is in accordance with nanosized particles contained in HPHT as-grown diamond single crystals. The nanosized particles with several to several tens of nanometers in dimension distribute homogeneously in the metallic film and in the diamond matrix. Generally, the size of the particles in the thin metallic film is relatively larger than that within the diamond matrix. Selected area electron diffraction patterns suggest that the nanosized particles in the metallic film and nanometer inclusions within the diamond are mainly composed of f.c.c. (FeNi)23C6, hexagonal graphite and cubic γ-(FeNi). The formation of the nanosized inclusions within the diamond single crystals is thought not only to relate to the growth process and rapid quenching from high temperature after diamond synthesis, but also to be associated with large amounts of defects in the diamond, because the free energy in these defect areas is very high. The critical size of carbide, γ-(FeNi)and graphite particles within the diamond matrix should decrease and not increase according to thermodynamic theory during quenching from HPHT to room temperature and ambient pressure.

  14. Cooling device featuring thermoelectric and diamond materials for temperature control of heat-dissipating devices

    NASA Technical Reports Server (NTRS)

    Vandersande, Ian W. (Inventor); Ewell, Richard (Inventor); Fleurial, Jean-Pierre (Inventor); Lyon, Hylan B. (Inventor)

    1998-01-01

    A cooling device for lowering the temperature of a heat-dissipating device. The cooling device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with the heat-dissipating device. During operation, heat flows from the heat-dissipating device into the heat-conducting substrate, where it is spread out over a relatively large area. A thermoelectric cooling material (e.g., a Bi.sub.2 Te.sub.3 -based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. Application of electrical power to the thermoelectric material drives the thermoelectric material to pump heat into a second heat-conducting substrate which, in turn, is attached to a heat sink.

  15. Method to fabricate micro and nano diamond devices

    DOEpatents

    Morales, Alfredo M; Anderson, Richard J; Yang, Nancy Y. C.; Skinner, Jack L; Rye, Michael J

    2014-10-07

    A method including forming a diamond material on the surface of a substrate; forming a first contact and a separate second contact; and patterning the diamond material to form a nanowire between the first contact and the second contact. An apparatus including a first contact and a separate second contact on a substrate; and a nanowire including a single crystalline or polycrystalline diamond material on the substrate and connected to each of the first contact and the second contact.

  16. Method to fabricate micro and nano diamond devices

    DOEpatents

    Morales, Alfredo M.; Anderson, Richard J.; Yang, Nancy Y. C.; Skinner, Jack L.; Rye, Michael J.

    2017-04-11

    A method including forming a diamond material on the surface of a substrate; forming a first contact and a separate second contact; and patterning the diamond material to form a nanowire between the first contact and the second contact. An apparatus including a first contact and a separate second contact on a substrate; and a nanowire including a single crystalline or polycrystalline diamond material on the substrate and connected to each of the first contact and the second contact.

  17. Fluid inclusions in carbonado diamond_Implication to the crystal growth environment

    NASA Astrophysics Data System (ADS)

    Kagi, H.; Ishibashi, H.; Sakurai, H.; Ohfuji, H.

    2010-12-01

    Diamond is a unique geological material carrying inside fluid and solid inclusions which are pristine witnesses of diamond crystallization media. Carbonado is natural polycrystalline diamond whose origin is still under hot depate. Our previous study on Central African carbonado reported the presence of fluid inclusions and high residual pressure in the diamond [1]. These results suggested that C-O-H mantle fluid was trapped in the carbonado sample and carbonado had grown in the volatile-rich environment in the mantle. However, it was unclear that the fluid inclusions in carbonado existed inside of diamond grains or in the grain boundaries. In this study, we precisely investigated the location of fluid inclusions from spectroscopic measurements and TEM observations. A carbonado grain with hundreds of micrometer in diameter was heated incrementally at temperatures from 700 to 1100°C under vacuum. After heating at each temperature condition, infrared absorption spectra were measured. Dehydration of hydrous minerals were observed with increasing temperature. In contrast, absorption bands assignable to liquid water were observed up to 950°C right before graphitization occurred. This observation strongly suggests that the fluid was trapped inside of diamond grains. For obtaining direct evidence of fluid inclusion existing inside of a diamond grain, we conducted TEM observations on an FIB-fabricated thin foil of carbonado. We found a void in the carbonado sample. The void was surrounded by (111) equivalent crystal faces. The octahedral void controlled by crystal habit of host diamond strongly suggests that the void is the negative crystal of diamond. The existence of negative crystal of diamond indicates that the fluid equilibrated with surrounding diamond crystals. Moreover, it was found that the grain boundary of the polished carbonado sample was in zig-zag texture. The detailed EBSD analyses on the grain boundary indicated that the grain boundary corresponded to the

  18. Crystallization of diamond from a silicate melt of kimberlite composition in high-pressure and high-temperature experiments

    SciTech Connect

    Arima, Makoto; Nakayama, Kazuhiro ); Akaishi, Minoru; Yamaoka, Shinobu; Kanda, Hisao )

    1993-11-01

    In high-pressure and high-temperature experiments (1800-2200[degrees]C and 7.0-7.7 GPa), diamond crystallized and grew in a volatile-rich silicate melt of kimberlite composition. This diamond has well-developed [111] faces, and its morphologic characteristics resemble those of natural diamond but differ from those of synthetic diamond grown from metallic solvent-catalysts. The kimberlite melt has a strong solvent-catalytic effect on diamond formation, supporting the view that some natural diamonds crystallized from volatile-rich melts in the upper mantle. 19 refs., 3 figs., 1 tab.

  19. Adhesion and friction of single-crystal diamond in contact with transition metals

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1980-01-01

    An investigation was conducted to examine the adhesion and friction of single-crystal diamond in contact with various transition metals and the nature of metal transfer to diamond. Sliding friction experiments were conducted with diamond in sliding contact with the metals yttrium, titanium, zirconium, vanadium, iron, cobalt, nickel, tungsten, platinum, rhenium and rhodium. All experiments were conducted with loads of 0.05 to 0.3 N, at a sliding velocity of 0.003 m per minute, in a vacuum of 10 to the -8th Pa, at room temperature, and on the (111) plane of diamond with sliding in the 110 line type direction. The results of the investigation indicate that the coefficient of friction for diamond in contact with various metals is related to the relative chemical activity of the metals in high vacuum. The more active the metal, the higher the coefficient of friction. All the metals examined transferred to the surface of diamond in sliding.

  20. Single-crystal diamond pyramids: synthesis and application for atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Tuyakova, Feruza T.; Obraztsova, Ekaterina A.; Ismagilov, Rinat R.

    2016-03-01

    Here we present the results of investigations aimed at the development and testing of robust, chemically inert single-crystal diamond probes for atomic force microscopy (AFM). The probes were prepared by assembling common silicon probes with micrometer-sized pyramid-shaped single-crystal diamonds (SCD). The SCD were obtained by the selective thermal oxidation of the polycrystalline films grown by chemical vapor deposition. Electrostatic spray of adhesive coating onto silicon probes was used to attach individual SCD. Geometrical parameters of produced AFM SCD probes were revealed with transmission electron microscopy: the apex angle of the pyramidal diamond crystallite was ˜10 deg, and the curvature radius at the apex was ˜2 to 10 nm. The diamond AFM probes were used for surface imaging of deoxyribonucleic acid deposited on graphite substrate. Obtained results demonstrate high efficiency of the diamond AFM probes, allowing improvement of the image quality compared to standard silicon probes.

  1. Coupling of silicon-vacancy centers to a single crystal diamond cavity.

    PubMed

    Lee, Jonathan C; Aharonovich, Igor; Magyar, Andrew P; Rol, Fabian; Hu, Evelyn L

    2012-04-09

    Optical coupling of an ensemble of silicon-vacancy (SiV) centers to single-crystal diamond microdisk cavities is demonstrated. The cavities are fabricated from a single-crystal diamond membrane generated by ion implantation and electrochemical liftoff followed by homo-epitaxial overgrowth. Whispering gallery modes spectrally overlap with the zero-phonon line (ZPL) of the SiV centers and exhibit quality factors ∼ 2200. Lifetime reduction from 1.8 ns to 1.48 ns is observed from SiV centers in the cavity compared to those in the membrane outside the cavity. These results are pivotal in developing diamond integrated photonics networks.

  2. GaN-on-diamond electronic device reliability: Mechanical and thermo-mechanical integrity

    SciTech Connect

    Liu, Dong; Sun, Huarui; Pomeroy, James W.; Kuball, Martin; Francis, Daniel; Faili, Firooz; Twitchen, Daniel J.

    2015-12-21

    The mechanical and thermo-mechanical integrity of GaN-on-diamond wafers used for ultra-high power microwave electronic devices was studied using a micro-pillar based in situ mechanical testing approach combined with an optical investigation of the stress and heat transfer across interfaces. We find the GaN/diamond interface to be thermo-mechanically stable, illustrating the potential for this material for reliable GaN electronic devices.

  3. A single-crystal diamond-based thermal neutron beam monitor for instruments at pulsed neutron sources

    NASA Astrophysics Data System (ADS)

    Pietropaolo, A.; Verona Rinati, G.; Verona, C.; Schooneveld, E. M.; Angelone, M.; Pillon, M.

    2009-11-01

    Single-crystal diamond detectors manufactured through a Chemical Vapour Deposition (CVD) technique are recent technology devices that have been employed in reactor and Tokamak environments in order to detect both thermal and almost monochromatic 14 MeV neutrons produced in deuterium-tritium ( d-t) nuclear fusion reactions. Their robustness and compactness are the key features that can be exploited for different applications as well. Aim of the present experimental investigation is the assessment of the performance of a diamond detector as a thermal neutron beam monitor at pulsed neutron sources. To this aim, a test measurement was carried out on the Italian Neutron Experimental Station (INES) beam line at the ISIS spallation neutron source (Great Britain). The experiment has shown the capability of these devices to work at a pulsed neutron source for beam monitoring purposes. Other interesting possible applications are also suggested.

  4. Electron Microscopy of Natural and Epitaxial Diamond

    NASA Technical Reports Server (NTRS)

    Posthill, J. B.; George, T.; Malta, D. P.; Humphreys, T. P.; Rudder, R. A.; Hudson, G. C.; Thomas, R. E.; Markunas, R. J.

    1993-01-01

    Semiconducting diamond films have the potential for use as a material in which to build active electronic devices capable of operating at high temperatures or in high radiation environments. Ultimately, it is preferable to use low-defect-density single crystal diamond for device fabrication. We have previously investigated polycrystalline diamond films with transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and homoepitaxial films with SEM-based techniques. This contribution describes some of our most recent observations of the microstructure of natural diamond single crystals and homoepitaxial diamond thin films using TEM.

  5. Influence of annealing treatment on as-grown Ib-type diamond crystal at a high temperature and high pressure

    NASA Astrophysics Data System (ADS)

    Huang, Guo-Feng; Yin, Ji-Wen; Bai, Hong-Bo; Hu, Yi-Ga; Kai, Li; Jing, Jing; Ma, Hong-An; Jia, Xiao-Peng

    2012-10-01

    In this paper, we report on the influence of annealing treatment on as-grown Ib-type diamond crystal under high pressure and high temperature in a china-type cubic anvil high-pressure apparatus. Experiments are carried out at a pressure of 7.0 GPa and temperatures ranging from 1700 °C to 1900 °C for 1 h. Annealing treatment of the diamond crystal shows that the aggregation rate constant of nitrogen atoms in the as-grown Ib-type diamond crystal strongly depends on diamond morphology and annealing temperature. The aggregation rate constant of nitrogen remarkably increases with the increase of annealing temperature and its value in octahedral diamond is much higher than that in cubic diamond annealed at the same temperature. The colour of octahedral diamond crystal is obviously reduced from yellow to nearly colorless after annealing treatment for 1 h at 1900 °C, which is induced by nitrogen aggregation in a diamond lattice. The extent of nitrogen aggregation in an annealed diamond could approach approximately 98% indicated from the infrared absorption spectra. The micro-Raman spectrum reveals that the annealing treatment can improve the crystalline quality of Ib-type diamond characterized by a half width at full maximum at first order Raman peak, and therefore the annealed diamond crystals exhibit nearly the same properties as the natural IaA-type diamond stones of high quality in the Raman measurements.

  6. EBS/C proton spectra from a virgin diamond crystal

    NASA Astrophysics Data System (ADS)

    Erich, M.; Kokkoris, M.; Fazinić, S.; Petrović, S.

    2016-08-01

    In the present work, elastic backscattering channeling spectra, EBS/C, of protons in a <1 0 0> diamond crystal were experimentally and theoretically studied via a new computer simulation code. Proton incident energies for EBS/C spectra were in the energy range from 1.0 MeV to 1.9 MeV. The energy range was chosen in order to explore a distinct strong resonance of the 12C(p,p0)12C elastic scattering at 1737 keV. The computer simulation code applied for the fitting of the experimental spectra in the random mode was compared with the corresponding SIMNRA results. In the channeling mode, it assumes a Gompertz type sigmoidal dechanneling function, which has two fitting parameters, xc and k, the dechanneling range and rate, respectively. It also uses α, ratio of the channeling to random energy losses, as a fitting parameter. It was observed that xc increases, k decreases and α stays relatively constant with the proton incident energy. These observations confirm the physical interpretation of the fitting parameters. Also, they constitute the basics for the further development of the code for the quantification of induced amorphization and depth profiling of implanted ions.

  7. The mechanical properties of various chemical vapor deposition diamond structures compared to the ideal single crystal

    NASA Astrophysics Data System (ADS)

    Hess, Peter

    2012-03-01

    The structural and electronic properties of the diamond lattice, leading to its outstanding mechanical properties, are discussed. These include the highest elastic moduli and fracture strength of any known material. Its extreme hardness is strongly connected with the extreme shear modulus, which even exceeds the large bulk modulus, revealing that diamond is more resistant to shear deformation than to volume changes. These unique features protect the ideal diamond lattice also against mechanical failure and fracture. Besides fast heat conduction, the fast vibrational movement of carbon atoms results in an extreme speed of sound and propagation of crack tips with comparable velocity. The ideal mechanical properties are compared with those of real diamond films, plates, and crystals, such as ultrananocrystalline (UNC), nanocrystalline, microcrystalline, and homo- and heteroepitaxial single-crystal chemical vapor deposition (CVD) diamond, produced by metastable synthesis using CVD. Ultrasonic methods have played and continue to play a dominant role in the determination of the linear elastic properties, such as elastic moduli of crystals or the Young's modulus of thin films with substantially varying impurity levels and morphologies. A surprising result of these extensive measurements is that even UNC diamond may approach the extreme Young's modulus of single-crystal diamond under optimized deposition conditions. The physical reasons for why the stiffness often deviates by no more than a factor of two from the ideal value are discussed, keeping in mind the large variety of diamond materials grown by various deposition conditions. Diamond is also known for its extreme hardness and fracture strength, despite its brittle nature. However, even for the best natural and synthetic diamond crystals, the measured critical fracture stress is one to two orders of magnitude smaller than the ideal value obtained by ab initio calculations for the ideal cubic lattice. Currently

  8. Liquid crystal device and method thereof

    DOEpatents

    Shiyanovskii, Sergij V; Gu, Mingxia; Lavrentovich, Oleg D

    2012-10-23

    The invention provides a liquid crystal device and method thereof. Subsequent to applying a first electrical voltage on a liquid crystal to induce a reorientation of the liquid crystal, a second electrical voltage with proper polarity is applied on the liquid crystal to assist the relaxation of the reorientation that was induced by the first electrical voltage. The "switch-off" phase of the liquid crystal can therefore be accelerated or temporally shortened, and the device can exhibit better performance such as fast response to on/off signals. The invention can be widely used LCD, LC shutter, LC lens, spatial light modulator, telecommunication device, tunable filter, beam steering device, and electrically driven LC device, among others.

  9. Kelvin probe characterization of buried graphitic microchannels in single-crystal diamond

    SciTech Connect

    Bernardi, E. Battiato, A.; Olivero, P.; Vittone, E.; Picollo, F.

    2015-01-14

    In this work, we present an investigation by Kelvin Probe Microscopy (KPM) of buried graphitic microchannels fabricated in single-crystal diamond by direct MeV ion microbeam writing. Metal deposition of variable-thickness masks was adopted to implant channels with emerging endpoints and high temperature annealing was performed in order to induce the graphitization of the highly-damaged buried region. When an electrical current was flowing through the biased buried channel, the structure was clearly evidenced by KPM maps of the electrical potential of the surface region overlying the channel at increasing distances from the grounded electrode. The KPM profiling shows regions of opposite contrast located at different distances from the endpoints of the channel. This effect is attributed to the different electrical conduction properties of the surface and of the buried graphitic layer. The model adopted to interpret these KPM maps and profiles proved to be suitable for the electronic characterization of buried conductive channels, providing a non-invasive method to measure the local resistivity with a micrometer resolution. The results demonstrate the potential of the technique as a powerful diagnostic tool to monitor the functionality of all-carbon graphite/diamond devices to be fabricated by MeV ion beam lithography.

  10. Growth, Characterization and Device Development in Monocrystalline Diamond Films

    DTIC Science & Technology

    1993-10-31

    of these phases must be determined by HRTEM . The research of this grant has included the studies of the process parameters and substrate3 effects on...resolution transmission electron mi- cleation). Fedoseev et al.5- 7 presented theoretical argu- croscopy ( HRTEM ) of diamond nucleation on "diamond ments...diffusivity of the predeposition of carbonaceous layers of diamondlike carbon in the respective carbide. However, attempts in carbon2 -2 ( DLC ) or even oil

  11. Effect of CO2 on crystallization and properties of diamond from ultra-alkaline carbonate melt

    NASA Astrophysics Data System (ADS)

    Palyanov, Yuri N.; Kupriyanov, Igor N.; Sokol, Alexander G.; Borzdov, Yuri M.; Khokhryakov, Alexander F.

    2016-11-01

    An experimental study on diamond crystallization in CO2-rich sodium-carbonate melts has been undertaken at a pressure of 6.3 GPa in the temperature range of 1250-1570 °C and at 7.5 GPa in the temperature range of 1300-1700 °C. Sodium oxalate (Na2C2O4) was used as the starting material, which over the course of the experiment decomposed to form sodium carbonate, carbon dioxide and elemental carbon. The effects of pressure, temperature and dissolved CO2 in the ultra-alkaline carbonate melt on diamond crystallization, morphology, internal structure and defect-and-impurity content of diamond crystals are established. Diamond growth is found to proceed with formation of vicinal structures on the {100} and {111} faces, resulting eventually in the formation of rounded polyhedrons, whose shape is determined by the combination tetragon-trioctahedron, trigon-trioctahedron and cube faces. Spectroscopic studies reveal that the crystallized diamonds are characterized by specific infrared absorption and photoluminescence spectra. The defects responsible for the 1065 cm- 1 band dominating in the IR spectra and the 566 nm optical system dominating in the PL spectra are tentatively assigned to oxygen impurities in diamond.

  12. Radial mosaic internal structure of rounded diamond crystals from alluvial placers of Siberian platform

    NASA Astrophysics Data System (ADS)

    Ragozin, A. L.; Zedgenizov, D. A.; Kuper, K. E.; Shatsky, V. S.

    2016-12-01

    The specific gray to almost black diamonds of rounded morphology are especially typical in alluvial placers of the northeastern part of the Siberian platform. The results of study of internal structure of these diamonds are presented. X-ray topography and birefringence patterns of polished plates of studied diamonds show their radial mosaic structure. Diamonds consists of slightly misorientated (up to 20') subindividuals which are combined to mosaic wedge-shaped sectors. Electron back-scatter diffraction technique has demonstrated that subindividuals are often combined in the single large blocks (subgrains). The whole crystals commonly consist of several large subgrains misoriented up to 5° to one another. The total nitrogen content of these diamonds vary in the range 900-3300 ppm and nitrogen aggregation state (NB/(NB + NA)*100) from 25 to 64 %. Rounded diamond crystals of variety V are suggested to have been formed at the high growth rate caused by the high oversaturation of carbon in the crystallization medium. It may result in the splitting of growing crystal and their radial mosaic structure as a sequence. High content of structural nitrogen defects and the great number of mechanical impurities - various mineral and fluid inclusions may also favor to generation of this structure.

  13. Invited Article: Precision nanoimplantation of nitrogen vacancy centers into diamond photonic crystal cavities and waveguides

    NASA Astrophysics Data System (ADS)

    Schukraft, M.; Zheng, J.; Schröder, T.; Mouradian, S. L.; Walsh, M.; Trusheim, M. E.; Bakhru, H.; Englund, D. R.

    2016-05-01

    We demonstrate a self-aligned lithographic technique for precision generation of nitrogen vacancy (NV) centers within photonic nanostructures on bulk diamond substrates. The process relies on a lithographic mask with nanoscale implantation apertures for NV creation, together with larger features for producing waveguides and photonic nanocavities. This mask allows targeted nitrogen ion implantation, and precision dry etching of nanostructures on bulk diamond. We demonstrate high-yield generation of single NVs at pre-determined nanoscale target regions on suspended diamond waveguides. We report implantation into the mode maximum of diamond photonic crystal nanocavities with a single-NV per cavity yield of ˜26% and Purcell induced intensity enhancement of the zero-phonon line. The generation of NV centers aligned with diamond photonic structures marks an important tool for scalable production of optically coupled spin memories.

  14. Effects of hydrogen on diamond single crystal synthesized under high pressure and high temperature

    NASA Astrophysics Data System (ADS)

    Li, Yong; Jia, Xiaopeng; Song, Mousheng; Ma, Hong-An; Zhou, Zhenxiang; Fang, Chao; Wang, Fangbiao; Chen, Ning; Wang, Ying

    2015-09-01

    In this paper, diamond single crystals doped with LiH and boron additives were synthesized in Fe64Ni36-C system under high pressure and high temperature. Under the fixed pressure condition, we found that the synthesis temperature increased slightly after the addition of LiH in the synthesis system. The {100}-orientated surface morphology was investigated by scanning electron microscopy (SEM). The nitrogen concentration in the obtained diamond was analyzed and evaluated using Fourier transmission infrared spectroscopy (FTIR). Furthermore, the electrical properties of Ib-type and boron-doped diamond before and after hydrogenation using Hall effect measurement, which suggested that the conductivity of diamond co-doped with hydrogen and boron was obviously enhanced than that of boron-doped diamond.

  15. Stress engineering of high-quality single crystal diamond by heteroepitaxial lateral overgrowth

    NASA Astrophysics Data System (ADS)

    Tang, Y.-H.; Golding, B.

    2016-02-01

    A method for lateral overgrowth of low-stress single crystal diamond by chemical vapor deposition (CVD) is described. The process is initiated by deposition of a thin (550 nm) (001) diamond layer on Ir-buffered a-plane sapphire. The diamond is partially masked by periodic thermally evaporated Au stripes using photolithography. Lateral overgrowth of the Au occurs with extremely effective filtering of threading dislocations. Thermal stress resulting from mismatch of the low thermal expansion diamond and the sapphire substrate is largely accommodated by the ductile Au layer. The stress state of the diamond is investigated by Raman spectroscopy for two thicknesses: at 10 μm where the film has just overgrown the Au mask and at 180 μm where the film thickness greatly exceeds the scale of the masking. For the 10-μm film, the Raman linewidth shows spatial oscillations with the period of the Au stripes with a factor of 2 to 3 reduction relative to the unmasked region. In a 180-μm thick diamond film, the overall surface stress was extremely low, 0.00 ± 0.16 GPa, obtained from the Raman shift averaged over the 7.5 mm diameter of the crystal at its surface. We conclude that the metal mask protects the overgrown diamond layer from substrate-induced thermal stress and cracking. It is also responsible for low internal stress by reducing dislocation density by several orders of magnitude.

  16. Patterning of nanocrystalline diamond films for diamond microstructures useful in MEMS and other devices

    DOEpatents

    Gruen, Dieter M.; Busmann, Hans-Gerd; Meyer, Eva-Maria; Auciello, Orlando; Krauss, Alan R.; Krauss, Julie R.

    2004-11-02

    MEMS structure and a method of fabricating them from ultrananocrystalline diamond films having average grain sizes of less than about 10 nm and feature resolution of less than about one micron . The MEMS structures are made by contacting carbon dimer species with an oxide substrate forming a carbide layer on the surface onto which ultrananocrystalline diamond having average grain sizes of less than about 10 nm is deposited. Thereafter, microfabrication process are used to form a structure of predetermined shape having a feature resolution of less than about one micron.

  17. Relationship between carbon isotope composition and crystal morphology of coated and polycrystalline diamonds

    NASA Astrophysics Data System (ADS)

    Janson, G. F.; Muehlenbachs, K.; Stachel, T.

    2009-12-01

    The carbon isotope composition of diamond coats from Diavik Mine, Canada was measured by secondary ion mass spectrometry (SIMS). In most cases, carbon isotope ratio increases outwards from approximately -8.5 to approximately -6.5‰. Although it has not been widely noted in the literature due to sparse data coverage, this trend is consistent with measurements by other researchers at other sampling localities and therefore represents a unique insight into fluid evolution during the formation of diamond coat. We model the outwards increase in carbon isotope ratio by Rayleigh fractionation during growth of diamond coat in a closed system from an oxidized, carbon supersaturated fluid with a mantle-like carbon isotope signature. The carbon may have been exsolved as a volatile-rich fluid from upwelling kimberlite magma at depths greater than 120 km. The fluid either encountered preexisting diamond ‘seed’ crystals which served as nuclei for the coats or, in the absence of such seeds, precipitated opaque cuboid crystals. Reduction of oxidized carbon to diamond would be driven by the reduced character of the depleted lithosphere (Haggerty and Tompkins, 1983). Several polycrystalline diamonds were also studied by SIMS. These are homogeneous with respect to δ13C and therefore show no isotopic evidence of fluid evolution during their growth. The degree of supersaturation of a fluid commonly determines the crystal habit of minerals precipitated from the fluid. In the case of diamonds, dendritic coat is interpreted as a product of conditions intermediate between the low degree carbon supersaturation that produces polyhedral and hopper morphologies, and the very high supersaturation responsible for the growth of polycrystalline diamond. During closed system growth, precipitation of diamond depletes the fluid reservoir of carbon, resulting in isotopic profiles consistent with Rayleigh fractionation. This depletion necessarily reduces the chemical potential between fluid and

  18. Microfabricated phononic crystal devices and applications

    NASA Astrophysics Data System (ADS)

    Olsson, R. H., III; El-Kady, I.

    2009-01-01

    Phononic crystals are the acoustic wave analogue of photonic crystals. Here a periodic array of scattering inclusions located in a homogeneous host material forbids certain ranges of acoustic frequencies from existence within the crystal, thus creating what are known as acoustic bandgaps. The majority of previously reported phononic crystal devices have been constructed by hand, assembling scattering inclusions in a viscoelastic medium, predominantly air, water or epoxy, resulting in large structures limited to frequencies below 1 MHz. Recently, phononic crystals and devices have been scaled to VHF (30-300 MHz) frequencies and beyond by utilizing microfabrication and micromachining technologies. This paper reviews recent developments in the area of micro-phononic crystals including design techniques, material considerations, microfabrication processes, characterization methods and reported device structures. Micro-phononic crystal devices realized in low-loss solid materials are emphasized along with their potential application in radio frequency communications and acoustic imaging for medical ultrasound and nondestructive testing. The reported advances in batch micro-phononic crystal fabrication and simplified testing promise not only the deployment of phononic crystals in a number of commercial applications but also greater experimentation on a wide variety of phononic crystal structures.

  19. Morphology of diamond crystals grown in magnesium-based systems at high temperatures and high pressures

    NASA Astrophysics Data System (ADS)

    Khokhryakov, Alexander F.; Sokol, Alexander G.; Borzdov, Yuri M.; Palyanov, Yuri N.

    2015-09-01

    A series of experiments on diamond growth in the Mg45Cu55-C, Mg50Ni50-C, Mg50Cu25Ni25-C, Mg50Ag25Ni25-C and Mg25Cu25Ni50-C systems at a pressure of 6.3 GPa in the temperature range of 1550-1650 °C was conducted. The morphology of diamond crystals and the features of their growth were studied. The {111} and {100} faces, with the cube faces playing the dominant role, were found to be the plane-faced forms of diamond crystal growth. If the magnesium content in the system is 45-50 at%, crystal growth occurs in the regime of inhibition of the {100} faces with the formation of antiskeletal crystals. In case of a constant intensity of the face inhibition up to its complete growing out, the quasi-faces of trapezohedron {311} are formed with striations in the [110] direction. The inhibition of face growth and formation of antiskeletal crystals are related to oxygen inflow from the cell parts and are accompanied by crystallization of magnesium oxide on the diamond surface. A reduction in the magnesium content in the system from 50 to 25 at% or an increase in the temperature leads to the cessation of {100} face inhibition and promotes growth of plane-faced crystals.

  20. Integration of high-dielectric constant Ta{sub 2}O{sub 5} oxides on diamond for power devices

    SciTech Connect

    Cheng Shaoheng; Sang Liwen; Liao Meiyong; Imura, Masataka; Liu Jiangwei; Li Hongdong; Koide, Yasuo

    2012-12-03

    The authors report on the direct integration of high-dielectric constant (high-k) Ta{sub 2}O{sub 5} films on p-type single crystal diamond for high-power electronic devices. Crystallized hexagonal phase {delta}-Ta{sub 2}O{sub 5} film is achieved on diamond by annealing the amorphous Ta{sub 2}O{sub 5} film deposited by a sputter-deposition technique. The electrical properties of the Ta{sub 2}O{sub 5} thin films are investigated by fabricating metal-insulator-semiconductor (MIS) diodes. The leakage current of the MIS diode is as low as 10{sup -8} A/cm{sup 2} for the as-deposited amorphous Ta{sub 2}O{sub 5} film and 10{sup -2} A/cm{sup 2} for the crystallized film, which is 10{sup 8} and 10{sup 2} times lower than that of the Schottky diode at a forward bias of -3 V, respectively. The dielectric constant of the amorphous Ta{sub 2}O{sub 5} films is measured to be 16 and increases to 29 after annealing at 800 Degree-Sign C. Different current leakage mechanisms and charge trapping behaviors are proposed for the amorphous and crystallized Ta{sub 2}O{sub 5} thin films.

  1. Science and technology of ultrananocrystalline diamond (UNCD) thin films for multifunctional devices

    SciTech Connect

    Auciello, O.; Krauss, A. R.; Gruen, D. M.; Jayatissa, A.; Sumant, A.; Tucek, J.; Mancini, D.; Molodvan, N.; Erdemir, A.; Ersoy, D.; Gardos, M. N.; Busman, H. G.; Meyer, E. M.

    2000-08-24

    MEMS devices are currently fabricated primarily in silicon because of the available surface machining technology. However, Si has poor mechanical and tribological properties, and practical MEMS devices are currently limited primarily to applications involving only bending and flexural motion, such as cantilever accelerometers and vibration sensors. However, because of the poor flexural strength and fracture toughness of Si, and the tendency of Si to adhere to hydrophyllic surfaces, even these simple devices have limited dynamic range. Future MEMS applications that involve significant rolling or sliding contact will require the use of new materials with significantly improved mechanical and tribological properties, and the ability to perform well in harsh environments. Diamond is a superhard material of high mechanical strength, exceptional chemical inertness, and outstanding thermal stability. The brittle fracture strength is 23 times that of Si, and the projected wear life of diamond MEMS moving mechanical assemblies (MEMS-MMAs) is 10,000 times greater than that of Si MMAs. However, as the hardest known material, diamond is notoriously difficult to fabricate. Conventional CVD thin film deposition methods offer an approach to the fabrication of ultra-small diamond structures, but the films have large grain size, high internal stress, poor intergranular adhesion, and very rough surfaces, and are consequently ill-suited for MEMS-MMA applications. A thin film deposition process has been developed that produces phase-pure nanocrystalline diamond with morphological and mechanical properties that are ideally suited for MEMS applications in general, and MMA use in particular. The authors have developed lithographic techniques for the fabrication of diamond microstructure including cantilevers and multi-level devices, acting as precursors to micro-bearings and gears, making nanocrystalline diamond a promising material for the development of high performance MEMS devices.

  2. Adaptive optics for high power beam lines using diamond crystal monochromators

    SciTech Connect

    Sharma, S.; Berman, L.E.; Hastings, J.B.; Hart, M.

    1992-12-31

    Preserving the high source brightness of the third generation of synchrotron radiation facilities will require that thermal and pressure deformations of the monochromator crystals be maintained within a few arc- seconds. Recent experiments at the National Synchrotron Light Source (NSLS) have demonstrated the potential of adaptive crystal optics to cope with high power densities. In this technique the crystals deformations are minimized both by an efficient water-jet cooling and by externally applied pressure loads. Thermal deformation can be reduced further with diamond crystals because of their high thermal conductivity and low coefficient of thermal expansion. In this paper we describe the results achieved by optimization of adaptive crystal optics for diamond crystals.

  3. Adaptive optics for high power beam lines using diamond crystal monochromators

    SciTech Connect

    Sharma, S.; Berman, L.E.; Hastings, J.B. ); Hart, M. )

    1992-01-01

    Preserving the high source brightness of the third generation of synchrotron radiation facilities will require that thermal and pressure deformations of the monochromator crystals be maintained within a few arc- seconds. Recent experiments at the National Synchrotron Light Source (NSLS) have demonstrated the potential of adaptive crystal optics to cope with high power densities. In this technique the crystals deformations are minimized both by an efficient water-jet cooling and by externally applied pressure loads. Thermal deformation can be reduced further with diamond crystals because of their high thermal conductivity and low coefficient of thermal expansion. In this paper we describe the results achieved by optimization of adaptive crystal optics for diamond crystals.

  4. Diamond crystallization in a CO2-rich alkaline carbonate melt with a nitrogen additive

    NASA Astrophysics Data System (ADS)

    Khokhryakov, Alexander F.; Palyanov, Yuri N.; Kupriyanov, Igor N.; Nechaev, Denis V.

    2016-09-01

    Diamond crystallization was experimentally studied in a CO2-bearing alkaline carbonate melt with an increased content of nitrogen at pressure of 6.3 GPa and temperature of 1500 °C. The growth rate, morphology, internal structure of overgrown layers, and defect-impurity composition of newly formed diamond were investigated. The type of growth patterns on faces, internal structure, and nitrogen content were found to be controlled by both the crystallographic orientation of the growth surfaces and the structure of the original faces of diamond seed crystals. An overgrown layer has a uniform structure on the {100} plane faces of synthetic diamond and a fibrillar (fibrous) structure on the faceted surfaces of a natural diamond cube. The {111} faces have a polycentric vicinal relief with numerous twin intergrowths and micro twin lamellae. The stable form of diamond growth under experimental conditions is a curved-face hexoctahedron with small cube faces. The nitrogen impurity concentration in overgrown layers varies depending on the growth direction and surface type, from 100 to 1100 ppm.

  5. Performance of a beam-multiplexing diamond crystal monochromator at the Linac Coherent Light Source.

    PubMed

    Zhu, Diling; Feng, Yiping; Stoupin, Stanislav; Terentyev, Sergey A; Lemke, Henrik T; Fritz, David M; Chollet, Matthieu; Glownia, J M; Alonso-Mori, Roberto; Sikorski, Marcin; Song, Sanghoon; van Driel, Tim B; Williams, Garth J; Messerschmidt, Marc; Boutet, Sébastien; Blank, Vladimir D; Shvyd'ko, Yuri V; Robert, Aymeric

    2014-06-01

    A double-crystal diamond monochromator was recently implemented at the Linac Coherent Light Source. It enables splitting pulses generated by the free electron laser in the hard x-ray regime and thus allows the simultaneous operations of two instruments. Both monochromator crystals are High-Pressure High-Temperature grown type-IIa diamond crystal plates with the (111) orientation. The first crystal has a thickness of ~100 μm to allow high reflectivity within the Bragg bandwidth and good transmission for the other wavelengths for downstream use. The second crystal is about 300 μm thick and makes the exit beam of the monochromator parallel to the incoming beam with an offset of 600 mm. Here we present details on the monochromator design and its performance.

  6. Performance of a beam-multiplexing diamond crystal monochromator at the Linac Coherent Light Source

    SciTech Connect

    Zhu, Diling Feng, Yiping; Lemke, Henrik T.; Fritz, David M.; Chollet, Matthieu; Glownia, J. M.; Alonso-Mori, Roberto; Sikorski, Marcin; Song, Sanghoon; Williams, Garth J.; Messerschmidt, Marc; Boutet, Sébastien; Robert, Aymeric; Stoupin, Stanislav; Shvyd'ko, Yuri V.; Terentyev, Sergey A.; Blank, Vladimir D.; Driel, Tim B. van

    2014-06-15

    A double-crystal diamond monochromator was recently implemented at the Linac Coherent Light Source. It enables splitting pulses generated by the free electron laser in the hard x-ray regime and thus allows the simultaneous operations of two instruments. Both monochromator crystals are High-Pressure High-Temperature grown type-IIa diamond crystal plates with the (111) orientation. The first crystal has a thickness of ∼100 μm to allow high reflectivity within the Bragg bandwidth and good transmission for the other wavelengths for downstream use. The second crystal is about 300 μm thick and makes the exit beam of the monochromator parallel to the incoming beam with an offset of 600 mm. Here we present details on the monochromator design and its performance.

  7. A photoemission study of the diamond and the single crystal C60

    SciTech Connect

    Wu, Jin

    1994-03-01

    This report studied the elctronic structure of diamond (100) and diamond/metal interface and C60, using angle-resolved and core level photoemission. The C(100)-(2X1) surface electronic structure was studied using both core level and angle resolved valence band photoemission spectroscopy. The surface component of the C 1s core level spectrum agrees with theoretical existence of only symmetrical dimers. In the case of metal/diamond interfaces, core level and valence photoelectron spectroscopy and LEED studies WERE MADE OF B and Sb on diamond (100) and (111) surfaces. In the case of single-crystal C60, photoemission spectra show sharp molecular features, indicating that the molecular orbitals are relatively undisturbed in solid C60.

  8. Erbium ion implantation into diamond - measurement and modelling of the crystal structure.

    PubMed

    Cajzl, Jakub; Nekvindová, Pavla; Macková, Anna; Malinský, Petr; Sedmidubský, David; Hušák, Michal; Remeš, Zdeněk; Varga, Marián; Kromka, Alexander; Böttger, Roman; Oswald, Jiří

    2017-02-22

    Diamond is proposed as an extraordinary material usable in interdisciplinary fields, especially in optics and photonics. In this contribution we focus on the doping of diamond with erbium as an optically active centre. In the theoretical part of the study based on DFT simulations we have developed two Er-doped diamond structural models with 0 to 4 carbon vacancies in the vicinity of the Er atom and performed geometry optimizations by the calculation of cohesive energies and defect formation energies. The theoretical results showed an excellent agreement between the calculated and experimental cohesive energies for the parent diamond. The highest values of cohesive energies and the lowest values of defect formation energies were obtained for models with erbium in the substitutional carbon position with 1 or 3 vacancies in the vicinity of the erbium atom. From the geometry optimization the structural model with 1 vacancy had an octahedral symmetry whereas the model with 3 vacancies had a coordination of 10 forming a trigonal structure with a hexagonal ring. In the experimental part, erbium doped diamond crystal samples were prepared by ion implantation of Er(+) ions using ion implantation fluences ranging from 1 × 10(14) ions per cm(2) to 5 × 10(15) ions per cm(2). The experimental results revealed a high degree of diamond structural damage after the ion implantation process reaching up to 69% of disordered atoms in the samples. The prepared Er-doped diamond samples annealed at the temperatures of 400, 600 and 800 °C in a vacuum revealed clear luminescence, where the 〈110〉 cut sample has approximately 6-7 times higher luminescence intensity than the 〈001〉 cut sample with the same ion implantation fluence. The reported results are the first demonstration of the Er luminescence in the single crystal diamond structure for the near-infrared spectral region.

  9. TH-C-19A-06: Measurements with a New Commercial Synthetic Single Crystal Diamond Detector

    SciTech Connect

    Laub, W; Crilly, R

    2014-06-15

    Purpose: A commercial version of a synthetic single crystal diamond detector in a Scottky diode configuration was recently released as the new type 60019 microDiamond detector (PTW-Freiburg). In this study we investigate the dosimetric properties of this detector and explore if the use of the microDiamond detector can be expanded to high energy photon beams of up to 15MV and to large field measurements. Methods: Energy dependency was investigated. Photon and electron depth-dose curves were measured. Photon PDDs were measured with the Semiflex type 31010, microLion type 31018, P-Diode type 60016, SRS Diode type 60018, and the microDiamond type 60019 detector. Electron depth-dose curves were measured with a Markus chamber type 23343, an E Diode type 60017 and the microDiamond type 60019 detector (all PTW-Freiburg). Profiles were measured with the E-Diode and microDiamond at dose maximum depths. Results: The microDiamond detector shows no energy dependence in high energy photon or electron dosimetry. Electron PDD measurements with the E-Diode and microDiamond are in good agreement except for the bremsstrahlungs region, where values are about 0.5 % lower with the microDiamond detector. Markus detector measurements agree with E-Diode measurements in this region. For depths larger than dmax, depth-dose curves of photon beams measured with the microDiamond detector are in close agreement to those measured with the microLion detector for small fields and with those measured with a Semiflex 0.125cc ionization chamber for large fields. For profile measurements, microDiamond detector measurements agree well with microLion and P-Diode measurements in the high-dose region and the penumbra region. For areas outside the open field, P-Diode measurements are about 0.5–1.0% higher than microDiamond and microLion measurements. Conclusion: The investigated diamond detector is suitable for a wide range of applications in high energy photon and electron dosimetry and is interesting

  10. Growth, Characterization and Device Development in Monocrystalline Diamond Films

    DTIC Science & Technology

    1990-02-01

    that the 7.51 misfit present in such particles has been accommodated at the twin boundaries rather than by elastic deformation. This creates a twin...high; however, a dramatic reduction in the defect density near the twin boundaries was observed. This defect reduction is significant because if its...view sample of a diamond film grown at 0.3% CH,. can be attributed to the presence of either stacking faults or coherent twin boundaries . A preliminary

  11. Science and technology of ultrananocrystalline diamond (UNCD) thin films for multifunctional devices.

    SciTech Connect

    Auciello, O.; Gruen, D. M.; Krauss, A. R.; Jayatissa, A.; Sumant, A.; Tucek, J.; Mancini, D.; Moldovan, N.; Erdemir, A.; Ersoy, D.; Gardos, M. N.; Busmann, H. G.; Meyer, E. M.

    2000-11-15

    MEMS devices are currently fabricated primarily in silicon because of the available surface machining technology. However, Si has poor mechanical and tribological properties, and practical MEMS devices are currently limited primarily to applications involving only bending and flexural motion, such as cantilever accelerometers and vibration sensors, However, because of the poor flexural strength and fracture toughness of Si, and the tendency of Si to adhere to hydrophyllic surfaces, even these simple devices have limited dynamic range. Future MEMS applications that involve significant rolling or sliding contact will require the use of new materials with significantly improved mechanical and tribological properties, and the ability to perform well in harsh environments. Diamond is a superhard material of high mechanical strength, exceptional chemical inertness, and outstanding thermal stability. The brittle fracture strength is 23 times that of Si, and the projected wear life of diamond MEMS moving mechanical assemblies (MEMS-MMAS) is 10,000 times greater than that of Si MMAs. However, as the hardest known material, diamond is notoriously difficult to fabricate. Conventional CVD thin film deposition methods offer an approach to the fabrication of ultra-small diamond structures, but the films have large grain size, high internal stress, poor intergranular adhesion, and very rough surfaces, and are consequently ill-suited for MEMS-MMA applications. A thin film deposition process has been developed that produces phase-pure ultrananocrystalline diamond (UNCD) with morphological and mechanical properties that are ideally suited for MEMS applications in general, and MMA use in particular. We have developed lithographic techniques for the fabrication of diamond microstructure including cantilevers and multi-level devices, acting as precursors to micro-bearings and gears, making UNCD a promising material for the development of high performance MEMS devices.

  12. Single-Crystal Diamond Nanowire Tips for Ultrasensitive Force Microscopy.

    PubMed

    Tao, Y; Degen, C L

    2015-12-09

    We report the fabrication, integration, and assessment of sharp diamond tips for ultrasensitive force microscopy experiments. Two types of tips, corresponding to the upper and lower halves of a diamond nanowire, were fabricated by top-down plasma etching from a single-crystalline substrate. The lower, surface-attached halves can be directly integrated into lithographically defined nanostructures, like cantilevers. The upper, detachable halves result in diamond nanowires with a tunable diameter (50-500 nm) and lengths of a few microns. Tip radii were around 10 nm and tip apex angles around 15°. We demonstrate the integration of diamond nanowires for use as scanning tips onto ultrasensitive pendulum-style silicon cantilevers. We find the noncontact friction and frequency jitter to be exceptionally low, with no degradation in the intrinsic mechanical quality factor (Q ≈ 130,000) down to tip-to-surface distances of about 10 nm. Our results are an encouraging step toward further improvement of the sensitivity and resolution of force-detected magnetic resonance imaging.

  13. Growth, Characterization and Device Development in Monocrystalline Diamond Films

    DTIC Science & Technology

    1993-09-01

    step of the selection process used a program called ORPHEUS developed by Braun [6, 7]. The program overlays the reciprocal surface nets of the substrate... ORPHEUS program. 4 J l i •mmmm •mm [ m ] m m immI Those results are summarized in Table II. The strain energy density was lowest for Ni{O01) interlayers on...hydrogen evolves and the surface to change to a positive electron affinity. The free diamond (M(X)) surface has two unsatisfied bonds which would in

  14. Potentiality of semiconducting diamond as the base material of millimeter-wave and terahertz IMPATT devices

    NASA Astrophysics Data System (ADS)

    Acharyya, Aritra; Banerjee, Suranjana; Banerjee, J. P.

    2014-03-01

    An attempt is made in this paper to explore the potentiality of semiconducting type-IIb diamond as the base material of double-drift region (DDR) impact avalanche transit time (IMPATT) devices operating at both millimetre-wave (mm-wave) and terahertz (THz) frequencies. A rigorous large-signal (L-S) simulation based on the non-sinusoidal voltage excitation (NSVE) model developed earlier by the authors is used in this study. At first, a simulation study based on avalanche response time reveals that the upper cut-off frequency for DDR diamond IMPATTs is 1.5 THz, while the same for conventional DDR Si IMPATTs is much smaller, i.e. 0.5 THz. The L-S simulation results show that the DDR diamond IMPATT device delivers a peak RF power of 7.79 W with an 18.17% conversion efficiency at 94 GHz; while at 1.5 THz, the peak power output and conversion efficiency decrease to 6.19 mW and 8.17% respectively, taking 50% voltage modulation. A comparative study of DDR IMPATTs based on diamond and Si shows that the former excels over the later as regards high frequency and high power performance at both mm-wave and THz frequency bands. The effect of band to band tunneling on the L-S properties of DDR diamond and Si IMPATTs has also been studied at different mm-wave and THz frequencies.

  15. Fabrication of three-dimensional terahertz photonic crystals with diamond structure by particle manipulation assembly

    NASA Astrophysics Data System (ADS)

    Takagi, Kenta; Kawasaki, Akira

    2009-01-01

    We reported the fabrication of terahertz photonic crystals by three-dimensional (3D) particle manipulation assembly. Our method, which is based on pick-and-place manipulation and interparticle laser welding, enabled accurate assembling of an arbitrary 3D structure, regardless of particle polydispersity. By using this method, we fabricated a diamond crystal from ZrO2/polyethylene composite particles (diameter of 400 μm). The obtained crystal exhibited a photonic stop gap in the ⟨111⟩ direction; this result was in good agreement with the theoretical result, suggesting that the crystal has a full photonic bandgap at around 0.2 THz.

  16. Development of Single Crystal Chemical Vapor Deposition Diamonds for Detector Applications

    SciTech Connect

    Kagan, Harris; Kass, Richard; Gan, K. K.

    2014-01-23

    With the LHC upgrades in 2013, and further LHC upgrades scheduled in 2018, most LHC experiments are planning for detector upgrades which require more radiation hard technologies than presently available. At present all LHC experiments now have some form of diamond detector. As a result Chemical Vapor Deposition (CVD) diamond has now been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of all LHC experiments. Moreover CVD diamond is now being discussed as an alternative sensor material for tracking very close to the interaction region of the HL-LHC where the most extreme radiation conditions will exist. Our work addressed the further development of the new material, single-crystal Chemical Vapor Deposition diamond, towards reliable industrial production of large pieces and new geometries needed for detector applications. Our accomplishments include: • Developed a two U.S.companies to produce electronic grade diamond, • Worked with companies and acquired large area diamond pieces, • Performed radiation hardness tests using various proton energies: 70 MeV (Cyric, Japan), 800 MeV (Los Alamos), and 24 GeV (CERN).

  17. Scalable Fabrication of Integrated Nanophotonic Circuits on Arrays of Thin Single Crystal Diamond Membrane Windows.

    PubMed

    Piracha, Afaq H; Rath, Patrik; Ganesan, Kumaravelu; Kühn, Stefan; Pernice, Wolfram H P; Prawer, Steven

    2016-05-11

    Diamond has emerged as a promising platform for nanophotonic, optical, and quantum technologies. High-quality, single crystalline substrates of acceptable size are a prerequisite to meet the demanding requirements on low-level impurities and low absorption loss when targeting large photonic circuits. Here, we describe a scalable fabrication method for single crystal diamond membrane windows that achieves three major goals with one fabrication method: providing high quality diamond, as confirmed by Raman spectroscopy; achieving homogeneously thin membranes, enabled by ion implantation; and providing compatibility with established planar fabrication via lithography and vertical etching. On such suspended diamond membranes we demonstrate a suite of photonic components as building blocks for nanophotonic circuits. Monolithic grating couplers are used to efficiently couple light between photonic circuits and optical fibers. In waveguide coupled optical ring resonators, we find loaded quality factors up to 66 000 at a wavelength of 1560 nm, corresponding to propagation loss below 7.2 dB/cm. Our approach holds promise for the scalable implementation of future diamond quantum photonic technologies and all-diamond photonic metrology tools.

  18. Wettability of ultrananocrystalline diamond and graphite nanowalls films: a comparison with their single crystal analogs.

    PubMed

    Ostrovskaya, L Y u; Ralchenko, V G; Bolshakov, A P; Saveliev, A V; Dzbanovsky, N N; Shmegera, S V

    2009-06-01

    Dramatic changes in wettability of diamond and graphite are observed when these materials are prepared in nanostructured forms--undoped and nitrogen-doped ultrananocrystalline diamond (UNCD) films, and graphite nanowalls (GNW), respectively. The nanostructured carbon films were deposited on Si by microwave plasma CVD processes. The advancing contact angle theta for water on hydrogenated undoped UNCD films increases to 106 +/- 3 degrees compared to hydrogenated single crystal diamond (theta = 92 degrees). Nitrogen doping (N2 addition to plasma) during UNCD growth makes the film more hydrophilic. The GNW films exhibited superhydrophobic behavior with theta = 144 +/- 3 degrees for water, which is higher than the contact angle of monocrystalline graphite (the basal plane) by a factor of 1.8. No chemical surface treatment is necessary to achieve such high hydrophobicity, it is accomplished solely by a specific (nanoporous, high aspect ratio) surface morphology with very low free surface energy inherent in it. The wetting behaviour of nanostructured films can be described with the Cassie-Baxter equation for heterophase nanoporous surfaces. Oxidation and hydrogenation of UNCD films make it possible to control theta over a much wider range as compared to a single crystal diamond. The influence of diamond grain size on wetting is considered taking into account the surface treatment. The corresponding variation in surface energy has been determined by the modified Young's equation.

  19. Effects of catalyst height on diamond crystal morphology under high pressure and high temperature

    NASA Astrophysics Data System (ADS)

    Ya-Dong, Li; Xiao-Peng, Jia; Bing-Min, Yan; Ning, Chen; Chao, Fang; Yong, Li; Hong-An, Ma

    2016-04-01

    The effect of the catalyst height on the morphology of diamond crystal is investigated by means of temperature gradient growth (TGG) under high pressure and high temperature (HPHT) conditions with using a Ni-based catalyst in this article. The experimental results show that the morphology of diamond changes from an octahedral shape to a cub-octahedral shape as the catalyst height rises. Moreover, the finite element method (FEM) is used to simulate the temperature field of the melted catalyst/solvent. The results show that the temperature at the location of the seed diamond continues to decrease with the increase of catalyst height, which is conducive to changing the morphology of diamond. This work provides a new way to change the diamond crystal morphology. Project supported by the National Natural Science Foundation of China (Grant No. 51172089), the Program for New Century Excellent Talents in University, the Natural Science Foundation of Guizhou Provincial Education Department (Grant No. KY[2013]183), and the Collaborative Fund of Science and Technology Office of Guizhou Province, China (Grant No. LH[2015]7232).

  20. Characterization of a synthetic single crystal diamond Schottky diode for radiotherapy electron beam dosimetry

    SciTech Connect

    Di Venanzio, C.; Marinelli, Marco; Milani, E.; Prestopino, G.; Verona, C.; Verona-Rinati, G.; Falco, M. D.; Bagala, P.; Santoni, R.; Pimpinella, M.

    2013-02-15

    Purpose: To investigate the dosimetric properties of synthetic single crystal diamond based Schottky diodes under irradiation with therapeutic electron beams from linear accelerators. Methods: A single crystal diamond detector was fabricated and tested under 6, 8, 10, 12, and 15 MeV electron beams. The detector performances were evaluated using three types of commercial detectors as reference dosimeters: an Advanced Markus plane parallel ionization chamber, a Semiflex cylindrical ionization chamber, and a p-type silicon detector. Preirradiation, linearity with dose, dose rate dependence, output factors, lateral field profiles, and percentage depth dose profiles were investigated and discussed. Results: During preirradiation the diamond detector signal shows a weak decrease within 0.7% with respect to the plateau value and a final signal stability of 0.1% (1{sigma}) is observed after about 5 Gy. A good linear behavior of the detector response as a function of the delivered dose is observed with deviations below {+-}0.3% in the dose range from 0.02 to 10 Gy. In addition, the detector response is dose rate independent, with deviations below 0.3% in the investigated dose rate range from 0.17 to 5.45 Gy/min. Percentage depth dose curves obtained from the diamond detector are in good agreement with the ones from the reference dosimeters. Lateral beam profile measurements show an overall good agreement among detectors, taking into account their respective geometrical features. The spatial resolution of solid state detectors is confirmed to be better than that of ionization chambers, being the one from the diamond detector comparable to that of the silicon diode. A good agreement within experimental uncertainties was also found in terms of output factor measurements between the diamond detector and reference dosimeters. Conclusions: The observed dosimetric properties indicate that the tested diamond detector is a suitable candidate for clinical electron beam dosimetry.

  1. Electrocatalytic processes promoted by diamond nanoparticles in enzymatic biosensing devices.

    PubMed

    Briones, M; Petit-Domínguez, M D; Parra-Alfambra, A M; Vázquez, L; Pariente, F; Lorenzo, E; Casero, E

    2016-10-01

    We have developed a biosensing platform for lactate determination based on gold electrodes modified with diamond nanoparticles of 4nm of nominal diameter, employing the enzyme lactate oxidase and (hydroxymethyl)ferrocene (HMF) as redox mediator in solution. This system displays a response towards lactate that is completely different to those typically observed for lactate biosensors based on other nanomaterials, such as graphene, carbon nanotubes, gold nanoparticles or even diamond nanoparticles of greater size. We have observed by cyclic voltammetry that, under certain experimental conditions, an irreversible wave (E(0)=+0.15V) appears concomitantly with the typical Fe(II)/Fe(III) peaks (E(0)=+0.30V) of HMF. In this case, the biosensor response to lactate shows simultaneous electrocatalytic peaks at +0.15V and +0.30V, indicating the concurrence of different feedback mechanisms. The achievement of a biosensor response to lactate at +0.15V is very convenient in order to avoid potential interferences. The developed biosensor presents a linear concentration range from 0.02mM to 1.2mM, a sensitivity of 6.1μAmM(-1), a detection limit of 5.3μM and excellent stability. These analytical properties compare well with those obtained for other lactate-based biosensors that also include nanomaterials and employ HMF as redox mediator.

  2. White electroluminescence of n-ZnO:Al/p-diamond heterostructure devices

    NASA Astrophysics Data System (ADS)

    Yang, Can; Wang, Xiao-Ping; Wang, Li-Jun; Pan, Xiu-Fang; Li, Song-Kun; Jing, Long-Wei

    2013-08-01

    An n-ZnO:Al/p-boron-doped diamond heterostructure electroluminescent device is produced, and a rectifying behavior can be observed. The electroluminescence spectrum at room temperature exhibits two visible bands centred at 450 nm-485 nm (blue emission) and 570 nm-640 nm (yellow emission). Light emission with a luminance of 15 cd/m2 is observed from the electroluminescent device at a forward applied voltage of 85 V, which is distinguished from white light by the naked eye.

  3. Ultrananocrystalline diamond thin films for MEMS and moving mechanical assembly devices.

    SciTech Connect

    Krauss, A. R.; Gruen, D. M.; Jayatissa, A.; Sumant, A.; Tucek, J.; Auciello, O.; Mancini, D.; Moldovan, N.; Erdemir, A.; Ersoy, D.; Gardos, M. N.; Busmann, H. G.; Meyer, E. M.; Ding, M. Q.; Univ. of Illinois at Chicago; Raytheon Electronic Systems Comp.; Fraunhofer Inst. for Applied Materials Science; Univ. of Bremen; Beijing Inst. of Electronics

    2001-11-01

    MEMS devices are currently fabricated primarily in silicon because of the available surface machining technology. A major problem with the Si-based MEMS technology is that Si has poor mechanical and tribological properties [J.J. Sniegowski, in: B. Bushan (Ed.), Tribology Issues and Opportunities in MEMS, Kluwer Academic Publisher, The Netherlands, 1998, p. 325; A.P. Lee, A.P. Pisano, M.G. Lim, Mater. Res. Soc. Symp. Proc. 276 (1992) 67.], and practical MEMS devices are currently limited primarily to applications involving only bending and flexural motion, such as cantilever accelerometers and vibration sensors. However, because of the poor flexural strength and fracture toughness of Si, and the tendency of Si to adhere to hydrophilic surfaces, even these simple devices have limited dynamic range. Future MEMS applications that involve significant rolling or sliding contact will require the use of new materials with significantly improved mechanical and tribological properties, and the ability to perform well in harsh environments, Diamond is a superhard material of high mechanical strength, exceptional chemical inertness, and outstanding thermal stability. The brittle fracture strength is 23 times that of Si, and the projected wear life of diamond MEMS moving mechanical assemblies (MEMS MMAs) is 10 000 times greater than that of Si MMAs. However, as the hardest known material, diamond is notoriously difficult to fabricate. Conventional CVD thin film deposition methods offer an approach to the fabrication of ultra-small diamond structures, but the films have large grain size, high internal stress, poor intergranular adhesion, and very rough surfaces, and are consequently ill-suited for MEMS MMA applications. Diamond-like films are also being investigated for application to MEMS devices. However, they involve mainly physical vapor deposition methods that are not suitable for good conformal deposition on high aspect ratio features, and generally they do not exhibit the

  4. Diamond photonic crystal slab: leaky modes and modified photoluminescence emission of surface-deposited quantum dots.

    PubMed

    Ondič, Lukáš; Babchenko, Oleg; Varga, Marián; Kromka, Alexander; Ctyroký, Jiří; Pelant, Ivan

    2012-01-01

    Detailed analysis of a band diagram of a photonic crystal (PhC) slab prepared on a nano-diamond layer is presented. Even though the PhC is structurally imperfect, the existence of leaky modes, determined both theoretically and experimentally in the broad spectral region, implies that an efficient light interaction with a material periodicity occurs in the sample. It is shown that the luminescence emission spectrum of a light source placed directly on the PhC surface can be modified by employing the optical modes of the studied structure. We stress also the impact of intrinsic optical losses of the nano-diamond on this modification.

  5. Single-crystal CVD diamonds as small-angle X-ray scattering windows for high-pressure research.

    PubMed

    Wang, Suntao; Meng, Yu-Fei; Ando, Nozomi; Tate, Mark; Krasnicki, Szczesny; Yan, Chih-Shiue; Liang, Qi; Lai, Joseph; Mao, Ho-Kwang; Gruner, Sol M; Hemley, Russell J

    2012-06-01

    Small-angle X-ray scattering (SAXS) was performed on single-crystal chemical vapor deposition (CVD) diamonds with low nitrogen concentrations, which were fabricated by microwave plasma-assisted chemical vapor deposition at high growth rates. High optical quality undoped 500 µm-thick single-crystal CVD diamonds grown without intentional nitrogen addition proved to be excellent as windows on SAXS cells, yielding parasitic scattering no more intense than a 7.5 µm-thick Kapton film. A single-crystal CVD diamond window was successfully used in a high-pressure SAXS cell.

  6. Development of Single Crystal Chemical Vapor Deposition Diamonds for Detector Applications

    SciTech Connect

    Rainer Wallny

    2012-10-15

    Diamond was studied as a possible radiation hard technology for use in future high radiation environments. With the commissioning of the LHC expected in 2010, and the LHC upgrades expected in 2015, all LHC experiments are planning for detector upgrades which require radiation hard technologies. Chemical Vapor Deposition (CVD) diamond has now been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle and CDF and is installed and operational in all LHC experiments. As a result, this material is now being discussed as an alternative sensor material for tracking very close to the interaction region of the super-LHC where the most extreme radiation conditions will exist. Our work addressed the further development of the new material, single-crystal Chemical Vapor Deposition diamond, towards reliable industrial production of large pieces and new geometries needed for detector applications.

  7. Time Dependent DD Neutrons Measurement Using a Single Crystal Chemical Vapor Deposition Diamond Detector on EAST

    NASA Astrophysics Data System (ADS)

    Du, Tengfei; Peng, Xingyu; Chen, Zhongjing; Hu, Zhimeng; Ge, Lijian; Hu, Liqun; Zhong, Guoqiang; Pu, Neng; Chen, Jinxiang; Fan, Tieshuan

    2016-09-01

    A single crystal chemical vapor deposition (scCVD) diamond detector has been successfully employed for neutron measurements in the EAST (Experimental Advanced Superconducting Tokamak) plasmas. The scCVD diamond detector coated with a 5 μm 6LiF (95% 6Li enriched) layer was placed inside a polyethylene moderator to enhance the detection efficiency. The time-dependent neutron emission from deuteron plasmas during neutral beam injection (NBI) heating was obtained. The measured results are compared with that of fission chamber detectors, which always act as standard neutron flux monitors. The scCVD diamond detector exhibits good reliability, stability and the capability to withstand harsh radiation environments despite its low detection efficiency due to the small active volume. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB106004 and 2012GB101003) and National Natural Science Foundation of China (No. 91226102)

  8. Diamond fiber field emitters

    DOEpatents

    Blanchet-Fincher, Graciela B.; Coates, Don M.; Devlin, David J.; Eaton, David F.; Silzars, Aris K.; Valone, Steven M.

    1996-01-01

    A field emission electron emitter comprising an electrode formed of at least one diamond, diamond-like carbon or glassy carbon composite fiber, said composite fiber having a non-diamond core and a diamond, diamond-like carbon or glassy carbon coating on said non-diamond core, and electronic devices employing such a field emission electron emitter.

  9. Science and technology of piezoelectric/diamond heterostructures for monolithically integrated high performance MEMS/NEMS/CMOS devices.

    SciTech Connect

    Auciello, O.; Sumant, A. V.; Hiller, J.; Kabius, B.; Ma, Z.; Srinivasan, S.

    2008-12-01

    This paper describes the fundamental and applied science performed to integrate piezoelectric PbZr{sub x}Ti{sub 1-x}O{sub 3} and AlN films with a novel mechanically robust ultrananocrystalline diamond layer to enable a new generation of low voltage/high-performance piezoactuated hybrid piezoelectric/diamond MEMS/NEMS devices.

  10. Clinical radiation therapy measurements with a new commercial synthetic single crystal diamond detector.

    PubMed

    Laub, Wolfram U; Crilly, Richard

    2014-11-08

    A commercial version of a synthetic single crystal diamond detector (SCDD) in a Schottky diode configuration was recently released as the new type 60019 microDiamond detector (PTW-Freiburg, Germany). In this study we investigate the dosimetric properties of this detector to independently confirm that findings from the developing group of the SCDDs still hold true for the commercial version of the SCDDs. We further explore if the use of the microDiamond detector can be expanded to high-energy photon beams of up to 15 MV and to large field measure- ments. Measurements were performed with an Elekta Synergy linear accelerator delivering 6, 10, and 15 MV X-rays, as well as 6, 9, 12, 15, and 20 MeV electron beams. The dependence of the microdiamond detector response on absorbed dose after connecting the detector was investigated. Furthermore, the dark current of the diamond detector was observed after irradiation. Results are compared to similar results from measurements with a diamond detector type 60003. Energy dependency was investigated, as well. Photon depth-dose curves were measured for field sizes 3 × 3, 10 × 10, and 30 × 30 cm2. PDDs were measured with the Semiflex type 31010 detector, microLion type 31018 detector, P Diode type 60016, SRS Diode type 60018, and the microDiamond type 60019 detector (all PTW-Freiburg). Photon profiles were measured at a depth of 10 cm. Electron depth-dose curves normalized to the dose maximum were measured with the 14 × 14 cm2 electron cone. PDDs were measured with a Markus chamber type 23343, an E Diode type 60017 and the microDiamond type 60019 detector (all PTW-Freiburg). Profiles were measured with the E Diode and microDiamond at half of D90, D90, D70, and D50 depths and for electron cone sizes of 6 × 6 cm2, 14 × 14 cm2, and 20 × 20 cm2. Within a tol- erance of 0.5% detector response of the investigated detector was stable without any preirradiation. After preirradition with approximately 250 cGy the detector response

  11. N-type control of single-crystal diamond films by ultra-lightly phosphorus doping

    NASA Astrophysics Data System (ADS)

    Kato, Hiromitsu; Ogura, Masahiko; Makino, Toshiharu; Takeuchi, Daisuke; Yamasaki, Satoshi

    2016-10-01

    A wide impurity doping range of p- and n-type diamond semiconductors will facilitate the development of various electronics. This study focused on producing n-type diamond with ultra-lightly impurity doping concentrations. N-type single-crystal diamond films were grown on (111)-oriented diamond substrates by phosphorus doping using the optimized doping conditions based on microwave plasma-enhanced chemical vapor deposition with a high magnetron output power of 3600 W. The surface morphology was investigated by an optical microscopy using the Nomarski prism and confocal laser microscopy, and the phosphorus concentration was estimated by a secondary ion mass spectrometry. The phosphorus concentration was reproducibly controlled to between 2 × 1015 and 3 × 1017 cm-3 using a standard mass flow controller, and the average incorporation efficiency was around 0.1%. The electrical properties of the films were characterized by the Hall effect measurements as a function of temperature over a wide range from 220 to 900 K. N-type conductivity with thermal activation from a phosphorus donor level at around 0.57 eV was clearly observed for all the phosphorus-doped diamond films. The electron mobility of the film with a phosphorus concentration of 2 × 1015 cm-3 was recorded at 1060 cm2/V s at 300 K and 1500 cm2/V s at 225 K.

  12. First in-situ single-crystal structure refinement of a garnet included in diamond

    NASA Astrophysics Data System (ADS)

    Nestola, Fabrizio; Nimis, Paolo; Longo, Micaela; Kopylova, Maya; de Stefano, Andrea; Marzoli, Andrea; Fedortchouk, Yana; Manghnani, Murli; Harris, Jeff W.

    2010-05-01

    The study of mineral inclusions in diamond is providing invaluable insight into the geodynamics of the Earth's mantle. A complete characterization of inclusions in diamond is fundamental in order to evaluate the P-T-ƒO2 conditions and thus they represent a real "Earth's ultra-deep microprobe". The in-situ investigation of the inclusions using non-destructive techniques remains challenging. One of the potentially most powerful non-destructive methods is single-crystal X-ray diffraction. The application of such technique on inclusions in diamond is hampered by the complicated centering of the X-ray beam on the inclusion single-crystal (Kunz et al. 2002). Because of this experimental problem, in-situ single-crystal structure refinements of inclusions in diamond have never been carried out. In this work we investigated by X-ray diffraction a diamond-hosted garnet single-crystal from the Jericho kimberlite (Slave Craton, Canada). The garnet, not clearly visible under the microscope due to the irregular shape of the diamond host, had the largest size not greater than 100 microns. We used two STADI-IV STOE single-crystal diffractometers: the first instrument, equipped with a CCD detector, allowed us to collect a large number of diffraction reflections and to obtain an approximate orientation matrix for the garnet. Using this matrix, we mounted the diamond on the second instrument, equipped with a point detector and the software SINGLE (Angel et al. 2000), capable of obtaining an accurate X-ray beam centering through the 8-position centering method (this method is often used in high-pressure, in-situ X-ray studies). Such a procedure allowed us to measure with very high accuracy and precision the unit-cell edge (a = 11.5826(2)Å). Then we mounted back the diamond with the perfectly centered garnet on the first diffractometer and collected a complete X-ray intensity dataset in order to obtain complete structural information. We collected 410 unique reflections up to 2theta

  13. Numerical modeling of thermal loading of diamond crystal in X-ray FEL oscillators

    NASA Astrophysics Data System (ADS)

    Song, Mei-Qi; Zhang, Qing-Min; Guo, Yu-Hang; Li, Kai; Deng, Hai-Xiao

    2016-04-01

    Due to high reflectivity and high resolution of X-ray pulses, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono-chromator in the next generation of free electron lasers (FELs). The energy deposition of X-rays will result in thermal heating, and thus lattice expansion of the diamond crystal, which may degrade the performance of X-ray FELs. In this paper, the thermal loading effect of diamond crystal for X-ray FEL oscillators has been systematically studied by combined simulation with Geant4 and ANSYS, and its dependence on the environmental temperature, crystal size, X-ray pulse repetition rate and pulse energy are presented. Our results show that taking the thermal loading effects into account, X-ray FEL oscillators are still robust and promising with an optimized design. Supported by National Natural Science Foundation of China (11175240, 11205234, 11322550) and Program for Changjiang Scholars and Innovative Research Team in University (IRT1280)

  14. Electroluminescence from a diamond device with ion-beam-micromachined buried graphitic electrodes

    NASA Astrophysics Data System (ADS)

    Forneris, J.; Battiato, A.; Gatto Monticone, D.; Picollo, F.; Amato, G.; Boarino, L.; Brida, G.; Degiovanni, I. P.; Enrico, E.; Genovese, M.; Moreva, E.; Traina, P.; Verona, C.; Verona Rinati, G.; Olivero, P.

    2015-04-01

    Focused MeV ion microbeams are suitable tools for the direct writing of conductive graphitic channels buried in an insulating diamond bulk, as demonstrated in previous works with the fabrication of multi-electrode ionizing radiation detectors and cellular biosensors. In this work we investigate the suitability of the fabrication method for the electrical excitation of color centers in diamond. Differently from photoluminescence, electroluminescence requires an electrical current flowing through the diamond sub-gap states for the excitation of the color centers. With this purpose, buried graphitic electrodes with a spacing of 10 μm were fabricated in the bulk of a detector-grade CVD single-crystal diamond sample using a scanning 1.8 MeV He+ micro-beam. The current flowing in the gap region between the electrodes upon the application of a 450 V bias voltage was exploited as the excitation pump for the electroluminescence of different types of color centers localized in the above-mentioned gap. The bright light emission was spatially mapped using a confocal optical microscopy setup. The spectral analysis of electroluminescence revealed the emission from neutrally-charged nitrogen-vacancy centers (NV0, λZPL = 575 nm), as well as from cluster crystal dislocations (A-band, λ = 400-500 nm). Moreover, an electroluminescence signal with appealing spectral features (sharp emission at room temperature, low phonon sidebands) from He-related defects was detected (λZPL = 536.3 nm, λZPL = 560.5 nm); a low and broad peak around λ = 740 nm was also observed and tentatively ascribed to Si-V or GR1 centers. These results pose interesting future perspectives for the fabrication of electrically-stimulated single-photon emitters in diamond for applications in quantum optics and quantum cryptography.

  15. Liquid crystal devices for photonics applications

    NASA Astrophysics Data System (ADS)

    Chigrinov, Vladimir G.

    2007-11-01

    Liquid crystal (LC) devices for Photonics applications is a hot topic of research. Such elements begin to appear in Photonics market. Passive elements for fiber optical communication systems (DWDM components) based on LC cells can successfully compete with the other elements used for the purpose, such as micro electromechanical (MEM), thermo-optical, opto-mechanical or acousto-optical devices. Application of nematic and ferroelectric LC for high speed communication systems, producing elements that are extremely fast, stable, durable, of low loss, operable over a wide temperature range, and that require small operating voltages and extremely low power consumption. The known LC applications in fiber optics enable to produce switches, filters, attenuators, equalizers, polarization controllers, phase emulators and other fiber optical components. Good robustness due to the absence of moving parts and compatibility with VLSI technology, excellent parameters in a large photonic wavelength range, whereas the complexity of the design and the cost of the device are equivalent to regular passive matrix LC displays makes LC fiber optical devices very attractive for mass production. We have already successfully fabricated certain prototypes of the optical switches based on ferroelectric and nematic LC materials. The electrooptical modes used for the purpose included the light polarization rotation, voltage controllable diffraction and fast switching of the LC refractive index. We used the powerful software to optimize the LC modulation characteristics. Use of photo-alignment technique pioneered by us makes it possible to develop new LC fiber components. Almost all the criteria of perfect LC alignment are met in case of azo-dye layers. We have already used azo-dye materials to align LC in superthin photonic holes, curved and 3D surfaces and as cladding layers in microring silicon based resonators. The prototypes of new LC efficient Photonics devices are envisaged. Controllable

  16. Optical emission diagnostics of plasmas in chemical vapor deposition of single-crystal diamond

    SciTech Connect

    Hemawan, Kadek W.; Hemley, Russell J.

    2015-08-03

    Here, a key aspect of single crystal diamond growth via microwave plasma chemical vapor deposition is in-process control of the local plasma-substrate environment, that is, plasma gas phase concentrations of activated species at the plasma boundary layer near the substrate surface. Emission spectra of the plasma relative to the diamond substrate inside the microwave plasma reactor chamber have been analyzed via optical emission spectroscopy. The spectra of radical species such as CH, C2, and H (Balmer series) important for diamond growth were found to be more depndent on operating pressure than on microwave power. Plasma gas temperatures were calculated from measurements of the C2 Swan band (d3Π → a3Π transition) system. The plasma gas temperature ranges from 2800 to 3400 K depending on the spatial location of the plasma ball, microwave power and operating pressure. Addition of Ar into CH4 + H2 plasma input gas mixture has little influence on the Hα, Hβ, and Hγ intensities and single-crystal diamond growth rates.

  17. Optical emission diagnostics of plasmas in chemical vapor deposition of single-crystal diamond

    SciTech Connect

    Hemawan, Kadek W. Hemley, Russell J.

    2015-11-15

    A key aspect of single crystal diamond growth via microwave plasma chemical vapor deposition is in-process control of the local plasma–substrate environment, that is, plasma gas phase concentrations of activated species at the plasma boundary layer near the substrate surface. Emission spectra of the plasma relative to the diamond substrate inside the microwave plasma reactor chamber have been analyzed via optical emission spectroscopy. The spectra of radical species such as CH, C{sub 2}, and H (Balmer series) important for diamond growth were identified and analyzed. The emission intensities of these electronically excited species were found to be more dependent on operating pressure than on microwave power. Plasma gas temperatures were calculated from measurements of the C{sub 2} Swan band (d{sup 3}Π → a{sup 3}Π transition) system. The plasma gas temperature ranges from 2800 to 3400 K depending on the spatial location of the plasma ball, microwave power and operating pressure. Addition of Ar into CH{sub 4}+H{sub 2} plasma input gas mixture has little influence on the Hα, Hβ, and Hγ intensities and single-crystal diamond growth rates.

  18. Optical emission diagnostics of plasmas in chemical vapor deposition of single-crystal diamond

    DOE PAGES

    Hemawan, Kadek W.; Hemley, Russell J.

    2015-08-03

    Here, a key aspect of single crystal diamond growth via microwave plasma chemical vapor deposition is in-process control of the local plasma-substrate environment, that is, plasma gas phase concentrations of activated species at the plasma boundary layer near the substrate surface. Emission spectra of the plasma relative to the diamond substrate inside the microwave plasma reactor chamber have been analyzed via optical emission spectroscopy. The spectra of radical species such as CH, C2, and H (Balmer series) important for diamond growth were found to be more depndent on operating pressure than on microwave power. Plasma gas temperatures were calculated frommore » measurements of the C2 Swan band (d3Π → a3Π transition) system. The plasma gas temperature ranges from 2800 to 3400 K depending on the spatial location of the plasma ball, microwave power and operating pressure. Addition of Ar into CH4 + H2 plasma input gas mixture has little influence on the Hα, Hβ, and Hγ intensities and single-crystal diamond growth rates.« less

  19. Cryptic iridescence in a fossil weevil generated by single diamond photonic crystals.

    PubMed

    McNamara, Maria E; Saranathan, Vinod; Locatelli, Emma R; Noh, Heeso; Briggs, Derek E G; Orr, Patrick J; Cao, Hui

    2014-11-06

    Nature's most spectacular colours originate in integumentary tissue architectures that scatter light via nanoscale modulations of the refractive index. The most intricate biophotonic nanostructures are three-dimensional crystals with opal, single diamond or single gyroid lattices. Despite intense interest in their optical and structural properties, the evolution of such nanostructures is poorly understood, due in part to a lack of data from the fossil record. Here, we report preservation of single diamond (Fd-3m) three-dimensional photonic crystals in scales of a 735,000 year old specimen of the brown Nearctic weevil Hypera diversipunctata from Gold Run, Canada, and in extant conspecifics. The preserved red to green structural colours exhibit near-field brilliancy yet are inconspicuous from afar; they most likely had cryptic functions in substrate matching. The discovery of pristine fossil examples indicates that the fossil record is likely to yield further data on the evolution of three-dimensional photonic nanostructures and their biological functions.

  20. Cryptic iridescence in a fossil weevil generated by single diamond photonic crystals

    PubMed Central

    McNamara, Maria E.; Saranathan, Vinod; Locatelli, Emma R.; Noh, Heeso; Briggs, Derek E. G.; Orr, Patrick J.; Cao, Hui

    2014-01-01

    Nature's most spectacular colours originate in integumentary tissue architectures that scatter light via nanoscale modulations of the refractive index. The most intricate biophotonic nanostructures are three-dimensional crystals with opal, single diamond or single gyroid lattices. Despite intense interest in their optical and structural properties, the evolution of such nanostructures is poorly understood, due in part to a lack of data from the fossil record. Here, we report preservation of single diamond (Fd-3m) three-dimensional photonic crystals in scales of a 735 000 year old specimen of the brown Nearctic weevil Hypera diversipunctata from Gold Run, Canada, and in extant conspecifics. The preserved red to green structural colours exhibit near-field brilliancy yet are inconspicuous from afar; they most likely had cryptic functions in substrate matching. The discovery of pristine fossil examples indicates that the fossil record is likely to yield further data on the evolution of three-dimensional photonic nanostructures and their biological functions. PMID:25185581

  1. The world's first high voltage GaN-on-Diamond power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Baltynov, Turar; Unni, Vineet; Narayanan, E. M. Sankara

    2016-11-01

    This paper presents the detailed fabrication method and extensive electrical characterisation results of the first-ever demonstrated high voltage GaN power semiconductor devices on CVD Diamond substrate. Fabricated circular GaN-on-Diamond HEMTs with gate-to-drain drift length of 17 μm and source field plate length of 3 μm show an off-state breakdown voltage of ∼1100 V. Temperature characterisation of capacitance-voltage characteristics and on-state characteristics provides insight on the temperature dependence of key parameters such as threshold voltage, 2DEG sheet carrier concentration, specific on-state resistance, and drain saturation current in the fabricated devices.

  2. Growth, Characterization and Device Development in Monocrystalline Diamond Films

    DTIC Science & Technology

    1991-09-30

    involving the diffusion of dissolved C down thermal gradients have resulted in the formation of graphite at the surface or interface of the Cu crystals. Metal...hotter interface. The resultant concentration gradient provides a driving force to move solute through the liquid zone from the hotter to the cooler...the Ni surface . C. Results & Discussion 1. Ion Implantation and Annealing An XPS survey scan was performed on the Cu (100) implanted substrate following

  3. Color center fluorescence and spin manipulation in single crystal, pyramidal diamond tips

    NASA Astrophysics Data System (ADS)

    Nelz, Richard; Fuchs, Philipp; Opaluch, Oliver; Sonusen, Selda; Savenko, Natalia; Podgursky, Vitali; Neu, Elke

    2016-11-01

    We investigate bright fluorescence of nitrogen (NV)- and silicon-vacancy color centers in pyramidal, single crystal diamond tips, which are commercially available as atomic force microscope probes. We coherently manipulate NV electronic spin ensembles with T2 = 7.7(3) μs. Color center lifetimes in different tip heights indicate effective refractive index effects and quenching. Using numerical simulations, we verify enhanced photon rates from emitters close to the pyramid apex rendering them promising as scanning probe sensors.

  4. Characterization of single crystal chemical vapor deposition diamond detectors for neutron spectrometry.

    PubMed

    Gagnon-Moisan, F; Zimbal, A; Nolte, R; Reginatto, M; Schuhmacher, H

    2012-10-01

    Detectors made from artificial chemical vapor deposition single crystal diamond have shown great potential for fast neutron spectrometry. In this paper, we present the results of measurements made at the Physikalisch-Technische Bundesanstalt accelerator using neutron fields in the energy range from 7 MeV to 16 MeV. This study presents the first results of the characterization of the detector in this energy range.

  5. Thermal crystallization of sputter-deposited amorphous Ge films: Competition of diamond cubic and hexagonal phases

    NASA Astrophysics Data System (ADS)

    Okugawa, M.; Nakamura, R.; Ishimaru, M.; Yasuda, H.; Numakura, H.

    2016-12-01

    Following our previous studies on crystallization induced by electron irradiation, we have investigated the crystallization of sputter-deposited amorphous germanium films by heat treatments. On continuous heating, samples aged for 3 days and 4 months at room temperature crystallized at 500°C to form coarse spherical particles of a hexagonal structure, of about 100 nm in diameter, whereas samples aged for 7 months turned to homogeneous nanograins of the diamond cubic structure at 600°C. When the films aged for 4 months at room temperature were annealed at 350°C for 2 h and then heated, they crystallized at 550°C to form a mixture of the two microstructures, and those annealed at 350°C and further at 500°C for 1 h crystallized at 600°C mostly to nanograins. Crystallization by electron irradiation at 350°C to 4-month-aged samples has also been studied. With increasing annealing time at 350°C, coarse particles of a hexagonal structure ceased to appear, and were replaced by fine nanograins of the diamond cubic structure. These observations can be understood in terms of structural instability of sputter-deposited amorphous films. Medium-range ordered clusters must initially be present in the films and serve as nuclei of the metastable hexagonal phase. They are unstable, however, and are eliminated by annealing, resulting in the reduction in size and number of coarse particles with a metastable structure.

  6. Nanoimplantation and Purcell enhancement of single nitrogen-vacancy centers in photonic crystal cavities in diamond

    SciTech Connect

    Riedrich-Möller, Janine; Becher, Christoph; Pezzagna, Sébastien; Meijer, Jan; Pauly, Christoph; Mücklich, Frank; Markham, Matthew; Edmonds, Andrew M.

    2015-06-01

    We present the controlled creation of single nitrogen-vacancy (NV) centers via ion implantation at the center of a photonic crystal cavity which is fabricated in an ultrapure, single crystal diamond membrane. High-resolution placement of NV centers is achieved using collimation of a 5 keV-nitrogen ion beam through a pierced tip of an atomic force microscope. We demonstrate coupling of the implanted NV centers' broad band fluorescence to a cavity mode and observe Purcell enhancement of the spontaneous emission. The results are in good agreement with a master equation model for the cavity coupling.

  7. Observations on the crystallization of spodumene from aqueous solutions in a hydrothermal diamond-anvil cell

    USGS Publications Warehouse

    Li, Jianking; Chou, I-Ming; Yuan, Shunda; Burruss, Robert A.

    2013-01-01

    Crystallization experiments were conducted in a new type of hydrothermal diamond-anvil cell (HDAC; type V) using LiAlSi2O6 (S) gel and H2O (W) as starting materials. A total of 21 experiments were performed at temperatures up to 950°C and pressures up to 788 MPa. In the samples with relatively low W/S ratios, many small crystals formed in the melt phase during cooling. In those with high W/S ratios, only a few crystals with smooth surfaces crystallized from the aqueous fluid in the presence of melt droplets, which were gradually consumed during crystal growth, indicating rapid transfer of material from the melt to the crystals through the aqueous fluid. The nucleation of crystals started at 710 (±70)°C and 520 (±80) MPa, and crystal growth ended at 570 (±40)°C and 320 (±90) MPa, with the cooling P-T path within the stability field of spodumene + quartz in the S-W system. The observed linear crystal growth rates in the aqueous phase, calculated by dividing the maximum length of a single crystal by the duration of the entire growth step, were 4.7 × 10−6 and 5.7 × 10−6 cm s−1 for the cooling rates of 0.5 and 1°C min−1, respectively. However, a rapid crystal growth rate of 3.6 × 10−5 cm s−1 in the aqueous fluid was observed when the components were supplied by nearby melt droplets. Our results show that when crystals nucleate in the aqueous fluid instead of the melt phase, there are fewer nuclei formed, and they grow much faster due to the low viscosity of the aqueous fluid, which accelerates diffusion of components for the growth of crystals. Therefore, the large crystals in granitic pegmatite can crystallize directly from aqueous fluids rather than hydrosilicate melt.

  8. Hybrid Quantum Device with Nitrogen-Vacancy Centers in Diamond Coupled to Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Li, Peng-Bo; Xiang, Ze-Liang; Rabl, Peter; Nori, Franco

    2016-07-01

    We show that nitrogen-vacancy (NV) centers in diamond interfaced with a suspended carbon nanotube carrying a dc current can facilitate a spin-nanomechanical hybrid device. We demonstrate that strong magnetomechanical interactions between a single NV spin and the vibrational mode of the suspended nanotube can be engineered and dynamically tuned by external control over the system parameters. This spin-nanomechanical setup with strong, intrinsic, and tunable magnetomechanical couplings allows for the construction of hybrid quantum devices with NV centers and carbon-based nanostructures, as well as phonon-mediated quantum information processing with spin qubits.

  9. Fabrication of triangular nanobeam waveguide networks in bulk diamond using single-crystal silicon hard masks

    SciTech Connect

    Bayn, I.; Mouradian, S.; Li, L.; Goldstein, J. A.; Schröder, T.; Zheng, J.; Chen, E. H.; Gaathon, O.; Englund, Dirk; Lu, M.; Stein, A.; Ruggiero, C. A.; Salzman, J.; Kalish, R.

    2014-11-24

    A scalable approach for integrated photonic networks in single-crystal diamond using triangular etching of bulk samples is presented. We describe designs of high quality factor (Q = 2.51 × 10{sup 6}) photonic crystal cavities with low mode volume (V{sub m} = 1.062 × (λ/n){sup 3}), which are connected via waveguides supported by suspension structures with predicted transmission loss of only 0.05 dB. We demonstrate the fabrication of these structures using transferred single-crystal silicon hard masks and angular dry etching, yielding photonic crystal cavities in the visible spectrum with measured quality factors in excess of Q = 3 × 10{sup 3}.

  10. Evaluation of freestanding boron-doped diamond grown by chemical vapour deposition as substrates for vertical power electronic devices

    SciTech Connect

    Issaoui, R.; Achard, J.; Tallaire, A.; Silva, F.; Gicquel, A.; Bisaro, R.; Servet, B.; Garry, G.; Barjon, J.

    2012-03-19

    In this study, 4 x 4 mm{sup 2} freestanding boron-doped diamond single crystals with thickness up to 260 {mu}m have been fabricated by plasma assisted chemical vapour deposition. The boron concentrations measured by secondary ion mass spectroscopy were 10{sup 18} to 10{sup 20} cm{sup -3} which is in a good agreement with the values calculated from Fourier transform infrared spectroscopy analysis, thus indicating that almost all incorporated boron is electrically active. The dependence of lattice parameters and crystal mosaicity on boron concentrations have also been extracted from high resolution x-ray diffraction experiments on (004) planes. The widths of x-ray rocking curves have globally shown the high quality of the material despite a substantial broadening of the peak, indicating a decrease of structural quality with increasing boron doping levels. Finally, the suitability of these crystals for the development of vertical power electronic devices has been confirmed by four-point probe measurements from which electrical resistivities as low as 0.26 {Omega} cm have been obtained.

  11. Nanocrystalline diamond micro-anvil grown on single crystal diamond as a generator of ultra-high pressures

    NASA Astrophysics Data System (ADS)

    Samudrala, Gopi K.; Moore, Samuel L.; Velisavljevic, Nenad; Tsoi, Georgiy M.; Baker, Paul A.; Vohra, Yogesh K.

    2016-09-01

    By combining mask-less lithography and chemical vapor deposition (CVD) techniques, a novel two-stage diamond anvil has been fabricated. A nanocrystalline diamond (NCD) micro-anvil 30 μ m in diameter was grown at the center of a [100]-oriented, diamond anvil by utilizing microwave plasma CVD method. The NCD micro-anvil has a diamond grain size of 115 nm and micro-focused Raman and X-ray Photoelectron spectroscopy analysis indicate sp3-bonded diamond content of 72%. These CVD grown NCD micro-anvils were tested in an opposed anvil configuration and the transition metals osmium and tungsten were compressed to high pressures of 264 GPa in a diamond anvil cell.

  12. Diamond Opal-Replica Photonic Crystals and Graphitic Metallic Photonic Band Gap Structures: Fabrication and Properties

    NASA Astrophysics Data System (ADS)

    Zakhidov, A. A.; Baughman, R. H.; Iqbal, Z.; Khayrullin, I. I.; Ralchenko, V. G.

    1998-03-01

    We demonstrate a new method for the formation of photonic bandgap crystals that operate at optical wavelengths. This method involves the templating of a self-assempled SiO2 lattice with diamond, graphite, or amorphous forms of carbon, followed by the removal of the original SiO2 lattice matrix by chemical means. Such carbon opal replicas are the "air type" of photonic crystal (where air replaces silica spheres) that are most favourable for photonic bandgap formation. Surprisingly, the structure of the original opal lattice having a typical cubic lattice dimension of 250 nm) is reliably replicated down to the nanometer scale using either a diamond, graphite, or amorphous carbon templated material. The optical properties of these photonic bandgap crystals are reported and compared with both theory and experimental results on other types of opal-derived lattices that we have investigated. The graphitic reverse opal is the first example of a network type metallic photonic crystal for the optical domain, for which a large photonic bandgap have been predicted.

  13. Pulse-height defect in single-crystal CVD diamond detectors

    NASA Astrophysics Data System (ADS)

    Beliuskina, O.; Strekalovsky, A. O.; Aleksandrov, A. A.; Aleksandrova, I. A.; Devaraja, H. M.; Heinz, C.; Heinz, S.; Hofmann, S.; Ilich, S.; Imai, N.; Kamanin, D. V.; Kis, M.; Knyazheva, G. N.; Kozhuharov, C.; Kuznetsova, E. A.; Maurer, J.; Mishinsky, G. V.; Pomorski, M.; Pyatkov, Yu. V.; Strekalovsky, O. V.; Träger, M.; Zhuchko, V. E.

    2017-02-01

    The pulse-height versus deposited energy response of a single-crystal chemical vapor deposition (scCVD) diamond detector was measured for ions of Ti, Cu, Nb, Ag, Xe, Au, and of fission fragments of 252 Cf at different energies. For the fission fragments, data were also measured at different electric field strengths of the detector. Heavy ions have a significant pulse-height defect in CVD diamond material, which increases with increasing energy of the ions. It also depends on the electrical field strength applied at the detector. The measured pulse-height defects were explained in the framework of recombination models. Calibration methods known from silicon detectors were modified and applied. A comparison with data for the pulse-height defect in silicon detectors was performed.

  14. Parabolic single-crystal diamond lenses for coherent x-ray imaging

    NASA Astrophysics Data System (ADS)

    Terentyev, Sergey; Blank, Vladimir; Polyakov, Sergey; Zholudev, Sergey; Snigirev, Anatoly; Polikarpov, Maxim; Kolodziej, Tomasz; Qian, Jun; Zhou, Hua; Shvyd'ko, Yuri

    2015-09-01

    We demonstrate parabolic single-crystal diamond compound refractive lenses designed for coherent x-ray imaging resilient to extreme thermal and radiation loading expected from next generation light sources. To ensure the preservation of coherence and resilience, the lenses are manufactured from the highest-quality single-crystalline synthetic diamond material grown by a high-pressure high-temperature technique. Picosecond laser milling is applied to machine lenses to parabolic shapes with a ≃ 1 μ m precision and surface roughness. A compound refractive lens comprised of six lenses with a radius of curvature R = 200 μ m at the vertex of the parabola and a geometrical aperture A = 900 μ m focuses 10 keV x-ray photons from an undulator source at the Advanced Photon Source facility to a focal spot size of ≃ 20 × 90 μ m 2 with a gain factor of ≃ 50 - 100 .

  15. Effect of nitrogen on the growth of boron doped single crystal diamond

    DOE PAGES

    Karna, Sunil; Vohra, Yogesh

    2013-11-18

    Boron-doped single crystal diamond films were grown homoepitaxially on synthetic (100) Type Ib diamond substrates using microwave plasma assisted chemical vapor deposition. A modification in surface morphology of the film with increasing boron concentration in the plasma has been observed using atomic force microscopy. Use of nitrogen during boron doping has been found to improve the surface morphology and the growth rate of films but it lowers the electrical conductivity of the film. The Raman spectra indicated a zone center optical phonon mode along with a few additional bands at the lower wavenumber regions. The change in the peak profilemore » of the zone center optical phonon mode and its downshift were observed with the increasing boron content in the film. Furthermore, sharpening and upshift of Raman line was observed in the film that was grown in presence of nitrogen along with diborane in process gas.« less

  16. Single-crystal diamond refractive lens for focusing X-rays in two dimensions.

    PubMed

    Antipov, S; Baryshev, S V; Butler, J E; Antipova, O; Liu, Z; Stoupin, S

    2016-01-01

    The fabrication and performance evaluation of single-crystal diamond refractive X-ray lenses of which the surfaces are paraboloids of revolution for focusing X-rays in two dimensions simultaneously are reported. The lenses were manufactured using a femtosecond laser micromachining process and tested using X-ray synchrotron radiation. Such lenses were stacked together to form a standard compound refractive lens (CRL). Owing to the superior physical properties of the material, diamond CRLs could become indispensable wavefront-preserving primary focusing optics for X-ray free-electron lasers and the next-generation synchrotron storage rings. They can be used for highly efficient refocusing of the extremely bright X-ray sources for secondary optical schemes with limited aperture such as nanofocusing Fresnel zone plates and multilayer Laue lenses.

  17. Single-crystal diamond refractive lens for focusing X-rays in two dimensions

    SciTech Connect

    Antipov, S.; Baryshev, Sergey; Butler, J. E.; Antipova, O.; Liu, Zunping; Stoupin, S.

    2016-01-01

    The fabrication and performance evaluation of single-crystal diamond refractive X-ray lenses of which the surfaces are paraboloids of revolution for focusing X-rays in two dimensions simultaneously are reported. The lenses were manufactured using a femtosecond laser micromachining process and tested using X-ray synchrotron radiation. Such lenses were stacked together to form a standard compound refractive lens (CRL). Owing to the superior physical properties of the material, diamond CRLs could become indispensable wavefront-preserving primary focusing optics for X-ray free-electron lasers and the next-generation synchrotron storage rings. They can be used for highly efficient refocusing of the extremely bright X-ray sources for secondary optical schemes with limited aperture such as nanofocusing Fresnel zone plates and multilayer Laue lenses.

  18. Linear parabolic single-crystal diamond refractive lenses for synchrotron X-ray sources.

    PubMed

    Terentyev, Sergey; Polikarpov, Maxim; Snigireva, Irina; Di Michiel, Marco; Zholudev, Sergey; Yunkin, Vyacheslav; Kuznetsov, Sergey; Blank, Vladimir; Snigirev, Anatoly

    2017-01-01

    Linear parabolic diamond refractive lenses are presented, designed to withstand high thermal and radiation loads coming from upgraded accelerator X-ray sources. Lenses were manufactured by picosecond laser treatment of a high-quality single-crystal synthetic diamond. Twelve lenses with radius of curvature at parabola apex R = 200 µm, geometrical aperture A = 900 µm and length L = 1.5 mm were stacked as a compound refractive lens and tested at the ESRF ID06 beamline. A focal spot of size 2.2 µm and a gain of 20 were measured at 8 keV. The lens profile and surface quality were estimated by grating interferometry and X-ray radiography. In addition, the influence of X-ray glitches on the focusing properties of the compound refractive lens were studied.

  19. Effect of nitrogen on the growth of boron doped single crystal diamond

    SciTech Connect

    Karna, Sunil; Vohra, Yogesh

    2013-11-18

    Boron-doped single crystal diamond films were grown homoepitaxially on synthetic (100) Type Ib diamond substrates using microwave plasma assisted chemical vapor deposition. A modification in surface morphology of the film with increasing boron concentration in the plasma has been observed using atomic force microscopy. Use of nitrogen during boron doping has been found to improve the surface morphology and the growth rate of films but it lowers the electrical conductivity of the film. The Raman spectra indicated a zone center optical phonon mode along with a few additional bands at the lower wavenumber regions. The change in the peak profile of the zone center optical phonon mode and its downshift were observed with the increasing boron content in the film. Furthermore, sharpening and upshift of Raman line was observed in the film that was grown in presence of nitrogen along with diborane in process gas.

  20. Enhancing the plasma illumination behaviour of microplasma devices using microcrystalline/ultra-nanocrystalline hybrid diamond materials as cathodes.

    PubMed

    Chang, Tinghsun; Lou, Shiucheng; Chen, Huangchin; Chen, Chulung; Lee, Chiyoung; Tai, Nyanhwa; Lin, Inan

    2013-08-21

    The properties of capacity-type microplasma devices were significantly enhanced due to the utilisation of hybrid diamond films as cathodes. The performance of the microplasma devices was closely correlated with the electron field emission (EFE) properties of the diamond cathode materials. The nanoemitters, which were prepared by growing duplex-structured diamond films [microcrystalline diamond (MCD)/ultra-nanocrystalline diamond (UNCD)] on Si-pyramid templates via a two-step microwave plasma enhanced chemical vapour deposition (MPE-CVD) process, exhibited improved EFE properties (E0 = 5.99 V μm(-1), J(e) = 1.10 mA cm(-2) at 8.50 V μm(-1) applied field), resulting in superior microplasma device performance (with a lower threshold field of 200 V mm(-1) and a higher plasma current density of 7.80 mA cm(-2)) in comparison with UNCD film devices prepared using a single-step MPE-CVD process. The superior EFE properties of the duplex-structured MCD-UNCD films relative to those of the UNCD films can be attributed to the unique granular structure of the diamond films. High-resolution transmission electron microscopy reveals that the MCD-UNCD films consisted of abundant graphitic phases located at the periphery of large diamond aggregates and at the boundaries between the ultra-small diamond grains. The presence of the graphite phase is presumed to be the prime factor that renders these films more conductive and causes these films to exhibit higher EFE properties, thus resulting in the improved plasma illumination properties of the microplasma devices.

  1. Thermal property characterization of single crystal diamond with varying isotopic composition

    SciTech Connect

    Wei, L.

    1993-01-01

    The mirage-effect/thermal wave technique as a modern technique for thermal property characterization is described. The thermal diffusivity of a material is determined by measuring the time and space varying temperature distribution (thermal wave) in the material generated by an intensity modulated heating laser beam. These thermal waves are detected through the deflection of a probe laser beam due to modulation of gradient of the index of refraction (mirage effect) either in the air above the specimens (the in-air technique) or in the specimen itself (the in-solid technique). Three-dimensional theories, for both in-air and in-solid mirage techniques, are represented. In order to extract the material parameters by comparing the theory with experimental data, an extensive data analysis procedure based on multiparameter-least-squares has been developed. The experimental and data analysis details are discussed. Topics concerns with the quality and reliability of the measurements are addressed. This technique has been successfully applied to the thermal property characterization of single crystal diamond with varying isotope contents. The results showed a 50% enhancement in the thermal conductivity by removal of C[sup 13] content from 1.1% to 0.1% in diamond at room temperature. The technique has also been adapted to function in cryogenic temperatures. The temperature dependence of thermal conductivity in the temperature range 80-378K for natural IIA specimen and 187-375K for isotopically enriched specimen are obtained, the former results agree with previous works and the latter results demonstrate the isotope effect on the thermal conductivity of single crystal diamond consistently in a large temperature range. The physical source of this enhancement in diffusivity due to the isotope effect in diamond is discussed. The discussion is based on the full Callaway's theory with emphasizing the role of N-processes in the phonon scattering mechanism.

  2. Development and high temperature testing by 14 MeV neutron irradiation of single crystal diamond detectors

    NASA Astrophysics Data System (ADS)

    Pilotti, R.; Angelone, M.; Pagano, G.; Loreti, S.; Pillon, M.; Sarto, F.; Marinelli, M.; Milani, E.; Prestopino, G.; Verona, C.; Verona-Rinati, G.

    2016-06-01

    In the present paper, the performances of single crystal diamond detectors "ad hoc" designed to operate at high temperature are reported. The detectors were realized using commercial CVD single crystal diamond films, 500 micron thick with metal contacts deposited by sputtering method on each side. The new detector layout is based upon mechanical contacts between the diamond film and the electric ground. The detector was first characterized by measuring the leakage current as function of temperature and applied biasing voltage (I-V characteristics). The results obtained using two different metal contacts, Pt and Ag respectively, while irradiated with 14 MeV neutrons at the Frascati neutron generator (FNG) are reported and compared. It is shown that diamond detectors with Ag metal contacts can be properly operated in spectrometric mode up to 240oC with energy resolution (FWHM) of about 3.5%.

  3. Effects of additive NaN3 on the HPHT synthesis of large single crystal diamond grown by TGM

    NASA Astrophysics Data System (ADS)

    Huang, Guofeng; Jia, Xiaopeng; Li, Shangsheng; Hu, Meihua; Li, Yong; Zhao, Ming; Yan, Bingmin; Ma, Hongan

    2010-10-01

    In this paper, large single crystal diamond with perfect shape and high nitrogen concentration approximately 1671-1742 ppm was successfully synthesized by temperature gradient method (TGM) under high pressure and high temperature (HPHT). The HPHT synthesis conditions were about 5.5 GPa and 1500-1550 K. Sodium azide (NaN3) with different amount was added as the source of nitrogen into the synthesis system of high pure graphite and kovar alloy. The effects of additive NaN3 on crystal growth habit were investigated in detail. The crystal morphology, nitrogen concentration and existing form in synthetic diamond were characterized by means of scanning electron microscope (SEM) and infrared (IR) absorption spectra, respectively. The results show that with an increase of the content of NaN3 added in the synthesis system, the region of synthesis temperature for high-quality diamond becomes narrow, and crystal growth rate is restricted, whereas the nitrogen concentration in synthetic diamond increases. Nitrogen exists in diamond mainly in dispersed form (C-centers) and partially aggregated form (A-centers). The defects occur more frequently on crystal surface when excessive NaN3 is added in the synthesis system.

  4. Electronic properties of single-crystal diamonds heavily doped with boron

    SciTech Connect

    Buga, S. G.; Blank, V. D.; Terent'ev, S. A.; Kuznetsov, M. S.; Nosukhin, S. A.; Kulbachinskii, V. A. Krechetov, A. V.; Kytin, V. G.; Kytin, G. A.

    2007-04-15

    Single-crystal diamonds with characteristic sizes of 2-7 mm doped with boron in the concentration range 10{sup 19}-10{sup 20} cm{sup -3} have been grown by the temperature gradient method at high static pressures. The temperature dependence of the resistance R of the synthesized single crystals has been measured in the range 0.5 K < T < 297 K. An activated dependence R(T) with an activation energy of about 50 meV is observed in the range from room temperature to T {approx} 200 K. At temperatures below approximately 50 K, the temperature dependence of the conductivity for heavily doped crystals is proportional to T{sup 1/2}, which is characteristic of degenerate semiconductors with a high number of defects.

  5. Fast ion energy distribution from third harmonic radio frequency heating measured with a single crystal diamond detector at the Joint European Torus

    SciTech Connect

    Nocente, M.; Rebai, M.; Gorini, G.; Cazzaniga, C.; Tardocchi, M.; Giacomelli, L.; Muraro, A.; Binda, F.; Eriksson, J.; Sharapov, S.; Collaboration:

    2015-10-15

    Neutron spectroscopy measurements with a single crystal diamond detector have been carried out at JET, for the first time in an experiment aimed at accelerating deuterons to MeV energies with radio frequency heating at the third harmonic. Data are interpreted by means of the expected response function of the detector and are used to extract parameters of the highly non-Maxwellian distribution function generated in this scenario. A comparison with observations using a time of flight and liquid scintillator neutron spectrometers is also presented. The results demonstrate the capability of diamond detectors to contribute to fast ion physics studies at JET and are of more general relevance in view of the application of such detectors for spectroscopy measurements in the neutron camera of next step tokamak devices.

  6. Effects of FeNi-phosphorus-carbon system on crystal growth of diamond under high pressure and high temperature conditions

    NASA Astrophysics Data System (ADS)

    Hu, Mei-Hua; Bi, Ning; Li, Shang-Sheng; Su, Tai-Chao; Zhou, Ai-Guo; Hu, Qiang; Jia, Xiao-Peng; Ma, Hong-An

    2015-03-01

    This paper reports the crystal growth of diamond from the FeNi-Carbon system with additive phosphorus at high pressures and high temperatures of 5.4-5.8 GPa and 1280-1360 °C. Attributed to the presence of additive phosphorus, the pressure and temperature condition, morphology, and color of diamond crystals change obviously. The pressure and temperature condition of diamond growth increases evidently with the increase of additive phosphorus content and results in the moving up of the V-shape region. The surfaces of the diamonds also become coarse as the additive phosphorus added in the growth system. Raman spectra indicate that diamonds grown from the FeNi-phosphorus-carbon system have more crystal defects and impurities. This work provides a new way to enrich the doping of diamond and improve the experimental exploration for future material applications. Project supported by the Doctoral Fund of Henan Polytechnic University, China (Grant Nos. B2013-013 and B2013-044) and the Research Projects of Science and Technology of the Education Department of Henan Province, China (Grant Nos. 14B430026 and 12A430010).

  7. High-reflectivity High-resolution X-ray Crystal Optics with Diamonds

    SciTech Connect

    Shvyd’ko, Y.; Stoupin, S; Cunsolo, A; Said, A; Huang, X

    2010-01-01

    Owing to the depth to which hard X-rays penetrate into most materials, it is commonly accepted that the only way to realize hard-X-ray mirrors with near 100% reflectance is under conditions of total external reflection at grazing incidence to a surface. At angles away from grazing incidence, substantial reflectance of hard X-rays occurs only as a result of constructive interference of the waves scattered from periodically ordered atomic planes in crystals (Bragg diffraction). Theory predicts that even at normal incidence the reflection of X-rays from diamond under the Bragg condition should approach 100% - substantially higher than from any other crystal. Here we demonstrate that commercially produced synthetic diamond crystals do indeed show an unprecedented reflecting power at normal incidence and millielectronvolt-narrow reflection bandwidths for hard X-rays. Bragg diffraction measurements of reflectivity and the energy bandwidth show remarkable agreement with theory. Such properties are valuable to the development of hard-X-ray optics, and could greatly assist the realization of fully coherent X-ray sources, such as X-ray free-electron laser oscillators.

  8. Curved diamond-crystal spectrographs for x-ray free-electron laser noninvasive diagnostics.

    PubMed

    Terentyev, Sergey; Blank, Vladimir; Kolodziej, Tomasz; Shvyd'ko, Yuri

    2016-12-01

    We report on the manufacturing and X-ray tests of bent diamond-crystal X-ray spectrographs, designed for noninvasive diagnostics of the X-ray free-electron laser (XFEL) spectra in the spectral range from 5 to 15 keV. The key component is a curved, 20-μm thin, single crystalline diamond triangular plate in the (110) orientation. The radius of curvature can be varied between R = 0.6 m and R = 0.1 m in a controlled fashion, ensuring imaging in a spectral window of up to 60 eV for ≃8 keV X-rays. All of the components of the bending mechanism (about 10 parts) are manufactured from diamond, thus ensuring safe operations in intense XFEL beams. The spectrograph is transparent to 88% for 5-keV photons and to 98% for 15-keV photons. Therefore, it can be used for noninvasive diagnostics of the X-ray spectra during XFEL operations.

  9. Enhanced Optical Properties of Chemical Vapor Deposited Single Crystal Diamond by Low-Pressure/High-Temperature Annealing

    SciTech Connect

    Meng, Y.; Yan, C; Lai, Y; Krasnicki, S; Shu, H; Yu, T; Liang, Q; Mao, H; Hemley, R

    2008-01-01

    Single crystal diamond produced by chemical vapor deposition (CVD) at very high growth rates (up to 150 em/h) has been successfully annealed without graphitization at temperatures up to 2200 C and pressures <300 torr. Crystals were annealed in a hydrogen environment by using microwave plasma techniques for periods of time ranging from a fraction of minute to a few hours. This low-pressure/high-temperature (LPHT) annealing enhances the optical properties of this high-growth rate CVD single crystal diamond. Significant decreases are observed in UV, visible, and infrared absorption and photoluminescence spectra. The decrease in optical absorption after the LPHT annealing arises from the changes in defect structure associated with hydrogen incorporation during CVD growth. There is a decrease in sharp line spectral features indicating a reduction in nitrogen-vacancy-hydrogen (NVH-) defects. These measurements indicate an increase in relative concentration of nitrogen-vacancy (NV) centers in nitrogen-containing LPHT-annealed diamond as compared with as-grown CVD material. The large overall changes in optical properties and the specific types of alterations in defect structure induced by this facile LPHT processing of high-growth rate single-crystal CVD diamond will be useful in the creation of diamond for a variety of scientific and technological applications.

  10. Enhanced optical properties of chemical vapor deposited single crystal diamond by low-pressure/high-temperature annealing.

    PubMed

    Meng, Yu-fei; Yan, Chih-shiue; Lai, Joseph; Krasnicki, Szczesny; Shu, Haiyun; Yu, Thomas; Liang, Qi; Mao, Ho-kwang; Hemley, Russell J

    2008-11-18

    Single crystal diamond produced by chemical vapor deposition (CVD) at very high growth rates (up to 150 microm/h) has been successfully annealed without graphitization at temperatures up to 2200 degrees C and pressures <300 torr. Crystals were annealed in a hydrogen environment by using microwave plasma techniques for periods of time ranging from a fraction of minute to a few hours. This low-pressure/high-temperature (LPHT) annealing enhances the optical properties of this high-growth rate CVD single crystal diamond. Significant decreases are observed in UV, visible, and infrared absorption and photoluminescence spectra. The decrease in optical absorption after the LPHT annealing arises from the changes in defect structure associated with hydrogen incorporation during CVD growth. There is a decrease in sharp line spectral features indicating a reduction in nitrogen-vacancy-hydrogen (NVH(-)) defects. These measurements indicate an increase in relative concentration of nitrogen-vacancy (NV) centers in nitrogen-containing LPHT-annealed diamond as compared with as-grown CVD material. The large overall changes in optical properties and the specific types of alterations in defect structure induced by this facile LPHT processing of high-growth rate single-crystal CVD diamond will be useful in the creation of diamond for a variety of scientific and technological applications.

  11. Characterization of a new commercial single crystal diamond detector for photon- and proton-beam dosimetry

    PubMed Central

    Akino, Yuichi; Gautam, Archana; Coutinho, Len; Würfel, Jan; Das, Indra J.

    2015-01-01

    A synthetic single crystal diamond detector (SCDD) is commercially available and is characterized for radiation dosimetry in various radiation beams in this study. The characteristics of the commercial SCDD model 60019 (PTW) with 6- and 15-MV photon beams, and 208-MeV proton beams, were investigated and compared with the pre-characterized detectors: Semiflex (model 31010) and PinPoint (model 31006) ionization chambers (PTW), the EDGE diode detector (Sun Nuclear Corp) and the SFD Stereotactic Dosimetry Diode Detector (IBA). To evaluate the effects of the pre-irradiation, the diamond detector, which had not been irradiated on the day, was set up in the water tank, and the response to 100 MU was measured every 20 s. The depth–dose and profiles data were collected for various field sizes and depths. For all radiation types and field sizes, the depth–dose data of the diamond chamber showed identical curves to those of the ionization chambers. The profile of the diamond detector was very similar to those of the EDGE and SFD detectors, although the Semiflex and PinPoint chambers showed volume-averaging effects in the penumbrae region. The temperature dependency was within 0.7% in the range of 4–41°C. A dose of 900 cGy and 1200 cGy was needed to stabilize the chamber to the level within 0.5% and 0.2%, respectively. The PTW type 60019 SCDD detector showed suitable characteristics for radiation dosimetry, for relative dose, depth–dose and profile measurements for a wide range of field sizes. However, at least 1000 cGy of pre-irradiation will be needed for accurate measurements. PMID:26268483

  12. Photonic crystal cavities and integrated optical devices

    NASA Astrophysics Data System (ADS)

    Gan, Lin; Li, ZhiYuan

    2015-11-01

    This paper gives a brief introduction to our recent works on photonic crystal (PhC) cavities and related integrated optical structures and devices. Theoretical background and numerical methods for simulation of PhC cavities are first presented. Based on the theoretical basis, two relevant quantities, the cavity mode volume and the quality factor are discussed. Then the methods of fabrication and characterization of silicon PhC slab cavities are introduced. Several types of PhC cavities are presented, such as the usual L3 missing-hole cavity, the new concept waveguide-like parallel-hetero cavity, and the low-index nanobeam cavity. The advantages and disadvantages of each type of cavity are discussed. This will help the readers to decide which type of PhC cavities to use in particular applications. Furthermore, several integrated optical devices based on PhC cavities, such as optical filters, channel-drop filters, optical switches, and optical logic gates are described in both the working principle and operation characteristics. These devices designed and realized in our group demonstrate the wide range of applications of PhC cavities and offer possible solutions to some integrated optical problems.

  13. Tailoring liquid crystals to become fast and efficient terahertz devices

    NASA Astrophysics Data System (ADS)

    Pickwell-MacPherson, E.; Parrott, E. P. J.; Park, H.; Fan, F.; Chigrinov, V. G.

    2012-10-01

    Liquid crystals have been employed for several decades in devices such as phase shifters, Fabry-Perot filters, polarizers, phase gratings, and Bragg switches at optical frequencies. However it is only recently that such devices have been demonstrated at terahertz frequencies. This is because of several fundamental frequency dependent relationships between device properties and frequency of operation. When designing liquid crystal devices, we need to find liquid crystals with high birefringence, low viscosity and low absorption at terahertz frequencies. In this paper we will present some measurements and simulations of potentially suitable liquid crystal mixtures.

  14. Unusual paired pattern of radiohaloes on a diamond crystal from Guaniamo (Venezuela)

    NASA Astrophysics Data System (ADS)

    Schulze, Daniel J.; Nasdala, Lutz

    2016-11-01

    An octahedral diamond crystal from Guaniamo, Venezuela shows a multitude of round radiocolouration spots that indicate a remarkable formation history. Spots always occur in pairs, with similar spacing and intensity ratio between the two spots of each pair. We interpret this pattern to be the result of long-term irradiation of the stone emanating from a multitude of radioactive point sources. At some point during the irradiation, the stone must have experienced a translational movement which shifted it ca. 50 μm relative to the adjacent material [i.e., the (111) crystal face was a fault plane], after which irradiation continued. The Neoproterozoic age of the Guaniamo kimberlites and the high degree of radiation damage suggest that both of the two irradiation periods lasted over hundreds of millions of years. This interpretation is supported by results of He-irradiation experiments.

  15. I19, the small-molecule single-crystal diffraction beamline at Diamond Light Source.

    PubMed

    Nowell, Harriott; Barnett, Sarah A; Christensen, Kirsten E; Teat, Simon J; Allan, David R

    2012-05-01

    The dedicated small-molecule single-crystal X-ray diffraction beamline (I19) at Diamond Light Source has been operational and supporting users for over three years. I19 is a high-flux tunable-wavelength beamline and its key details are described in this article. Much of the work performed on the beamline involves structure determination from small and weakly diffracting crystals. Other experiments that have been supported to date include structural studies at high pressure, studies of metastable species, variable-temperature crystallography, studies involving gas exchange in porous materials and structural characterizations that require analysis of the diffuse scattering between Bragg reflections. A range of sample environments to facilitate crystallographic studies under non-ambient conditions are available as well as a number of options for automation. An indication of the scope of the science carried out on the beamline is provided by the range of highlights selected for this paper.

  16. Practical approach for a rod-connected diamond photonic crystal operating at optical wavelengths

    NASA Astrophysics Data System (ADS)

    Aoki, Kanna

    2009-11-01

    Production of a rod-connected diamond (RCD) photonic crystal structure in a semiconductor material is proposed. Periodic shifting of only one building block can create a complicated three-dimensional network, with a RCD structure exhibiting a full bandgap as wide as 0.20 on a gap/midgap (Δω /ωM) basis. A point defect cavity in the structure sustains single-mode resonance throughout the operative range because of its low symmetry. The resonant mode's highest quality factor (Q-factor) was calculated as 1.5×104 for a crystal of 11.5ax×4.25ay×12az for ai (i =x,y,z) representing three axes' period lengths.

  17. Methane-related diamond crystallization in the Earth's mantle: Stable isotope evidences from a single diamond-bearing xenolith

    NASA Astrophysics Data System (ADS)

    Thomassot, E.; Cartigny, P.; Harris, J. W.; (Fanus) Viljoen, K. S.

    2007-05-01

    Mineralogical studies of deep-seated xenoliths and mineral inclusions in diamonds indicate that there is significant variability in oxygen fugacity within the Earth's upper mantle. This variability is consistent both with the occurrence of reduced (methane-bearing) or oxidized (CO 2/carbonate-bearing) fluids. Invariably, direct sampling of reduced deep fluids is not possible as they are unquenchable and re-equilibrate with either the surrounding mantle or are affected by degassing. Key information about the nature of such fluids might be found in diamond if it were possible to study a population related to a single source. Usually, diamonds within a kimberlite pipe have different parageneses and can be shown to have formed at different times and depths. We studied 59 diamonds extracted from a single diamondiferous peridotite xenolith (with a volume of only 27 cm 3), from the Cullinan mine (formerly called the Premier mine) in South Africa. Diamond sizes range from 0.0005 to 0.169 carats (0.1 to 33.8 mg). A correlation between the nitrogen contents of the diamonds (range 40 to 1430 ppm) and their nitrogen aggregation state (varying from 10 to 85% of IaB defects) is compatible with a single growth event. δ 13C-values range from - 4.2‰ to - 0.1‰, with slight internal variability measured in the largest diamonds. Nitrogen isotope measurements show δ 15N ranging from - 1.2‰ to + 7.2‰. On the centimeter scale of this upper mantle rock, the variations for nitrogen content, nitrogen aggregation state, carbon and nitrogen isotopic compositions, respectively, cover 64%, 75%, 15% and 23% of the ranges known for peridotitic diamonds. In spite of such large ranges, N-content, δ 13C and δ 15N within this diamond population are distinctly coupled. These relationships do not support a mixing of carbon sources, but are best explained by a Rayleigh distillation within the sub-continental mantle at depths > 150 km and T > 1200 °C, which precipitates diamonds from methane

  18. Tracking performance of a single-crystal and a polycrystalline diamond pixel-detector

    SciTech Connect

    Menasce, D.; et al.

    2013-06-01

    We present a comparative characterization of the performance of a single-crystal and a polycrystalline diamond pixel-detector employing the standard CMS pixel readout chips. Measurements were carried out at the Fermilab Test Beam Facility, FTBF, using protons of momentum 120 GeV/c tracked by a high-resolution pixel telescope. Particular attention was directed to the study of the charge-collection, the charge-sharing among adjacent pixels and the achievable position resolution. The performance of the single-crystal detector was excellent and comparable to the best available silicon pixel-detectors. The measured average detection-efficiency was near unity, ε = 0.99860±0.00006, and the position-resolution for shared hits was about 6 μm. On the other hand, the performance of the polycrystalline detector was hampered by its lower charge collection distance and the readout chip threshold. A new readout chip, capable of operating at much lower threshold (around 1 ke$-$), would be required to fully exploit the potential performance of the polycrystalline diamond pixel-detector.

  19. Pulse height reduction effects of single-crystal CVD diamond detector for low-energy heavy ions

    NASA Astrophysics Data System (ADS)

    Sato, Y.; Shimaoka, T.; Kaneko, J. H.; Murakami, H.; Miyazaki, D.; Tsubota, M.; Chayahara, A.; Umezawa, H.; Shikata, S.

    2013-10-01

    The performance of a diamond detector made of single-crystal diamond grown by chemical vapour deposition was studied for heavy ions, having energy of 3 MeV. Energy peaks of these low-energy ions were clearly observed. However, the pulse height for individual incident ion decreases with increasing atomic number of the ions. For understanding this pulse height reduction effect, we calculated the amount of ionizing and non-ionizing energy loss of incident ions in the diamond detector. The results of our calculation suggest the contribution of charge loss mechanisms other than the recombination effect of electron-hole pairs produced along the ionized track. We also mentioned the incomplete charge collection near the boundary region between the metal electrode and the diamond surface.

  20. Electron-beam induced diamond-like-carbon passivation of plasmonic devices

    NASA Astrophysics Data System (ADS)

    Balaur, Eugeniu; Sadatnajafi, Catherine; Langley, Daniel; Lin, Jiao; Kou, Shan Shan; Abbey, Brian

    2015-12-01

    Engineered materials with feature sizes on the order of a few nanometres offer the potential for producing metamaterials with properties which may differ significantly from their bulk counterpart. Here we describe the production of plasmonic colour filters using periodic arrays of nanoscale cross shaped apertures fabricated in optically opaque silver films. Due to its relatively low loss in the visible and near infrared range, silver is a popular choice for plasmonic devices, however it is also unstable in wet or even ambient conditions. Here we show that ultra-thin layers of Diamond-Like Carbon (DLC) can be used to prevent degradation due to oxidative stress, ageing and corrosion. We demonstrate that DLC effectively protects the sub-micron features which make up the plasmonic colour filter under both atmospheric conditions and accelerated aging using iodine gas. Through a systematic study we confirm that the nanometre thick DLC layers have no effect on the device functionality or performance.

  1. Functional photonic crystal fiber sensing devices

    NASA Astrophysics Data System (ADS)

    Villatoro, Joel; Finazzi, Vittoria; Pruneri, Valerio

    2011-12-01

    We report on a functional, highly reproducible and cost effective sensing platform based on photonic crystal fibers (PCFs). The platform consists of a centimeter-length segment of an index-guiding PCF fusion spliced to standard single mode fibers (SMFs). The voids of the PCF are intentionally sealed over an adequate length in the PCF-SMF interfaces. A microscopic collapsed region in the PCF induces a mode field mismatch which combined with the axial symmetry of the structure allow the efficient excitation and recombination or overlapping of azimuthal symmetric modes in the PCF. The transmission or reflection spectrum of the devices exhibits a high-visibility interference pattern or a single, profound and narrow notch. The interference pattern or the notch position shifts when the length of the PCF experiences microelongations or when liquids or coatings are present on the PCF surface. Thus, the platform here proposed can be useful for sensing diverse parameters such as strain, vibration, pressure, humidity, refractive index, gases, etc. Unlike other PCF-based sensing platforms the multiplexing of the devices here proposed is simple for which it is possible to implement PCF-based sensor arrays or networks.

  2. Nonreciprocal Electromagnetic Devices in Gyromagnetic Photonic Crystals

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Yuan; Liu, Rong-Juan; Gan, Lin; Fu, Jin-Xin; Lian, Jin

    2014-01-01

    Gyromagnetic photonic crystal (GPC) offers a promising way to realize robust transport of electromagnetic waves against backscattering from various disorders, perturbations and obstacles due to existence of unique topological electromagnetic states. The dc magnetic field exerting upon the GPC brings about the time-reversal symmetry breaking, splits the band degeneracy and opens band gaps where the topological chiral edge states (CESs) arise. The band gap can originate either from long-range Bragg-scattering effect or from short-range localized magnetic surface plasmon resonance (MSP). These topological edge states can be explored to construct backscattering-immune one-way waveguide and other nonreciprocal electromagnetic devices. In this paper we review our recent theoretical and experimental studies of the unique electromagnetic properties of nonreciprocal devices built in GPCs. We will discuss various basic issues like experimental instrumental setup, sample preparations, numerical simulation methods, tunable properties against magnetic field, band degeneracy breaking and band gap opening and creation of topological CESs. We will investigate the unidirectional transport properties of one-way waveguide under the influence of waveguide geometries, interface morphologies, intruding obstacles, impedance mismatch, lattice disorders, and material dissipation loss. We will discuss the unique coupling properties between one-wave waveguide and resonant cavities and their application as novel one-way bandstop filter and one-way channel-drop filter. We will also compare the CESs created in the Bragg-scattering band gap and the MSP band gap under the influence of lattice disorders. These results can be helpful for designing and exploring novel nonreciprocal electromagnetic devices for optical integration and information processing.

  3. A new single crystal diamond dosimeter for small beam: comparison with different commercial active detectors.

    PubMed

    Marsolat, F; Tromson, D; Tranchant, N; Pomorski, M; Le Roy, M; Donois, M; Moignau, F; Ostrowsky, A; De Carlan, L; Bassinet, C; Huet, C; Derreumaux, S; Chea, M; Cristina, K; Boisserie, G; Bergonzo, P

    2013-11-07

    Recent developments of new therapy techniques using small photon beams, such as stereotactic radiotherapy, require suitable detectors to determine the delivered dose with a high accuracy. The dosimeter has to be as close as possible to tissue equivalence and to exhibit a small detection volume compared to the size of the irradiation field, because of the lack of lateral electronic equilibrium in small beam. Characteristics of single crystal diamond (tissue equivalent material Z = 6, high density) make it an ideal candidate to fulfil most of small beam dosimetry requirements. A commercially available Element Six electronic grade synthetic diamond was used to develop a single crystal diamond dosimeter (SCDDo) with a small detection volume (0.165 mm(3)). Long term stability was studied by irradiating the SCDDo in a (60)Co beam over 14 h. A good stability (deviation less than ± 0.1%) was observed. Repeatability, dose linearity, dose rate dependence and energy dependence were studied in a 10 × 10 cm(2) beam produced by a Varian Clinac 2100 C linear accelerator. SCDDo lateral dose profile, depth dose curve and output factor (OF) measurements were performed for small photon beams with a micro multileaf collimator m3 (BrainLab) attached to the linac. This study is focused on the comparison of SCDDo measurements to those obtained with different commercially available active detectors: an unshielded silicon diode (PTW 60017), a shielded silicon diode (Sun Nuclear EDGE), a PinPoint ionization chamber (PTW 31014) and two natural diamond detectors (PTW 60003). SCDDo presents an excellent spatial resolution for dose profile measurements, due to its small detection volume. Low energy dependence (variation of 1.2% between 6 and 18 MV photon beam) and low dose rate dependence of the SCDDo (variation of 1% between 0.53 and 2.64 Gy min(-1)) are obtained, explaining the good agreement between the SCDDo and the efficient unshielded diode (PTW 60017) in depth dose curve

  4. Ion bombardment induced buried lateral growth: the key mechanism for the synthesis of single crystal diamond wafers

    PubMed Central

    Schreck, Matthias; Gsell, Stefan; Brescia, Rosaria; Fischer, Martin

    2017-01-01

    A detailed mechanism for heteroepitaxial diamond nucleation under ion bombardment in a microwave plasma enhanced chemical vapour deposition setup on the single crystal surface of iridium is presented. The novel mechanism of Ion Bombardment Induced Buried Lateral Growth (IBI-BLG) is based on the ion bombardment induced formation and lateral spread of epitaxial diamond within a ~1 nm thick carbon layer. Starting from one single primary nucleation event the buried epitaxial island can expand laterally over distances of several microns. During this epitaxial lateral growth typically thousands of isolated secondary nuclei are generated continuously. The unique process is so far only observed on iridium surfaces. It is shown that a diamond single crystal with a diameter of ~90 mm and a weight of 155 carat can be grown from such a carbon film which initially consisted of 2 · 1013 individual grains. PMID:28294167

  5. Ion bombardment induced buried lateral growth: the key mechanism for the synthesis of single crystal diamond wafers

    NASA Astrophysics Data System (ADS)

    Schreck, Matthias; Gsell, Stefan; Brescia, Rosaria; Fischer, Martin

    2017-03-01

    A detailed mechanism for heteroepitaxial diamond nucleation under ion bombardment in a microwave plasma enhanced chemical vapour deposition setup on the single crystal surface of iridium is presented. The novel mechanism of Ion Bombardment Induced Buried Lateral Growth (IBI-BLG) is based on the ion bombardment induced formation and lateral spread of epitaxial diamond within a ~1 nm thick carbon layer. Starting from one single primary nucleation event the buried epitaxial island can expand laterally over distances of several microns. During this epitaxial lateral growth typically thousands of isolated secondary nuclei are generated continuously. The unique process is so far only observed on iridium surfaces. It is shown that a diamond single crystal with a diameter of ~90 mm and a weight of 155 carat can be grown from such a carbon film which initially consisted of 2 · 1013 individual grains.

  6. Diamond-based MEMS devices for biosensing based on electrochemical and gravimetric

    NASA Astrophysics Data System (ADS)

    Carlisle, John

    2005-03-01

    Diamond offers several potential advantages as a platform material for bioinorganic interfaces, including chemical and bio-inertness, electrochemistry, and high acoustic velocity. Ultrananocrystalline diamond (UNCD), with a unique combination of physical, chemical and electrical properties, is attractive for a variety of biochemical/biomedical applications such as hermetic bio-inert coatings, MEMS compatible biosensors, and electrochemical biointerfaces. Over the past several years we have worked on both the fundamental and applied science related to enabling UNCD-based bioMEMS devices, which has encompassed both the development of UNCD surface functionalization strategies that allow fine control of surface hydrophobicity and bioactivity, as well as the development of material integration strategies and surface micromachining techniques to enable the microfabrication of UNCD structural layers (e.g. cantilevers) that incorporate these functionalized surfaces into MEMS devices which are back-end compatible with CMOS electronics. These devices could thus combine the electrochemical and gravimetric transduction of the selective adsorption of target analytes in MEMS structures fabricated directly on top of a silicon microchip.. In the past year we have successfully demonstrated the use of conducting UNCD thin films as electrochemical biointerfaces, via the successful attachment of a redox enzyme onto the UNCD surface, Glucose oxidase (GOD). The procedure to achieve GOD immobilization involved the electrochemical immobilization of nitrophenyl groups to the UNCD surface and transformation of nitrophenyl to aminophenyl groups and the covalent bonding of GOD to the carboxyl groups using the diisopropylcarbodiimide/ N-hydroxysuccinimide (DCC/NHS) as the catalyst. After immobilization, the activity of the enzyme was demonstrated via the direct electrochemical detection of hydrogen peroxide. We have also developed CMOS-compatible UNCD MEMS cantilevers and fixed-fixed beam

  7. Processing of Diamond for Integrated Optic Devices Using Q-Switched Nd:YAG Laser at Different Wavelengths

    NASA Astrophysics Data System (ADS)

    Sudheer, S. K.; Pillai, V. P. Mahadevan; Nayar, V. U.

    In the present investigation, a Q-switched Nd:YAG laser is used to study the various aspects of diamond processing for fabricating integrated optic and UV optoelectronic devices. Diamond is a better choice of substrate compared to silicon and gallium arsenide for the fabrication of waveguides to perform operations such as modulation, switching, multiplexing, and filtering, particularly in the ultraviolet spectrum. The experimental setup of the present investigation consists of two Q-Switched Nd:YAG lasers capable of operating at wavelengths of 1064 nm and 532 nm. The diamond cutting is performed using these two wavelengths by making the "V"-shaped groove with various opening angle. The variation of material loss of diamond during cutting is noted for the two wavelengths. The cut surface morphology and elemental and structural analysis of graphite formed during processing in both cases are compared using scanning electron microscopy (SEM) and laser Raman spectroscopy. Both the Q-Switched Nd:YAG laser systems (at 1064 nm and 532 nm) show very good performance in terms of peak-to-peak output stability, minimal spot diameter, smaller divergence angle, higher peak power in Q-switched mode, and good fundamental TEM00 mode quality for processing natural diamond stones. Less material loss and minimal micro cracks are achieved with wavelength 532 nm whereas a better diamond cut surface is achieved with processing at 1064 nm with minimum roughness.

  8. Experimental characterisation of PD SOI MOSFET devices fabricated with diamond-shaped body contact

    NASA Astrophysics Data System (ADS)

    Daghighi, Arash; Osman, Mohamed A.

    2011-06-01

    The design of diamond-shaped body-contacted (DSBC) devices using standard layers in a 0.35 µm silicon-on-insulator (SOI) complementary metal-oxide-semiconductor process is described in this article. The technology is based on a manufacturable partially depleted SOI process targeted for radio frequency applications. The experimental measurements of drain induced barrier lowering for the fabricated DSBC structure showed suppression of floating body effects (FBE) at the promising rate of 24 mV/V. The measurement results confirmed current drive (I DS) improvement by 25% at V DS = 1.5 V and V GS = 1.5 V compared to conventional body-tied-source (BTS) device. A constant and steady output conductance (g DS) in the saturation region was observed for the DSBC structure. The gate trans-conductance (g m) is improved by 34% at V DS = 1.5 V and V GS = 1.5 V compared to conventional BTS device. Three-dimensional device simulation provides insight on FBE suppression and channel current improvement. Experimental results confirmed the area efficiency of the DSBC structure and its excellent current drive performance.

  9. Design of a three-dimensional photonic crystal nanocavity based on a \\langle 110\\rangle -layered diamond structure

    NASA Astrophysics Data System (ADS)

    Tajiri, Takeyoshi; Takahashi, Shun; Tandaechanurat, Aniwat; Iwamoto, Satoshi; Arakawa, Yasuhiko

    2014-01-01

    We design a three-dimensional (3D) photonic crystal (PC) nanocavity based on a \\langle 110\\rangle -layered diamond structure. The designed structure, comprised of self-sustainable layers, is suitable for fabrication by layer stacking techniques. Quality factors (Q-factors) of nanocavities were calculated for the \\langle 110\\rangle -layered diamond and a commonly-used woodpile structures, both of which are generated from the same diamond lattice with a lattice constant adiamond. The Q-factor of the designed nanocavity can reach as high as 230,000 with 35 stacked layers and a square in-plane PC area of the length of one side of 5\\sqrt{2} a^{\\text{diamond}}. This is 1.5 times higher than that of a 3D PC nanocavity based on the woodpile structure with the same in-plane PC size and with the same number of stacked layers. The higher Q-factor in the \\langle 110\\rangle -layered diamond structure originates from its stronger in-plane light confinement over the woodpile structure. The \\langle 110\\rangle -layered diamond structure will be beneficial for improving experimentally attainable Q-factors of 3D PC nanocavities particularly fabricated by a micromanipulation method.

  10. Bistable liquid crystal device fabricated via microscale liquid crystal alignment

    NASA Astrophysics Data System (ADS)

    Honma, Michinori; Toyoshima, Wataru; Nose, Toshiaki

    2016-10-01

    Bistable liquid crystal (LC) molecular orientation properties in micropatterned LC cells were investigated experimentally and theoretically. When an LC cell was heated to the phase-transition temperature and then cooled, an LC orientation with ±π/2-twist domains (±π/2-twist mode) was obtained. Furthermore, a different LC orientation with ±π-twist domains (±π-twist mode) was observed when a 10-V potential was applied across a sample LC cell. Both orientation states were stably retained over a long period. Herein, cross-sectional LC orientation models in the ±π/2- and ±π-twist modes are proposed to explain the generation and behavior of two different disclination lines. The total energies within one period in the ±π/2- and ±π-twist modes (F±π/2 and F±π, respectively) were estimated theoretically. These energies were found to depend on the LC layer thickness and to cross over at a certain thickness; this indicates that F±π is equal to F±π/2 at this equilibrium thickness. The best temporal stability is likely attained at this equilibrium thickness. We demonstrated a bistable color-switching device by combining a full-wave plate and crossed polarizers. When these optical components were configured properly, stable bistable switching between two colors was achieved.

  11. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1983-01-01

    GaAs device technology has recently reached a new phase of rapid advancement, made possible by the improvement of the quality of GaAs bulk crystals. At the same time, the transition to the next generation of GaAs integrated circuits and optoelectronic systems for commercial and government applications hinges on new quantum steps in three interrelated areas: crystal growth, device processing and device-related properties and phenomena. Special emphasis is placed on the establishment of quantitative relationships among crystal growth parameters-material properties-electronic properties and device applications. The overall program combines studies of crystal growth on novel approaches to engineering of semiconductor material (i.e., GaAs and related compounds); investigation and correlation of materials properties and electronic characteristics on a macro- and microscale; and investigation of electronic properties and phenomena controlling device applications and device performance.

  12. Improvement of the quality factor of single crystal diamond mechanical resonators

    NASA Astrophysics Data System (ADS)

    Liao, Meiyong; Toda, Masaya; Sang, Liwen; Teraji, Tokuyuki; Imura, Masataka; Koide, Yasuo

    2017-02-01

    Single-crystal diamond (SCD) has the potential to boost microelectromechanical system (MEMS) with unprecedented performance in terms of its intrinsic mechanical, chemical, and electronic properties, especially in the applications under extreme conditions. On the basis of the analysis of the energy dissipation in diamond mechanical resonators, the authors report on the marked improvement of the quality factor of SCD-MEMS resonators. Ion implantation assisted lift-off technique (IAL) is utilized to fabricate the SCD resonators. The quality factor of the resonator fabricated from the ion-damaged SCD layer alone is as low as 100-300 owing to the bulk or surface defects. The growth of homoepitaxial layers on the ion-implanted SCD substrates significantly improves the quality factor by more than 100 times. Cantilevers made of SCD epilayers of different thicknesses are examined. It is found that the quality factor increases with increasing the epilayer thickness. The maximum quality factor of the SCD cantilevers fabricated by the IAL technique reaches 3.9 × 104. A bilayer model is proposed to describe the variation of the quality factor.

  13. Parabolic single-crystal diamond compound refractive lenses for coherent x-ray imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Terentyev, Sergey; Blank, Vladimir D.; Polyakov, Sergey; Zholudev, Sergey; Snigirev, Anatoly A.; Polikarpov, Maxim; Kolodziej, Tomasz; Qian, Jun; Zhou, Hua; Shvyd'ko, Yuri V.

    2016-09-01

    We demonstrate parabolic single-crystal diamond compound refractive lenses [1] designed for coherent x-ray imaging resilient to extreme thermal and radiation loading expected from next generation light sources. To ensure the preservation of coherence and resilience, the lenses are manufactured from the highest-quality single-crystalline synthetic diamond material grown by a high-pressure high-temperature technique. Picosecond laser milling is applied to machine lenses to parabolic shapes with a 1-micron precision and surface roughness. A compound refractive lens comprised of six lenses with a radius of curvature R=200 microns at the vertex of the parabola and a geometrical aperture A=900 microns focuses 10 keV x-ray photons from an undulator source at the Advanced Photon Source facility to a focal spot size of 10x40 microns^2 with a gain factor of 100. [1] S. Terentyev, V. Blank, S. Polyakov, S. Zholudev, A. Snigirev, M. Polikarpov, T. Kolodziej, J. Qian, H. Zhou, and Yu. Shvyd'ko Applied Physics Letters 107, 111108 (2015); doi: 10.1063/1.4931357

  14. Study of the dispersive properties of three-dimensional photonic crystals with diamond lattices containing metamaterials

    NASA Astrophysics Data System (ADS)

    Zhang, Hai-Feng; Liu, Shao-Bin; Kong, Xiang-Kun

    2013-10-01

    In this paper, the dispersive properties of three-dimensional photonic crystals with diamond lattices containing isotropic dielectric and metamaterials are theoretically studied by a modified plane wave expansion method. In order to simplify the study, one only kind of the metamaterials is considered—the epsilon-negative materials. The eigenvalue equations of their structure depending on the diamond lattice realization (spheres with epsilon-negative materials inserted in the dielectric background) are deduced. A photonic band gap (PBG), a flatband region, and the first two stop band gaps (SBGs) above the flatband region in the Γ-X and Γ-L directions are found to appear. The results show that the upper edge of the flatband region cannot be tuned by any parameters except for the electronic plasma frequency. The PBG and first SBGs above the flatband region in the Γ-X and Γ-L directions for PCs can be modulated by the filling factor, relative dielectric constant and electronic plasma frequency, respectively. However, the damping factor has no effect on the locations of first PBG and the SBGs above the flatband region in the Γ-X and Γ-L directions.

  15. Boron Doped Diamond Paste Electrodes for Microfluidic Paper-Based Analytical Devices.

    PubMed

    Nantaphol, Siriwan; Channon, Robert B; Kondo, Takeshi; Siangproh, Weena; Chailapakul, Orawon; Henry, Charles S

    2017-04-04

    Boron doped diamond (BDD) electrodes have exemplary electrochemical properties; however, widespread use of high-quality BDD has previously been limited by material cost and availability. In the present article, we report the use of a BDD paste electrode (BDDPE) coupled with microfluidic paper-based analytical devices (μPADs) to create a low-cost, high-performance electrochemical sensor. The BDDPEs are easy to prepare from a mixture of BDD powder and mineral oil and can be easily stencil-printed into a variety of electrode geometries. We demonstrate the utility and applicability of BDDPEs through measurements of biological species (norepinephrine and serotonin) and heavy metals (Pb and Cd) using μPADs. Compared to traditional carbon paste electrodes (CPE), BDDPEs exhibit a wider potential window, lower capacitive current, and are able to circumvent the fouling of serotonin. These results demonstrate the capability of BDDPEs as point-of-care sensors when coupled with μPADs.

  16. Integration of piezoelectric aluminum nitride and ultrananocrystalline diamond films for implantable biomedical microelectromechanical devices

    NASA Astrophysics Data System (ADS)

    Zalazar, M.; Gurman, P.; Park, J.; Kim, D.; Hong, S.; Stan, L.; Divan, R.; Czaplewski, D.; Auciello, O.

    2013-03-01

    The physics for integration of piezoelectric aluminum nitride (AlN) films with underlying insulating ultrananocrystalline diamond (UNCD), and electrically conductive grain boundary nitrogen-incorporated UNCD (N-UNCD) and boron-doped UNCD (B-UNCD) layers, as membranes for microelectromechanical system implantable drug delivery devices, has been investigated. AlN films deposited on platinum layers on as grown UNCD or N-UNCD layer (5-10 nm rms roughness) required thickness of ˜400 nm to induce (002) AlN orientation with piezoelectric d33 coefficient ˜1.91 pm/V at ˜10 V. Chemical mechanical polished B-UNCD films (0.2 nm rms roughness) substrates enabled (002) AlN film 200 nm thick, yielding d33 = 5.3 pm/V.

  17. A 3D diamond detector for particle tracking

    NASA Astrophysics Data System (ADS)

    Bachmair, F.; Bäni, L.; Bergonzo, P.; Caylar, B.; Forcolin, G.; Haughton, I.; Hits, D.; Kagan, H.; Kass, R.; Li, L.; Oh, A.; Phan, S.; Pomorski, M.; Smith, D. S.; Tyzhnevyi, V.; Wallny, R.; Whitehead, D.

    2015-06-01

    A novel device using single-crystal chemical vapour deposited diamond and resistive electrodes in the bulk forming a 3D diamond detector is presented. The electrodes of the device were fabricated with laser assisted phase change of diamond into a combination of diamond-like carbon, amorphous carbon and graphite. The connections to the electrodes of the device were made using a photo-lithographic process. The electrical and particle detection properties of the device were investigated. A prototype detector system consisting of the 3D device connected to a multi-channel readout was successfully tested with 120 GeV protons proving the feasibility of the 3D diamond detector concept for particle tracking applications for the first time.

  18. Single-crystal Diamond Detector for DT and DD plasmas diagnostic

    NASA Astrophysics Data System (ADS)

    Rebai, M.; Cazzaniga, C.; Tardocchi, M.; Grosso, G.; Croci, G.; Perelli Cippo, E.; Calvani, P.; Girolami, M.; Trucchi, D. M.; Gorini, G.

    2016-11-01

    Single-crystal Diamond Detectors (SDD) are good candidates as high-energy neutron detectors in the extreme conditions of the next generation thermonuclear fusion facilities like the ITER experiment, due to their high radiation hardness, fast response time and small size. Neutron detection in SDDs is based on the collection of electron-hole pairs produced by charged particles generated by neutron interaction on 12 C . In this work the SDD response to neutrons with energies between 2.8 and 3.8MeV was determined at the Legnaro CN accelerator at the INFN Laboratories in Legnaro (PD, Italy). This work is relevant for the characterization of SDDs response functions, which are key points for Deuterium-Deuterium and Deuterium-Tritium plasma diagnostic.

  19. A Bayesian method to estimate the neutron response matrix of a single crystal CVD diamond detector

    SciTech Connect

    Reginatto, Marcel; Araque, Jorge Guerrero; Nolte, Ralf; Zbořil, Miroslav; Zimbal, Andreas; Gagnon-Moisan, Francis

    2015-01-13

    Detectors made from artificial chemical vapor deposition (CVD) single crystal diamond are very promising candidates for applications where high resolution neutron spectrometry in very high neutron fluxes is required, for example in fusion research. We propose a Bayesian method to estimate the neutron response function of the detector for a continuous range of neutron energies (in our case, 10 MeV ≤ E{sub n} ≤ 16 MeV) based on a few measurements with quasi-monoenergetic neutrons. This method is needed because a complete set of measurements is not available and the alternative approach of using responses based on Monte Carlo calculations is not feasible. Our approach uses Bayesian signal-background separation techniques and radial basis function interpolation methods. We present the analysis of data measured at the PTB accelerator facility PIAF. The method is quite general and it can be applied to other particle detectors with similar characteristics.

  20. A Bayesian method to estimate the neutron response matrix of a single crystal CVD diamond detector

    NASA Astrophysics Data System (ADS)

    Reginatto, Marcel; Gagnon-Moisan, Francis; Araque, Jorge Guerrero; Nolte, Ralf; Zbořil, Miroslav; Zimbal, Andreas

    2015-01-01

    Detectors made from artificial chemical vapor deposition (CVD) single crystal diamond are very promising candidates for applications where high resolution neutron spectrometry in very high neutron fluxes is required, for example in fusion research. We propose a Bayesian method to estimate the neutron response function of the detector for a continuous range of neutron energies (in our case, 10 MeV ≤ En ≤ 16 MeV) based on a few measurements with quasi-monoenergetic neutrons. This method is needed because a complete set of measurements is not available and the alternative approach of using responses based on Monte Carlo calculations is not feasible. Our approach uses Bayesian signal-background separation techniques and radial basis function interpolation methods. We present the analysis of data measured at the PTB accelerator facility PIAF. The method is quite general and it can be applied to other particle detectors with similar characteristics.

  1. Amorphous diamond-structured photonic crystal in the feather barbs of the scarlet macaw

    PubMed Central

    Yin, Haiwei; Dong, Biqin; Liu, Xiaohan; Zhan, Tianrong; Shi, Lei; Zi, Jian; Yablonovitch, Eli

    2012-01-01

    Noniridescent coloration by the spongy keratin in parrot feather barbs has fascinated scientists. Nonetheless, its ultimate origin remains as yet unanswered, and a quantitative structural and optical description is still lacking. Here we report on structural and optical characterizations and numerical simulations of the blue feather barbs of the scarlet macaw. We found that the sponge in the feather barbs is an amorphous diamond-structured photonic crystal with only short-range order. It possesses an isotropic photonic pseudogap that is ultimately responsible for the brilliant noniridescent coloration. We further unravel an ingenious structural optimization for attaining maximum coloration apparently resulting from natural evolution. Upon increasing the material refractive index above the level provided by nature, there is an interesting transition from a photonic pseudogap to a complete bandgap. PMID:22615350

  2. Demonstration of a three-dimensional photonic crystal nanocavity in a 〈110〉-layered diamond structure

    SciTech Connect

    Tajiri, T.; Takahashi, S.; Ota, Y.; Tatebayashi, J.; Iwamoto, S.; Arakawa, Y.

    2015-08-17

    We experimentally demonstrate a three-dimensional photonic crystal (3D PC) nanocavity in a 〈110〉-layered diamond structure with a quality factor (Q-factor) of 12 800 at a wavelength of 1.1 μm. The observed Q is 1.2 times higher than that of a 3D PC nanocavity in a woodpile structure with the same in-plane size and the same number of stacked layers. This result indicates the potential importance of the 〈110〉-layered diamond structure for getting high Q 3D PC nanocavities within a limited in-plane space.

  3. Fine Structure in the Secondary Electron Emission Peak for Diamond Crystal with (100) Negative Electron Affinity Surface

    NASA Technical Reports Server (NTRS)

    Asnin, V. M.; Krainsky, I. L.

    1998-01-01

    A fine structure was discovered in the low-energy peak of the secondary electron emission spectra of the diamond surface with negative electron affinity. We studied this structure for the (100) surface of the natural type-IIb diamond crystal. We have found that the low-energy peak consists of a total of four maxima. The relative energy positions of three of them could be related to the electron energy minima near the bottom of the conduction band. The fourth peak, having the lowest energy, was attributed to the breakup of the bulk exciton at the surface during the process of secondary electron emission.

  4. Research on subsurface defects of potassium dihydrogen phosphate crystals fabricated by single point diamond turning technique

    NASA Astrophysics Data System (ADS)

    Tie, Guipeng; Dai, Yifan; Guan, Chaoliang; Chen, Shaoshan; Song, Bing

    2013-03-01

    Potassium dihydrogen phosphate (KDP) crystals, which are widely used in high-power laser systems, are required to be free of defects on fabricated subsurfaces. The depth of subsurface defects (SSD) of KDP crystals is significantly influenced by the parameters used in the single point diamond turning technique. In this paper, based on the deliquescent magnetorheological finishing technique, the SSD of KDP crystals is observed and the depths under various cutting parameters are detected and discussed. The results indicate that no SSD is generated under small parameters and with the increase of cutting parameters, SSD appears and the depth rises almost linearly. Although the ascending trends of SSD depths caused by cutting depth and feed rate are much alike, the two parameters make different contributions. Taking the same material removal efficiency as a criterion, a large cutting depth generates shallower SSD depth than a large feed rate. Based on the experiment results, an optimized cutting procedure is obtained to generate defect-free surfaces.

  5. Single Crystal Preparation for High-Pressure Experiments in the Diamond Anvil Cell

    SciTech Connect

    Aracne, C; Farber, D; Benterou, J; Occelli, F; Krisch, M; Antonangeli, D; Requardt, H; Fiquet, G

    2003-07-01

    Most research conducted in diamond anvil cells (DAC) is performed on polycrystalline samples. While data from polycrystalline samples are sufficient for determining the bulk properties, high-pressure experiments on single crystals allow for measurements on a range of tensor properties such as: thermal and electrical conductivity; magnetic susceptibility; elasticity; and plasticity. However, in order to achieve pressures above 1 Mbar in a DAC, single crystal samples must be <50 m in diameter and <15 m thick while maintaining a high degree of crystallinity. Thus, we have developed new procedures for producing extremely high-quality micro single crystal samples from commercially available material. Our sample preparation steps include cutting, classical metallographic polishing, and laser ablation. The key to our new process is the preservation of crystallinity during cutting and thinning. We have been successful in maintaining orientation, along with an extremely high degree of crystallinity in completed metal samples. To date, we have analyzed cobalt and molybdenum samples with both white-light interferometry and synchrotron x-ray diffraction, and are in the process of extending these methods to other metals and ceramics.

  6. Constitutive Description of Large Elastic Deformations in Diamond and Silicon Crystals from First-Principles

    NASA Astrophysics Data System (ADS)

    Salvetti, M.; Duchenne, S.; Parks, D. M.; Marzari, N.

    2010-03-01

    Within a continuum approach, the prediction of the mechanical response of single crystals at large elastic deformations relies on the accurate description of the strain energy density function ψ. The coupling of hydrostatic and deviatoric terms at high compressions is of particular interest for applications, and the effect is generally not taken into account by current models available in the literature [1,2]. We present a general approach that leads to the construction of strain energy density functions of cubic single crystals based on data obtained from density functional theory (DFT) calculations. We connect the deformation-induced energy changes and Cauchy stress calculated from DFT calculations to the Lagrangian description frequently adopted within the continuum theory of hyperelasticity [3]. In particular, we adopt a coordinate--free invariant formulation [4] that intrinsically preserves the properties of the cubic symmetry group. We present results on diamond and silicon single crystals, and highlight both similarities and striking differences. [1] R.G.Veprek et. al, Mater. Sci. Eng. A 4248, 366-378 (2007) [2] B.P Gearing, L. Anand, Int. J. Solids Struct. 41, 827-845 (2004) [3] A.N. Norris, J. Mech. Mater. Struct. 3, No.2, 243-260 (2008) [4] J.P. Boehler, Z. Angew. Math. Mech. 59, 157-167 (1979)

  7. Fluorinated diamond-like carbon as antithrombogenic coating for blood-contacting devices.

    PubMed

    Hasebe, Terumitsu; Shimada, Atsushi; Suzuki, Tetsuya; Matsuoka, Yoshiaki; Saito, Toshiya; Yohena, Satoshi; Kamijo, Aki; Shiraga, Nobuyuki; Higuchi, Mutsumi; Kimura, Kanako; Yoshimura, Hirokuni; Kuribayashi, Sachio

    2006-01-01

    Diamond-like carbon (DLC) is being considered for widespread clinical use as a surface coating for cardiovascular devices. We synthesized fluorinated DLC (F-DLC) coatings in order to create a more hydrophobic surface with improved antithrombogenicity and flexibility when compared with conventional DLC coatings by combining the inertness of DLC films with the advantage of fluorination. The purpose of this study was to evaluate the in vitro hemocompatibility and in vivo biocompatibility of the F-DLC coating for medical devices. The in vitro whole blood model confirmed that platelet loss was lower in the F-DLC group than in the noncoated group (SUS316L), which suggests the adhesion of a smaller number of platelets to F-DLC-coated materials. Furthermore, the biomarkers of mechanically induced platelet activation (beta-thromboglobulin) and activated coagulation (thrombin-antithrombin-three complex) were markedly reduced in the F-DLC-coated group. In vivo rat implant model studies revealed no excessive local and systemic inflammatory responses in the F-DLC group. The thickness of the fibrous tissue capsule surrounding the F-DLC-coated disk was almost equal to that of the noncoated SUS316L disk, which has the favorable biocompatibility for metallic implant materials. F-DLC coating thus appears to be a promising candidate for use as a coating material in blood-contacting devices.

  8. Photonic crystal devices formed by a charged-particle beam

    DOEpatents

    Lin, Shawn-Yu; Koops, Hans W. P.

    2000-01-01

    A photonic crystal device and method. The photonic crystal device comprises a substrate with at least one photonic crystal formed thereon by a charged-particle beam deposition method. Each photonic crystal comprises a plurality of spaced elements having a composition different from the substrate, and may further include one or more impurity elements substituted for spaced elements. Embodiments of the present invention may be provided as electromagnetic wave filters, polarizers, resonators, sources, mirrors, beam directors and antennas for use at wavelengths in the range from about 0.2 to 200 microns or longer. Additionally, photonic crystal devices may be provided with one or more electromagnetic waveguides adjacent to a photonic crystal for forming integrated electromagnetic circuits for use at optical, infrared, or millimeter-wave frequencies.

  9. Large single crystal diamond grown in FeNiMnCo-S-C system under high pressure and high temperature conditions

    NASA Astrophysics Data System (ADS)

    Zhang, He; Li, Shangsheng; Su, Taichao; Hu, Meihua; Li, Guanghui; Ma, Hongan; Jia, Xiaopeng

    2016-11-01

    Large diamonds have successfully been synthesized from FeNiMnCo-S-C system at temperatures of 1255-1393 °C and pressures of 5.3-5.5 GPa. Because of the presence of sulfur additive, the morphology and color of the large diamond crystals change obviously. The content and shape of inclusions change with increasing sulfur additive. It is found that the pressure and temperature conditions required for the synthesis decrease to some extent with the increase of S additive, which results in left down of the V-shape region. The Raman spectra show that the introduction of additive sulfur reduces the quality of the large diamond crystals. The x-ray photoelectron spectroscopy (XPS) spectra show the presence of S in the diamonds. Furthermore, the electrical properties of the large diamond crystals are tested by a four-point probe and the Hall effect method. When sulfur in the cell of diamond is up to 4.0 wt.%, the resistance of the diamond is 9.628×105 Ω·cm. It is shown that the large single crystal samples are n type semiconductors. This work is helpful for the further research and application of sulfur-doped semiconductor large diamond. Project supported by the National Natural Science Foundation of China (Grant No. 51172089), the Education Department of Henan Province, China (Grant No. 12A430010), and the Fundamental Research Funds for the Universities of Henan Province, China (Grant No. NSFRF140110).

  10. Methods of making composite optical devices employing polymer liquid crystal

    DOEpatents

    Jacobs, S.D.; Marshall, K.L.; Cerqua, K.A.

    1991-10-08

    Composite optical devices are disclosed using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T[sub g]) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device. 7 figures.

  11. Methods of making composite optical devices employing polymer liquid crystal

    DOEpatents

    Jacobs, Stephen D.; Marshall, Kenneth L.; Cerqua, Kathleen A.

    1991-01-01

    Composite optical devices using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T.sub.g) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device.

  12. Multiple delta doping of single crystal cubic boron nitride films heteroepitaxially grown on (001)diamonds

    NASA Astrophysics Data System (ADS)

    Yin, H.; Ziemann, P.

    2014-06-01

    Phase pure cubic boron nitride (c-BN) films have been epitaxially grown on (001) diamond substrates at 900 °C. The n-type doping of c-BN epitaxial films relies on the sequential growth of nominally undoped (p-) and Si doped (n-) layers with well-controlled thickness (down to several nanometer range) in the concept of multiple delta doping. The existence of nominally undoped c-BN overgrowth separates the Si doped layers, preventing Si dopant segregation that was observed for continuously doped epitaxial c-BN films. This strategy allows doping of c-BN films can be scaled up to multiple numbers of doped layers through atomic level control of the interface in the future electronic devices. Enhanced electronic transport properties with higher hall mobility (102 cm2/V s) have been demonstrated at room temperature as compared to the normally continuously Si doped c-BN films.

  13. Changes in the content and crystal morphology of diamonds from Paleozoic and Mesozoic kimberlits in the northeastern Yakutian kimberlite province

    NASA Astrophysics Data System (ADS)

    Biller, Anastasia; Smelov, Alexander; Zaitsev, Albert

    2010-05-01

    The Yakutian kimberlite province combines more than 1000 kimberlite bodies. It is subdivided into two parts: southern and northeastern. The southern part contains highly diamondiferous kimberlite pipes of Middle Paleozoic age. In the northeastern part, weakly diamondiferous or barren kimberlite pipes of Paleozoic and Mesozoic age are found. The content of diamond-bearing pipes in the southern part is 27 %, and in the northeastern part - 0.06 %. The kimberlite pipes from the northeastern part are characterized by kimberlite- and Brazilian-type diamonds present in different proportions. We have made a statistical analyses of the content of morphologically different diamonds in these kimberlites with regard to their age. The most representative information was obtained for the kimberlite pipes Zapolyarnaya (360 Ma), Komsomol'skaya (382 Ma), Novinka (355 Ma), Leninrgad (380 Ma), Aerologicheskaya (409 Ma), Djanga (243 Ma), Malokuonapskaya (170 Ma), Grenada and Nadezhda (159 Ma) as well as for the Luchekan field kimberlites with an average age of 197 Ma. Diamonds from the Paleozoic and Mesozoic kimberlites reveal a reverse relationship between the contents of octahedral and rounded crystals (r = - 0.969). Such relationship is characteristic of a single geologic body. The younger kimberlites contain higher amounts of Brazilian-type diamonds. In the age interval of 400-160 Ma, the average degree of diamond content in kimberlites decreases by about 85 %, and average weight of crystals by 55 %. More complex relationships are established in the systems: octahedral crystals - kimberlite age and rounded crystals - kimberlite age. The first system is characterized by a decrease in the amount of octahedra in the 400-250 Ma interval (r = 0.848,) and their increase in the interval from 250 to 160 Ma (r = - 0.901). Characteristic of the second system is the growing content of rounded diamonds in the interval 400-250 Ma (r = - 0.835) and their decline in the interval from 250 to 160

  14. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1984-01-01

    The crystal growth, device processing and device related properties and phenomena of GaAs are investigated. Our GaAs research evolves about these key thrust areas. The overall program combines: (1) studies of crystal growth on novel approaches to engineering of semiconductor materials (i.e., GaAs and related compounds); (2) investigation and correlation of materials properties and electronic characteristics on a macro- and microscale; (3) investigation of electronic properties and phenomena controlling device applications and device performance. The ground based program is developed which would insure successful experimentation with and eventually processing of GaAs in a near zero gravity environment.

  15. Bandgap properties of diamond structure photonic crystal heterostructures with inclined and curved interfaces

    SciTech Connect

    Lei, Haitao; Li, Yong; Wang, Hong

    2014-06-14

    The 3D (dimensional) diamond structure photonic crystal heterostructures with different lattice constants were prepared using rapid prototyping and gel casting with alumina. In this paper, heterostructures with inclined and curved interfaces were designed and its bandgap properties were studied. The normalized resonant intensity of electromagnetic wave in heterostructure with inclined and curved interface is stronger than that in the ordinary heterostructure without modified interface. The influence of curved interface on transmission properties of electromagnetic wave was investigated with the radius of curvature ranging from 17 mm to 37 mm at 5 mm interval. The results show that two resonant modes appear in the photonic band gap, being similar to the band gap characteristics of the photonic crystals with two defects inside. With the increasing of the radius of curvature, the resonant mode shift to higher frequency. In the structure with a radius of curvature of 32 mm, a guiding band appears in the photonic band gap. Further increase in the radius of curvature, the guiding band will split into two resonant modes again and the two resonant modes shift to lower frequencies.

  16. Design and fabrication of high-performance diamond triple-gate field-effect transistors

    PubMed Central

    Liu, Jiangwei; Ohsato, Hirotaka; Wang, Xi; Liao, Meiyong; Koide, Yasuo

    2016-01-01

    The lack of large-area single-crystal diamond wafers has led us to downscale diamond electronic devices. Here, we design and fabricate a hydrogenated diamond (H-diamond) triple-gate metal-oxide-semiconductor field-effect transistor (MOSFET) to extend device downscaling and increase device output current. The device’s electrical properties are compared with those of planar-type MOSFETs, which are fabricated simultaneously on the same substrate. The triple-gate MOSFET’s output current (174.2 mA mm−1) is much higher than that of the planar-type device (45.2 mA mm−1), and the on/off ratio and subthreshold swing are more than 108 and as low as 110 mV dec−1, respectively. The fabrication of these H-diamond triple-gate MOSFETs will drive diamond electronic device development forward towards practical applications. PMID:27708372

  17. Nano-inclusions in diamond: Evidence of diamond genesis

    NASA Astrophysics Data System (ADS)

    Wirth, R.

    2015-12-01

    The use of Focused Ion Beam technology (FIB) for TEM sample preparation introduced approximately 15 years ago revolutionized the application of TEM in Geosciences. For the first time, FIB enabled cutting samples for TEM use from exactly the location we are interested in. Applied to diamond investigation, this technique revealed the presence of nanometre-sized inclusions in diamond that have been simply unknown before. Nanoinclusions in diamond from different location and origin such as diamonds from the Lower and Upper Mantle, metamorphic diamonds (Kazakhstan, Erzgebirge, Bohemia), diamonds from ophiolites (Tibet, Mongolia, Xinjiang, Ural Mountains), diamonds from igneous rocks (Hawaii, Kamchatka) and impact diamonds (Popigai Crater, Siberia) have been investigated during the last 15 years. The major conclusion of all these TEM studies is, that the nanoinclusions, their phases and phase composition together with the micro- and nanostructure evidence the origin of diamond and genesis of diamond. We can discriminate Five different mechanisms of diamond genesis in nature are observed: Diamond crystallized from a high-density fluid (Upper mantle and metamorphic diamond). Diamond crystallized from carbonatitic melt (Lower mantle diamond). Diamond precipitates from a metal alloy melt (Diamond from ophiolites). Diamond crystallized by gas phase condensation or chemical vapour condensation (CVD) (Lavas from Kamchatka, xenoliths in Hawaiian lavas). Direct transformation of graphite into diamond.

  18. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals

    SciTech Connect

    Stoupin, Stanislav; Shvyd'ko, Yuri; Shu Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey

    2012-02-15

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub X}{approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  19. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals.

    PubMed

    Stoupin, Stanislav; Shvyd'ko, Yuri; Shu, Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey

    2012-02-01

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of ΔE(X) ≃ 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E(H) = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  20. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals.

    SciTech Connect

    Stoupin, S.; Shvydko, Y.; Shu, D.; Khachatryan, R.; Xiao, X.

    2012-01-01

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub x} {approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  1. Pulse shape distortion of output signals from single-crystal CVD diamond detector in few-GHz broadband amplifiers

    NASA Astrophysics Data System (ADS)

    Sato, Y.; Shimaoka, T.; Kaneko, J. H.; Murakami, H.; Miyazaki, D.; Tsubota, M.; Chayahara, A.; Umezawa, H.; Shikata, S.

    2014-04-01

    The response of a diamond detector made from a single crystal grown by chemical vapour deposition was studied using a broadband amplifier. A short pulse width of {\\sim}1\\ \\text{ns} for 241Am-α-particles was observed with a digital oscilloscope. To discuss pulse shape distortion from the detector in a measurement system, we simulated waveforms with a SPICE simulator using an equivalent circuit model that contained three main parts: detector, amplifier, and oscilloscope. In the simulation, we found that the pulse width spread by more than 200 ps following amplification. We discuss the effects of the detector read-out circuit time constant on the observed waveforms and confirm that the pulse width spread was restrained by use of a short time constant compared with carrier drift time in diamond crystals.

  2. Evaluation of the dosimetric properties of a synthetic single crystal diamond detector in high energy clinical proton beams

    SciTech Connect

    Mandapaka, A. K.; Ghebremedhin, A.; Patyal, B.; Marinelli, Marco; Prestopino, G.; Verona, C.; Verona-Rinati, G.

    2013-12-15

    Purpose: To investigate the dosimetric properties of a synthetic single crystal diamond Schottky diode for accurate relative dose measurements in large and small field high-energy clinical proton beams.Methods: The dosimetric properties of a synthetic single crystal diamond detector were assessed by comparison with a reference Markus parallel plate ionization chamber, an Exradin A16 microionization chamber, and Exradin T1a ion chamber. The diamond detector was operated at zero bias voltage at all times. Comparative dose distribution measurements were performed by means of Fractional depth dose curves and lateral beam profiles in clinical proton beams of energies 155 and 250 MeV for a 14 cm square cerrobend aperture and 126 MeV for 3, 2, and 1 cm diameter circular brass collimators. ICRU Report No. 78 recommended beam parameters were used to compare fractional depth dose curves and beam profiles obtained using the diamond detector and the reference ionization chamber. Warm-up/stability of the detector response and linearity with dose were evaluated in a 250 MeV proton beam and dose rate dependence was evaluated in a 126 MeV proton beam. Stem effect and the azimuthal angle dependence of the diode response were also evaluated.Results: A maximum deviation in diamond detector signal from the average reading of less than 0.5% was found during the warm-up irradiation procedure. The detector response showed a good linear behavior as a function of dose with observed deviations below 0.5% over a dose range from 50 to 500 cGy. The detector response was dose rate independent, with deviations below 0.5% in the investigated dose rates ranging from 85 to 300 cGy/min. Stem effect and azimuthal angle dependence of the diode signal were within 0.5%. Fractional depth dose curves and lateral beam profiles obtained with the diamond detector were in good agreement with those measured using reference dosimeters.Conclusions: The observed dosimetric properties of the synthetic single

  3. Large-surface-area diamond (111) crystal plates for applications in high-heat-load wavefront-preserving X-ray crystal optics.

    PubMed

    Stoupin, Stanislav; Antipov, Sergey; Butler, James E; Kolyadin, Alexander V; Katrusha, Andrey

    2016-09-01

    Fabrication and results of high-resolution X-ray topography characterization of diamond single-crystal plates with large surface area (10 mm × 10 mm) and (111) crystal surface orientation for applications in high-heat-load X-ray crystal optics are reported. The plates were fabricated by laser-cutting of the (111) facets of diamond crystals grown using high-pressure high-temperature methods. The intrinsic crystal quality of a selected 3 mm × 7 mm crystal region of one of the studied samples was found to be suitable for applications in wavefront-preserving high-heat-load crystal optics. Wavefront characterization was performed using sequential X-ray diffraction topography in the pseudo plane wave configuration and data analysis using rocking-curve topography. The variations of the rocking-curve width and peak position measured with a spatial resolution of 13 µm × 13 µm over the selected region were found to be less than 1 µrad.

  4. Lithium niobate single-crystal and photo-functional device

    DOEpatents

    Gopalan, Venkatraman; Mitchell, Terrence E.; Kitamura, Kenji; Furukawa, Yasunori

    2001-01-01

    Provided are lithium niobate single-crystal that requires a low voltage of not larger than 10 kV/nm for its ferroelectric polarization inversion and of which the polarization can be periodically inverted with accuracy even at such a low voltage, and a photo-functional device comprising the crystal. The crystal has a molar fraction of Li.sub.2 O/(Nb.sub.2 O.sub.5 +Li.sub.2 O) of falling between 0.49 and 0.52. The photo-functional device can convert a laser ray being incident thereon.

  5. In situ crystal chemical study of solid diamond inclusions from Quaternary alluvial deposit in the Siberian craton

    NASA Astrophysics Data System (ADS)

    Dera, P. K.; Manghnani, M. H.; Hushur, A.; Sobolev, N. V.; Logvinova, A. M.; Newville, M.; Lanzirotti, A.

    2013-12-01

    Kimberlites belong to rare rock type available only within the Earth's cratonic areas and have been a subject of detailed studies because of the great depth of their origin in the mantle. Kimberlitic diamonds often contain pristine inclusions derived from significant depths with different histories of their origins. Many of kimberlitic diamonds were formed in ultramafic (peridotitic) and mafic (eclogitic) environments of the upper mantle. Thus far only a handful of comprehensive in situ studies including single-crystal X-ray diffraction characterization of pristine diamond solid inclusions have been reported (e.g. Kunz et al. 2001, Nestola et al. 2011). In this study five single-crystal solid inclusions from diamonds found in the Quaternary alluvial deposit in NW of the Siberian craton have been investigated using a combination of in situ single-crystal X-ray diffraction, Raman spectroscopy, synchrotron X-ray microfluorescence and X-ray Absorption Near Edge Spectroscopy (XANES). The grains were identified to be a suite of major upper mantle minerals including olivine, enstatite orthopyroxene (opx), C2/c omphacite clinopyroxene (cpx) and majoritic garnet (two grains), indicating eclogitic origin. All five inclusions are chemically homogeneous, do not show compositional zoning, and exhibit very similar major element chemistry, with significant amounts of Mn2+, Ni2+ and Cr3+ incorporated into the crystal structures, suggesting common geologic origin. All samples were studied in situ, while still embedded in the diamond crystals. High quality single-crystal X-ray diffraction data was collected at the Advanced Photon Source, Argonne National Laboratory to reveal details of the crystal structures and provide crystal chemical information. Some of the structural characteristics of the solid inclusions were found to be fairly uncommon, e.g. the orthoenstatite exhibits an unusually high Ca2+ content (Carlson et al. 1988), and omphacite occurs as the less common C2/c

  6. Device for isolation of seed crystals during processing of solution

    DOEpatents

    Montgomery, Kenneth E.; Zaitseva, Natalia P.; Deyoreo, James J.; Vital, Russell L.

    1999-01-01

    A device for isolation of see crystals during processing of solutions. The device enables a seed crystal to be introduced into the solution without exposing the solution to contaminants or to sources of drying and cooling. The device constitutes a seed protector which allows the seed to be present in the growth solution during filtration and overheating operations while at the same time preventing the seed from being dissolved by the under saturated solution. When the solution processing has been completed and the solution cooled to near the saturation point, the seed protector is opened, exposing the seed to the solution and allowing growth to begin.

  7. Device for isolation of seed crystals during processing of solution

    DOEpatents

    Montgomery, K.E.; Zaitseva, N.P.; Deyoreo, J.J.; Vital, R.L.

    1999-05-18

    A device is described for isolation of seed crystals during processing of solutions. The device enables a seed crystal to be introduced into the solution without exposing the solution to contaminants or to sources of drying and cooling. The device constitutes a seed protector which allows the seed to be present in the growth solution during filtration and overheating operations while at the same time preventing the seed from being dissolved by the under saturated solution. When the solution processing has been completed and the solution cooled to near the saturation point, the seed protector is opened, exposing the seed to the solution and allowing growth to begin. 3 figs.

  8. Diffractive devices based on blue phase liquid crystals

    NASA Astrophysics Data System (ADS)

    Li, Yan; Huang, Shuaijia; Su, Yikai

    2016-09-01

    Blue phase liquid crystal (BPLC) has been attractive for display and photonic applications for its sub-millisecond response time, no need for surface alignment, and an optically isotropic dark state. Because of these advantages, diffractive devices based on blue phase liquid crystals have great potential for wide applications. In this work, we present several BPLC diffractive devices. The operation principles, fabrication and experimental measurements will be discussed in details for two BPLC gratings realized by holographic method and a BPLC Fresnel lens using a spatial light modulator projector. All of these devices exhibit several attractive features such as sub-millisecond response, relatively high spatial resolution and polarization-independence.

  9. Non-linear optical crystal vibration sensing device

    DOEpatents

    Kalibjian, R.

    1994-08-09

    A non-linear optical crystal vibration sensing device including a photorefractive crystal and a laser is disclosed. The laser produces a coherent light beam which is split by a beam splitter into a first laser beam and a second laser beam. After passing through the crystal the first laser beam is counter-propagated back upon itself by a retro-mirror, creating a third laser beam. The laser beams are modulated, due to the mixing effect within the crystal by vibration of the crystal. In the third laser beam, modulation is stable and such modulation is converted by a photodetector into a usable electrical output, intensity modulated in accordance with vibration applied to the crystal. 3 figs.

  10. Non-linear optical crystal vibration sensing device

    DOEpatents

    Kalibjian, Ralph

    1994-01-11

    A non-linear optical crystal vibration sensing device (10) including a photorefractive crystal (26) and a laser (12). The laser (12 ) produces a coherent light beam (14) which is split by a beam splitter (18) into a first laser beam (20) and a second laser beam (22). After passing through the crystal (26) the first laser beam (20) is counter-propagated back upon itself by a retro-mirror (32), creating a third laser beam (30). The laser beams (20, 22, 30) are modulated, due to the mixing effect within the crystal (26) by vibration of the crystal (30). In the third laser beam (30), modulation is stable and such modulation is converted by a photodetector (34) into a usable electrical output, intensity modulated in accordance with vibration applied to the crystal (26).

  11. Small Device for Protein Crystal Growth

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Dr. Daniel Carter (center), president of New Century Pharmaceuticals, and Dr. Joseph Ho (right), vice president, examine a diffusion Controlled Apparatus for Microgravity (DCAM). At left, Dr. John Ruble, a senior scientist, examines some specimens. The plastic DCAM has two chambers joined by a porous plug through which fluids can diffuse at a controlled rate. This allows researchers to mix protein solutions on Earth and load them aboard the Space Shuttle shortly before launch. The diffusion and crystallization processes are already under way, but at such a slow pace that crystals do not start growing before the DCAM is in orbit aboard the Shuttle or a space station. Dozens of DCAM units can be flown in a small volume and require virtually no crew attention. Specimens are returned to Earth for analysis. Photo credit: NASA/Marshall Space Flight Center

  12. Enhanced Extraction of Silicon-Vacancy Centers Light Emission Using Bottom-Up Engineered Polycrystalline Diamond Photonic Crystal Slabs.

    PubMed

    Ondič, Lukáš; Varga, Marian; Hruška, Karel; Fait, Jan; Kapusta, Peter

    2017-03-03

    Silicon vacancy (SiV) centers are optically active defects in diamond. The SiV centers, in contrast to nitrogen vacancy (NV) centers, possess narrow and efficient luminescence spectrum (centered at ≈738 nm) even at room temperature, which can be utilized for quantum photonics and sensing applications. However, most of light generated in diamond is trapped in the material due to the phenomenon of total internal reflection. In order to overcome this issue, we have prepared two-dimensional photonic crystal slabs from polycrystalline diamond thin layers with high density of SiV centers employing bottom-up growth on quartz templates. We have shown that the spectral overlap between the narrow light emission of the SiV centers and the leaky modes extracting the emission into almost vertical direction (where it can be easily detected) can be obtained by controlling the deposition time. More than 14-fold extraction enhancement of the SiV centers photoluminescence was achieved compared to an uncorrugated sample. Computer simulation confirmed that the extraction enhancement originates from the efficient light-matter interaction between light emitted from the SiV centers and the photonic crystal slab.

  13. The effect of substrate temperature and growth rate on the doping efficiency of single crystal boron doped diamond

    SciTech Connect

    Demlow, SN; Rechenberg, R; Grotjohn, T

    2014-10-01

    The substrate growth temperature dependence of the plasma gas-phase to solid-phase doping efficiency in single crystal, boron doped diamond (BDD) deposition is investigated. Single crystal diamond (SCD) is grown by microwave plasma assisted chemical vapor deposition (MPACVD) on high pressure, high temperature (HPHT) type Ib substrates. Samples are grown at substrate temperatures of 850-950 degrees C for each of five doping concentration levels, to determine the effect of the growth temperature on the doping efficiency and defect morphology. The substrate temperature during growth is shown to have a significant effect on the grown sample defect morphology, and a temperature dependence of the doping efficiency is also shown. The effect of the growth rate on the doping efficiency is discussed, and the ratio of the boron concentration in the gas phase to the flux of carbon incorporated into the solid diamond phase is shown to be a more predictive measure of the resulting boron concentration than the gas phase boron to carbon ratio that is more commonly reported. (C) 2014 Elsevier B.V. All rights reserved.

  14. Semiconducting polymer single crystals and devices (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Dong, Huanli

    2016-11-01

    Highly ordered organic semiconductors in solid state with optimal molecular packing are critical to their electrical performance. Single crystals with long-range molecular orders and nearly perfect molecular packing are the best candidates, which already have been verified to exhibit the highest performance whether based on inorganic or small organic materials. However, in comparison, preparing high quality polymer crystals remains a big challenge in polymer science because of the easy entanglements of the long and flexible polymer chains during self-assembly process, which also significantly limits the development of their crystalline polymeric electronic devices. Here we have carried out systematical investigations to prepare high quality semiconducting polymers and high performance semiconducting polymer crystal optoelectronic devices have been successfully fabricated. The semiconducting polymeric devices demonstrate significantly enhanced charge carreir transport compared to their thin films, and the highest carreir mobiltiy could be approcahing 30 cm2 V-1s-1, one of the highest mobiltiy values for polymer semiconductors.

  15. Plasma spraying method for forming diamond and diamond-like coatings

    DOEpatents

    Holcombe, C.E.; Seals, R.D.; Price, R.E.

    1997-06-03

    A method and composition is disclosed for the deposition of a thick layer of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate. The softened or molten composition crystallizes on the substrate to form a thick deposition layer comprising at least a diamond or diamond-like material. The selected composition includes at least glassy carbon as a primary constituent and may include at least one secondary constituent. Preferably, the secondary constituents are selected from the group consisting of at least diamond powder, boron carbide (B{sub 4}C) powder and mixtures thereof. 9 figs.

  16. Plasma spraying method for forming diamond and diamond-like coatings

    DOEpatents

    Holcombe, Cressie E.; Seals, Roland D.; Price, R. Eugene

    1997-01-01

    A method and composition for the deposition of a thick layer (10) of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition (12) including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate (20). The softened or molten composition (18) crystallizes on the substrate (20) to form a thick deposition layer (10) comprising at least a diamond or diamond-like material. The selected composition (12) includes at least glassy carbon as a primary constituent (14) and may include at least one secondary constituent (16). Preferably, the secondary constituents (16) are selected from the group consisting of at least diamond powder, boron carbide (B.sub.4 C) powder and mixtures thereof.

  17. Modeling of Optical Aberration Correction using a Liquid Crystal Device

    NASA Technical Reports Server (NTRS)

    Xinghua, Wang; Bin, Wang; McManamon, Paul F.; Pouch, John J.; Miranda, Felix A.

    2006-01-01

    Gruneisen (sup 1-3), has shown that small, light weight, liquid crystal based devices can correct for the optical distortion caused by an imperfect primary mirror in a telescope and has discussed the efficiency of this correction. In this paper we expand on that work and propose a semi-analytical approach for quantifying the efficiency of a liquid crystal based wavefront corrector for this application.

  18. Use of a miniature diamond-anvil cell in high-pressure single-crystal neutron Laue diffraction

    PubMed Central

    Binns, Jack; Kamenev, Konstantin V.; McIntyre, Garry J.; Moggach, Stephen A.; Parsons, Simon

    2016-01-01

    The first high-pressure neutron diffraction study in a miniature diamond-anvil cell of a single crystal of size typical for X-ray diffraction is reported. This is made possible by modern Laue diffraction using a large solid-angle image-plate detector. An unexpected finding is that even reflections whose diffracted beams pass through the cell body are reliably observed, albeit with some attenuation. The cell body does limit the range of usable incident angles, but the crystallographic completeness for a high-symmetry unit cell is only slightly less than for a data collection without the cell. Data collections for two sizes of hexamine single crystals, with and without the pressure cell, and at 300 and 150 K, show that sample size and temperature are the most important factors that influence data quality. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamine with bond lengths and angles that agree with literature data within experimental error. This technique is shown to be suitable for low-symmetry crystals, and in these cases the transmission of diffracted beams through the cell body results in much higher completeness values than are possible with X-rays. The way is now open for joint X-ray and neutron studies on the same sample under identical conditions. PMID:27158503

  19. Use of a miniature diamond-anvil cell in high-pressure single-crystal neutron Laue diffraction.

    PubMed

    Binns, Jack; Kamenev, Konstantin V; McIntyre, Garry J; Moggach, Stephen A; Parsons, Simon

    2016-05-01

    The first high-pressure neutron diffraction study in a miniature diamond-anvil cell of a single crystal of size typical for X-ray diffraction is reported. This is made possible by modern Laue diffraction using a large solid-angle image-plate detector. An unexpected finding is that even reflections whose diffracted beams pass through the cell body are reliably observed, albeit with some attenuation. The cell body does limit the range of usable incident angles, but the crystallographic completeness for a high-symmetry unit cell is only slightly less than for a data collection without the cell. Data collections for two sizes of hexamine single crystals, with and without the pressure cell, and at 300 and 150 K, show that sample size and temperature are the most important factors that influence data quality. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamine with bond lengths and angles that agree with literature data within experimental error. This technique is shown to be suitable for low-symmetry crystals, and in these cases the transmission of diffracted beams through the cell body results in much higher completeness values than are possible with X-rays. The way is now open for joint X-ray and neutron studies on the same sample under identical conditions.

  20. Soft x-ray measurements using photoconductive type-IIa and single-crystal chemical vapor deposited diamond detectors.

    PubMed

    Moore, A S; Bentley, C D; Foster, J M; Goedhart, G; Graham, P; Taylor, M J; Hellewell, E

    2008-10-01

    Photoconductive detectors (PCDs) are routinely used alongside vacuum x-ray diodes (XRDs) to provide an alternative x-ray flux measurement at laser facilities such as HELEN at AWE Aldermaston, UK, and Omega at the Laboratory for Laser Energetics. To evaluate diamond PCDs as an alternative to XRD arrays, calibration measurements made at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory are used to accurately calculate the x-ray flux from a laser-heated target. This is compared to a flux measurement using the Dante XRD diagnostic. Estimates indicate that the photoinduced conductivity from measurements made at Omega are too large, and calculations using the radiometric calibrations made at the NSLS agree with this hypothesis. High-purity, single-crystal, chemical vapor deposited (CVD) diamond samples are compared to natural type-IIa PCDs and show promising high resistivity effects, the corollary of which preliminary results show is a slower response time.

  1. Tool wear of a single-crystal diamond tool in nano-groove machining of a quartz glass plate

    NASA Astrophysics Data System (ADS)

    Yoshino, Masahiko; Nakajima, Satoshi; Terano, Motoki

    2015-12-01

    Tool wear characteristics of a diamond tool in ductile mode machining are presented in this paper. Nano-groove machining of a quartz glass plate was conducted to examine the tool wear rate of a single-crystal diamond tool. Effects of lubrication on the tool wear rate were also evaluated. A numerical simulation technique was developed to evaluate the tool temperature and normal stress acting on the wear surface. From the simulation results it was found that the tool temperature does not increase during the machining experiment. It is also demonstrated that tool wear is attributed to the abrasive wear mechanism, but the effect of the adhesion wear mechanism is minor in nano-groove machining. It is found that the tool wear rate is reduced by using water or kerosene as a lubricant.

  2. Electrically Driven Photonic Crystal Nanocavity Devices

    DTIC Science & Technology

    2012-01-01

    material, here gallium arsenide and indium arsenide self- assembled quantum dots (QDs). QDs are preferred for the gain medium because they can have...implantation [22]. LCI has become routine for silicon -based electro-optic ring modulators in recent years owing to mature device process knowledge [26...a 220-nm thick membrane of GaAs with embedded InAs QDs. (b) Si and Be ions are implanted through a silicon nitride mask patterned by electron beam

  3. Small liquid-crystal display device for projection

    NASA Astrophysics Data System (ADS)

    Miyajima, Akira; Morokawa, Shigeru; Yamada, Osamu; Arai, Motonao

    1990-08-01

    In recent years, LCDs have drawn the attention of persons who present data such as sentences and patterns on the screen. This paper describes a new type of the device for projection using the LCD. CITIZEN has developed a multi-pixel, high-density and small-sized liquid crystal cell, using the Chip on Glass method. Driver ICs are directly connected to glass substrates. CITIZEN has developed a small liquid crystal display device, which is located between the light source and the lens of a conventional slide projector so that an image on the LCD is projected.

  4. Polymer-dispersed liquid crystal devices with graphene electrodes.

    PubMed

    Chung, Seok-Hwan; Noh, Hee Yeon

    2015-12-14

    Although polymer-dispersed liquid crystal (PDLC) devices have considerable potential application in smart windows, the high material cost of the indium tin oxide (ITO) electrodes conventionally used in these devices hinders their wide usage. In this work, we explore the use of graphene electrodes as a potential substitute for ITO electrodes in PDLC devices. The fabricated PDLC devices with graphene electrodes exhibit higher contrast and faster response than PDLC devices with ITO electrodes fabricated using the same chemical formulation and polymerization process. However, they also exhibit higher operation voltage and haze, which is primarily attributed to the inherently large resistance and inhomogeneity of the large-area graphene sheets initially transferred onto the transparent substrates. PDLC devices with graphene electrodes are robust under standard operating conditions and also have the advantage of flexibility and stretchability, unlike PDLCs with ITO electrodes.

  5. Design, Build & Test of a Double Crystal Monochromator for Beamlines I09 & I23 at the Diamond Light Source

    NASA Astrophysics Data System (ADS)

    Kelly, J.; Lee, T.; Alcock, S.; Patel, H.

    2013-03-01

    A high stability Double Crystal Monochromator has been developed at The Diamond Light Source for beamlines I09 and I23. The design specification was a cryogenic, fixed exit, energy scanning monochromator, operating over an energy range of 2.1 - 25 keV using a Si(111) crystal set. The novel design concepts are the direct drive, air bearing Bragg axis, low strain crystal mounts and the cooling scheme. The instrument exhibited superb stability and repeatability on the B16 Test Beamline. A 20 keV Si(555), 1.4 μrad rocking curve was demonstrated. The DCM showed good stability without any evidence of vibration or Bragg angle nonlinearity.

  6. Growth of large size diamond single crystals by plasma assisted chemical vapour deposition: Recent achievements and remaining challenges

    NASA Astrophysics Data System (ADS)

    Tallaire, Alexandre; Achard, Jocelyn; Silva, François; Brinza, Ovidiu; Gicquel, Alix

    2013-02-01

    Diamond is a material with outstanding properties making it particularly suited for high added-value applications such as optical windows, power electronics, radiation detection, quantum information, bio-sensing and many others. Tremendous progresses in its synthesis by microwave plasma assisted chemical vapour deposition have allowed obtaining single crystal optical-grade material with thicknesses of up to a few millimetres. However the requirements in terms of size, purity and crystalline quality are getting more and more difficult to achieve with respect to the forecasted applications, thus pushing the synthesis method to its scientific and technological limits. In this paper, after a short description of the operating principles of the growth technique, the challenges of increasing crystal dimensions both laterally and vertically, decreasing and controlling point and extended defects as well as modulating crystal conductivity by an efficient doping will be detailed before offering some insights into ways to overcome them.

  7. Single-color centers implanted in diamond nanostructures

    NASA Astrophysics Data System (ADS)

    Hausmann, Birgit J. M.; Babinec, Thomas M.; Choy, Jennifer T.; Hodges, Jonathan S.; Hong, Sungkun; Bulu, Irfan; Yacoby, Amir; Lukin, Mikhail D.; Lončar, Marko

    2011-04-01

    The development of material-processing techniques that can be used to generate optical diamond nanostructures containing a single-color center is an important problem in quantum science and technology. In this work, we present the combination of ion implantation and top-down diamond nanofabrication in two scenarios: diamond nanopillars and diamond nanowires. The first device consists of a 'shallow' implant (~20 nm) to generate nitrogen-vacancy (NV) color centers near the top surface of the diamond crystal prior to device fabrication. Individual NV centers are then mechanically isolated by etching a regular array of nanopillars in the diamond surface. Photon anti-bunching measurements indicate that a high yield (>10%) of the devices contain a single NV center. The second device demonstrates 'deep' (~1 μm) implantation of individual NV centers into diamond nanowires as a post-processing step. The high single-photon flux of the nanowire geometry, combined with the low background fluorescence of the ultrapure diamond, allowed us to observe sustained photon anti-bunching even at high pump powers.

  8. Diamond detector - material science, design and application

    NASA Astrophysics Data System (ADS)

    Gaowei, Mengjia

    Modern synchrotrons, such as the NSLS-II, will enable unprecedented science by having extremely high brightness and flux with exceptional beam stability. These capabilities create a harsh and demanding environment for measuring the characteristics of the x-ray beam. In many cases, existing measurement techniques fail completely, requiring the development of new detectors which can meet the demands of the synchrotron. The combination of diamond properties ranked diamond an appealing candidate in the field of radiation detection in extreme conditions and it has been used as x-ray sensor material for decades. However, only until the development of chemical vapor deposition (CVD) process in the synthesis of diamond that has it been considered for wider applications in the state-of-art synchrotron light sources as part of beamline diagnostics, including the detection of x-ray beam flux and position. While defects and dislocations in CVD grown single crystal diamonds are inevitable, there are solutions in other aspects of a device fabrication to compensate this technological downside, including improving device performance in engineering diamond surface electrode materials and patterns and slicing and polishing diamond plates into thinner pieces. The content of this dissertation summarizes our effort in addressing several problems we encounter in the process of design and fabrication of single crystal CVD diamond based electronic devices. In order to study the generation of post-anneal photoconductive gain in our devices we have discussed in section 3 and 4 the two criteria for the observation of photoconductive current. In section 3 we reveal the correlation between structural defects in diamond and the post-anneal photoconductive regions. Section 4 introduces the measurements of hard x-ray photoelectron spectroscopy (HAXPES) we applied to investigate the diamond-metal Schottky barrier height for several metals and diamond surface terminations. The position of the

  9. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1985-01-01

    The present program has been aimed at solving the fundamental and technological problems associated with Crystal Growth of Device Quality in Space. The initial stage of the program was devoted strictly to ground-based research. The unsolved problems associated with the growth of bulk GaAs in the presence of gravitational forces were explored. Reliable chemical, structural and electronic characterization methods were developed which would permit the direct relation of the salient materials parameters (particularly those affected by zero gravity conditions) to the electronic characteristics of single crystal GaAs, in turn to device performance. These relationships are essential for the development of optimum approaches and techniques. It was concluded that the findings on elemental semiconductors Ge and Si regarding crystal growth, segregation, chemical composition, defect interactions, and materials properties-electronic properties relationships are not necessarily applicable to GaAs (and to other semiconductor compounds). In many instances totally unexpected relationships were found to prevail.

  10. Single crystal diamond detector measurements of deuterium-deuterium and deuterium-tritium neutrons in Joint European Torus fusion plasmas.

    PubMed

    Cazzaniga, C; Sundén, E Andersson; Binda, F; Croci, G; Ericsson, G; Giacomelli, L; Gorini, G; Griesmayer, E; Grosso, G; Kaveney, G; Nocente, M; Perelli Cippo, E; Rebai, M; Syme, B; Tardocchi, M

    2014-04-01

    First simultaneous measurements of deuterium-deuterium (DD) and deuterium-tritium neutrons from deuterium plasmas using a Single crystal Diamond Detector are presented in this paper. The measurements were performed at JET with a dedicated electronic chain that combined high count rate capabilities and high energy resolution. The deposited energy spectrum from DD neutrons was successfully reproduced by means of Monte Carlo calculations of the detector response function and simulations of neutron emission from the plasma, including background contributions. The reported results are of relevance for the development of compact neutron detectors with spectroscopy capabilities for installation in camera systems of present and future high power fusion experiments.

  11. Single crystal diamond detector measurements of deuterium-deuterium and deuterium-tritium neutrons in Joint European Torus fusion plasmas

    SciTech Connect

    Cazzaniga, C. Gorini, G.; Nocente, M.; Sundén, E. Andersson; Binda, F.; Ericsson, G.; Croci, G.; Grosso, G.; Cippo, E. Perelli; Tardocchi, M.; Giacomelli, L.; Rebai, M.; Griesmayer, E.; Kaveney, G.; Syme, B.; Collaboration: JET-EFDA Contributors

    2014-04-15

    First simultaneous measurements of deuterium-deuterium (DD) and deuterium-tritium neutrons from deuterium plasmas using a Single crystal Diamond Detector are presented in this paper. The measurements were performed at JET with a dedicated electronic chain that combined high count rate capabilities and high energy resolution. The deposited energy spectrum from DD neutrons was successfully reproduced by means of Monte Carlo calculations of the detector response function and simulations of neutron emission from the plasma, including background contributions. The reported results are of relevance for the development of compact neutron detectors with spectroscopy capabilities for installation in camera systems of present and future high power fusion experiments.

  12. Radiation damage in single crystal CVD diamond material investigated with a high current relativistic 197Au beam

    NASA Astrophysics Data System (ADS)

    Pietraszko, J.; Galatyuk, T.; Grilj, V.; Koenig, W.; Spataro, S.; Träger, M.

    2014-11-01

    Single-crystal Chemical Vapor Deposition (ScCVD) diamond based prototype detectors have been constructed for the high intensity heavy ion experiments HADES and CBM at the future FAIR facility at GSI Darmstadt. Their properties have been studied with a high current density beam (about 2-3×106/s/mm2) of 1.25A GeV Au69+197 ions. Details of the design, the intrinsic properties of the detectors and their performance after irradiation with such a beam are reported.

  13. Bent diamond-crystal x-ray spectrographs for x-ray free-electron laser noninvasive diagnostics

    NASA Astrophysics Data System (ADS)

    Terentyev, Sergey; Blank, Vladimir; Kolodziej, Tomasz; Shvyd'ko, Yuri

    2016-09-01

    We report on the manufacturing and X-ray tests of bent diamond-crystal X-ray spectrographs, designed for noninvasive diagnostics of the X-ray free-electron laser (XFEL) spectra in the spectral range from 5 to 15 keV. The key component is a curved, 20-μm thin, single crystalline diamond triangular plate in the (110) orientation. The radius of curvature can be varied between R = 0:6 m and R = 0:1 m in a controlled fashion, ensuring imaging in a spectral window of up to 60 eV for 8 keV X-rays. All of the components of the bending mechanism (about 10 parts) are manufactured from diamond, thus ensuring safe operations in intense XFEL beams. The spectrograph is transparent to 88% for 5-keV photons, and to 98% for 15-keV photons. Therefore, it can be used for noninvasive diagnostics of the X-ray spectra during XFEL operations.

  14. Diamond Analyzed by Secondary Electron Emission Spectroscopy

    NASA Technical Reports Server (NTRS)

    Krainsky, Isay L.

    1998-01-01

    Diamond is a promising semiconductor material for novel electronic applications because of its chemical stability and inertness, heat conduction properties, and so-called negative electron affinity (NEA). When a surface has NEA, electrons generated inside the bulk of the material are able to come out into the vacuum without any potential barrier (work function). Such a material would have an extremely high secondary electron emission coefficient o, very high photoelectron (quantum) yield, and would probably be an efficient field emitter. Chemical-vapor-deposited (CVD) polycrystalline diamond films have even more advantages than diamond single crystals. Their fabrication is relatively easy and inexpensive, and they can be grown with high levels of doping--consequently, they can have relatively high conductivity. Because of these properties, diamond can be used for cold cathodes and photocathodes in high-power electronics and in high-frequency and high-temperature semiconductor devices.

  15. Boron Arsenide and Boron Phosphide for High Temperature and Luminescent Devices. [semiconductor devices - crystal growth/crystal structure

    NASA Technical Reports Server (NTRS)

    Chu, T. L.

    1975-01-01

    The crystal growth of boron arsenide and boron phosphide in the form of bulk crystals and epitaxial layers on suitable substrates is discussed. The physical, chemical, and electrical properties of the crystals and epitaxial layers are examined. Bulk crystals of boron arsenide were prepared by the chemical transport technique, and their carrier concentration and Hall mobility were measured. The growth of boron arsenide crystals from high temperature solutions was attempted without success. Bulk crystals of boron phosphide were also prepared by chemical transport and solution growth techniques. Techniques required for the fabrication of boron phosphide devices such as junction shaping, diffusion, and contact formation were investigated. Alloying techniques were developed for the formation of low-resistance ohmic contacts to boron phosphide. Four types of boron phosphide devices were fabricated: (1) metal-insulator-boron phosphide structures, (2) Schottky barriers; (3) boron phosphide-silicon carbide heterojunctions; and (4) p-n homojunctions. Easily visible red electroluminescence was observed from both epitaxial and solution grown p-n junctions.

  16. Hybrid graphene nematic liquid crystal light scattering device

    NASA Astrophysics Data System (ADS)

    Qasim, M. M.; Khan, A. A.; Kostanyan, A.; Kidambi, P. R.; Cabrero-Vilatela, A.; Braeuninger-Weimer, P.; Gardiner, D. J.; Hofmann, S.; Wilkinson, T. D.

    2015-08-01

    A hybrid graphene nematic liquid crystal (LC) light scattering device is presented. This device exploits the inherent poly-crystallinity of chemical vapour deposited (CVD) graphene films to induce directional anchoring and formation of LC multi-domains. This thereby enables efficient light scattering without the need for crossed polarisers or separate alignment layers/additives. The hybrid LC device exhibits switching thresholds at very low electric fields (< 1 V μm-1) and repeatable, hysteresis free characteristics. This exploitation of LC alignment effects on CVD graphene films enables a new generation of highly efficient nematic LC scattering displays as well as many other possible applications.A hybrid graphene nematic liquid crystal (LC) light scattering device is presented. This device exploits the inherent poly-crystallinity of chemical vapour deposited (CVD) graphene films to induce directional anchoring and formation of LC multi-domains. This thereby enables efficient light scattering without the need for crossed polarisers or separate alignment layers/additives. The hybrid LC device exhibits switching thresholds at very low electric fields (< 1 V μm-1) and repeatable, hysteresis free characteristics. This exploitation of LC alignment effects on CVD graphene films enables a new generation of highly efficient nematic LC scattering displays as well as many other possible applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04094a

  17. Ultrananocrystalline diamond-CMOS device integration route for high acuity retinal prostheses.

    PubMed

    Ahnood, A; Escudie, M C; Cicione, R; Abeyrathne, C D; Ganesan, K; Fox, K E; Garrett, D J; Stacey, A; Apollo, N V; Lichter, S G; Thomas, C D L; Tran, N; Meffin, H; Prawer, S

    2015-01-01

    High density electrodes are a new frontier for biomedical implants. Increasing the density and the number of electrodes used for the stimulation of retinal ganglion cells is one possible strategy for enhancing the quality of vision experienced by patients using retinal prostheses. The present work presents an integration strategy for a diamond based, high density, stimulating electrode array with a purpose built application specific integrated circuit (ASIC). The strategy is centered on flip-chip bonding of indium bumps to create high count and density vertical interconnects between the stimulator ASIC and an array of diamond neural stimulating electrodes. The use of polydimethylsiloxane (PDMS) housing prevents cross-contamination of the biocompatible diamond electrode with non-biocompatible materials, such as indium, used in the microfabrication process. Micro-imprint lithography allowed edge-to-edge micro-scale pattering of the indium bumps on non-coplanar substrates that have a form factor that can conform to body organs and thus are ideally suited for biomedical applications. Furthermore, micro-imprint lithography ensures the compatibility of lithography with the silicon ASIC and aluminum contact pads. Although this work focuses on 256 stimulating diamond electrode arrays with a pitch of 150 μm, the use of indium bump bonding technology and vertical interconnects facilitates implants with tens of thousands electrodes with a pitch as low as 10 μm, thus ensuring validity of the strategy for future high acuity retinal prostheses, and bionic implants in general.

  18. Device and method for screening crystallization conditions in solution crystal growth

    NASA Technical Reports Server (NTRS)

    Carter, Daniel C. (Inventor)

    1995-01-01

    A device and method for detecting optimum protein crystallization conditions and for growing protein crystals in either 1g or microgravity environments comprising a housing, defining at least one pair of chambers for containing crystallization solutions is presented. The housing further defines an orifice therein for providing fluid communication between the chambers. The orifice is adapted to receive a tube which contains a gelling substance for limiting the rate of diffusive mixing of the crystallization solutions. The solutions are diffusively mixed over a period of time defined by the quantity of gelling substance sufficient to achieve equilibration and to substantially reduce density driven convection disturbances therein. The device further includes endcaps to seal the first and second chambers. One of the endcaps includes a dialysis chamber which contains protein solution in which protein crystals are grown. Once the endcaps are in place, the protein solution is exposed to the crystallization solutions wherein the solubility of the protein solution is reduced at a rate responsive to the rate of diffusive mixing of the crystallization solutions. This allows for a controlled approach to supersaturation and allows for screening of crystal growth conditions at preselected intervals.

  19. Device and Method for Screening Crystallization Conditions in Solution Crystal Growth

    NASA Technical Reports Server (NTRS)

    Carter, Daniel C. (Inventor)

    1997-01-01

    A device and method for detecting optimum protein crystallization conditions and for growing protein crystals in either 1 g or microgravity environments comprising a housing defining at least one pair of chambers for containing crystallization solutions. The housing further defines an orifice therein for providing fluid communication between the chambers. The orifice is adapted to receive a tube which contains a gelling substance for limiting the rate of diffusive mixing of the crystallization solutions. The solutions are diffusively mixed over a period of time defined by the quantity of gelling substance sufficient to achieve equilibration and to substantially reduce density driven convection disturbances therein. The device further includes endcaps to seal the first and second chambers. One of the endcaps includes a dialysis chamber which contains protein solution in which protein crystals are grown. Once the endcaps are in place. the protein solution is exposed to the crystallization solutions wherein the solubility of the protein solution is reduced at a rate responsive to the rate of diffusive mixing of the crystallization solutions. This allows for a controlled approach to supersaturation and allows for screening of crystal growth conditions at preselected intervals.

  20. Thermally-induced single-crystal-to-single-crystal transformations from a 2D two-fold interpenetrating square lattice layer to a 3D four-fold interpenetrating diamond framework and its application in dye-sensitized solar cells.

    PubMed

    Gao, Song; Fan, Rui Qing; Wang, Xin Ming; Wei, Li Guo; Song, Yang; Du, Xi; Xing, Kai; Wang, Ping; Yang, Yu Lin

    2016-07-28

    In this work, a rare 2D → 3D single-crystal-to-single-crystal transformation (SCSC) is observed in metal-organic coordination complexes, which is triggered by thermal treatment. The 2D two-fold interpenetrating square lattice layer [Cd(IBA)2]n (1) is irreversibly converted into a 3D four-fold interpenetrating diamond framework {[Cd(IBA)2(H2O)]·2.5H2O}n (2) (HIBA = 4-(1H-imidazol-1-yl)benzoic acid). Consideration is given to these two complexes with different interpenetrating structures and dimensionality, and their influence on photovoltaic properties are studied. Encouraged by the UV-visible absorption and HOMO-LUMO energy states matched for sensitizing TiO2, the two complexes are employed in combination with N719 in dye-sensitized solar cells (DSSCs) to compensate absorption in the ultraviolet and blue-violet region, offset competitive visible light absorption of I3(-) and reducing charge the recombination of injected electrons. After co-sensitization with 1 and 2, the device co-sensitized by 1/N719 and 2/N719 to yield overall efficiencies of 7.82% and 8.39%, which are 19.94% and 28.68% higher than that of the device sensitized only by N719 (6.52%). Consequently, high dimensional interpenetrating complexes could serve as excellent co-sensitizers and have application in DSSCs.

  1. Realization of direct bonding of single crystal diamond and Si substrates

    NASA Astrophysics Data System (ADS)

    Liang, Jianbo; Masuya, Satoshi; Kasu, Makoto; Shigekawa, Naoteru

    2017-03-01

    Diamond/Si junctions have been achieved by surface activated bonding method without any chemical and heating treatments. Bonded interfaces were obtained that were free from voids and mechanical cracks. Observations by using transmission electron microscopy indicated that an amorphous layer with a thickness of ˜20 nm across the bonded interface was formed, and no structural defects were observed at the interface. The amorphous layer of the diamond side was confirmed to be the mixture of sp2 and sp3 carbons by electron energy loss spectroscopy analyzation. The sp3/(sp2 + sp3) ratio estimated from the X-ray photoemission spectra decreased from 53.8% to 27.5%, while the relative intensity of sp2 increased from 26.8% to 72.5% after the irradiation with Ar fast beam which should be predominantly attributable to the diamond-graphite conversion.

  2. The effect of pressure on the kinetics of γ-anhydrite crystallization investigated by diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Liu, Chuanjiang; Zheng, Haifei; Du, Jianguo; Wang, Duojun

    2015-01-01

    The crystallization kinetics of γ-anhydrite was investigated in the temperature and pressure ranges of 373-473 K and 1094-1903 MPa using a hydrothermal diamond anvil cell (HDAC) and Raman spectroscopy. A calcium sulfate solution was formed by dissolving gypsum in water at high pressure, and γ-anhydrite crystallized due to the increasing temperature. The relationship among the reaction rate, k, the temperature, T, and the pressure, P was established as k=-1.75×10-3+1.83×10-6P+3.57×10-7T, with an R2 value of 0.943, of which the applicable range is 373 K≤T≤473 K and 1196 MPa≤P≤1903 MPa. An elevation of T or P will accelerate the crystallization rate of γ-anhydrite. The time exponent n obtained between 0.96 and 1.29 indicates that the process of crystallization should be controlled by instant nucleation on the grain boundary and diffusion controlled growth. In the process of crystallization, the volume is reduced because of the decrease of pressure, and the volume change ΔV is equal to -6.05×10-6 m3/mol. The calculated activation energy Ea is 10.7 kJ/mol, and the pre-exponential factor A is 2.27×10-2 s-1.

  3. Crystal Phases in Hybrid Metal-Semiconductor Nanowire Devices.

    PubMed

    David, J; Rossella, F; Rocci, M; Ercolani, D; Sorba, L; Beltram, F; Gemmi, M; Roddaro, S

    2017-04-12

    We investigate the metallic phases observed in hybrid metal-GaAs nanowire devices obtained by controlled thermal annealing of Ni/Au electrodes. Devices are fabricated onto a SiN membrane compatible with transmission electron microscopy studies. Energy dispersive X-ray spectroscopy allows us to show that the nanowire body includes two Ni-rich phases that thanks to an innovative use of electron diffraction tomography can be unambiguously identified as Ni3GaAs and Ni5As2 crystals. The mechanisms of Ni incorporation leading to the observed phenomenology are discussed.

  4. Ca(Ti,Si)O3 Diamond Inclusions Crystallized From Carbonate Melts in the Transition Zone: Experimental Constraints

    NASA Astrophysics Data System (ADS)

    Armstrong, L. S.; Walter, M. J.; Keshav, S.; Bulanova, G.; Pickles, J.; Lord, O. T.; Lennie, A.

    2007-12-01

    Composite diamond inclusions consisting of coexisting endmember CaSiO3 and CaTiO3 are rare but occur in diamond populations from Juina, Brazil1-2. Phase relations show that above ~9 GPa (at 1500 K) a perovskite-structured solid solution exists between these endmembers, while at lower pressures intermediate compositions produce coexisting CaTiO3-perovskite and CaSiO3 in the walstromite structure3. Inclusions with `perovskite' stoichiometry are commonly interpreted as fragments of solid mantle from the transition zone or lower mantle4-6. Here we report on two composite diamond inclusions from Juina kimberlite, and can effectively eliminate a subsolidus origin on the basis of experimental mineral phase relations. Instead, based on new melting experiments we find that the inclusions most likely crystallized directly from Ca-rich carbonate melts. Like other workers1-2 we interpret the composite inclusions as exsolution products of a high-pressure Ca(Ti,Si)O3 perovskite stable in the transition zone. Our bulk inclusion compositions are estimated to contain 50- 65 mol% CaTiO3, and are remarkably low in MgSiO3 component at less than 0.2 mol%. Experiments have shown that in peridotite or eclogite lithologies, Ca-rich perovskite in equilibrium with an MgSiO3-phase (majorite or Mg-perovskite) have about 3 to 7 mol% MgSiO37-8. Here we report on new subsolidus laser-heated diamond anvil cell experiments at 20-50 GPa in the ternary system CaSiO3-CaTiO3-MgSiO3 that bracket the CaTi-rich limb of the solvus between Ca- and Mg-rich perovskites. All experiments were made at 2000 (±200) K for 45-75 min, and were analysed using synchrotron micro-focus X-ray diffraction. We find that the solubility of MgSiO3 in CaTi-perovskite solid solutions increases significantly with increasing CaTiO3 component. Thus, Ti-rich calcium perovskite in peridotite or eclogite lithologies should have very high, not exceptionally low, MgSiO3 component. Accordingly, a subsolidus paragenesis is unlikely for

  5. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, Harry C.; Lagowski, Jacek

    1989-01-01

    The program on Crystal Growth of Device Quality GaAs in Space was initiated in 1977. The initial stage covering 1977 to 1984 was devoted strictly to ground-based research. By 1985 the program had evolved into its next logical stage aimed at space growth experiments; however, since the Challenger disaster, the program has been maintained as a ground-based program awaiting activation of experimentation in space. The overall prgram has produced some 80 original scientific publications on GaAs crystal growth, crystal characterization, and new approaches to space processing. Publication completed in the last three years are listed. Their key results are outlined and discussed in the twelve publications included as part of the report.

  6. 75 FR 74080 - In the Matter of Certain Liquid Crystal Display Devices, Including Monitors, Televisions, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-30

    ... COMMISSION Inv. No. 337-TA-749 In the Matter of Certain Liquid Crystal Display Devices, Including Monitors... sale within the United States after importation of certain liquid crystal display devices, including... importation of certain liquid crystal display devices, including monitors, televisions, and modules,...

  7. A nitrogen doped low-dislocation density free-standing single crystal diamond plate fabricated by a lift-off process

    SciTech Connect

    Mokuno, Yoshiaki Kato, Yukako; Tsubouchi, Nobuteru; Chayahara, Akiyoshi; Yamada, Hideaki; Shikata, Shinichi

    2014-06-23

    A nitrogen-doped single crystal diamond plate with a low dislocation density is fabricated by chemical vapor deposition (CVD) from a high pressure high temperature synthetic type IIa seed substrate by ion implantation and lift-off processes. To avoid sub-surface damage, the seed surface was subjected to deep ion beam etching. In addition, we introduced a nitrogen flow during the CVD step to grow low-strain diamond at a relatively high growth rate. This resulted in a plate with low birefringence and a dislocation density as low as 400 cm{sup −2}, which is the lowest reported value for a lift-off plate. Reproducing this lift-off process may allow mass-production of single crystal CVD diamond plates with low dislocation density and consistent quality.

  8. Crystal Growth of Device Quality Gaas in Space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.

    1985-01-01

    The GaAs research evolves about these key thrust areas. The overall program combines: (1) studies of crystal growth on novel approaches to engineering of semiconductor material (i.e., GaAs and related compounds); (2) investigation and correlation of materials properties and electronic characteristics on a macro- and microscale; and (3) investigation of electronic properties and phenomena controlling device applications and device performance. This effort is aimed at the essential ground-based program which would insure successful experimentation with and eventually processing of GaAs in near zero gravity environment. It is believed that this program addresses in a unique way materials engineering aspects which bear directly on the future exploitation of the potential of GaAs and related materials in device and systems applications.

  9. Switchable Solar Window Devices Based on Polymer Dispersed Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Murray, Joseph; Ma, Dakang; Munday, Jeremy

    Windows are an interesting target for photovoltaics due to the potential for large area of deployment and because glass is already a ubiquitous component of solar cell devices. Many demonstrations of solar windows in recent years have used photovoltaic devices which are semitransparent in the visible region. Much research has focused on enhancing device absorption in the UV and IR ranges as a means to circumvent the basic tradeoff between efficiency and transparency to visible light. Use of switchable solar window is a less investigated alternative approach; these windows utilize the visible spectrum but can toggle between high transparency and high efficiency as needed. We present a novel switchable solar window device based on Polymer Dispersed Liquid Crystals (PDLC). By applying an electric field to the PDLC layer, the device can be switched from an opaque, light diffusing, efficient photovoltaic cell to a clear, transparent window. In the off state (i.e. scattering state), these devices have the added benefits of increased reflectivity for reduced lighting and cooling costs and haze for privacy. Further, we demonstrate that these windows have the potential for self-powering due to the very low power required to maintain the on, or high transparency, state. Support From: University of Maryland and Maryland Nano-center and its Fablab.

  10. Microwave Plasma Source for Fabrication of Micro- and Nano-Crystalline Diamond Thin Films for Electronic Devices

    NASA Astrophysics Data System (ADS)

    Paosawatyanyong, Boonchoat; Rujisamphan, Nopporn; Bhanthumnavin, Worawan

    2013-01-01

    The design and utilization of an affordable compact-size high-density plasma reactor for micro- and nano-crystalline diamond (MCD/NCD) thin film deposition is presented. The system is based on a 2.45 GHz domestic microwave oven magnetron. A switching power supply module, which yields a low-voltage high-current AC filament feeding and a high-voltage low-current DC cathode bias, is constructed to serve as the magnetron power source. With a high stability of the power module combined with the usage of water cooling gaskets, over 100 h of plasma processing time was achieved without overheating or causing any damage to the magnetron. Depositions of well-faceted MCD/NCD thin films, with distinct diamond Raman characteristics, were obtained using H2-CH4 discharge with 1-5% CH4. Metal-semiconductor diode structures were fabricated using gold and aluminum as ohmic and rectifying contacts, respectively, and their responses to DC signals revealed a high rectification ratio of up to 106 in the intrinsic MCD/NCD devices.

  11. Sub-band gap photo-enhanced secondary electron emission from high-purity single-crystal chemical-vapor-deposited diamond

    NASA Astrophysics Data System (ADS)

    Yater, J. E.; Shaw, J. L.; Pate, B. B.; Feygelson, T. I.

    2016-02-01

    Secondary-electron-emission (SEE) current measured from high-purity, single-crystal (100) chemical-vapor-deposited diamond is found to increase when sub-band gap (3.06 eV) photons are incident on the hydrogenated surface. Although the light does not produce photoemission directly, the SEE current increases by more than a factor of 2 before saturating with increasing laser power. In energy distribution curves (EDCs), the emission peak shows a corresponding increase in intensity with increasing laser power. However, the emission-onset energy in the EDCs remains constant, indicating that the bands are pinned at the surface. On the other hand, changes are observed on the high-energy side of the distribution as the laser power increases, with a well-defined shoulder becoming more pronounced. From an analysis of this feature in the EDCs, it is deduced that upward band bending is present in the near-surface region during the SEE measurements and this band bending suppresses the SEE yield. However, sub-band gap photon illumination reduces the band bending and thereby increases the SEE current. Because the bands are pinned at the surface, we conclude that the changes in the band levels occur below the surface in the electron transport region. Sample heating produces similar effects as observed with sub-band gap photon illumination, namely, an increase in SEE current and a reduction in band bending. However, the upward band bending is not fully removed by either increasing laser power or temperature, and a minimum band bending of ˜0.8 eV is established in both cases. The sub-band gap photo-excitation mechanism is under further investigation, although it appears likely at present that defect or gap states play a role in the photo-enhanced SEE process. In the meantime, the study demonstrates the ability of visible light to modify the electronic properties of diamond and enhance the emission capabilities, which may have potential impact for diamond-based vacuum electron

  12. Sub-band gap photo-enhanced secondary electron emission from high-purity single-crystal chemical-vapor-deposited diamond

    SciTech Connect

    Yater, J. E. Shaw, J. L.; Pate, B. B.; Feygelson, T. I.

    2016-02-07

    Secondary-electron-emission (SEE) current measured from high-purity, single-crystal (100) chemical-vapor-deposited diamond is found to increase when sub-band gap (3.06 eV) photons are incident on the hydrogenated surface. Although the light does not produce photoemission directly, the SEE current increases by more than a factor of 2 before saturating with increasing laser power. In energy distribution curves (EDCs), the emission peak shows a corresponding increase in intensity with increasing laser power. However, the emission-onset energy in the EDCs remains constant, indicating that the bands are pinned at the surface. On the other hand, changes are observed on the high-energy side of the distribution as the laser power increases, with a well-defined shoulder becoming more pronounced. From an analysis of this feature in the EDCs, it is deduced that upward band bending is present in the near-surface region during the SEE measurements and this band bending suppresses the SEE yield. However, sub-band gap photon illumination reduces the band bending and thereby increases the SEE current. Because the bands are pinned at the surface, we conclude that the changes in the band levels occur below the surface in the electron transport region. Sample heating produces similar effects as observed with sub-band gap photon illumination, namely, an increase in SEE current and a reduction in band bending. However, the upward band bending is not fully removed by either increasing laser power or temperature, and a minimum band bending of ∼0.8 eV is established in both cases. The sub-band gap photo-excitation mechanism is under further investigation, although it appears likely at present that defect or gap states play a role in the photo-enhanced SEE process. In the meantime, the study demonstrates the ability of visible light to modify the electronic properties of diamond and enhance the emission capabilities, which may have potential impact for diamond-based vacuum electron

  13. Improvement of radiation stability of semi-insulating gallium arsenide crystals by deposition of diamond-like carbon films

    NASA Astrophysics Data System (ADS)

    Klyui, N. I.; Lozinskii, V. B.; Liptuga, A. I.; Izotov, V. Yu.; Han, Wei; Liu, Bingbing

    2016-12-01

    We studied the properties of optical elements for the IR spectral range based on semi-insulating gallium arsenide (SI-GaAs) and antireflecting diamond-like carbon films (DLCF). Particular attention has been paid to the effect of penetrating γ-radiation on transmission of the developed optical elements. A Co60 source and step-by-step gaining of γ-irradiation dose were used for treatment of both an initial SI-GaAs crystal and DLCF/SI-GaAs structures. It was shown that DLCF deposition essentially increases degradation resistance of the SI-GaAs-based optical elements to γ-radiation. Particularly, the transmittance of the DLCF/SI-GaAs structure after γ-irradiation with a dose 9ṡ104 Gy even exceeds that of initial structures. The possible mechanism that explains the effect of γ-radiation on the SI-GaAs crystals and the DLCF/SI-GaAs structures at different irradiation doses was proposed. The effect of small doses is responsible for non-monotonic transmission changes in both SI-GaAs crystals and DLCF/SI-GaAs structures. At further increasing the γ-irradiation dose, the variation of properties of both DLCF and SI-GaAs crystal influences on the transmission of DLCF/SI-GaAs system. At high γ-irradiation dose 1.4ṡ105 Gy, passivation of radiation defects in the SI-GaAs bulk by hydrogen diffused from DLCF leads to increasing the degradation resistance of the SI-GaAs crystals coated with DLCF as compared with the crystals without DLCF.

  14. The properties of photonic band gaps for three-dimensional plasma photonic crystals in a diamond structure

    SciTech Connect

    Zhang Haifeng; Liu Shaobin; Kong Xiangkun, Chenchen; Bian Borui

    2013-04-15

    In this paper, the properties of photonic band gaps (PBGs) for two types of three-dimensional plasma photonic crystals (PPCs) composed of isotropic dielectric and unmagnetized plasma with diamond lattices are theoretically investigated for electromagnetic waves based on a modified plane wave expansion method. The equations for type-1 structure are theoretically deduced, which depend on the diamond lattices realization (dielectric spheres immersed in plasma background). The influences of dielectric constant of dielectric, plasma collision frequency, filling factor, and plasma frequency on PBGs are investigated, respectively, and some corresponding physical explanations and the possible methods to realize the three-dimensional PPCs in experiments are also given. From the numerical results, it has been shown that not only the locations but also the gap/midgap ratios of the PBGs for two types of PPCs can be tuned by plasma frequency, filling factor, and the relative dielectric constant, respectively. However, the plasma collision frequency has no effect on the frequency ranges and gap/midgap ratios of the PBGs for two types of PPCs.

  15. A diamond nanowire single-photon source.

    PubMed

    Babinec, Thomas M; Hausmann, Birgit J M; Khan, Mughees; Zhang, Yinan; Maze, Jeronimo R; Hemmer, Philip R; Loncar, Marko

    2010-03-01

    The development of a robust light source that emits one photon at a time will allow new technologies such as secure communication through quantum cryptography. Devices based on fluorescent dye molecules, quantum dots and carbon nanotubes have been demonstrated, but none has combined a high single-photon flux with stable, room-temperature operation. Luminescent centres in diamond have recently emerged as a stable alternative, and, in the case of nitrogen-vacancy centres, offer spin quantum bits with optical readout. However, these luminescent centres in bulk diamond crystals have the disadvantage of low photon out-coupling. Here, we demonstrate a single-photon source composed of a nitrogen-vacancy centre in a diamond nanowire, which produces ten times greater flux than bulk diamond devices, while using ten times less power. This result enables a new class of devices for photonic and quantum information processing based on nanostructured diamond, and could have a broader impact in nanoelectromechanical systems, sensing and scanning probe microscopy.

  16. Applicability check of ZnO crystals for device applications

    NASA Astrophysics Data System (ADS)

    Bhowmick, Mithun; Ullrich, Bruno; Ariza, David; Xi, Haowen

    2014-03-01

    There has always been vital interest in wide-band gap semiconductors for their applicability in short-wavelength photonic devices and in electronic devices operating in high frequency regime. Historically, ZnO was never favored as a potential material for the above applications primarily because of difficulty in growing it. This situation, however, has improved drastically in the past decade thereby renewing the attention on this material system. Hence, ZnO is being proposed for potential light emitting devices in the blue and UV regions of electromagnetic spectrum. ZnO single crystals are also being considered for high power transistors. In this work, we present investigations of optical properties of pure (99.99%) ZnO performing transmittance, reflectance, Raman, and photoluminescence measurements. The ZnO single crystals employed in this work, were obtained commercially. We present detailed analysis of the measured data through theoretical calculations. Our results identify the state-of-the-art application potential of commercially available ZnO, revealing its advantages and limitations when compared to similar materials such as GaN.

  17. Diamond heteroepitaxial lateral overgrowth

    NASA Astrophysics Data System (ADS)

    Tang, Yung-Hsiu

    This dissertation describes improvements in the growth of single crystal diamond by microwave plasma-assisted chemical vapor deposition (CVD). Heteroepitaxial (001) diamond was grown on 1 cm. 2 a-plane sapphiresubstrates using an epitaxial (001) Ir thin-film as a buffer layer. Low-energy ion bombardment of the Ir layer, a process known as bias-enhanced nucleation, is a key step in achieving a high density of diamond nuclei. Bias conditions were optimized to form uniformly-high nucleation densities across the substrates, which led to well-coalesced diamond thin films after short growth times. Epitaxial lateral overgrowth (ELO) was used as a means of decreasing diamond internal stress by impeding the propagation of threading dislocations into the growing material. Its use in diamond growth requires adaptation to the aggressive chemical and thermal environment of the hydrogen plasma in a CVD reactor. Three ELO variants were developed. The most successful utilized a gold (Au) mask prepared by vacuum evaporation onto the surface of a thin heteroepitaxial diamond layer. The Au mask pattern, a series of parallel stripes on the micrometer scale, was produced by standard lift-off photolithography. When diamond overgrows the mask, dislocations are largely confined to the substrate. Differing degrees of confinement were studied by varying the stripe geometry and orientation. Significant improvement in diamond quality was found in the overgrown regions, as evidenced by reduction of the Raman scattering linewidth. The Au layer was found to remain intact during diamond overgrowth and did not chemically bond with the diamond surface. Besides impeding the propagation of threading dislocations, it was discovered that the thermally-induced stress in the CVD diamond was significantly reduced as a result of the ductile Au layer. Cracking and delamination of the diamond from the substrate was mostly eliminated. When diamond was grown to thicknesses above 0.1 mm it was found that

  18. Epitaxial growth of mosaic diamond: Mapping of stress and defects in crystal junction with a confocal Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Shu, Guoyang; Dai, Bing; Ralchenko, V. G.; Khomich, A. A.; Ashkinazi, E. E.; Bolshakov, A. P.; Bokova-Sirosh, S. N.; Liu, Kang; Zhao, Jiwen; Han, Jiecai; Zhu, Jiaqi

    2017-04-01

    We studied defects and stress distributions in mosaic epitaxial diamond film using a confocal Raman spectroscopy, with a special attention to the junction area between the crystals. The mosaics was grown by microwave plasma CVD on closely arranged (1 0 0)-oriented HPHT type Ib substrates. The width of stress affected and defect enriched region around the junction show a tendency of extending with the film thickness, from ≈40 μm on the film-substrate interface to ≈250 μm in the layer 500 μm above the substrate, as found from the mosaics analysis in cross-section. The stress field around the junction demonstrates a complex pattern, with mixed domains of tensile and compressive stress, with maximum value of σ ≈ 0.6 GPa. A similar non-uniform pattern was observed for defect distribution as well. No sign of amorphous sp2 carbon in the junction zone was revealed.

  19. Making Diamond in the Laboratory

    ERIC Educational Resources Information Center

    Strong, Herbert

    1975-01-01

    Discusses the graphite to diamond transformation and a phase diagram for carbon. Describes high temperature-higher pressure experimental apparatus and growth of diamonds from seed crystals. Reviews properties of the diamond which suggest uses for the synthetic product. Illustrations with text. (GH)

  20. Exploring Novel Crystals and Designs for Acousto-Optic Devices

    NASA Astrophysics Data System (ADS)

    Pfeiffer, Jonathan B.

    Acousto-optic devices are a versatile technology that are driven electronically to precisely and rapidly control the intensity, frequency, and propagation direction of a laser beam. Applications include acousto-optic scanners, filters, mode lockers, and modulators. Despite the popularity of acousto-optic devices, there currently is no UV transparent device that can satisfy the requirements of the atomic clock and quantum computing communities. In this thesis, I describe my experimental efforts for discovering a new UV transparent, acousto-optic crystal that can meet the experimental requirements. I also present my graphical representations for locating practical and efficient acousto-optic designs in a given medium. The first part of this thesis describes how to measure the elastic-stiffness and photoelastic coefficients of a given crystal. The elastic-stiffness coefficients are essential for designing acousto-optic devices because they determine the velocity, diffraction, and polarization of acoustic waves in a given medium. I used both resonant ultrasound spectroscopy and a modified version of Schaefer-Bergman diffraction to measure elastic coefficients. I discuss in detail the strengths, differences, and similarities of the two experiments. The photoelastic coefficients are necessary for determining the diffraction efficiency of a given acousto-optic geometry. Similar to the elastic coefficients, I employ a modified version of the Schaefer-Bergmann experiment to measure the photoelastic coefficients. I corroborate the measured results with the well established Dixon experiment. The second part of this thesis describes four different graphical representations that help locate practical and efficient acousto-optic designs. I describe in detail each algorithm and how to interpret the calculated results. Several examples are provided for commonly used acosuto-optic materials. The thesis concludes by describing the design and performance of an acousto-optic frequency

  1. 75 FR 63856 - In the Matter of Certain Liquid Crystal Display Devices, Including Monitors, Televisions, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-18

    ... COMMISSION In the Matter of Certain Liquid Crystal Display Devices, Including Monitors, Televisions, and... sale for importation, and the sale within the United States after importation of certain liquid crystal... importation of certain liquid crystal display devices, including monitors, televisions, and modules,...

  2. Thermally switchable flexible liquid crystal devices in prepolymer-doped cholesteric liquid crystals

    NASA Astrophysics Data System (ADS)

    Fuh, A. Y.-G.; Li, J.-H.; Cheng, K.-T.

    2010-10-01

    This work describes an approach for fabricating thermally switchable flexible liquid crystal devices in prepolymer-doped cholesteric liquid crystals (CLCs). The roughness of the UV-cured polymer film eliminates the stability of planar CLCs, allowing the textures in the UV-cured regions to be changed from planar to focal conic. Impurities associated with doping with prepolymers cause the clearing temperature of LCs in the UV-cured regions to differ from that in the uncured regions as the prepolymers are polymerized. Therefore, the textures in these two regions can be switched by controlling the temperature. Thermally switchable flexible LC devices, such as optically addressed smart cards, light valves, and others, can be realized using this approach.

  3. Liquid crystal devices based on photoalignment and photopatterning materials

    NASA Astrophysics Data System (ADS)

    Chigrinov, Vladimir

    2014-02-01

    Liquid crystal (LC) display and photonics devices based on photo-alignment and photo-patterning LC cells are developed. A fast switchable grating based on ferroelectric liquid crystals and orthogonal planar alignment by means of photo alignments. Both 1D and 2D gratings have been constructed. The proposed diffracting element provides fast response time of around 20 μs, contrast of 7000:1 and high diffraction efficiency, at the electric field of 6V/μm. A switchable LC Fresnel zone lens was also developed with the efficiency of ~42% that can be further improved, and the switching time for the 3 μm thick cell is ~6.7 ms which is relatively fast in comparison of existing devices. Thus, because of the photoalignment technology the fabrication of Fresnel lens became considerably simpler than others. A thin high spatial resolution, photo-patterned micropolarizer array for complementary metal-oxide-semiconductor (CMOS) image sensors was implemented for the complete optical visualization of so called "invisible" objects, which are completely transparent (reflective) and colorless. Four Stokes parameters, which fully characterized the reflected light beam can be simultaneously detected using the array of photo-patterned polarizers on CMOS sensor plate. The cheap, high resolution photo-patterned LC matrix sensor was developed to be able successfully compete with the expensive and low reliable wire grid polarizer patterned arrays currently used for the purpose.

  4. Chiral multichromic single crystals for optical devices (LDRD 99406).

    SciTech Connect

    Kemp, Richard Alan; Felix, Ana M. (University of New Mexico, Albuquerque, NM)

    2006-12-01

    This report summarizes our findings during the study of a novel system that yields multi-colored materials as products. This system is quite unusual as it leads to multi-chromic behavior in single crystals, where one would expect that only a single color would exist. We have speculated that these novel solids might play a role in materials applications such as non-linear optics, liquid crystal displays, piezoelectric devices, and other similar applications. The system examined consisted of a main-group alkyl compound (a p block element such as gallium or aluminum) complexed with various organic di-imines. The di-imines had substituents of two types--either alkyl or aromatic groups attached to the nitrogen atoms. We observed that single crystals, characterized by X-ray crystallography, were obtained in most cases. Our research during January-July, 2006, was geared towards understanding the factors leading to the multi-chromic nature of the complexes. The main possibilities put forth initially considered (a) the chiral nature of the main group metal, (b) possible reduction of the metal to a lower-valent, radical state, (c) the nature of the ligand(s) attached to the main group metal, and (d) possible degradation products of the ligand leading to highly-colored products. The work carried out indicates that the most likely explanation considered involves degradation of the aromatic ligands (a combination of (c) and (d)), as the experiments performed can clearly rule out (a) and (b).

  5. Surface characterization and orientation interaction between diamond- like carbon layer structure and dimeric liquid crystals

    NASA Astrophysics Data System (ADS)

    Naradikian, H.; Petrov, M.; Katranchev, B.; Milenov, T.; Tinchev, S.

    2017-01-01

    Diamond-like carbon (DLC) and amorphous carbon films are very promising type of semiconductor materials. Depending on the hybridization sp2/sp3 ratio, the material’s band gap varies between 0.8 and 3 eV. Moreover carbon films possess different interesting for practice properties: comparable to the Silicon, Diamond like structure has 22-time better thermal conductivity etc. Here we present one type of implementation of such type nanostructure. That is one attempt for orientation of dimeric LC by using of pre-deposited DLC layer with different ratio of sp2/sp3 hybridized carbon content. It could be expected a pronounced π1-π2interaction between s and p orbital levels on the surface and the dimeric ring of LC. We present comparison of surface anchoring strengths of both orientation inter-surfaces DLC/dimeric LC and single wall carbon nanotubes (SWCNT)/dimeric LC. The mechanism of interaction of dimeric LC and activated surfaces with DLC or SWCNT will be discussed. In both cases we have π-π interaction, which in combination with hydrogen bonding, typical for the dimeric LCs, influence the LC alignment. The Raman spectroscopy data evidenced the presence of charge transfer between contacting hexagonal rings of DLC and the C = O groups of the LC molecules.

  6. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2001-01-01

    An overview of the industrial diamond industry is provided. More than 90 percent of the industrial diamond consumed in the U.S. and the rest of the world is manufactured diamond. Ireland, Japan, Russia, and the U.S. produce 75 percent of the global industrial diamond output. In 2000, the U.S. was the largest market for industrial diamond. Industrial diamond applications, prices for industrial diamonds, imports and exports of industrial diamonds, the National Defense Stockpile of industrial diamonds, and the outlook for the industrial diamond market are discussed.

  7. Structure and properties of diamond and diamond-like films

    SciTech Connect

    Clausing, R.E.

    1993-01-01

    This section is broken into four parts: (1) introduction, (2) natural IIa diamond, (3) importance of structure and composition, and (4) control of structure and properties. Conclusions of this discussion are that properties of chemical vapor deposited diamond films can compare favorably with natural diamond, that properties are anisotropic and are a strong function of structure and crystal perfection, that crystal perfection and morphology are functions of growth conditions and can be controlled, and that the manipulation of texture and thereby surface morphology and internal crystal perfection is an important step in optimizing chemically deposited diamond films for applications.

  8. Growth of bulk single crystals of organic materials for nonlinear optical devices - An overview

    NASA Technical Reports Server (NTRS)

    Penn, Benjamin G.; Cardelino, Beatriz H.; Moore, Craig E.; Shields, Angela W.; Frazier, D. O.

    1991-01-01

    Highly perfect single crystals of nonlinear optical organic materials are required for use in optical devices. An overview of the bulk crystal growth of these materials by melt, vapor, and solution processes is presented. Additionally, methods that may be used to purify starting materials, detect impurities at low levels, screen materials for crystal growth, and process grown crystals are discussed.

  9. Bent Diamond Crystals and Multilayer Based Optics at the new 5-Station Protein Crystallography Beamline 'Cassiopeia' at MAX-lab

    SciTech Connect

    Mammen, Christian B.; Als-Nielsen, Jens; Ursby, Thomas; Thunnissen, Marjolein

    2004-05-12

    A new 5-station beamline for protein crystallography is being commissioned at the Swedish synchrotron light source MAX-II at Lund University. Of the 2K/{gamma} = 14 mrad horizontal wiggler fan, the central 2 mrad are used and split in three parts. The central 1 mrad will be used for a station optimized for MAD experiments and on each side of the central fan, from 0.5 mrad to 1 mrad, there are two fixed energy stations using different energies of the same part of the beam. These, in total five stations, can be used simultaneously and independently for diffraction data collection. The two upstream monochromators for the side stations are meridionally bent asymmetric diamond(111) crystals in Laue transmission geometry. The monochromators for the downstream side stations are bent Ge(111) crystals in asymmetric Bragg reflection geometry. Curved multilayer mirrors inserted in the monochromatic beams provide focusing in the vertical plane. The first side station is under commissioning, and a preliminary test protein data set has been collected.

  10. Diamond Smoothing Tools

    NASA Technical Reports Server (NTRS)

    Voronov, Oleg

    2007-01-01

    Diamond smoothing tools have been proposed for use in conjunction with diamond cutting tools that are used in many finish-machining operations. Diamond machining (including finishing) is often used, for example, in fabrication of precise metal mirrors. A diamond smoothing tool according to the proposal would have a smooth spherical surface. For a given finish machining operation, the smoothing tool would be mounted next to the cutting tool. The smoothing tool would slide on the machined surface left behind by the cutting tool, plastically deforming the surface material and thereby reducing the roughness of the surface, closing microcracks and otherwise generally reducing or eliminating microscopic surface and subsurface defects, and increasing the microhardness of the surface layer. It has been estimated that if smoothing tools of this type were used in conjunction with cutting tools on sufficiently precise lathes, it would be possible to reduce the roughness of machined surfaces to as little as 3 nm. A tool according to the proposal would consist of a smoothing insert in a metal holder. The smoothing insert would be made from a diamond/metal functionally graded composite rod preform, which, in turn, would be made by sintering together a bulk single-crystal or polycrystalline diamond, a diamond powder, and a metallic alloy at high pressure. To form the spherical smoothing tip, the diamond end of the preform would be subjected to flat grinding, conical grinding, spherical grinding using diamond wheels, and finally spherical polishing and/or buffing using diamond powders. If the diamond were a single crystal, then it would be crystallographically oriented, relative to the machining motion, to minimize its wear and maximize its hardness. Spherically polished diamonds could also be useful for purposes other than smoothing in finish machining: They would likely also be suitable for use as heat-resistant, wear-resistant, unlubricated sliding-fit bearing inserts.

  11. Single crystal artificial diamond detectors for VUV and soft X-rays measurements on JET thermonuclear fusion plasma

    NASA Astrophysics Data System (ADS)

    Angelone, M.; Pillon, M.; Marinelli, Marco; Milani, E.; Prestopino, G.; Verona, C.; Verona-Rinati, G.; Coffey, I.; Murari, A.; Tartoni, N.; JET-EFDA contributors

    2010-11-01

    Diamond appears to be a promising material for VUV and soft X-ray radiation detection. Its wide band-gap (5.5 eV) results in a very low leakage current (it can operate above room temperature) and its electronic properties (high carrier mobility) allow a fast time response. More importantly, it is optimally suited for harsh environment applications, like those in the JET Tokamak located at the Culham laboratory (UK). Its extreme radiation hardness is well known and another interesting feature, again related to the wide band-gap, is its selective sensitivity to radiation with wavelengths shorter than 225 nm (visible-blind detectors).We report on the performances of two photodetectors based on Chemical Vapor Deposition (CVD) single crystal diamonds, one optimized for extreme UV detection, the other for soft X-ray radiation detection in the 0.8-8 keV range. These detectors have been fabricated at Roma "Tor Vergata" University using a p-type/intrinsic/metal configuration and they behave like photodiodes allowing operation with no external applied voltage. They have been installed on JET inside a vacuum chamber with a direct horizontal view of JET plasma without any wavelength selection. Their low thickness, low sensitivity to gamma ray and the unbiased operation mode make both detectors ideal for a Tokamak environment. The measurements routinely performed at JET show a low intrinsic dark current (˜0.01 pA) and very high signal to noise ratio (50 dB). Both detectors show a fast response and their signals are acquired using an electronic chain and ADC able to operate at 200 kHz, providing very interesting results for MHD and Edge Localized Modes (ELMs) instability studies on fusion plasmas.

  12. Surface properties and blood compatibility of commercially available diamond-like carbon coatings for cardiovascular devices.

    PubMed

    Fedel, Mariangela; Motta, Antonella; Maniglio, Devid; Migliaresi, Claudio

    2009-07-01

    The aim of this study was to determine the relationships between the surface properties and blood compatibility of in-use diamond-like carbon (DLC) coatings for cardiovascular components. Commercially available DLC films were characterized with respect to surface topography and wettability, protein adsorption from human plasma, and platelets adhesion/activation. Fibrinogen (Fng) and human serum albumin (HSA) adsorbed onto the sample surfaces were in particular quantified as two of the main proteins involved in blood compatibility. A low tendency of platelets to spread and form aggregates onto the DLC-coated surfaces has been described and related to a low Fng-to-HSA adsorption ratio. This study provides evidence that the rapid and tenacious binding of albumin molecules to DLC materials tends to passivate the surfaces and to inhibit Fng adsorption, thus imparting thromboresistance to the carbon coatings by rendering the surfaces less adhesive and activating for platelets. Albumin preferential adsorption was ascribed to high chemical heterogeneity of the DLC sample surfaces. The DLC films tested present a favorable behavior as regards blood compatibility with respect to platelet thrombus formation by reason of their surface properties.

  13. Single photon emission from diamond nanocrystals in an opal photonic crystal.

    PubMed

    Stewart, L A; Zhai, Y; Dawes, J M; Steel, M J; Rabeau, J R; Withford, M J

    2009-09-28

    We present the first optical measurement of a single nitrogen-vacancy (NV) center in a three-dimensional photonic crystal. The photonic crystal, fabricated by self-assembly of polystyrene microspheres, exhibits a photonic stopband that overlaps the NV photoluminescence spectrum. A modified emission spectrum and photon antibunching were measured from the NV centers. Time-resolved fluorescence measurements revealed a 30% increase in the source lifetime. Encapsulation of single NV centers in a three-dimensional photonic crystal is a step towards controlling emission properties of a single photon source.

  14. Visible scintillation photodetector device incorporating chalcopyrite semiconductor crystals

    DOEpatents

    Stowe, Ashley C.; Burger, Arnold

    2017-04-04

    A photodetector device, including: a scintillator material operable for receiving incident radiation and emitting photons in response; a photodetector material coupled to the scintillator material operable for receiving the photons emitted by the scintillator material and generating a current in response, wherein the photodetector material includes a chalcopyrite semiconductor crystal; and a circuit coupled to the photodetector material operable for characterizing the incident radiation based on the current generated by the photodetector material. Optionally, the scintillator material includes a gamma scintillator material and the incident radiation received includes gamma rays. Optionally, the photodetector material is further operable for receiving thermal neutrons and generating a current in response. The circuit is further operable for characterizing the thermal neutrons based on the current generated by the photodetector material.

  15. Biokinetics and tissue response to ultrananocrystalline diamond nanoparticles employed as coating for biomedical devices.

    PubMed

    Tasat, Deborah R; Bruno, Marcos E; Domingo, Mariela; Gurman, Pablo; Auciello, Orlando; Paparella, María L; Evelson, Pablo; Guglielmotti, María B; Olmedo, Daniel G

    2016-09-12

    Although Ultrananocrystalline diamond (UNCD) has been proposed as a coating material for titanium biomedical implants, the biological effects and toxicity of UNCD particles that could eventually detach have not been studied to date. The biokinetics and biological effects of UNCD compared to titanium dioxide (TiO2 ) nanoparticles was evaluated in vivo using Wistar rats (n = 30) i.p. injected with TiO2 , UNCD or saline solution. After 6 months, blood, lung, liver, and kidney samples were histologically analyzed. Oxidative damage by membrane lipidperoxidation (thiobarbituric acid reactive substances-TBARS), generation of reactive oxygen species (superoxide anion- O2-), and antioxidant enzymes (superoxide dismutase-SOD, catalase-CAT) was evaluated in lung and liver. Histologic observation showed agglomerates of TiO2 or UNCD in the parenchyma of the studied organs, though there were fewer UNCD than TiO2 deposits. In addition, TiO2 caused areas compatibles with foci of necrosis in the liver and renal hyaline cylinders. Regarding UNCD, no membrane damage (TBARS) or mobilization of enzymatic antioxidants was observed either in lung or liver samples. No variations in O2- generation were observed in lung (Co: 35.1 ± 4.02 vs. UNCD: 48 ± 9.1, p > 0.05). Conversely, TiO2 exposure caused production of O2- in alveolar macrophages and consumption of catalase (p < 0.05). The studied parameters suggest that UNCD caused neither biochemical nor histological alterations, and therefore may prove useful as a surface coating for biomedical implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

  16. Switchable Photonic Crystals Using One-Dimensional Confined Liquid Crystals for Photonic Device Application.

    PubMed

    Ryu, Seong Ho; Gim, Min-Jun; Lee, Wonsuk; Choi, Suk-Won; Yoon, Dong Ki

    2017-01-25

    Photonic crystals (PCs) have recently attracted considerable attention, with much effort devoted to photonic bandgap (PBG) control for varying the reflected color. Here, fabrication of a modulated one-dimensional (1D) anodic aluminum oxide (AAO) PC with a periodic porous structure is reported. The PBG of the fabricated PC can be reversibly changed by switching the ultraviolet (UV) light on/off. The AAO nanopores contain a mixture of photoresponsive liquid crystals (LCs) with irradiation-activated cis/trans photoisomerizable azobenzene. The resultant mixture of LCs in the porous AAO film exhibits a reversible PBG, depending on the cis/trans configuration of azobenzene molecules. The PBG switching is reliable over many cycles, suggesting that the fabricated device can be used in optical and photonic applications such as light modulators, smart windows, and sensors.

  17. Topics in Nanophotonic Devices for Nitrogen-Vacancy Color Centers in Diamond

    ERIC Educational Resources Information Center

    Babinec, Thomas Michael

    2012-01-01

    Recently, developments in novel and high-purity materials allow for the presence of a single, solitary crystalline defect to define the electronic, magnetic, and optical functionality of a device. The discrete nature of the active dopant, whose properties are defined by a quantum mechanical description of its structure, enables radically new…

  18. Liquid crystal devices especially for use in liquid crystal point diffraction interferometer systems

    NASA Technical Reports Server (NTRS)

    Marshall, Kenneth L. (Inventor)

    2009-01-01

    Liquid crystal point diffraction interferometer (LCPDI) systems that can provide real-time, phase-shifting interferograms that are useful in the characterization of static optical properties (wavefront aberrations, lensing, or wedge) in optical elements or dynamic, time-resolved events (temperature fluctuations and gradients, motion) in physical systems use improved LCPDI cells that employ a "structured" substrate or substrates in which the structural features are produced by thin film deposition or photo resist processing to provide a diffractive element that is an integral part of the cell substrate(s). The LC material used in the device may be doped with a "contrast-compensated" mixture of positive and negative dichroic dyes.

  19. Liquid crystal devices especially for use in liquid crystal point diffraction interferometer systems

    SciTech Connect

    Marshall, Kenneth L.

    2009-02-17

    Liquid crystal point diffraction interferometer (LCPDI) systems that can provide real-time, phase-shifting interferograms that are useful in the characterization of static optical properties (wavefront aberrations, lensing, or wedge) in optical elements or dynamic, time-resolved events (temperature fluctuations and gradients, motion) in physical systems use improved LCPDI cells that employ a "structured" substrate or substrates in which the structural features are produced by thin film deposition or photo resist processing to provide a diffractive element that is an integral part of the cell substrate(s). The LC material used in the device may be doped with a "contrast-compensated" mixture of positive and negative dichroic dyes.

  20. Optical and Acoustic Device Applications of Ferroelastic Crystals

    NASA Astrophysics Data System (ADS)

    Meeks, Steven Wayne

    This dissertation presents the discovery of a means of creating uniformly periodic domain gratings in a ferroelastic crystal of neodymium pentaphosphate (NPP). The uniform and non-uniform domain structures which can be created in NPP have the potential applications as tunable active gratings for lasers, tunable diffraction gratings, tunable Bragg reflection gratings, tunable acoustic filters, optical modulators, and optical domain wall memories. The interaction of optical and acoustic waves with ferroelastic domain walls in NPP is presented in detail. Acoustic amplitude reflection coefficients from a single domain wall in NPP are much larger than other ferroelastic-ferroelectrics such as gadolinium molybdate (GMO). Domain walls of NPP are used to make two demonstration acoustic devices: a tunable comb filter and a tunable delay line. The tuning process is accomplished by moving the position of the reflecting surface (the domain wall). A theory of the reflection of optical waves from NPP domain walls is discussed. The optical reflection is due to a change in the polarization of the wave, and not a change in the index, as the wave crosses the domain wall. Theoretical optical power reflection coefficients show good agreement with the experimentally measured values. The largest optical reflection coefficient of a single domain wall is at a critical angle and is 2.2% per domain wall. Techniques of injecting periodic and aperiodic domain walls into NPP are presented. The nucleation process of the uniformly periodic domain gratings in NPP is described in terms of a newly-discovered domain structure, namely the ferroelastic bubble. A ferroelastic bubble is the elastic analogue to the well-known magnetic bubble. The period of the uniformly periodic domain grating is tunable from 100 to 0.5 microns and the grating period may be tuned relatively rapidly. The Bragg efficiency of these tunable gratings is 77% for an uncoated crystal. Several demonstration devices which use

  1. Toward high-throughput screening of NAD(P)-dependent oxidoreductases using boron-doped diamond microelectrodes and microfluidic devices.

    PubMed

    Oyobiki, Ryo; Kato, Taisuke; Katayama, Michinobu; Sugitani, Ai; Watanabe, Takeshi; Einaga, Yasuaki; Matsumoto, Yoshinori; Horisawa, Kenichi; Doi, Nobuhide

    2014-10-07

    Although oxidoreductases are widely used in many applications, such as biosensors and biofuel cells, improvements in the function of existing oxidoreductases or the discovery of novel oxidoreductases with greater activities is desired. To increase the activity of oxidoreductases by directed evolution, a powerful screening technique for oxidoreductases is required. In this study, we demonstrate the utility of boron-doped diamond (BDD) microelectrodes for quantitative and potentially high-throughput measurement of the activity of NAD(P)-dependent oxidoreductases. We first confirmed that BDD microelectrodes can quantify the activity of low concentrations (10-100 pM) of glucose-6-phosphate dehydrogenase and alcohol dehydrogenase with a measuring time of 1 ms per sample. In addition, we found that poisoning of BDD microelectrodes can be repressed by optimizing the pH and by adding l-arginine to the enzyme solution as an antiaggregation agent. Finally, we fabricated a microfluidic device containing a BDD electrode for the first time and observed the elevation of the oxidation current of NADH with increasing flow rate. These results imply that the combination of a BDD microelectrode and microfluidics can be used for high-throughput screening of an oxidoreductase library containing a large number (>10(6)) of samples, each with a small (nanoliter) sample volume.

  2. Full characterization of laser-accelerated ion beams using Faraday cup, silicon carbide, and single-crystal diamond detectors

    SciTech Connect

    Margarone, D.; Prokupek, J.; Rus, B.; Krasa, J.; Velyhan, A.; Laska, L.; Giuffrida, L.; Torrisi, L.; Picciotto, A.; Nowak, T.; Musumeci, P.; Mocek, T.; Ullschmied, J.

    2011-05-15

    Multi-MeV beams of light ions have been produced using the 300 picosecond, kJ-class iodine laser, operating at the Prague Asterix Laser System facility in Prague. Real-time ion diagnostics have been performed by the use of various time-of-flight (TOF) detectors: ion collectors (ICs) with and without absorber thin films, new prototypes of single-crystal diamond and silicon carbide detectors, and an electrostatic ion mass spectrometer (IEA). In order to suppress the long photopeak induced by soft X-rays and to avoid the overlap with the signal from ultrafast particles, the ICs have been shielded with Al foil filters. The application of large-bandgap semiconductor detectors (>3 eV) ensured cutting of the plasma-emitted visible and soft-UV radiation and enhancing the sensitivity to the very fast proton/ion beams. Employing the IEA spectrometer, various ion species and charge states in the expanding laser-plasma have been determined. Processing of the experimental data based on the TOF technique, including estimation of the plasma fast proton maximum and peak energy, ion beam currents and total charge, total number of fast protons, as well as deconvolution processes, ion stopping power, and ion/photon transmission calculations for the different metallic filters used, are reported.

  3. Full characterization of laser-accelerated ion beams using Faraday cup, silicon carbide, and single-crystal diamond detectors

    NASA Astrophysics Data System (ADS)

    Margarone, D.; Krása, J.; Giuffrida, L.; Picciotto, A.; Torrisi, L.; Nowak, T.; Musumeci, P.; Velyhan, A.; Prokůpek, J.; Láska, L.; Mocek, T.; Ullschmied, J.; Rus, B.

    2011-05-01

    Multi-MeV beams of light ions have been produced using the 300 picosecond, kJ-class iodine laser, operating at the Prague Asterix Laser System facility in Prague. Real-time ion diagnostics have been performed by the use of various time-of-flight (TOF) detectors: ion collectors (ICs) with and without absorber thin films, new prototypes of single-crystal diamond and silicon carbide detectors, and an electrostatic ion mass spectrometer (IEA). In order to suppress the long photopeak induced by soft X-rays and to avoid the overlap with the signal from ultrafast particles, the ICs have been shielded with Al foil filters. The application of large-bandgap semiconductor detectors (>3 eV) ensured cutting of the plasma-emitted visible and soft-UV radiation and enhancing the sensitivity to the very fast proton/ion beams. Employing the IEA spectrometer, various ion species and charge states in the expanding laser-plasma have been determined. Processing of the experimental data based on the TOF technique, including estimation of the plasma fast proton maximum and peak energy, ion beam currents and total charge, total number of fast protons, as well as deconvolution processes, ion stopping power, and ion/photon transmission calculations for the different metallic filters used, are reported.

  4. Generation of octave-spanning supercontinuum by Raman-assisted four-wave mixing in single-crystal diamond.

    PubMed

    Lu, Chih-Hsuan; Yang, Li-Fan; Zhi, Miaochan; Sokolov, Alexei V; Yang, Shang-Da; Hsu, Chia-Chen; Kung, A H

    2014-02-24

    An octave-spanning coherent supercontinuum is generated by non-collinear Raman-assisted four-wave mixing in single-crystal diamond using 7.7 fs laser pulses that have been chirped to about 420 fs in duration. The use of ultrabroad bandwidth pulses as input results in substantial overlap of the generated spectrum of the anti-Stokes sidebands, creating a phase-locked supercontinuum when all the sidebands are combined to overlap in time and space. The overall bandwidth of the generated supercontinuum is sufficient to support its compression to isolated few-to-single cycle attosecond transients. The significant spectral overlap of adjacent anti-Stokes sidebands allows the utilization of straight-forward spectral interferometry to test the relative phase coherence of the anti-Stokes outputs and is demonstrated here for two adjacent pairs of sidebands. The method can subsequently be employed to set the relative phase of the sidebands for pulse compression and for the synthesis of arbitrary field transients.

  5. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2003-01-01

    Statistics on the production, consumption, cost, trade, and government stockpile of natural and synthetic industrial diamond are provided. The outlook for the industrial diamond market is also considered.

  6. Polarization properties of the variable-grating-mode liquid-crystal device.

    PubMed

    Tanguay, A R; Chavel, P; Strand, T C; Wu, C S; Soffer, B H

    1984-05-01

    The principal features of the liquid-crystal molecular orientation within the variable-grating-mode liquid-crystal device have been determined as a function of the applied voltage across the cell by measurement of the polarization properties of light diffracted by the liquid-crystal birefringent phase grating.

  7. Crystal structure engineering for improved performance of emerging nanoscale devices

    NASA Astrophysics Data System (ADS)

    Chimalgi, Vinay Uday

    Recent advances in growth techniques and increasing number of experimental studies have made nanostructures grown along different crystallographic directions a reality. These new structures could not only benefit the electronic devices used in mainstream information technology but also show great promise for applications in lasers, solid-state lighting, near-field photolithography, free-space quantum cryptography, consumer displays, quantum computation, as well as diagnostic medicine and imaging. However, only few theoretical investigations have been performed on these structures due to the complex nature of the interplay of atomicity, structural fields, polarization, and quantum size-quantization, all strong function of the crystallographic direction. The objective of this work is mainly four-fold: (1) Integrate a computational framework employing a combination of fully atomistic valence force-field molecular mechanics and 20-band sp3s*d5-SO tight-binding based electronic band­structure models, and numerically investigate the effects of internal fields on the electronic and optical properties of zincblende InAs/GaAs quantum dots grown on (100), (110), and (111) orientated substrates. (2) Augment/extend the open source NEMO 3-D bandstructure simulator by incorporating a recently proposed first principles based model to gauge the importance of nonlinear piezoelectricity on the single-particle electronic states and interband optical transitions in emerging In(Ga)N/GaN disk-in-wire LED structures having c-plane and m-plane wurtzite crystal symmetry. (3) Coupling the NEMO 3-D software toolkit with a commercial TCAD simulator to determine the terminal electrical and optical characteristics of InGaN/GaN disk-in-wire LEDs; and (4) Finding an optimum crystallographic device for InGaN/GaN disk-in-wire LEDs to achieve improved internal quantum efficiency (IQE).

  8. Mean carrier transport properties and charge collection dynamics of single-crystal, natural type IIa diamonds from ion-induced conductivity measurements

    SciTech Connect

    Han, Sung Su

    1993-09-01

    Ion-induced conductivity has been used to investigate the detector characteristics of diamond detectors. Both integrated-charge, and time-resolved current measurements were performed to examine the mean carrier transport properties of diamond and the dynamics of charge collection under highly-localized and high-density excitation conditions. The integrated-charge measurements were conducted with a standard pulse-counting system with 241Am radioactivity as the excitation source for the detectors. The time-resolved current measurements were performed using a 70 GHz random sampling oscilloscope with the detectors incorporated into high-speed microstrip transmission lines and the excitation source for these measurements was an ion beam of either 5-MeV He+ or 10-MeV Si3+. The detectors used in both experiments can be described as metal-semiconductor-metal (MSM) devices where a volume of the detector material is sandwiched between two metal plates. A charge collection model was developed to interpret the integrated-charge measurements which enabled estimation of the energy required to produce an electron-hole pair (ϵdi) and the mean carrier transport properties in diamond, such as carrier mobility and lifetime, and the behavior of the electrical contacts to diamond.

  9. Growth and characterization of large, high quality single crystal diamond substrates via microwave plasma assisted chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Nad, Shreya

    Single crystal diamond (SCD) substrates can be utilized in a wide range of applications. Important issues in the chemical vapor deposition (CVD) of such substrates include: shrinking of the SCD substrate area, stress and cracking, high defect density and hence low electronic quality and low optical quality due to high nitrogen impurities. The primary objective of this thesis is to begin to address these issues and to find possible solutions for enhancing the substrate dimensions and simultaneously improving the quality of the grown substrates. The deposition of SCD substrates is carried out in a microwave cavity plasma reactor via the microwave plasma assisted chemical vapor deposition technique. The operation of the reactor was first optimized to determine the safe and efficient operating regime. By adjusting the matching of the reactor cavity with the help of four internal tuning length variables, the system was further matched to operate at a maximum overall microwave coupling efficiency of ˜ 98%. Even with adjustments in the substrate holder position, the reactor remains well matched with a coupling efficiency of ˜ 95% indicating good experimental performance over a wide range of operating conditions. SCD substrates were synthesized at a high pressure of 240 Torr and with a high absorbed power density of 500 W/cm3. To counter the issue of shrinking substrate size during growth, the effect of different substrate holder designs was studied. An increase in the substrate dimensions (1.23 -- 2.5 times) after growth was achieved when the sides of the seeds were shielded from the intense microwave electromagnetic fields in a pocket holder design. Using such pocket holders, high growth rates of 16 -- 32 mum/hr were obtained for growth times of 8 -- 72 hours. The polycrystalline diamond rim deposition was minimized/eliminated from these growth runs, hence successfully enlarging the substrate size. Several synthesized CVD SCD substrates were laser cut and separated

  10. Substantiation of Epitaxial Growth of Diamond Crystals on the Surface of Carbide Fe3AlC0.66 Phase Nanoparticles.

    PubMed

    Dzevin, Ievgenij M; Mekhed, Alexander A

    2017-12-01

    Samples of Fe-Al-C alloys of varying composition were synthesized under high pressures and temperatures. From X-ray analysis data, only K-phase with usual for it average parameter of elemental lattice cell, a = 0.376 nm, carbide Fe3C and cubic diamond reflexes were present before and after cooling to the temperature of liquid nitrogen.Calculations were made of the parameters of unit cells, the enthalpy of formation of the Fe3AlC, Fe3.125Al0.825C0.5, Fe3.5Al0.5C0.5, Fe3.5Al0.5C, Fe3Al0.66C0.66, and Fe3AlC0.66 unit cells and crystallographic planes were identified on which epitaxial growth of the diamond phase was possible, using density functional theory as implemented in the WIEN2k package.The possibility of epitaxial growth of diamond crystals on Fe3AlC0.66 (K-phase) nanoparticles was, therefore, demonstrated. The [200] plane was established to be the most suitable plane for diamond growth, having four carbon atoms arranged in a square and a central vacancy which can be occupied by carbon during thermal-and-pressure treatment. Distances between carbon atoms in the [200] plane differ by only 5% from distances between the carbon atoms of a diamond. The electronic structure and energetic parameters of the substrate were also investigated. It was shown that the substrate with at least four intermediate layers of K-phase exhibits signs of stability such as negative enthalpy of formation and the Fermi level falling to minimum densities of states.

  11. Single-crystal CVD diamond detector for low-energy charged particles with energies ranging from 100 keV to 2 MeV

    SciTech Connect

    Yuki Sato; Hiroyuki Murakami; Takehiro Shimaoka; Masakatsu Tsubota; Junichi, H. Kaneko

    2015-07-01

    The performance of a diamond detector made of a single-crystal diamond grown by chemical vapor deposition was studied for charged particles, having energies ranging from 100 keV to 2 MeV. Energy peaks of these low-energy ions were clearly observed. However, we observed that the pulse height for individual incident ion decreases with increasing atomic number of the ions. We estimated the charge collection efficiency of the generated charge carriers by charged particle incident. The charge collection above ∼95% is achieved for helium (He{sup +}) with the energy above 1.5 MeV. On the other hand, the charge collection efficiency for heavy-ions shows wrong values compared with that of He{sup +}, ∼70% for silicon (Si{sup +}) and 35 to 40% for gold (Au{sup 3+}), at the same incident energy range, respectively. (authors)

  12. NCD Diamond Semiconductor System for Advanced Power Electronics Systems Integration : CRADA report

    SciTech Connect

    Sumant, Anirudha

    2016-07-22

    The integration of 2D materials such as molybdenum disulphide (MoS2) with diamond (3D) was achieved by forming an heterojunction between these two materials and its electrical performance was studied experimentally. The device charactertics did show good rectifying nature when p-type single crystal diamond was integrated with n-type MoS2. These results are very encouraging indicating possible applications in semiconductor electronics, however further studies are required for a detailed understanding of the transport phenomena at the MoS2/diamond interface.

  13. Measurement-device-independent quantum key distribution with nitrogen vacancy centers in diamond

    NASA Astrophysics Data System (ADS)

    Lo Piparo, Nicoló; Razavi, Mohsen; Munro, William J.

    2017-02-01

    Memory-assisted measurement-device-independent quantum key distribution (MA-MDI-QKD) has recently been proposed as a possible intermediate step towards the realization of quantum repeaters. Despite its relaxing some of the requirements on quantum memories, the choice of memory in relation to the layout of the setup and the protocol has a stark effect on our ability to beat existing no-memory systems. Here, we investigate the suitability of nitrogen vacancy (NV) centers, as quantum memories, in MA-MDI-QKD. We particularly show that moderate cavity enhancement is required for NV centers if we want to outperform no-memory QKD systems. Using system parameters mostly achievable by today's state of the art, we then anticipate some total key rate advantage in the distance range between 300 and 500 km for cavity-enhanced NV centers. Our analysis accounts for major sources of error including the dark current, the channel loss, and the decoherence of the quantum memories.

  14. Single Crystal Substrates for Surface Acoustic Wave Devices.

    DTIC Science & Technology

    1981-01-01

    APPROVED: aJ. 2 .C. PAUL H. CARR Project Engineer APPROVED: PHILIPP BLACKSMITH , Acting Chief Electromagnetic Sciences Division FOR THE COMMANDER: /?p...relations between properties, composition and crystal structure . (ii) Both exploratory and systematic crystal arowth studies on a variety of materials...the piezoelectric constants for a qiven crystal structure . In conjunction with earlier criteria for identifyina temperature compensated materials

  15. Fabrication of UV Photodetector on TiO2/Diamond Film

    PubMed Central

    Liu, Zhangcheng; Li, Fengnan; Li, Shuoye; Hu, Chao; Wang, Wei; Wang, Fei; Lin, Fang; Wang, Hongxing

    2015-01-01

    The properties of ultraviolet (UV) photodetector fabricated on TiO2/diamond film were investigated. Single crystal diamond layer was grown on high-pressure-high-temperature Ib-type diamond substrate by microwave plasma chemical vapor deposition method, upon which TiO2 film was prepared directly using radio frequency magnetron sputtering technique in Ar and O2 mixing atmosphere. Tungsten was used as electrode material to fabricate metal-semiconductor-metal UV photodetector. The dark current is measured to be 1.12 pA at 30 V. The photo response of the device displays an obvious selectivity between UV and visible light, and the UV-to-visible rejection ratio can reach 2 orders of magnitude. Compared with that directly on diamond film, photodetector on TiO2/diamond film shows higher responsivity. PMID:26399514

  16. Fabrication of UV Photodetector on TiO2/Diamond Film.

    PubMed

    Liu, Zhangcheng; Li, Fengnan; Li, Shuoye; Hu, Chao; Wang, Wei; Wang, Fei; Lin, Fang; Wang, Hongxing

    2015-09-24

    The properties of ultraviolet (UV) photodetector fabricated on TiO2/diamond film were investigated. Single crystal diamond layer was grown on high-pressure-high-temperature Ib-type diamond substrate by microwave plasma chemical vapor deposition method, upon which TiO2 film was prepared directly using radio frequency magnetron sputtering technique in Ar and O2 mixing atmosphere. Tungsten was used as electrode material to fabricate metal-semiconductor-metal UV photodetector. The dark current is measured to be 1.12 pA at 30 V. The photo response of the device displays an obvious selectivity between UV and visible light, and the UV-to-visible rejection ratio can reach 2 orders of magnitude. Compared with that directly on diamond film, photodetector on TiO2/diamond film shows higher responsivity.

  17. Fabrication of UV Photodetector on TiO2/Diamond Film

    NASA Astrophysics Data System (ADS)

    Liu, Zhangcheng; Li, Fengnan; Li, Shuoye; Hu, Chao; Wang, Wei; Wang, Fei; Lin, Fang; Wang, Hongxing

    2015-09-01

    The properties of ultraviolet (UV) photodetector fabricated on TiO2/diamond film were investigated. Single crystal diamond layer was grown on high-pressure-high-temperature Ib-type diamond substrate by microwave plasma chemical vapor deposition method, upon which TiO2 film was prepared directly using radio frequency magnetron sputtering technique in Ar and O2 mixing atmosphere. Tungsten was used as electrode material to fabricate metal-semiconductor-metal UV photodetector. The dark current is measured to be 1.12 pA at 30 V. The photo response of the device displays an obvious selectivity between UV and visible light, and the UV-to-visible rejection ratio can reach 2 orders of magnitude. Compared with that directly on diamond film, photodetector on TiO2/diamond film shows higher responsivity.

  18. 75 FR 10311 - In the Matter of Certain Liquid Crystal Display Devices and Products Containing the Same; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-05

    ... Liquid Crystal Display Devices and Products Containing the Same; Notice of Commission Determination To... importation of certain liquid crystal display (``LCD'') devices and products containing the same by reason...

  19. Optical hyperpolarization of nitrogen donor spins in bulk diamond

    NASA Astrophysics Data System (ADS)

    Loretz, M.; Takahashi, H.; Segawa, T. F.; Boss, J. M.; Degen, C. L.

    2017-02-01

    We report hyperpolarization of the electronic spins associated with substitutional nitrogen defects in bulk diamond crystals. Hyperpolarization is achieved by optical pumping of nitrogen vacancy centers followed by rapid cross relaxation at the energy level matching condition in a 51 mT bias field. The maximum observed donor spin polarization is 0.9 % , corresponding to an enhancement of 25 compared to the thermal Boltzmann polarization. A further accumulation of polarization is impeded by an anomalous optical saturation effect that we attribute to charge state conversion processes. Hyperpolarized nitrogen donors may form a useful resource for increasing the efficiency of diamond-based dynamic nuclear polarization devices.

  20. 76 FR 39897 - In the Matter of Certain Liquid Crystal Display Devices and Products Containing the Same; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ... COMMISSION In the Matter of Certain Liquid Crystal Display Devices and Products Containing the Same; Notice... the United States after importation of certain liquid crystal display devices and products containing... importation of certain liquid crystal display devices and products containing the same that infringe one...

  1. 76 FR 11512 - In the Matter of Certain Liquid Crystal Display Devices, Products Containing Same, and Methods...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-02

    ... COMMISSION In the Matter of Certain Liquid Crystal Display Devices, Products Containing Same, and Methods for... within the United States after importation of certain liquid crystal display devices, products containing... after importation of certain liquid crystal display devices, products containing same, and methods...

  2. 75 FR 445 - In the Matter of Certain Liquid Crystal Display Devices and Products Containing the Same; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... Crystal Display Devices and Products Containing the Same; Notice of Investigation AGENCY: U.S... importation, and the sale within the United States after importation of certain liquid crystal display devices... crystal display devices or products containing same that infringe one or more of claims 1, 3, and 6 of...

  3. CVD diamond metallization and characterization

    NASA Astrophysics Data System (ADS)

    Fraimovitch, D.; Adelberd, A.; Marunko, S.; Lefeuvre, G.; Ruzin, A.

    2017-02-01

    In this study we compared three diamond substrate grades: polycrystalline, optical grade single crystal, and electronic grade single crystal for detector application. Beside the bulk type, the choice of contact material, pre-treatment, and sputtering process details have shown to alter significantly the diamond detector performance. Characterization of diamond substrate permittivity and losses indicate grade and crystallinity related, characteristic differences for frequencies in 1 kHz-1 MHz range. Substantial grade related variations were also observed in surface electrostatic characterization performed by contact potential difference (CPD) mode of an atomic force microscope. Study of conductivity variations with temperature reveal that bulk trap energy levels are also dependent on the crystal grade.

  4. Applications Of Diamond In Optics

    NASA Astrophysics Data System (ADS)

    Seal, M.; van Enckevort, W. J. P.

    1989-01-01

    This paper reviews existing and new applications of single crystal diamond, both natural and synthetic, in optical science. The traditional application is as transmissive components, making use of the very wide spectral transmission range, high thermal conductivity, and chemical inertness of diamond. Diamond windows for corrosive environments are well known; diamond surgical endoscope components are under development; and the use of sharpened diamonds as combined surgical cutting instruments and light pipes for internal illumination of the edge is commercial reality. The superb ability of diamond to conduct heat, combined with its very low thermal expansion coefficient makes it suitable for the transmission of high power laser energy, though there is a problem currently being addressed of a high surface reflection coefficient. It is very probable that CVD diamond-like films will form good anti-reflection coatings for diamond. In new applications, the technology of making diamond lenses is being developed. The use of diamond as a detector of ionising radiation is well known, but recent work shows its possibilities in thermoluminescent as well as conduction and pulse counting modes. There are further possibilities of using diamond for the detection and measurement of optical radiation. Examples are low, medium, and high intensity far ultraviolet (< 225 nm) and very high intensity near ultraviolet and visible light from excimer, dye, or argon lasers. Diamond is very radiation resistant! Sensitivities, response times and impurity trap levels have been measured and appropriate diamonds can be synthesised. The use of diamond as fast opto-electronic switches has been reported in the literature and the mechanical and thermal design of diamond "heat sink" substrates for semiconductor laser diodes is advancing rapidly.

  5. In situ serial Laue diffraction on a microfluidic crystallization device

    PubMed Central

    Perry, Sarah L.; Guha, Sudipto; Pawate, Ashtamurthy S.; Henning, Robert; Kosheleva, Irina; Srajer, Vukica; Kenis, Paul J. A.; Ren, Zhong

    2014-01-01

    Renewed interest in room-temperature diffraction has been prompted by the desire to observe structural dynamics of proteins as they function. Serial crystallography, an experimental strategy that aggregates small pieces of data from a large uniform pool of crystals, has been demonstrated at synchrotrons and X-ray free-electron lasers. This work utilizes a microfluidic crystallization platform for serial Laue diffraction from macroscopic crystals and proposes that a collection of small slices of Laue data from many individual crystals is a realistic solution to the difficulties in dynamic studies of irreversible biochemical reactions. PMID:25484843

  6. The influence of detector size relative to field size in small-field photon-beam dosimetry using synthetic diamond crystals as sensors

    NASA Astrophysics Data System (ADS)

    Ade, N.; Nam, T. L.

    2015-08-01

    The choice of a detector for small-field dosimetry remains a challenge due to the size/volume effect of detectors in small fields. Aimed at selecting a suitable crystal type and detector size for small-field dosimetry, this study investigates the relationship between detector and field size by analysing output factors (OFs) measured with a Diode E (reference detector), a Farmer chamber and synthetic diamond detectors of various types and sizes in the dosimetry of a 6 MV photon beam with small fields between 0.3×0.3 cm2 and 10×10 cm2. The examined diamond sensors included two HPHT samples (HP1 and HP2) and six polycrystalline CVD specimens of optical grade (OG) and detector grade (DG) qualities with sizes between 0.3 and 1.0 cm. Each diamond was encapsulated in a tissue-equivalent probe housing which can hold crystals of various dimensions up to 1.0×1.0×0.1 cm3 and has different exposure geometries ('edge-on' and 'flat-on') for impinging radiation. The HPHT samples were found to show an overall better performance compared to the CVD crystals with the 'edge-on' orientation being a preferred geometry for OF measurement especially for very small fields. For instance, down to a 0.4×0.4 cm2 field a maximum deviation of 1.9% was observed between the OFs measured with Diode E and HP2 in the 'edge-on' orientation compared to a 4.6% deviation in the 'flat-on' geometry. It was observed that for fields below 4×4 cm2, the dose deviation between the OFs measured with the detectors and Diode E increase with increasing detector size. It was estimated from an established relationship between the dose deviation and the ratio of detector size to field size for the detectors that the dose deviation probably due to the volume averaging effect would be >3% when the detector size is >3/4 of the field size. A sensitivity value of 223 nC Gy-1 mm-3 was determined in a 0.5×0.5 cm2 field with HP2 compared to a value of 159.2 nC Gy-1 mm-3 obtained with the diode. The results of this

  7. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during...

  8. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during...

  9. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during...

  10. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during...

  11. 21 CFR 872.4535 - Dental diamond instrument.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during...

  12. 77 FR 5055 - Certain Liquid Crystal Display Devices and Products Containing the Same; Determination Not To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Liquid Crystal Display Devices and Products Containing the Same; Determination Not To Review Initial Determination Granting Joint Motion To Terminate Based on Settlement...

  13. 77 FR 45375 - Certain Liquid Crystal Display Devices, Including Monitors, Televisions, Modules, and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-31

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Liquid Crystal Display Devices, Including Monitors, Televisions, Modules, and Components Thereof; Commission Determination Not To Review an Initial Determination Terminating the Investigation...

  14. 77 FR 20048 - Certain Liquid Crystal Display Devices, Including Monitors, Televisions, Modules, and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-03

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Liquid Crystal Display Devices, Including Monitors, Televisions, Modules, and Components Thereof; Notice of Commission Determination To Review-In-Part a Final Determination; Schedule for...

  15. Simulation of planar channeling-radiation spectra of relativistic electrons and positrons channeled in a diamond-structure or tungsten single crystal (classical approach)

    NASA Astrophysics Data System (ADS)

    Azadegan, B.; Wagner, W.

    2015-01-01

    We present a Mathematica package for simulation of spectral-angular distributions and energy spectra of planar channeling radiation of relativistic electrons and positrons channeled along major crystallographic planes of a diamond-structure or tungsten single crystal. The program is based on the classical theory of channeling radiation which has been successfully applied to study planar channeling of light charged particles at energies higher than 100 MeV. Continuous potentials for different planes of diamond, Si, Ge and W single crystals are calculated using the Doyle-Turner approximation to the atomic scattering factor and taking thermal vibrations of the crystal atoms into account. Numerical methods are applied to solve the classical one-dimensional equation of motion. The code is designed to calculate the trajectories, velocities and accelerations of electrons (positrons) channeled by the planar continuous potential. In the framework of classical electrodynamics, these data allow realistic simulations of spectral-angular distributions and energy spectra of planar channeling radiation. Since the generated output is quantitative, the results of calculation may be useful, e.g., for setup configuration and crystal alignment in channeling experiments, for the study of the dependence of channeling radiation on the input parameters of particle beams with respect to the crystal orientation, but also for the simulation of positron production by means of pair creation what is mandatory for the design of efficient positron sources necessary in high-energy and collider physics. Although the classical theory of channeling is well established for long time, there is no adequate library program for simulation of channeling radiation up to now, which is commonly available, sufficiently simple and effective to employ and, therefore, of benefit as for special investigations as for a quick overview of basic features of this type of radiation.

  16. Ferroelectric Tungsten Bronze Bulk Crystals and Epitaxial Thin Films for Electro-Optic Device Applications

    DTIC Science & Technology

    1983-05-01

    23 FERROELECTRIC TUNGSTEN BRONZE BULK CRYSTALS AND EPITAXIAL THIN FILMS FOR ELECTRO-OPTIC DEVICE APPLICATIONS 10 CO O Semi-Annual Technical... THIN FILMS FOR ELECTRO-OPTIC DEVICE APPLICATIONS s TV^C or REPORT * pcmoo COVCHCO Semi-Annual Tec1! Rpt #1 for period 09/30/82-03/31/83...months, considerable progress has been made in several areas, including single crystal and thin film growth and characteriza- tion. The new

  17. Crystallographic orientations of olivine inclusions in diamonds

    NASA Astrophysics Data System (ADS)

    Milani, S.; Nestola, F.; Angel, R. J.; Nimis, P.; Harris, J. W.

    2016-11-01

    In this work we report for the first time the crystallographic orientations of olivine inclusions trapped in diamonds from the Kaapvaal craton (South Africa) determined by single-crystal X-ray diffraction, and analyze them together with all available data in the literature. The overall data set indicates no preferred orientation of the olivine inclusions with respect to their diamond hosts. However, diamonds containing multiple olivine inclusions sometimes show clusters of olivines with the same orientation in the same diamond host. We conclude that such clusters can only be interpreted as the remnants of single olivine crystals pre-dating the growth of the host diamonds.

  18. 75 FR 14470 - Enforcement Proceeding; In the Matter of Certain Liquid Crystal Display Devices and Products...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-25

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Enforcement Proceeding; In the Matter of Certain Liquid Crystal Display Devices and Products... importation, and the sale within the United States after importation of certain liquid crystal display...

  19. High-temperature long-lasting stability assessment of a single-crystal diamond detector under high-flux neutron irradiation

    NASA Astrophysics Data System (ADS)

    Pilotti, R.; Angelone, M.; Marinelli, M.; Milani, E.; Verona-Rinati, G.; Verona, C.; Prestopino, G.; Montereali, R. M.; Vincenti, M. A.; Schooneveld, E. M.; Scherillo, A.; Pietropaolo, A.

    2016-11-01

    An innovative diamond detector layout is presented that is designed to operate at high temperature under intense neutron and gamma fluxes. It is made of a 500 μm “electronic grade” diamond film with 100 nm thick Ag metal contacts deposited onto each surface of the film by means of thermal evaporation. A 2 μ \\text{m} thick layer of 6LiF has been deposited on top of one of the two Ag contacts to make the detector sensitive to thermal neutrons. The device was tested at the ISIS spallation neutron source (Rutherford Appleton Laboratory, UK) using the INES beam line. The detector was continuously irradiated for 100 hours in vacuum (p = 10-5 \\text{mbar}) , exposed to a neutron flux of about 106 n cm-2 s-1 at a temperature T =150 ^\\circ \\text{C} . The aim of this experiment was to study the time dependence of the diamond detector performance while operating at high temperature under irradiation, providing a first experimental proof of reliable continuous operation for 100 hours at high temperature in a harsh environment.

  20. Behavior of crystal defects in synthetic type-IIa single-crystalline diamond at high temperatures under normal pressure

    NASA Astrophysics Data System (ADS)

    Tatsumi, Natsuo; Tamasaku, Kenji; Ito, Toshimichi; Sumiya, Hitoshi

    2017-01-01

    The behavior of dislocation lines (DLs) and stacking faults (SFs) in synthetic type-IIa single-crystalline diamond at high temperatures under normal pressure has been investigated. After annealing the diamond at 1500 °C for 60 min in pure N2 atmosphere, straight DLs were bent to converge to fewer curved dislocation bundles, so that some of the stacking faults were extinct while new DLs appeared at the edges of the removed SFs. These results indicate that SFs in the diamond examined belong to the Shockley type, and that the Shockley partials changed to a perfect dislocation. From this result, the following generation mechanism has been proposed for SFs in diamond. On one hand, because [112] dislocations in the (111) growth sector are contained in the slip plane labelled as (1 ̅ 1 ̅ 1), one perfect dislocation tends to be split into two Shockley partials and a SF when an appropriate stress is applied. On the other hand, the angle between the {111} slip plane and the direction of bundled dislocations in the (001) growth sector is as high as 54.7°, so that a perfect dislocation can hardly slip into partial dislocations. Thus, SFs exist only in the (111) growth sector of type IIa diamond.

  1. Ultimate Atomic Bling: Nanotechnology of Diamonds

    SciTech Connect

    Dahl, Jeremy

    2010-05-25

    Diamonds exist in all sizes, from the Hope Diamond to minuscule crystals only a few atoms across. The smallest of these diamonds are created naturally by the same processes that make petroleum. Recently, researchers discovered that these 'diamondoids' are formed in many different structural shapes, and that these shapes can be used like LEGO blocks for nanotechnology. This talk will discuss the discovery of these nano-size diamonds and highlight current SLAC/Stanford research into their applications in electronics and medicine.

  2. Nitrogen termination of single crystal (100) diamond surface by radio frequency N{sub 2} plasma process: An in-situ x-ray photoemission spectroscopy and secondary electron emission studies

    SciTech Connect

    Chandran, Maneesh E-mail: choffman@tx.technion.ac.il; Shasha, Michal; Michaelson, Shaul; Hoffman, Alon E-mail: choffman@tx.technion.ac.il

    2015-09-14

    In this letter, we report the electronic and chemical properties of nitrogen terminated (N-terminated) single crystal (100) diamond surface, which is a promising candidate for shallow NV{sup −} centers. N-termination is realized by an indirect RF nitrogen plasma process without inducing a large density of surface defects. Thermal stability and electronic property of N-terminated diamond surface are systematically investigated under well-controlled conditions by in-situ x-ray photoelectron spectroscopy and secondary electron emission. An increase in the low energy cut-off of the secondary electron energy distribution curve (EDC), with respect to a bare diamond surface, indicates a positive electron affinity of the N-terminated diamond. Exposure to atomic hydrogen results in reorganization of N-terminated diamond to H-terminated diamond, which exhibited a negative electron affinity surface. The change in intensity and spectral features of the secondary electron EDC of the N-terminated diamond is discussed.

  3. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1980-01-01

    The apparatus and techniques used in effort to determine the relationships between crystal growth and electronic properties are described with emphasis on electroepitaxy and melt-grown gallium aresenide crystal. Applications of deep level transient spectroscopy, derivative photocapitance spectroscopy, and SEM-cathodoluminescene in characterizing wide bandgap semiconductors; determining photoionization in MOS, Schottky barriers, and p-n junctions; and for identifying inhomogeneities are examined, as well as the compensation of indium phosphide.

  4. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2012-01-01

    Estimated 2011 world production of natural and synthetic industrial diamond was about 4.45 billion carats. During 2011, natural industrial diamonds were produced in more than 20 countries, and synthetic industrial diamond was produced in at least 13 countries. About 98 percent of the combined natural and synthetic global output was produced in China, Ireland, Japan, Russia, South Africa and the United States. China is the world's leading producer of synthetic industrial diamond followed by Russia and the United States.

  5. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2013-01-01

    Estimated 2012 world production of natural and synthetic industrial diamond was about 4.45 billion carats. During 2012, natural industrial diamonds were produced in at least 20 countries, and synthetic industrial diamond was produced in at least 12 countries. About 99 percent of the combined natural and synthetic global output was produced in Belarus, China, Ireland, Japan, Russia, South Africa and the United States. During 2012, China was the world’s leading producer of synthetic industrial diamond followed by the United States and Russia. In 2012, the two U.S. synthetic producers, one in Pennsylvania and the other in Ohio, had an estimated output of 103 million carats, valued at about $70.6 million. This was an estimated 43.7 million carats of synthetic diamond bort, grit, and dust and powder with a value of $14.5 million combined with an estimated 59.7 million carats of synthetic diamond stone with a value of $56.1 million. Also in 2012, nine U.S. firms manufactured polycrystalline diamond (PCD) from synthetic diamond grit and powder. The United States government does not collect or maintain data for either domestic PCD producers or domestic chemical vapor deposition (CVD) diamond producers for quantity or value of annual production. Current trade and consumption quantity data are not available for PCD or for CVD diamond. For these reasons, PCD and CVD diamond are not included in the industrial diamond quantitative data reported here.

  6. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2011-01-01

    Estimated world production of natural and synthetic industrial diamond was about 4.44 billion carats in 2010. Natural industrial diamond deposits have been found in more than 35 countries, and synthetic industrial diamond is produced in at least 15 countries.

  7. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2006-01-01

    In 2005, estimated world production of natural and synthetic industrial diamond was 630 million carats. Natural industrial diamond deposits were found in more than 35 countries. Synthetic industrial diamond is produced in at least 15 countries. More than 81% of the combined natural and synthetic global output was produced in Ireland, Japan, Russia, South Africa and the United States.

  8. Timekeeping with electron spin states in diamond

    NASA Astrophysics Data System (ADS)

    Hodges, J. S.; Yao, N. Y.; Maclaurin, D.; Rastogi, C.; Lukin, M. D.; Englund, D.

    2013-03-01

    Frequency standards based on atomic states, such as Rb or Cs vapors, or single-trapped ions, are the most precise measures of time. Here we propose and analyze a precision oscillator approach based upon spins in a solid-state system, in particular, the nitrogen-vacancy defect in single-crystal diamond. We show that this system can have stability approaching portable atomic standards and is readily incorporable as a chip-scale device. Using a pulsed spin-echo technique, we anticipate an Allan deviation of σy=10-7τ-1/2 limited by thermally-induced strain variations; in the absence of such thermal fluctuations, the system is limited by spin dephasing and harbors an Allan deviation nearing ˜10-12τ-1/2. Potential improvements based upon advanced diamond material processing, temperature stabilization, and nanophotonic engineering are discussed.

  9. Plasmonic resonators for enhanced diamond NV-center single photon sources.

    PubMed

    Bulu, Irfan; Babinec, Thomas; Hausmann, Birgit; Choy, Jennifer T; Loncar, Marko

    2011-03-14

    We propose a novel source of non-classical light consisting of plasmonic aperture with single-crystal diamond containing a single Nitrogen-Vacancy (NV) color center. Theoretical calculations of optimal structures show that these devices can simultaneously enhance optical pumping by a factor of 7, spontaneous emission rates by Fp~50 (Purcell factor), and offer collection efficiencies up to 40%. These excitation and collection enhancements occur over a broad range of wavelengths (~30 nm), and are independently tunable with device geometry, across the excitation (~530 nm) and emission (~600-800 nm) spectrum of the NV center. Implementing this system with top-down techniques in bulk diamond crystals will provide a scalable architecture for a myriad of diamond NV center applications.

  10. Analysis of diamond and diamondlike thin films using neutron depth profiling

    SciTech Connect

    Lamaze, G.P.

    1994-12-31

    Much progress in recent years has been made on the development of the technology for the production of thin films of diamond and diamond-like materials. Because of its physical properties, much interest has been shown in diamond as a material to construct semiconductor devices. Among the most important of these physical properties are the highest known thermal conductivity (20 W/cm {times} K), wide energy gap (5.5 eV), and high breakdown fields (107 V/cm). Natural type-II diamond crystals are known to be semiconductors where boron is the dominant acceptor with an activation energy of {approximately}0.3 eV. Recent efforts have concentrated on introducing the boron during the synthesis of thin diamond and diamond-like films. Fujimori et al. have shown that boron doping can be accomplished during the gas-phase growth by adding B{sub 2}H{sub 6} to the gas mixture. Knowing both the concentration and distribution of dopants in the diamond is important both for understanding the synthesis process and the correlation with the physical properties of the material. Neutron depth profiling is a procedure that allows the measurement of the concentration and distribution of the dopant (boron) in chemical vapor deposition diamonds.

  11. Simulation and bonding of dopants in nanocrystalline diamond.

    PubMed

    Barnard, A S; Russo, S P; Snook, I K

    2005-09-01

    The doping of the wide-band gap semiconductor diamond has led to the invention of many electronic and optoelectronic devices. Impurities can be introduced into diamond during chemical vapor deposition or high pressure-high temperature growth, resulting in materials with unusual physical and chemical properties. For electronic applications one of the main objectives in the doping of diamond is the production of p-type and n-type semiconductors materials; however, the study of dopants in diamond nanoparticles is considered important for use in nanodevices, or as qubits for quantum computing. Such devices require that bonding of dopants in nanodiamond must be positioned substitutionally at a lattice site, and must exhibit minimal or no possibility of diffusion to the nanocrystallite surface. In light of these requirements, a number of computational studies have been undertaken to examine the stability of various dopants in various forms of nanocrystalline diamond. Presented here is a review of some such studies, undertaken using quantum mechanical based simulation methods, to provide an overview of the crystal stability of doped nanodiamond for use in diamondoid nanodevices.

  12. Versatile alignment layer method for new types of liquid crystal photonic devices

    SciTech Connect

    Finnemeyer, V.; Bryant, D.; Lu, L.; Bos, P.; Reich, R.; Clark, H.; Berry, S.; Bozler, C.; Yaroshchuk, O.

    2015-07-21

    Liquid crystal photonic devices are becoming increasingly popular. These devices often present a challenge when it comes to creating a robust alignment layer in pre-assembled cells. In this paper, we describe a method of infusing a dye into a microcavity to produce an effective photo-definable alignment layer. However, previous research on such alignment layers has shown that they have limited stability, particularly against subsequent light exposure. As such, we further describe a method of utilizing a pre-polymer, infused into the microcavity along with the liquid crystal, to provide photostability. We demonstrate that the polymer layer, formed under ultraviolet irradiation of liquid crystal cells, has been effectively localized to a thin region near the substrate surface and provides a significant improvement in the photostability of the liquid crystal alignment. This versatile alignment layer method, capable of being utilized in devices from the described microcavities to displays, offers significant promise for new photonics applications.

  13. Omnidirectional refractive devices for flexural waves based on graded phononic crystals

    SciTech Connect

    Torrent, Daniel Pennec, Yan; Djafari-Rouhani, Bahram

    2014-12-14

    Different omnidirectional refractive devices for flexural waves in thin plates are proposed and numerically analyzed. Their realization is explained by means phononic crystal plates, where a previously developed homogenization theory is employed for the design of graded index refractive devices. These devices consist of a circular cluster of inclusions with a properly designed gradient in their radius. With this approach, the Luneburg and Maxwell lenses and a family of beam splitters for flexural waves are proposed and analyzed. Results show that these devices work properly in a broadband frequency region, being therefore an efficient approach for the design of refractive devices specially interesting for nano-scale applications.

  14. Fundamental display properties of flexible devices containing polymer-stabilized ferroelectric liquid crystal between plastic substrates

    NASA Astrophysics Data System (ADS)

    Fujikake, Hideo; Murashige, Takeshi; Sato, Hiroto; Iino, Yoshiki; Kawakita, Masahiro; Kikuchi, Hiroshi

    2002-09-01

    We describe several fundamental display properties of a flexible ferroelectric liquid crystal device containing polymer fibers between thin plastic substrates. The composite film of liquid crystal and polymer was created from a solution of liquid crystal and monomer materials between the plastic substrates under ultraviolet light irradiation. The dynamic electrooptic response to analog voltage pulses was examined with an incidence of laser beam light, and its light modulation property exhibited good linearity in continuous gray-scale capability. The excellent spatial uniformity of liquid crystal alignment formed between the flexible substrates resulted in high-contrast light modulation, although slight spontaneous bending of liquid crystal alignment in the device plane was recognized. When the laser light beam was obliquely incident on the flexible display device, the measured transmittance revealed that the device has a wide viewing angle of more than 100 deg without contrast reversal. This is considered to be caused by the molecular switching in the device plane and the thin electrooptic layer in the display device.

  15. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2000-01-01

    Part of the 1999 Industrial Minerals Review. A review of the state of the global industrial diamond industry in 1999 is presented. World consumption of industrial diamond has increased annually in recent years, with an estimated 500 million carats valued between $650 million and $800 million consumed in 1999. In 1999, the U.S. was the world's largest market for industrial diamond and was also one of the world's main producers; the others were Ireland, Russia, and South Africa. Uses of industrial diamonds are discussed, and prices of natural and synthetic industrial diamond are reported.

  16. Gradient index liquid crystal devices and method of fabrication thereof

    DOEpatents

    Lee, Jae-Cheul; Jacobs, Stephen

    1991-01-01

    Laser beam apodizers using cholesteric liquid crystals provides soft edge profile by use of two separate cholesteric liquid crystal mixtures with different selective reflection bands which in an overlap region have a gradient index where reflectivity changes as a function of position. The apodizers can be configured as a one-dimensional beam apod INTRODUCTION The U.S. government has rights in the invention under Contract No. DE-FC03-85DP40200 between the University of Rochester and the Department of Energy.

  17. Gradient index liquid crystal devices and method of fabrication thereof

    DOEpatents

    Lee, J.C.; Jacobs, S.

    1991-10-29

    Laser beam apodizers using cholesteric liquid crystals provides soft edge profile by use of two separate cholesteric liquid crystal mixtures with different selective reflection bands which in an overlap region have a gradient index where reflectivity changes as a function of position. The apodizers can be configured as a one-dimensional beam apod INTRODUCTION The U.S. government has rights in the invention under Contract No. DE-FC03-85DP40200 between the University of Rochester and the Department of Energy.

  18. PREFACE: Science's gem: diamond science 2009 Science's gem: diamond science 2009

    NASA Astrophysics Data System (ADS)

    Mainwood, Alison; Newton, Mark E.; Stoneham, Marshall

    2009-09-01

    dislocations. The understanding of the critical processes that are involved in CVD diamond growth are becoming clearer. Two papers in this issue model it on a microscopic scale [11, 12], and a further two explore the practical techniques [13, 14] in order to lead to improvement in deposition techniques. Diamond is emerging as an engineering material [3] with its cost no longer regarded as prohibitive even for some large-scale uses, such as the fusion reactor first wall. It is striking how few useful dopants can be put into diamond in a controlled way. The studies reported here, whether theory or experiment, concentrate on phosphorus [14] as the donor, and demonstrate that boron (although deep in semiconductor terms,) can act as the acceptor [3] in practical devices. Other impurities, with deeper levels, such as nitrogen [15], with the muon as an honorary hydrogen [16], are studied in depth. Here, many of the characterization techniques developed over several decades have been brought to bear, to attempt to quantify impurities and defects and ultimately assist in improving the crystal quality [17, 18, 15]. However, further, more novel techniques such as reflection anisotropy spectroscopy [19] and luminescence lifetime mapping [20] have been introduced to diamond in this issue, and one can see how such techniques might play a crucial role in areas such as systems for quantum information processing. The presence and migration of radiation damage defects [21, 22], vacancies and interstitials, and vacancy clusters can dramatically influence the exploitable properties of diamond [23, 24]. It is now apparent that charge traps not only impact on electrical properties, but also on the colour of diamond and that thermo-chromic and photo-chromic effects are more common than previously thought [25, 23]. Combinations, like the negatively charged nitrogen-vacancy centre, have proved impressive in quantum information studies [26]. But diamond has yet to benefit from the sort of dopant

  19. High-mobility diamond

    NASA Astrophysics Data System (ADS)

    Landstrass, Maurice I.

    1994-04-01

    Recent improvements in the CVD diamond deposition process have made possible the fabrication of diamond photoconductive diodes with carrier mobility and lifetime exceeding the values typical of natural gemstones. One of the more surprising recent results is that the best room-temperature carrier properties have been measured on polycrystalline diamond films. The combined electron- hole mobility, as measured by transient photoconductivity at low carrier densities, is 4000 square centimeters per volt per second at electric field of 200 volts per centimeter and is comparable to that of the best single-crystal IIa natural diamonds. Carrier lifetimes measured under the same conditions are 150 picoseconds for the CVD diamond films. The collection distance within the diamond films, at the highest applied fields, is comparable to the average film grain size, indicative of little or no carrier scattering at grain boundaries. A comparison of SIMS measurements with electrical results suggest that impurity incorporation in the near grain boundary regions are responsible for controlling the carrier mobility.

  20. A new approach to kinetics study of the anhydrite crystallization at 373 K using a diamond anvil cell with Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, C. J.; Zheng, H. F.

    2013-04-01

    A new approach to the kinetics study of anhydrite (CaSO4) crystallization has been performed in situ using a hydrothermal diamond anvil cell with Raman spectroscopy in the pressure range 896-1322 MPa and a constant temperature of 373 K. Transformed volume fraction X(t) was determined from Raman peak intensity of the sulfate ion in aqueous solution. The transformation-time plots display a sigmoidal shape with time, which indicates that the reaction rate is different at each stage of anhydrite crystallization. At 373 K, the rate constant k increases from 1.14 × 10-4 s-1 to 1.86 × 10-3 s-1, demonstrating a positive effect of pressure on the overall rate at isothermal condition. We first achieved the molar volume change (ΔVm) equal to -1.82 × 10-5 m3/mol in the course of anhydrite crystallization through Avrami kinetic theory, showing a process of reduction in volume at high pressure and high temperature. According to the exponent n derived from our experiments, a grain-boundary nucleation and diffusion-controlled growth kinetically dominates the crystallization of anhydrite.

  1. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1986-01-01

    It was established that the findings on elemental semiconductors Ge and Si regarding crystal growth, segregation, chemical composition, defect interactions, and materials properties-electronic properties relationships are not necessarily applicable to GaAs (and to other semiconductor compounds). In many instances totally unexpected relationships were found to prevail. It was further established that in compound semiconductors with a volatile constituent, control of stoichiometry is far more critical than any other crystal growth parameter. It was also shown that, due to suppression of nonstoichiometric fluctuations, the advantages of space for growth of semiconductor compounds extend far beyond those observed in elemental semiconductors. A novel configuration was discovered for partial confinement of GaAs melt in space which overcomes the two major problems associated with growth of semiconductors in total confinement. They are volume expansion during solidification and control of pressure of the volatile constituent. These problems are discussed in detail.

  2. Crystal growth of device quality GaAs in space

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1979-01-01

    The optimization of space processing of GaAs is described. The detailed compositional, structural, and electronic characterization of GaAs on a macro- and microscale and the relationships between growth parameters and the properties of GaAs are among the factors discussed. The key parameters limiting device performance are assessed.

  3. Electrically Switching Bistability of a Chiral Quasi-Homeotropic Liquid Crystal Device with Low Driving Voltage

    NASA Astrophysics Data System (ADS)

    Hsieh, Chih-Yung; Chen, Shu-Hsia

    2003-11-01

    We report a new electrically switching bistable chiral quasi-homeotropic liquid crystal device with low driving voltage. This device is operated from the initial twisted-homeotropic state to either +90° or -270° twisted static state showing dark and bright transmittances, respectively, using different switching processes. The critical applied voltage to achieve the switching bistability of our device is only 4.3 V, which is approximately twice its threshold voltage for Freedericksz transition. In addition, the switching characteristics of this device with different driving waveforms are also investigated in this paper.

  4. Optical devices combining an organic semiconductor crystal with a two-dimensional inorganic diffraction grating

    SciTech Connect

    Kitazawa, Takenori; Yamao, Takeshi Hotta, Shu

    2016-02-01

    We have fabricated optical devices using an organic semiconductor crystal as an emission layer in combination with a two-dimensional (2D) inorganic diffraction grating used as an optical cavity. We formed the inorganic diffraction grating by wet etching of aluminum-doped zinc oxide (AZO) under a 2D cyclic olefin copolymer (COC) diffraction grating used as a mask. The COC diffraction grating was fabricated by nanoimprint lithography. The AZO diffraction grating was composed of convex prominences arranged in a triangular lattice. The organic crystal placed on the AZO diffraction grating indicated narrowed peaks in its emission spectrum under ultraviolet light excitation. These are detected parallel to the crystal plane. The peaks were shifted by rotating the optical devices around the normal to the crystal plane, which reflected the rotational symmetries of the triangular lattice through 60°.

  5. Defects in silicon effect on device performance and relationship to crystal growth conditions

    NASA Technical Reports Server (NTRS)

    Jastrzebski, L.

    1985-01-01

    A relationship between material defects in silicon and the performance of electronic devices will be described. A role which oxygen and carbon in silicon play during the defects generation process will be discussed. The electronic properties of silicon are a strong function of the oxygen state in the silicon. This state controls mechanical properties of silicon efficiency for internal gettering and formation of defects in the device's active area. In addition, to temperature, time, ambience, and the cooling/heating rates of high temperature treatments, the oxygen state is a function of the crystal growth process. The incorporation of carbon and oxygen into silicon crystal is controlled by geometry and rotation rates applied to crystal and crucible during crystal growths. Also, formation of nucleation centers for oxygen precipitation is influenced by the growth process, although there is still a controversy which parameters play a major role. All these factors will be reviewed with special emphasis on areas which are still ambiguous and controversial.

  6. The ion capturing effect of 5° SiOx alignment films in liquid crystal devices

    NASA Astrophysics Data System (ADS)

    Huang, Yi; Bos, Philip J.; Bhowmik, Achintya

    2010-09-01

    We show that SiOx, deposited at 5° to the interior surface of a liquid crystal cell allows for a surprisingly substantial reduction in the ion concentration of liquid crystal devices. We have investigated this effect and found that this type of film, due to its surface morphology, captures ions from the liquid crystal material. Ion adsorption on 5° SiOx film obeys the Langmuir isotherm. Experimental results shown allow estimation of the ion capturing capacity of these films to be more than an order of 10 000/μm2. These types of materials are useful for new types of very low power liquid crystal devices such as e-books.

  7. Electro-optical properties of cholesteric liquid crystal devices and applications of dual frequency cholesteric liquid crystals

    NASA Astrophysics Data System (ADS)

    Xu, Ming

    2000-12-01

    The helical structure of cholesteric liquid crystals originates the optical property of Bragg reflection, employed in numerous devices. A typical cholesteric device consists of glass plates, electrodes, alignment layers and a cholesteric liquid crystal layer. We systematically studied the reflection from individual interfaces by measuring the reflection spectra under various polarization conditions and simulating the spectra using Berreman's 4 x 4 matrix method. The results demonstrate that device structures have significant effects on optical performance. We studied the optical behavior of various cholesteric textures. We report for the first time an anomalous reflection of the left circularly polarized light from imperfect planar textures with right-handed twist under normal incidence. We modeled the imperfect planar texture as a multi-domain structure and were able to simulate the reflection of the multi-domain planar texture. We also studied the optical properties of the gray scale states of the cholesteric reflective display. The results are very useful in the implementation of full color displays. We developed two types of devices utilizing dual frequency cholesteric liquid crystals, the dual frequency cholesteric light shutters and reflective displays. The advantages of these light shutters are their high on- state transmittance and low off-state transmittance. By designing and optimizing a 3-phased dual frequency drive scheme, we reduced the response time of the device from over 10 seconds to less than 50ms. The device is a good candidate for applications such as laser protection goggles. Unlike the conventional reflective display, the dual frequency one does not need a homeotropic state as an intermediate switching state. Thus it has the potential of reducing the drive voltage. We designed a dual frequency drive scheme to drive the display between various gray scale states directly, promising an easier implementation of gray scales.

  8. Nano-scale electronic and optoelectronic devices based on 2D crystals

    NASA Astrophysics Data System (ADS)

    Zhu, Wenjuan

    In the last few years, the research community has been rapidly growing interests in two-dimensional (2D) crystals and their applications. The properties of these 2D crystals are diverse -- ranging from semi-metal such as graphene, semiconductors such as MoS2, to insulator such as boron nitride. These 2D crystals have many unique properties as compared to their bulk counterparts due to their reduced dimensionality and symmetry. A key difference is the band structures, which lead to distinct electronic and photonic properties. The 2D nature of the material also plays an important role in defining their exceptional properties of mechanical strength, surface sensitivity, thermal conductivity, tunable band-gap and their interaction with light. These unique properties of 2D crystals open up a broad territory of applications in computing, communication, energy, and medicine. In this talk, I will present our work on understanding the electrical properties of graphene and MoS2, in particular current transport and band-gap engineering in graphene, interface between gate dielectrics and graphene, and gap states in MoS2. I will also present our work on the nano-scale electronic devices (RF and logic devices) and photonic devices (plasmonic devices and photo-detectors) based on these 2D crystals.

  9. High Average Power Raman Conversion in Diamond: ’Eyesafe’ Output and Fiber Laser Conversion

    DTIC Science & Technology

    2015-06-19

    optical effects (namely stress fracture , birefringence and end-facet distortion). Future work will need to involve these processes as DRL powers move...SBS can be obtained in a bulk crystal, in contrast to other crystalline media for which SBS has only been achieved in nano -structured devices, so...providing a new tool for creating diamond nano - and micro-devices. The project raises several questions for further research. As power scaling is

  10. Ridge waveguides in Nd:ABC3O7 disordered crystals produced by swift C5+ ion irradiation and precise diamond dicing: Broad band guidance and spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Luan, Qingfang; He, Ruiyun; Cheng, Chen; Akhmadaliev, Shavkat; Zhou, Shengqiang; Yu, Haohai; Zhang, Huaijin; Chen, Feng

    2015-05-01

    Optical ridge waveguides have been manufactured in the crystals of Nd:SrLaGa3O7 and Nd:SrGdGa3O7 by combining techniques of swift carbon ion irradiation with precise diamond blade dicing. The guiding properties of the waveguides are investigated at broadband (at wavelength of 633 nm, 1064 nm, and 4 μm). After annealing treatment at 200 °C for 1 h, the propagation losses of ridge waveguides could be reduced to as low as 1 dB/cm. The confocal microfluorescence emission spectra confirm that the fluorescence properties of Nd3+ ions are almost unchanged after the ion irradiation processing, showing promising potentials as application of miniature light sources in integrated optics.

  11. Response function of single crystal synthetic diamond detectors to 1-4 MeV neutrons for spectroscopy of D plasmas

    NASA Astrophysics Data System (ADS)

    Rebai, M.; Giacomelli, L.; Milocco, A.; Nocente, M.; Rigamonti, D.; Tardocchi, M.; Camera, F.; Cazzaniga, C.; Chen, Z. J.; Du, T. F.; Fan, T. S.; Giaz, A.; Hu, Z. M.; Marchi, T.; Peng, X. Y.; Gorini, G.

    2016-11-01

    A Single-crystal Diamond (SD) detector prototype was installed at Joint European Torus (JET) in 2013 and the achieved results have shown its spectroscopic capability of measuring 2.5 MeV neutrons from deuterium plasmas. This paper presents measurements of the SD response function to monoenergetic neutrons, which is a key point for the development of a neutron spectrometer based on SDs and compares them with Monte Carlo simulations. The analysis procedure allows for a good reconstruction of the experimental results. The good pulse height energy resolution (equivalent FWHM of 80 keV at 2.5 MeV), gain stability, insensitivity to magnetic field, and compact size make SDs attractive as compact neutron spectrometers of high flux deuterium plasmas, such as for instance those needed for the ITER neutron camera.

  12. Response function of single crystal synthetic diamond detectors to 1-4 MeV neutrons for spectroscopy of D plasmas.

    PubMed

    Rebai, M; Giacomelli, L; Milocco, A; Nocente, M; Rigamonti, D; Tardocchi, M; Camera, F; Cazzaniga, C; Chen, Z J; Du, T F; Fan, T S; Giaz, A; Hu, Z M; Marchi, T; Peng, X Y; Gorini, G

    2016-11-01

    A Single-crystal Diamond (SD) detector prototype was installed at Joint European Torus (JET) in 2013 and the achieved results have shown its spectroscopic capability of measuring 2.5 MeV neutrons from deuterium plasmas. This paper presents measurements of the SD response function to monoenergetic neutrons, which is a key point for the development of a neutron spectrometer based on SDs and compares them with Monte Carlo simulations. The analysis procedure allows for a good reconstruction of the experimental results. The good pulse height energy resolution (equivalent FWHM of 80 keV at 2.5 MeV), gain stability, insensitivity to magnetic field, and compact size make SDs attractive as compact neutron spectrometers of high flux deuterium plasmas, such as for instance those needed for the ITER neutron camera.

  13. Plastic yielding and work hardening of single crystals in a soft device

    NASA Astrophysics Data System (ADS)

    Le, K. C.; Nguyen, Q. S.

    2009-11-01

    An analytical solution to the problem of an anti-plane constrained shear of single crystals placed in a soft device within the continuum dislocation theory is found. The dependence of the nucleation stress on the grain size exhibits a modest deviation from the Hall-Petch relation. It is shown that, as soon as the dissipation is taken into account, the hardening behavior becomes nearly identical to that of single crystals in a hard device. To cite this article: K.C. Le, Q.S. Nguyen, C. R. Mecanique 337 (2009).

  14. Security devices based on liquid crystals doped with a colour dye

    NASA Astrophysics Data System (ADS)

    Carrasco-Vela, C.; Quintana, X.; Otón, E.; Geday, M. A.; Otón, J. M.

    2011-12-01

    Liquid crystal properties make them useful for the development of security devices in applications of authentication and detection of fakes. Induced orientation of liquid crystal molecules and birefringence are the two main properties used in security devices. Employing liquid crystal and dichroic colorants, we have developed devices that show, with the aid of a polarizer, multiple images on each side of the device. Rubbed polyimide is used as alignment layer on each substrate of the LC cell. By rubbing the polyimide in different directions in each substrate it is possible to create any kind of symbols, drawings or motifs with a greyscale; the more complex the created device is, the more difficult is to fake it. To identify the motifs it is necessary to use polarized light. Depending on whether the polarizer is located in front of the LC cell or behind it, different motifs from one or the other substrate are shown. The effect arises from the dopant colour dye added to the liquid crystal, the induced orientation and the twist structure. In practice, a grazing reflection on a dielectric surface is polarized enough to see the effect. Any LC flat panel display can obviously be used as backlight as well.

  15. The protective properties of ultra-thin diamond like carbon films for high density magnetic storage devices

    NASA Astrophysics Data System (ADS)

    Zhong, Min; Zhang, Chenhui; Luo, Jianbin; Lu, Xinchun

    2009-10-01

    With the increase of magnetic storage density, the thickness of the protective diamond like carbon (DLC) film on the surfaces of head and disk is required as thin as possible. In this paper, the structure, mechanical properties and corrosion and oxidation resistance of ultra-thin DLC films are investigated. The ultra-thin DLC films were deposited by using filtered cathodic vacuum arc (FCVA) technique. The exact thickness of the ultra-thin DLC film was determined by high resolution transmission electron microscope (HRTEM). Raman analysis indicates that the ultra-thin DLC film presents ta-C structure with high sp 3 fraction. In the wear test, a diamond tip was used to simulate a single-asperity contact with the film surface and the wear marks were produced on the film surface. The wear depths decrease with film thickness increasing. If the film thickness was 1.4 nm or above, the wear depth was much lower than that of Si substrate. This indicates that the ultra-thin DLC film with thickness of 1.4 nm shows excellent wear resistance. Corrosion tests in water and oxidation tests in air were carried out to investigate the diffusion barrier effect of the ultra-thin DLC films. The results show that the DLC film with thickness of 1.4 nm provides adequate coverage on the substrate and has good corrosion and oxidation resistance.

  16. An evaluation of liquid-crystal thermometry as a screening device for intraoperative hyperthermia.

    PubMed

    Lees, D E; Schuette, W; Bull, J M; Whang-Peng, J; Atkinson, E R; Macnamara, T E

    1978-01-01

    Disposable liquid-crystal temperature-trend indicators were evaluated under clinical conditions that simulated the development of intraoperative hyperthermia during anesthesia. Comparison was made to forehead thermistors for rapidity, accuracy, and linearity of response as well as correlation with esophageal and rectal thermistor recordings. The liquid-crystal monitors were comparable to the forehead thermistors in both rapidity and linearity or response, but not in accuracy. A linear correlation existed with the esophageal thermistor temperatures. Correlation with the rectal temperatures was not as exact. It is concluded that liquid-crystal thermometers may adequately serve as screening devices for intraoperative hyperthermia.

  17. Liquid crystal devices with continuous phase variation based on high-permittivity thin films

    NASA Astrophysics Data System (ADS)

    Willekens, Oliver; Neyts, Kristiaan; Beeckman, Jeroen

    2016-03-01

    Most liquid crystal devices use transparent conductive electrodes such as indium tin oxide (ITO) to apply a potential difference in order to achieve electro-optic switching. As an alternative, we study a device with narrow metallic electrodes in combination with dielectric layers with large dielectric permittivity. In this approach the applied voltage can be a continuous function of the lateral distance from the electrode line. Simulations for a one-dimensional beam-steering device show that the switching of the liquid crystal (LC) director depends indeed on the distance from the addressing electrodes and on the value of the relative permittivity. We show that in a device with electrodes spaced 60 µm apart, the LC director halfway between the electrodes shows a considerable reorientation, when a dielectric layer with permittivity of Epsilonr = 550 is used, whereas no reorientation is observed for the uncoated reference sample at the same voltage. An added advantage is that the proposed configuration only contains dielectric materials, without resistive losses, which means that almost no heat is dissipated. This indicates that this technology could be used in low-power LC devices. The results show that using dielectric thin films with high relative permittivity in liquid crystal devices could form a cost-efficient and low-power alternative to many LC technologies where a gradient electric field is desirable.

  18. Investigation of the Performance of Various CVD Diamond Crystal Qualities for the Measurement of Radiation Doses from a Low Energy Mammography X-Ray Beam, Compared with MC Code (PENELOPE) Calculations

    NASA Astrophysics Data System (ADS)

    Zakari, Y. I.; Mavunda, R. D.; Nam, T. L.; Keddy, R. J.

    The tissue equivalence of diamond allows for accurate radiation dose determination without large corrections for different attenuation values in biological tissue, but its low Z value limits this advantage however to the lower energy photons such as for example in Mammography X-ray beams. This paper assays the performance of nine Chemical Vapour Deposition (CVD) diamonds for use as radiation sensing material. The specimens fabricated in wafer form are classified as detector grade, optical grade and single crystals. It is well known that the presence of defects in diamonds, including CVD specimens, not only dictates but also affects the responds of diamond to radiation in different ways. In this investigation, tools such as electron spin resonance (ESR), thermoluminescence (TL) Raman spectroscopy and ultra violet (UV) spectroscopy were used to probe each of the samples. The linearity, sensitivity and other characteristics of the detector to photon interaction was analyzed, and from the I-V characteristics. The diamonds categorized into four each, of the so called Detector and Optical grades, and a single crystal CVD were exposed to low X-ray peak voltage range (22 to 27 KVp) with a trans-crystal polarizing fields of 0.4 kV.cm-1, 0.66 kV.cm-1 and 0.8 kV.cm-1. The presentation discusses the presence of defects identifiable by the techniques used and correlates the radiation performance of the three types of crystals to their presence. The choice of a wafer as either a spectrometer or as X-ray dosimeter within the selected energy range was made. The analyses was validated with Monte-Carlo code (PENELOPE)

  19. Development of diamond-based X-ray detection for high-flux beamline diagnostics.

    PubMed

    Bohon, Jen; Muller, Erik; Smedley, John

    2010-11-01

    High-quality single-crystal and polycrystalline chemical-vapor-deposition diamond detectors with platinum contacts have been tested at the white-beam X28C beamline at the National Synchrotron Light Source under high-flux conditions. The voltage dependence of these devices has been measured under both DC and pulsed-bias conditions, establishing the presence or absence of photoconductive gain in each device. Linear response consistent with the theoretically determined ionization energy has been achieved over eleven orders of magnitude when combined with previous low-flux studies. Temporal measurements with single-crystal diamond detectors have resolved the nanosecond-scale pulse structures of both the NSLS and the APS. Prototype single-crystal quadrant detectors have provided the ability to simultaneously resolve the X-ray beam position and obtain a quantitative measurement of the flux.

  20. 77 FR 37067 - Certain Liquid Crystal Display Devices, Including Monitors, Televisions, Modules, and Components...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-20

    ... [Federal Register Volume 77, Number 119 (Wednesday, June 20, 2012)] [Notices] [Pages 37067-37068] [FR Doc No: 2012-15005] INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-741/749] Certain Liquid Crystal Display Devices, Including Monitors, Televisions, Modules, and Components Thereof;...

  1. Epitaxial diamond-hexagonal silicon nano-ribbon growth on (001) silicon

    PubMed Central

    Qiu, Y.; Bender, H.; Richard, O.; Kim, M.-S.; Van Besien, E.; Vos, I.; de Potter de ten Broeck, M.; Mocuta, D.; Vandervorst, W.

    2015-01-01

    Silicon crystallizes in the diamond-cubic phase and shows only a weak emission at 1.1 eV. Diamond-hexagonal silicon however has an indirect bandgap at 1.5 eV and has therefore potential for application in opto-electronic devices. Here we discuss a method based on advanced silicon device processing to form diamond-hexagonal silicon nano-ribbons. With an appropriate temperature anneal applied to densify the oxide fillings between silicon fins, the lateral outward stress exerted on fins sandwiched between wide and narrow oxide windows can result in a phase transition from diamond-cubic to diamond-hexagonal Si at the base of these fins. The diamond-hexagonal slabs are generally 5–8 nm thick and can extend over the full width and length of the fins, i.e. have a nano-ribbon shape along the fins. Although hexagonal silicon is a metastable phase, once formed it is found being stable during subsequent high temperature treatments even during process steps up to 1050 ºC. PMID:26239286

  2. Diamonds in ophiolites: Contamination or a new diamond growth environment?

    NASA Astrophysics Data System (ADS)

    Howell, D.; Griffin, W. L.; Yang, J.; Gain, S.; Stern, R. A.; Huang, J.-X.; Jacob, D. E.; Xu, X.; Stokes, A. J.; O'Reilly, S. Y.; Pearson, N. J.

    2015-11-01

    For more than 20 years, the reported occurrence of diamonds in the chromites and peridotites of the Luobusa massif in Tibet (a complex described as an ophiolite) has been widely ignored by the diamond research community. This skepticism has persisted because the diamonds are similar in many respects to high-pressure high-temperature (HPHT) synthetic/industrial diamonds (grown from metal solvents), and the finding previously has not been independently replicated. We present a detailed examination of the Luobusa diamonds (recovered from both peridotites and chromitites), including morphology, size, color, impurity characteristics (by infrared spectroscopy), internal growth structures, trace-element patterns, and C and N isotopes. A detailed comparison with synthetic industrial diamonds shows many similarities. Cubo-octahedral morphology, yellow color due to unaggregated nitrogen (C centres only, Type Ib), metal-alloy inclusions and highly negative δ13C values are present in both sets of diamonds. The Tibetan diamonds (n = 3) show an exceptionally large range in δ15N (-5.6 to + 28.7 ‰) within individual crystals, and inconsistent fractionation between {111} and {100} growth sectors. This in contrast to large synthetic HPHT diamonds grown by the temperature gradient method, which have with δ15N = 0 ‰ in {111} sectors and + 30 ‰ in {100} sectors, as reported in the literature. This comparison is limited by the small sample set combined with the fact the diamonds probably grew by different processes. However, the Tibetan diamonds do have generally higher concentrations and different ratios of trace elements; most inclusions are a NiMnCo alloy, but there are also some small REE-rich phases never seen in HPHT synthetics. These characteristics indicate that the Tibetan diamonds grew in contact with a C-saturated Ni-Mn-Co-rich melt in a highly reduced environment. The stable isotopes indicate a major subduction-related contribution to the chemical environment. The

  3. Two- and three-dimensional ultrananocrystalline diamond (UNCD) structures for a high resolution diamond-based MEMS technology.

    SciTech Connect

    Auciello, O.; Krauss, A. R.; Gruen, D. M.; Busmann, H. G.; Meyer, E. M.; Tucek, J.; Sumant, A.; Jayatissa, A.; Moldovan, N.; Mancini, D. C.; Gardos, M. N.

    2000-01-17

    Silicon is currently the most commonly used material for the fabrication of microelectromechanical systems (MEMS). However, silicon-based MEMS will not be suitable for long-endurance devices involving components rotating at high speed, where friction and wear need to be minimized, components such as 2-D cantilevers that may be subjected to very large flexural displacements, where stiction is a problem, or components that will be exposed to corrosive environments. The mechanical, thermal, chemical, and tribological properties of diamond make it an ideal material for the fabrication of long-endurance MEMS components. Cost-effective fabrication of these components could in principle be achieved by coating Si with diamond films and using conventional lithographic patterning methods in conjunction with e. g. sacrificial Ti or SiO{sub 2} layers. However, diamond coatings grown by conventional chemical vapor deposition (CVD) methods exhibit a coarse-grained structure that prevents high-resolution patterning, or a fine-grained microstructure with a significant amount of intergranular non-diamond carbon. The authors demonstrate here the fabrication of 2-D and 3-D phase-pure ultrananocrystalline diamond (UNCD) MEMS components by coating Si with UNCD films, coupled with lithographic patterning methods involving sacrificial release layers. UNCD films are grown by microwave plasma CVD using C{sub 60}-Ar or CH{sub 4}-Ar gas mixtures, which result in films that have 3--5 nm grain size, are 10--20 times smoother than conventionally grown diamond films, are extremely resistant to corrosive environments, and are predicted to have a brittle fracture strength similar to that of single crystal diamond.

  4. High efficiency diamond solar cells

    DOEpatents

    Gruen, Dieter M.

    2008-05-06

    A photovoltaic device and method of making same. A layer of p-doped microcrystalline diamond is deposited on a layer of n-doped ultrananocrystalline diamond such as by providing a substrate in a chamber, providing a first atmosphere containing about 1% by volume CH.sub.4 and about 99% by volume H.sub.2 with dopant quantities of a boron compound, subjecting the atmosphere to microwave energy to deposit a p-doped microcrystalline diamond layer on the substrate, providing a second atmosphere of about 1% by volume CH.sub.4 and about 89% by volume Ar and about 10% by volume N.sub.2, subjecting the second atmosphere to microwave energy to deposit a n-doped ultrananocrystalline diamond layer on the p-doped microcrystalline diamond layer. Electrodes and leads are added to conduct electrical energy when the layers are irradiated.

  5. 76 FR 30968 - In the Matter of Certain Liquid Crystal Display Devices, Products Containing Same, and Methods...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-27

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION In the Matter of Certain Liquid Crystal Display Devices, Products Containing Same, and Methods for... importation of certain liquid crystal display (``LCD'') devices, products containing same, and methods...

  6. 76 FR 51054 - In the Matter of Certain Liquid Crystal Display Devices and Products Containing the Same; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-17

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION In the Matter of Certain Liquid Crystal Display Devices and Products Containing the Same; Notice... sale within the United States after importation of certain liquid crystal display devices and...

  7. Liquid Crystal-Based Beam Steering Device Development for NASA Applications

    NASA Technical Reports Server (NTRS)

    Pouch, John; Nguyen, Hung; Miranda, Felix; Bos, Philip; Lavrentovich, Oleg; Wang, Xinghua

    2004-01-01

    The NASA Computing, Information and Communications Technology (CICT) Program is supporting the development of liquid crystal-based beam steering devices. The device would use inexpensive, light-weight, optical components, and it would have the following capabilities: electronic beam scanning to angles above 1 milliradian, and submicroradian beam pointing accuracy. In order to correct for the imperfections resulting from the space-deployable optics, the technique of wave-front correction would be implemented. Hence, the output beam quality would be maintained. The potential applications could include satellite tracking, near-Earth inter-satellite communications, deep-space communications, and optical phased array systems. The status of the beam steering device development based on the liquid crystal technology and its relationship to prospective NASA mission scenarios will be described.

  8. Epitaxial growth of europium monoxide on diamond

    SciTech Connect

    Melville, A.; Heeg, T.; Mairoser, T.; Schmehl, A.; Fischer, M.; Gsell, S.; Schreck, M.; Awschalom, D. D.; Holländer, B.; Schubert, J.; Schlom, D. G.

    2013-11-25

    We report the epitaxial integration of phase-pure EuO on both single-crystal diamond and on epitaxial diamond films grown on silicon utilizing reactive molecular-beam epitaxy. The epitaxial orientation relationship is (001) EuO ‖ (001) diamond and [110] EuO ‖[100] diamond. The EuO layer is nominally unstrained and ferromagnetic with a transition temperature of 68 ± 2 K and a saturation magnetization of 5.5 ± 0.1 Bohr magnetons per europium ion on the single-crystal diamond, and a transition temperature of 67 ± 2 K and a saturation magnetization of 2.1 ± 0.1 Bohr magnetons per europium ion on the epitaxial diamond film.

  9. Superhard material comparable in hardness to diamond

    SciTech Connect

    Badzian, A.R.

    1988-12-19

    Superhard boron suboxides, with hardness close to that of diamond, were synthesized from boron/boron oxide mixtures. Such hardness is expected when a material's molar volume approaches the value characteristic for diamond. These materials consist of boron-rich phases belonging to the boron-oxygen system. The phase which contains 4 at. % oxygen and a crystal structure related to ..beta..rhombohedral boron can scratch diamond faces. During scratching of diamond the suboxide is worn also, and the wear debris is amorphized. Wear on the lt. slash/100/ diamond faces results from a cleavage mechanism which leaves a rough surface covered with cleaved lt. slash/111/ microfaces. The lt. slash/100/ faces are more easily abraded than the lt. slash/111/ diamond faces. Wear on lt. slash/111/ faces consumes much more energy and leaves grooves of plastically deformed diamond.

  10. Enhancement of broadband optical absorption in photovoltaic devices by band-edge effect of photonic crystals.

    PubMed

    Tanaka, Yoshinori; Kawamoto, Yosuke; Fujita, Masayuki; Noda, Susumu

    2013-08-26

    We numerically investigate broadband optical absorption enhancement in thin, 400-nm thick microcrystalline silicon (µc-Si) photovoltaic devices by photonic crystals (PCs). We realize absorption enhancement by coupling the light from the free space to the large area resonant modes at the photonic band-edge induced by the photonic crystals. We show that multiple photonic band-edge modes can be produced by higher order modes in the vertical direction of the Si photovoltaic layer, which can enhance the absorption on multiple wavelengths. Moreover, we reveal that the photonic superlattice structure can produce more photonic band-edge modes that lead to further optical absorption. The absorption average in wavelengths of 500-1000 nm weighted to the solar spectrum (AM 1.5) increases almost twice: from 33% without photonic crystal to 58% with a 4 × 4 period superlattice photonic crystal; our result outperforms the Lambertian textured structure.

  11. Diamond Coatings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.

  12. An empirical survey on the influence of machining parameters on tool wear in diamond turning of large single crystal silicon optics

    SciTech Connect

    Blaedel, K L; Carr, J W; Davis, P J; Goodman, W; Haack, J K; Krulewich, D; McClellan, M; Syn, C K; Zimmermann, M.

    1999-07-01

    The research described in this paper is a continuation of the collaborative efforts by Lawrence Livermore National Laboratory (LLNL), Schafer Corporation and TRW to develop a process for single point diamond turning (SPDT) of large single crystal silicon (SCSi) optical substrates on the Large Optic Diamond Turning Machine (LODTM). The principal challenge to obtaining long track lengths in SCSi has been to identify a set of machining parameters which yield a process that provides both low and predictable tool wear. Identifying such a process for SCSi has proven to be a formidable task because multiple crystallographic orientations with a range of hardness values are encountered when machining conical and annular optical substrates. The LODTM cutting program can compensate for tool wear if it is predictable. However, if the tool wear is not predictable then the figured area of the optical substrate may have unacceptably high error that can not be removed by post-polishing. The emphasis of this survey was limited to elucidating the influence of cutting parameters on the tool wear. We present two preliminary models that can be used to predict tool wear over the parameter space investigated. During the past two and one-half years a series of three evolutionary investigations were performed. The first investigation, the Parameter Assessment Study (PAS), was designed to survey fundamental machining parameters and assess their influence on tool wear [1]. The results of the PAS were used as a point-of-departure for designing the second investigation, the Parameter Selection Study (PSS). The goal of the PSS was to explore the trends identified in the PAS in more detail, to determine if the experimental results obtained in the PAS could be repeated on a different diamond turning machine (DTM), and to select a more optimal set of machining parameters that could be used in subsequent investigations such as the Fluid Down-Select Study (FDS). The goal of the FDS was to compare

  13. An assessment of radiotherapy dosimeters based on CVD grown diamond

    NASA Astrophysics Data System (ADS)

    Ramkumar, S.; Buttar, C. M.; Conway, J.; Whitehead, A. J.; Sussman, R. S.; Hill, G.; Walker, S.

    2001-03-01

    Diamond is potentially a very suitable material for use as a dosimeter for radiotherapy. Its radiation hardness, the near tissue equivalence and chemical inertness are some of the characteristics of diamond, which make it well suited for its application as a dosimeter. Recent advances in the synthesis of diamond by chemical vapour deposition (CVD) technology have resulted in the improvement in the quality of material and increased its suitability for radiotherapy applications. We report in this paper, the response of prototype dosimeters based on two different types (CVD1 and CVD2) of CVD diamond to X-rays. The diamond devices were assessed for sensitivity, dependence of response on dose and dose rate, and compared with a Scanditronix silicon photon diode and a PTW natural diamond dosimeter. The diamond devices of CVD1 type showed an initial increase in response with dose, which saturates after ≈6 Gy. The diamond devices of CVD2 type had a response at low fields (<1162.8 V/cm) that was linear with dose and dose rate. At high fields (>1162.8 V/cm), the CVD2-type devices showed polarisation and dose-rate dependence. The sensitivity of the CVD diamond devices varied between 82 and 1300 nC/Gy depending upon the sample type and the applied voltage. The sensitivity of CVD diamond devices was significantly higher than that of natural diamond and silicon dosimeters. The results suggest that CVD diamond devices can be fabricated for successful use in radiotherapy applications.

  14. Low-voltage tunable photonics devices: grove on thin porous structures containing liquid crystals

    NASA Astrophysics Data System (ADS)

    Criante, Luigino; Moretti, Luca; Scotognella, Francesco

    2013-09-01

    In this study we demonstrate the fabrication of one-dimensional porous multilayer photonic crystals made by metal oxide nanoparticles. We show the infiltration of these porous structures with a liquid crystal via a very simple method, resulting in a red shift of the photonic band gap due to increase of the effective refractive index of the medium. Taking advantage of structure thickness of only few micrometers, we have observed a blue shift of the photonic band gap owing the non-linear response of the liquid crystals by applying a very low external electric voltage, i.e. 8 V. The experimental observation of electric voltage tuning on the transmission spectrum has been corroborated by transfer matrix method simulations, by taking into account the non-linear optical properties of the liquid crystal. In this framework, we propose how the optical properties of these structure can be accurately predicted by our simulation software in terms of diffraction efficiency, of photonic band gap position when the porous photonic crystals is doped with a liquid crystal, of modulation of the photonic band gap position (electro-optic tuning) in the presence of applied voltage. According with results carried out by the custom simulation software it is possible to control the optical proprieties of the photonics crystal in very thin structures. Furthermore, the presented device could be very interesting for applications where high sensitivity sensor and selective color tunability is needed with the use of cheap and low voltage power supplies.

  15. Diamond detector for alpha-particle spectrometry.

    PubMed

    Dueñas, J A; de la Torre Pérez, J; Martín Sánchez, A; Martel, I

    2014-08-01

    An artificially grown high purity diamond was used as a detector for alpha-particle spectrometry. Diamond detectors can match the performance of silicon detectors employed in standard continuous air monitoring systems. Its radiation hardness and electronic properties make them ideal to work under extreme condition such as high temperature and ambient lights. A 50 μm thickness single-crystal diamond detector has been compared with a 300 μm passivated implanted planar silicon detector, under ambient conditions.

  16. Mineral resource of the month: diamond

    USGS Publications Warehouse

    Olson, Donald W.

    2009-01-01

    The article presents information on diamond, which is regarded as the world's most popular gemstone. It states that there is strength in the covalent bonding between its carbon atoms, resulting to the strength of its physical properties. The presence of colors in diamonds may be attributed to the impurities that settle in the crystal lattice. Diamonds have been used as decorative items since the ancient era.

  17. Rapid Sintering of Nano-Diamond Compacts

    SciTech Connect

    Osipov, A.; Nauyoks, S; Zerda, T; Zaporozhets, O

    2009-01-01

    Diamond compacts were sintered from nano-size diamond crystals at high pressure, 8 GPa, and temperature above 1500 degrees C for very short times ranging from 5 to 11 s. Structure and mechanical properties of the compacts have been characterized. Although we have not completely avoided graphitization of diamonds, the amount of graphite produced was low, less than 2%, and despite relatively high porosity, the compacts were characterized by high hardness, bulk and Young moduli.

  18. Diamond turning of glass

    SciTech Connect

    Blackley, W.S.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the critical cutting depth concepts for single point diamond turning of brittle, amorphous materials. Inorganic glasses and a brittle, thermoset polymer (organic glass) are the principal candidate materials. Interrupted cutting tests similar to those done in earlier research are Ge and Si crystals will be made to obtain critical depth values as a function of machining parameters. The results will provide systematic data with which to assess machining performance on glasses and amorphous materials

  19. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2007-01-01

    World production of natural and synthetic industrial diamond was about 648 million carats in 2006, with 79 percent of the production coming from Ireland, Japan, Russia, South Africa, and the U.S. U.S. consumption was was an estimated 602 million carats, imports were over 391 million carats, and exports were about 83 million carats. About 87 percent of the industrial diamonds market uses synthetic diamonds, which are expected to become less expensive as technology improves and competition from low-cost producers increases.

  20. Generation of microdischarges in diamond substrates

    NASA Astrophysics Data System (ADS)

    Mitea, S.; Zeleznik, M.; Bowden, M. D.; May, P. W.; Fox, N. A.; Hart, J. N.; Fowler, C.; Stevens, R.; StJ Braithwaite, N.

    2012-04-01

    We report the generation of microdischarges in devices composed of microcrystalline diamond. Discharges were generated in device structures with microhollow cathode discharge geometries. One structure consisted of an insulating diamond wafer coated with boron-doped diamond layers on both sides. A second structure consisted of an insulating diamond wafer coated with metal layers on both sides. In each case, a single sub-millimetre hole was machined through the conductor-insulator-conductor structure. The discharges were generated in a helium atmosphere. Breakdown voltages were around 500 V and discharge currents in the range 0.1-2.5 mA were maintained by a sustaining dc voltage of 300 V.

  1. Self-Restoration by Smectic Layer Structures of Monostable Ferroelectric Liquid Crystal in Flexible Devices

    NASA Astrophysics Data System (ADS)

    Fujikake, Hideo; Sato, Hiroto; Isaka, Fumito; Murashige, Takeshi; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2004-12-01

    In this paper, we discuss a self-restoration phenomenon affecting smectic layer deformation and molecular alignment in monostable ferroelectric liquid crystals used for flexible displays. First, the mechanical stability of tilted ‘bookshelf’ structures of smectic layers anchored on substrates using alignment layers was examined by precisely shearing two substrates. The microscopic texture of a monostable ferroelectric liquid crystal showed tolerance to shearing and the self-restoration was thought to be due to a smectic layer reconnection phenomenon, whereas a conventional bistable ferroelectric liquid crystal film generated alignment defects due to the tilting of the stable molecular direction. We then fabricated a flexible monostable device containing fine polymer fiber networks, where anchoring of molecularly aligned polymer fibers led to the observation of monostable liquid crystal switching. A uniform liquid crystal alignment was maintained in a 100 mm× 100 mm device even after bending more than 10000 times at a minimum radius of curvature of 20 mm, due to the enhanced shearing tolerance of the smectic layer structure.

  2. Red-green-blue 2 D tuneable liquid crystal laser devices

    NASA Astrophysics Data System (ADS)

    Coles, H. J.; Morris, S. M.; Ford, A. D.; Hands, P. J. W.; Wilkinson, T. D.

    2009-08-01

    In this paper, we review our recent experimental work on coherent and blue phase liquid crystal lasers.We will present results on thin-film photonic band edge lasing devices using dye-doped low molar mass liquid crystals in self-organised chiral nematic and blue phases. We show that high Q-factor lasers can be achieved in these materials and demonstrate that a single mode output with a very narrow line width can be readily achievable in well-aligned mono-domain samples. Further, we have found that the performance of the laser, i.e. the slope efficiency and the excitation threshold, are dependent upon the physical parameters of the low molar mass chiral nematic liquid crystals. Specifically, slope efficiencies greater than 60% could be achieved depending upon the materials used and the device geometry employed. We will discuss the important parameters of the liquid crystal host/dye guest materials and device configuration that are needed to achieve such high slope efficiencies. Further we demonstrate how the wavelength of the laser can be tuned using an in-plane electric field in a direction perpendicular to the helix axis via a flexoelectric mechanism as well as thermally using thermochromic effects. We will then briefly outline data on room temperature blue phase lasers and further show how liquid crystal/lenslet arrays have been used to demonstrate 2D laser emission of any desired wavelength. Finally, we present preliminary data on LED/incoherent pumping of RG liquid crystal lasers leading to a continuous wave output.

  3. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M.

    1994-01-01

    A method of forming synthetic hydrogen defect free diamond or diamond like films on a substrate. The method involves providing vapor containing fullerene molecules with or without an inert gas, providing a device to impart energy to the fullerene molecules, fragmenting at least in part some of the fullerene molecules in the vapor or energizing the molecules to incipient fragmentation, ionizing the fullerene molecules, impinging ionized fullerene molecules on the substrate to assist in causing fullerene fragmentation to obtain a thickness of diamond on the substrate.

  4. Industrial diamond

    USGS Publications Warehouse

    Olson, D.W.

    2004-01-01

    Part of the 2003 industrial minerals review. Supply and demand data for industrial diamond are provided. Topics discussed are consumption, prices, imports and exports, government stockpiles, and the outlook for 2004.

  5. Double bevel construction of a diamond anvil

    DOEpatents

    Moss, W.C.

    1988-10-11

    A double or multiple bevel culet geometry is used on a diamond anvil in a high pressure cell apparatus to provide increased sample pressure and stability for a given force applied to the diamond tables. Double or multiple bevel culet geometries can also be used for sapphire or other hard crystal anvils. Pressures up to and above 5 Megabars can be reached. 8 figs.

  6. Double bevel construction of a diamond anvil

    DOEpatents

    Moss, William C.

    1988-01-01

    A double or multiple bevel culet geometry is used on a diamond anvil in a high pressure cell apparatus to provide increased sample pressure and stability for a given force applied to the diamond tables. Double or multiple bevel culet geometries can also be used for sapphire or other hard crystal anvils. Pressures up to and above 5 Megabars can be reached.

  7. Technology development of high-quality semiconductor devices using solution-processed crystallization of pentacene

    NASA Astrophysics Data System (ADS)

    Liu, Hung-Wei

    Organic electronic materials and processing techniques have attracted considerable attention for developing organic thin-film transistors (OTFTs), since they may be patterned on flexible substrates which may be bent into a variety of shapes for applications such as displays, smart cards, solar devices and sensors Various fabrication methods for building pentacene-based OTFTs have been demonstrated. Traditional vacuum deposition and vapor deposition methods have been studied for deposition on plastic and paper, but these are unlikely to scale well to large area printing. Researchers have developed methods for processing OTFTs from solution because of the potential for low-cost and large area device manufacturing, such as through inkjet or offset printing. Most methods require the use of precursors which are used to make pentacene soluble, and these methods have typically produced much lower carrier mobility than the best vacuum deposited devices. We have investigated devices built from solution-processed pentacene that is locally crystallized at room temperature on the polymer substrates. Pentacene crystals grown in this manner are highly localized at pre-determined sites, have good crystallinity and show good carrier mobility, making this an attractive method for large area manufacturing of semiconductor devices.

  8. Effective angular and wavelength modeling of parallel aligned liquid crystal devices

    NASA Astrophysics Data System (ADS)

    Martínez, Francisco J.; Márquez, Andrés; Gallego, Sergi; Francés, Jorge; Pascual, Inmaculada; Beléndez, Augusto

    2015-11-01

    Parallel aligned liquid crystal (PA-LC) devices are widely used in many optics and photonics applications to control the amplitude, phase and/or state of polarization (SOP) of light beams. Simplified models yet with a good predictive capability are extremely useful in the optimal application of these devices. In this paper we propose and demonstrate the validity of a novel model enabling to calculate the voltage dependent retardance provided by parallel-aligned liquid crystal (PA-LC) devices for a very wide range of incidence angles and any wavelength in the visible. We derive the theoretical expressions, and both experimental and theoretical retardance results are obtained showing a very good agreement. The proposed model is robust and well adapted to a reverse-engineering approach for the calibration of its parameters, whose values are obtained without ambiguities. The model is based on only three physically related magnitudes: two off-state parameters per wavelength and one global voltage dependent parameter, the tilt angle of the LC molecules. To our knowledge it represents the most simplified model available for PA-LC devices yet showing predictive capability. Not only eases the design of experiments dealing with unconventional polarization states or complex amplitude modulation, but it also serves to analyze the physics and dynamics of PA-LC cells since we have estimation for their voltage dependent tilt angle within the device.

  9. Electrical Impact of SiC Structural Crystal Defects on High Electric Field Devices (Invited)

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.

    1999-01-01

    As illustrated by the invited paper at this conference and other works, SiC wafers and epilayers contain a variety of crystallographic imperfections, including micropipes, closed-core screw dislocations, grain boundaries, basal plane dislocations, heteropolytypic inclusions, and surfaces that are often damaged and contain atomically rough features like step bunching and growth pits or hillocks. Present understanding of the operational impact of various crystal imperfections on SiC electrical devices is reviewed, with an emphasis placed on high-field SiC power devices and circuits.

  10. Multipurpose high-pressure high-temperature diamond-anvil cell with a novel high-precision guiding system and a dual-mode pressurization device.

    PubMed

    Pippinger, Thomas; Miletich, Ronald; Burchard, Michael

    2011-09-01

    A novel diamond-anvil cell (DAC) design has been constructed and tested for in situ applications at high-pressure (HP) operations and has proved to be suitable even for HP sample environments at non-ambient temperature conditions. The innovative high-precision guiding mechanism, comparable to a dog clutch, consists of perpendicular planar sliding-plane elements and is integrated directly into the base body of the cylindrically shaped DAC. The combination of two force-generating devices, i.e., mechanical screws and an inflatable gas membrane, allows the user to choose independently between, and to apply individually, two different forcing mechanisms for pressure generation. Both mechanisms are basically independent of each other, but can also be operated simultaneously. The modularity of the DAC design allows for an easy exchange of functional core-element groups optimized not only for various analytical in situ methods but also for HP operation with or without high-temperature (HT) application. For HP-HT experiments a liquid cooling circuit inside the specific inner modular groups has been implemented to obtain a controlled and limited heat distribution within the outer DAC body.

  11. Laser processing in 3D diamond detectors

    NASA Astrophysics Data System (ADS)

    Murphy, S. A.; Booth, M.; Li, L.; Oh, A.; Salter, P.; Sun, B.; Whitehead, D.; Zadoroshnyj, A.

    2017-02-01

    A technique for electrode production within diamond using a femtosecond laser system is described. Diagnosis tests to quantify the stress, the diamond to graphite ratio, and the resistivity of these electrodes are discussed. A 3D electronic grade single crystal diamond detector produced using this technique is shown, and the electrodes have a resistivity of O(1 Ω cm). An improvement to the technique through the use of an adaptive wavefront shows a reduction of the diamond to graphite ratio, and smaller, higher quality electrodes were manufactured.

  12. A design of backing seat and gasket assembly in diamond anvil cell for accurate single crystal x-ray diffraction to 5 GPa.

    PubMed

    Komatsu, K; Kagi, H; Yasuzuka, T; Koizumi, T; Iizuka, R; Sugiyama, K; Yokoyama, Y

    2011-10-01

    We designed a new cell assembly of diamond anvil cells for single crystal x-ray diffraction under pressure and demonstrate the application of the cell to the crystallographic studies for ice VI and ethanol high-pressure (HP) phase at 0.95(5) GPa and 1.95(2) GPa, respectively. The features of the assembly are: (1) the platy anvil and unique-shaped backing seat (called as "Wing seat") allowing the extremely wide opening angle up to ±65°, (2) the PFA-bulk metallic glass composite gasket allowing the easy attenuation correction and less background. Thanks to the designed assembly, the R(int) values after attenuation corrections are fairly good (0.0125 and 0.0460 for ice VI and ethanol HP phase, respectively), and the errors of the refined parameters are satisfactory small even for hydrogen positions, those are comparable to the results which obtained at ambient conditions. The result for ice VI is in excellent agreement with the previous study, and that for ethanol HP phase has remarkable contributions to the revision to its structure; the H12 site, which makes gauche molecules with O1, C2, and C3 sites, may not exist so that only trans conformers are present at least at 1.95(2) GPa. The accurate intensities using the cell assembly allow us to extract the electron density for ethanol HP phase by the maximum entropy method.

  13. A novel paper-based device coupled with a silver nanoparticle-modified boron-doped diamond electrode for cholesterol detection.

    PubMed

    Nantaphol, Siriwan; Chailapakul, Orawon; Siangproh, Weena

    2015-09-03

    A novel paper-based analytical device (PAD) coupled with a silver nanoparticle-modified boron-doped diamond (AgNP/BDD) electrode was first developed as a cholesterol sensor. The AgNP/BDD electrode was used as working electrode after modification by AgNPs using an electrodeposition method. Wax printing was used to define the hydrophilic and hydrophobic areas on filter paper, and then counter and reference electrodes were fabricated on the hydrophilic area by screen-printing in house. For the amperometric detection, cholesterol and cholesterol oxidase (ChOx) were directly drop-cast onto the hydrophilic area, and H2O2 produced from the enzymatic reaction was monitored. The fabricated device demonstrated a good linearity (0.39 mg dL(-1) to 270.69 mg dL(-1)), low detection limit (0.25 mg dL(-1)), and high sensitivity (49.61 μA mM(-1) cm(-2)). The precision value for ten replicates was 3.76% RSD for 1 mM H2O2. In addition, this biosensor exhibited very high selectivity for cholesterol detection and excellent recoveries for bovine serum analysis (in the range of 99.6-100.8%). The results showed that this new sensing platform will be an alternative tool for cholesterol detection in routine diagnosis and offers the advantages of low sample/reagent consumption, low cost, portability, and short analysis time.

  14. Plasma, photon, and beam synthesis of diamond films and multilayered structures

    SciTech Connect

    Chang, R.P.H.

    1992-09-01

    In the area of nucleation, it was discovered that C{sub 70} thin films are perfect substitutes for diamond seeds in the growth of diamond films. This research, along with a careful study of diamond growth on carbon ion implanted single crystal copper, have clearly demonstrated that structured carbon is the best precursor for nucleation and growth of diamond films on non-diamond surfaces. In addition, by using fluorine chemistry during diamond growth, it has been shown that diamond films can grow on carbide substrates without the pretreatment of diamond seeding. The growth rates are higher and the film adhesion is much improved.

  15. Controlled polymorphic transformation of continuously crystallized solid lipid nanoparticles in a microstructured device: a feasibility study.

    PubMed

    Schoenitz, M; Joseph, S; Nitz, A; Bunjes, H; Scholl, S

    2014-04-01

    The contribution describes the transfer from a batch to a micro-continuous process for the production of stable solid lipid nanoparticles as drug carrier systems. Solid lipid nanoparticles are commonly prepared batch-wise often resulting in poorly defined product qualities with regard to the polymorphic state of their lipid matrix. In order to obtain solid lipid nanoparticle dispersions that meet the requirements for an acceptable pharmaceutical product, the manufacture of reproducible product qualities preferably containing the stable crystal form of the respective matrix lipid is necessary. These requests are addressed by the continuous preparation process of solid lipid nanoparticles. A four step feasibility study for the standardized evaluation whether or not a colloidal lipid dispersion is suitable for continuous crystallization of the particles resulting in stable crystal forms is presented. The process is based on the continuous crystallization and subsequent thermal treatment of differently stabilized, tripalmitin-based nanoparticle formulations in microstructured devices. The successful production of the stable crystal form by means of a continuous process chain is shown for a dispersion stabilized with a blend of hydrogenated soybean lecithin and sodium glycocholate.

  16. Single-crystal charge transfer interfaces for efficient photonic devices (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Alves, Helena; Pinto, Rui M.; Maçôas, Ermelinda M. S.; Baleizão, Carlos; Santos, Isabel C.

    2016-09-01

    Organic semiconductors have unique optical, mechanical and electronic properties that can be combined with customized chemical functionality. In the crystalline form, determinant features for electronic applications such as molecular purity, the charge mobility or the exciton diffusion length, reveal a superior performance when compared with materials in a more disordered form. Combining crystals of two different conjugated materials as even enable a new 2D electronic system. However, the use of organic single crystals in devices is still limited to a few applications, such as field-effect transistors. In 2013, we presented the first system composed of single-crystal charge transfer interfaces presenting photoconductivity behaviour. The system composed of rubrene and TCNQ has a responsivity reaching 1 A/W, corresponding to an external quantum efficiency of nearly 100%. A similar approach, with a hybrid structure of a PCBM film and rubrene single crystal also presents high responsivity and the possibility to extract excitons generated in acceptor materials. This strategy led to an extended action towards the near IR. By adequate material design and structural organisation of perylediimides, we demonstrate that is possible to improve exciton diffusion efficiency. More recently, we have successfully used the concept of charge transfer interfaces in phototransistors. These results open the possibility of using organic single-crystal interfaces in photonic applications.

  17. Laser-Damage-Resistant Photoalignment Layers for High-Peak-Power Liquid Crystal Device Applications

    SciTech Connect

    Marshall, K.L.; Gan, J.; Mitchell, G.; Papernov, S.; Rigatti, A.L.; Schmid, A.W.; Jacobs, S.D.

    2008-10-23

    Large-aperture liquid crystal (LC) devices have been in continuous use since 1995 as polarization control devices in the 40-TW, 351-nm, 60-beam OMEGA Nd:glass laser system at the University of Rochester’s Laboratory for Laser Energetics. The feasibility of using a noncontacting alignment method for high-peak-power LC laser optics by irradiation of a linearly photopolymerizable polymer with polarized UV light was recently investigated. These materials were found to have surprisingly large laser-damage thresholds at 1054 nm, approaching that of bare fused silica (30 to 60 J/cm^2). Their remarkable laser-damage resistance and ease in scalability to large apertures of these photoalignment materials, along with the ability to produce multiple alignment states by photolithographic patterning, opens new doorways for their application in LC devices for optics, photonics, and high-peak-power laser applications.

  18. Responsivity of Diamond X-ray Photodiodes Calibrated at NSLS

    SciTech Connect

    Keister,J.W.; Smedley, J.; Muller, E. M.; Bohon, J.

    2009-09-27

    Single crystal, high purity synthetic diamond is used as photoabsorption and carrier transport medium in x-ray photodiodes. While the thermal / mechanical robustness and high x-ray transmission of diamond make such devices attractive for synchrotron instrumentation, state-of-the-art quality material and electrical interfaces further make such detectors feasible. The present work develops methodology for attaining calculable responsivity (photocurrent yield) over a wide range of photon energies (0.2 to 28 keV) to within 5% accuracy. These methods achieve linear response for up to 0.2 W absorbed x-ray power and response time as low as 1 ns. Details of contact formation / robustness and bias configuration are explored.

  19. Nematic and blue phase liquid crystals for temperature stabilization and active optical tuning of silicon photonic devices (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Ptasinski, Joanna N.; Khoo, Iam Choon; Fainman, Yeshaiahu

    2015-10-01

    We describe the underlying theories and experimental demonstrations of passive temperature stabilization of silicon photonic devices clad in nematic liquid crystal mixtures, and active optical tuning of silicon photonic resonant structures combined with dye-doped nematic and blue phase liquid crystals. We show how modifications to the resonator device geometry allow for not only enhanced tuning of the resonator response, but also aid in achieving complete athermal operations of silicon photonic circuits. [Ref.: I.C. Khoo, "DC-field-assisted grating formation and nonlinear diffractions in methyl-red dye-doped blue phase liquid crystals," Opt. Lett. 40, 60-63 (2015); J. Ptasinski, I.C. Khoo, and Y. Fainman, "Enhanced optical tuning of modified-geometry resonators clad in blue phase liquid crystals," Opt. Lett. 39, 5435-5438 (2014); J. Ptasinski, I.C. Khoo, and Y. Fainman, "Passive Temperature Stabilization of Silicon Photonic Devices Using Liquid Crystals," Materials 7(3), 2229-2241 (2014)].

  20. A robust microfluidic device for the synthesis and crystal growth of organometallic polymers with highly organized structures.

    PubMed

    Liu, Xiao; Yi, Qiaolian; Han, Yongzhen; Liang, Zhenning; Shen, Chaohua; Zhou, Zhengyang; Sun, Jun-Liang; Li, Yizhi; Du, Wenbin; Cao, Rui

    2015-02-02

    A simple and robust microfluidic device was developed to synthesize organometallic polymers with highly organized structures. The device is compatible with organic solvents. Reactants are loaded into pairs of reservoirs connected by a 15 cm long microchannel prefilled with solvents, thus allowing long-term counter diffusion for self-assembly of organometallic polymers. The process can be monitored, and the resulting crystalline polymers are harvested without damage. The device was used to synthesize three insoluble silver acetylides as single crystals of X-ray diffraction quality. Importantly, for the first time, the single-crystal structure of silver phenylacetylide was determined. The reported approach may have wide applications, such as crystallization of membrane proteins, synthesis and crystal growth of organic, inorganic, and polymeric coordination compounds, whose single crystals cannot be obtained using traditional methods.

  1. Plasmon resonance enhanced temperature-dependent photoluminescence of Si-V centers in diamond

    SciTech Connect

    Cheng, Shaoheng; Song, Jie; Wang, Qiliang; Liu, Junsong; Li, Hongdong; Zhang, Baolin

    2015-11-23

    Temperature dependent optical property of diamond has been considered as a very important factor for realizing high performance diamond-based optoelectronic devices. The photoluminescence feature of the zero phonon line of silicon-vacancy (Si-V) centers in Si-doped chemical vapor deposited single crystal diamond (SCD) with localized surface plasmon resonance (LSPR) induced by gold nanoparticles has been studied at temperatures ranging from liquid nitrogen temperature to 473 K, as compared with that of the SCD counterpart in absence of the LSPR. It is found that with LSPR the emission intensities of Si-V centers are significantly enhanced by factors of tens and the magnitudes of the redshift (width) of the emissions become smaller (narrower), in comparison with those of normal emissions without plasmon resonance. More interestingly, these strong Si-V emissions appear remarkably at temperatures up to 473 K, while the spectral feature was not reported in previous studies on the intrinsic Si-doped diamonds when temperatures are higher than room temperature. These findings would lead to reaching high performance diamond-based devices, such as single photon emitter, quantum cryptography, biomarker, and so forth, working under high temperature conditions.

  2. Microring resonator-based diamond optothermal switch: a building block for a quantum computing network

    NASA Astrophysics Data System (ADS)

    Huang, Zhihong; Faraon, Andrei; Santori, Charles; Acosta, Victor; Beausoleil, Raymond G.

    2013-03-01

    The negatively-charged nitrogen-vacancy centers in diamond has motivated many groups building scalable quantum information processors based on diamond photonics. This is owning to the long-lived electronic spin coherence and the capability for spin manipulation and readout of NV centers.1-4 The primitive operation is to create entanglement between two NV centers, based on schemes such as 'atom-photon entanglement' proposed by Cabrillo et al.5To scale this type of scheme beyond two qubits, one important component is an optical switch that allows light emitted from a particular device to be routed to multiple locations. With such a switch, one has choices of routing photons to specified paths and has the benefit of improving the entanglement speed by entangling multiple qubits at the same time. Yield of the existing diamond cavities coupled with NV centers are inevitably low, due to the nature of randomness for NV placement and orientation, variation of spectral stability, and variation of cavity resonance frequency and quality factor. An optical switch provides the capability to tolerate a large fraction of defective devices by routing only to the working devices. Many type of switching devices were built on conventional semiconductor materials with mechanisms from mechanical, thermal switching to carrier injection, photonics crystal, and polymer refractive index tuning .6-8 In this paper, we build an optical-thermal switch on diamond with micro-ring waveguides, mainly for the simplicity of the diamond fabrication. The the switching function was realized by locally tuning the temperature of the diamond waveguides. Switching efficiency of 31% at 'drop' port and 73% at 'through' port were obtained.

  3. A Mathematica package for calculation of planar channeling radiation spectra of relativistic electrons channeled in a diamond-structure single crystal (quantum approach)

    NASA Astrophysics Data System (ADS)

    Azadegan, B.

    2013-03-01

    The presented Mathematica code is an efficient tool for simulation of planar channeling radiation spectra of relativistic electrons channeled along major crystallographic planes of a diamond-structure single crystal. The program is based on the quantum theory of channeling radiation which has been successfully applied to study planar channeling at electron energies between 10 and 100 MeV. Continuum potentials for different planes of diamond, silicon and germanium single crystals are calculated using the Doyle-Turner approximation to the atomic scattering factor and taking thermal vibrations of the crystal atoms into account. Numerical methods are applied to solve the one-dimensional Schrödinger equation. The code is designed to calculate the electron wave functions, transverse electron states in the planar continuum potential, transition energies, line widths of channeling radiation and depth dependencies of the population of quantum states. Finally the spectral distribution of spontaneously emitted channeling radiation is obtained. The simulation of radiation spectra considerably facilitates the interpretation of experimental data. Catalog identifier: AEOH_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOH_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 446 No. of bytes in distributed program, including test data, etc.: 209805 Distribution format: tar.gz Programming language: Mathematica. Computer: Platforms on which Mathematica is available. Operating system: Operating systems on which Mathematica is available. RAM: 1 MB Classification: 7.10. Nature of problem: Planar channeling radiation is emitted by relativistic charged particles during traversing a single crystal in direction parallel to a crystallographic plane. Channeling is modeled as the motion

  4. n-Type diamond and method for producing same

    DOEpatents

    Anderson, Richard J.

    2002-01-01

    A new n-type semiconducting diamond is disclosed, which is doped with n-type dopant atoms. Such diamond is advantageously formed by chemical vapor deposition from a source gas mixture comprising a carbon source compound for the diamond, and a volatile hot wire filament for the n-type impurity species, so that the n-type impurity atoms are doped in the diamond during its formation. A corresponding chemical vapor deposition method of forming the n-type semiconducting diamond is disclosed. The n-type semiconducting diamond of the invention may be usefully employed in the formation of diamond-based transistor devices comprising pn diamond junctions, and in other microelectronic device applications.

  5. Advances in crystal growth, device fabrication and characterization of thallium bromide detectors for room temperature applications

    NASA Astrophysics Data System (ADS)

    Datta, Amlan; Moed, Demi; Becla, Piotr; Overholt, Matthew; Motakef, Shariar

    2016-10-01

    Thallium bromide (TlBr) is a promising room-temperature radiation detector candidate with excellent charge transport properties. However, several critical issues need to be addressed before deployment of this material for long-term field applications can be realized. In this paper, progress made towards solving some of these challenges is discussed. The most significant factors for achieving long-term performance stability for TlBr devices include residual stress as generated during crystal growth and fabrication processes, surface conditions, and the choice of contact metal. Modifications to the commonly used traveling molten zone growth technique for TlBr crystals can significantly minimize the stresses generated by large temperature gradients near the melt-solid interface of the growing crystal. Plasma processing techniques were introduced for the first time to modify the Br-etched TlBr surfaces, which resulted in improvements to the surface conditions, and consequently the spectroscopic response of the detectors. Palladium electrodes resulted a 20-fold improvement in the room-temperature device lifetime when compared to its Br-etched Pt counterpart.

  6. 75 FR 13780 - In the Matter of Certain Liquid Crystal Display Devices and Products Containing the Same; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-23

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION In the Matter of Certain Liquid Crystal Display Devices and Products Containing the Same; Notice... crystal display modules, products containing the same, and methods for making the same by reason...

  7. Electrical Impact of SiC Structural Crystal Defects on High Electric Field Devices

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.

    1999-01-01

    Commercial epilayers are known to contain a variety of crystallographic imperfections. including micropipes, closed core screw dislocations. low-angle boundaries, basal plane dislocations, heteropolytypic inclusions, and non-ideal surface features like step bunching and pits. This paper reviews the limited present understanding of the operational impact of various crystal defects on SiC electrical devices. Aside from micropipes and triangular inclusions whose densities have been shrinking towards manageably small values in recent years, many of these defects appear to have little adverse operational and/or yield impact on SiC-based sensors, high-frequency RF, and signal conditioning electronics. However high-power switching devices used in power management and distribution circuits have historically (in silicon experience) demanded the highest material quality for prolonged safe operation, and are thus more susceptible to operational reliability problems that arise from electrical property nonuniformities likely to occur at extended crystal defects. A particular emphasis is placed on the impact of closed-core screw dislocations on high-power switching devices, because these difficult to observe defects are present in densities of thousands per cm,in commercial SiC epilayers. and their reduction to acceptable levels seems the most problematic at the present time.

  8. Influence on Diamonds During the Spraying of Diamond-Bronze Abrasive Coatings

    NASA Astrophysics Data System (ADS)

    Tillmann, W.; Vogli, E.; Nebel, J.; Buck, V.; Reuter, S.

    2010-01-01

    Detonation spraying provides the opportunity to produce diamond grinding tools for the machining of stone, cement, and concrete. Especially the atmospheric conditions of the spraying process yield in a high production flexibility. However, during detonation spraying, the oxygenic atmosphere as well as the thermal and kinetic energy have an impact on the processed diamond. Despite its importance for the tools’ performance, the influence of the spraying process on the superabrasive diamond is predominantly unknown. The potential decrease of the diamond durability and strength due to degradation effects during the production of sprayed diamond-CuSn 85/15 composites has not yet been determined. X-ray diffraction and Raman spectroscopy were used to verify thermally initiated surface reactions of the sprayed diamonds after exposure to the spraying process. Additionally, reference measurements on the degradation of diamonds in oxidizing and inert conditions were carried out to compare the spraying results. Differential thermal and thermogravimetric analyses were employed. To validate the mechanical properties of the diamond superabrasives, friability tests and fracture force tests were performed. It was found that under optimized detonation spraying conditions the thermal and mechanical impact remains low enough to ensure a good reliability of the processed diamonds. The diamond crystal structure endured the spraying process without detectable graphitization or oxidation. Deterioration indicators were not observed in SEM micrographs, x-ray diffraction patterns or Raman spectra. Furthermore, a high durability and strength of the sprayed diamonds were confirmed by mechanical testing.

  9. Transmissive liquid-crystal device correcting primary coma aberration and astigmatism in laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Tanabe, Ayano; Hibi, Terumasa; Ipponjima, Sari; Matsumoto, Kenji; Yokoyama, Masafumi; Kurihara, Makoto; Hashimoto, Nobuyuki; Nemoto, Tomomi

    2016-03-01

    Laser scanning microscopy allows 3D cross-sectional imaging inside biospecimens. However, certain aberrations produced can degrade the quality of the resulting images. We previously reported a transmissive liquid-crystal device that could compensate for the predominant spherical aberrations during the observations, particularly in deep regions of the samples. The device, inserted between the objective lens and the microscope revolver, improved the image quality of fixed-mouse-brain slices that were observed using two-photon excitation laser scanning microscopy, which was originally degraded by spherical aberration. In this study, we developed a transmissive device that corrects primary coma aberration and astigmatism, motivated by the fact that these asymmetric aberrations can also often considerably deteriorate image quality, even near the sample surface. The device's performance was evaluated by observing fluorescent beads using single-photon excitation laser scanning microscopy. The fluorescence intensity in the image of the bead under a cover slip tilted in the y-direction was increased by 1.5 times after correction by the device. Furthermore, the y- and z-widths of the imaged bead were reduced to 66% and 65%, respectively. On the other hand, for the imaged bead sucked into a glass capillary in the longitudinal x-direction, correction with the device increased the fluorescence intensity by 2.2 times compared to that of the aberrated image. In addition, the x-, y-, and z-widths of the bead image were reduced to 75%, 53%, and 40%, respectively. Our device successfully corrected several asymmetric aberrations to improve the fluorescent signal and spatial resolution, and might be useful for observing various biospecimens.

  10. Comparative efficiency of natural crystals and multilayers as dispersing devices in the copper L(2,3) range.

    PubMed

    Pirocchi, M; Barchewitz, R; Bodeur, S; Esteva, J M; Lepetre, Y; Rivoira, R; Philip, R; Rasigni, G

    1986-10-15

    Recent sputtering techniques have been used to produce layered synthetic microstructures (LSMs) as dispersing devices for varied applications in x-ray optics and spectroscopy. These analyzers, specially suited for synchrotron radiation, have been mounted in a two-parallel crystal monochromator. In this paper we show the first experimental results obtained with beryl crystals and multilayers for analyzing x-ray spectral distributions transmitted through screens or reflected on mirrors of copper near the L(2) and L(3) absorption edges. The significance of these findings is discussed in terms of comparison with natural and synthetic crystals and of designing a useful dispersing device for x-ray spectroscopy.

  11. Anisotropic mechanical amorphization drives wear in diamond.

    PubMed

    Pastewka, Lars; Moser, Stefan; Gumbsch, Peter; Moseler, Michael

    2011-01-01

    Diamond is the hardest material on Earth. Nevertheless, polishing diamond is possible with a process that has remained unaltered for centuries and is still used for jewellery and coatings: the diamond is pressed against a rotating disc with embedded diamond grit. When polishing polycrystalline diamond, surface topographies become non-uniform because wear rates depend on crystal orientations. This anisotropy is not fully understood and impedes diamond's widespread use in applications that require planar polycrystalline films, ranging from cutting tools to confinement fusion. Here, we use molecular dynamics to show that polished diamond undergoes an sp(3)-sp(2) order-disorder transition resulting in an amorphous adlayer with a growth rate that strongly depends on surface orientation and sliding direction, in excellent correlation with experimental wear rates. This anisotropy originates in mechanically steered dissociation of individual crystal bonds. Similarly to other planarization processes, the diamond surface is chemically activated by mechanical means. Final removal of the amorphous interlayer proceeds either mechanically or through etching by ambient oxygen.

  12. Diamonds in an Archean greenstone belt: Diamond suites in unconventional rocks of Wawa, Northern Ontario (Canada)

    NASA Astrophysics Data System (ADS)

    Kopylova, Maya; Bruce, Loryn; Ryder, John

    2010-05-01

    Diamonds typically are found on Archean cratons entrained by younger Phanerozoic kimberlites. In contrast, Wawa diamonds are hosted in "unconventional", non-kimberlitic rocks that formed contemporaneously with the mafic and sedimentary rocks of the Archean Michipicoten Greenstone Belt (MGB). We studied two diamond suites that occur within the 2.9-2.7 Ga greenschist facies rocks of MGB located in the southwest portion of the Superior Craton (E. Canada). The first diamond suite henceforth referred to as the Wawa breccia diamonds (384 stones), are hosted in the 2618-2744 Ma calc-alkaline lamprophyres and volcaniclastic breccias, contemporaneous with pillow basalts and felsic volcanics of MGB. The second suite, the Wawa conglomerate diamonds (80 crystals), are hosted in the 2697-2700 Ma poorly sorted sedimentary polymictic conglomerate which is interpreted as a proximal alluvial fan debris flow in a fan-delta environment. The majority of the diamonds was found within the matrix of the conglomerate. The diamondiferous breccia occurs 20 km north of the town of Wawa, whereas the conglomerate is found 12 km northeast of Wawa. Diamonds from the 2 occurrences were characterized and described for provenance studies. Both the breccia and conglomerate diamonds show similar crystal habits, with the predominance of octahedral single crystals and ~ 10% of cubes. The conglomerate diamonds are significantly less resorbed (no resorbtion in 43% of the stones) than the breccia diamonds (8% non-resorbed stones). In both suites, only 21-24% show high degrees of resorption. The majority of crystals in both suites are colourless, with some yellow, brown and grey stones. Conglomerate diamonds had a wider variety of colours that were not seen in the breccia diamonds, including green and pink. The breccia diamonds contain 0-740 ppm N and show two modes of N aggregation at 0-30 and 60-95%. Among the breccia diamonds, Type IaA stones comprise 17%, whereas IaAB stones make up 49% of the

  13. Integrated RF photonic devices based on crystal ion sliced lithium niobate

    NASA Astrophysics Data System (ADS)

    Stenger, Vincent; Toney, James; Pollick, Andrea; Busch, James; Scholl, Jon; Pontius, Peter; Sriram, Sri

    2013-03-01

    This paper reports on the development of thin film lithium niobate (TFLN™) electro-optic devices at SRICO. TFLN™ is formed on various substrates using a layer transfer process called crystal ion slicing. In the ion slicing process, light ions such as helium and hydrogen are implanted at a depth in a bulk seed wafer as determined by the implant energy. After wafer bonding to a suitable handle substrate, the implanted seed wafer is separated (sliced) at the implant depth using a wet etching or thermal splitting step. After annealing and polishing of the slice surface, the transferred film is bulk quality, retaining all the favorable properties of the bulk seed crystal. Ion slicing technology opens up a vast design space to produce lithium niobate electro-optic devices that were not possible using bulk substrates or physically deposited films. For broadband electro-optic modulation, TFLN™ is formed on RF friendly substrates to achieve impedance matched operation at up to 100 GHz or more. For narrowband RF filtering functions, a quasi-phase matched modulator is presented that incorporates domain engineering to implement periodic inversion of electro-optic phase. The thinness of the ferroelectric films makes it possible to in situ program the domains, and thus the filter response, using only few tens of applied volts. A planar poled prism optical beam steering device is also presented that is suitable for optically switched true time delay architectures. Commercial applications of the TFLN™ device technologies include high bandwidth fiber optic links, cellular antenna remoting, photonic microwave signal processing, optical switching and phased arrayed radar.

  14. Characteristics of Impact Diamonds

    NASA Astrophysics Data System (ADS)

    Skala, R.; Bouska, V. J.

    1992-07-01

    Having studied two Czech diamonds in UV light (lambda=366 nm) they appeared to be an extraordinary dirty orange color [1], the same as in the case of Popigai and ureilites impact diamonds (ID) [2]. SEM images show evidence of a thatch-like surface that is very similar to that of the Abee chondrite [3]. Commonly, the ID contain microscopic black plates which are formed by graphite or a carbon matter with indefinite structure, and they are always associated with hexagonal moissanite [2,4]. One unexplained fact is connected with a fabric of the ID aggregates, i.e. both Czech diamonds are single crystals, otherwise other ID form polycrystalline strongly textured aggregates. [1] Bouska V.J. and Skala R.M. (1992) Abstracts for International Conference on Large Meteorite Impacts and Planetary Evolution, in press. [2] Masaitis V.L., Shafranovskii G.I., Ezerskii V.A., and Reshetnyak N.B. (1990) Meteoritica 49, 180-196. [3] Russell S.S. and Pillinger C.T. (1991) Abstracts 54th Ann. Meet. Meteor. Soc. 200. [4] Bauer J., Fiala J., and Hrichova R. (1963) Amer. Mineral. 48, 620-634.

  15. Resonant x-ray scattering study of the antiferroelectric and ferrielectric phases in liquid crystal devices

    SciTech Connect

    Matkin, L. S.; Watson, S. J.; Gleeson, H. F.; Pindak, R.; Pitney, J.; Johnson, P. M.; Huang, C. C.; Barois, P.; Levelut, A.-M.; Srajer, G.

    2001-08-01

    Resonant x-ray scattering has been used to investigate the interlayer ordering of the antiferroelectric and ferrielectric smectic C{sup *} subphases in a device geometry. The liquid crystalline materials studied contain a selenium atom and the experiments were carried out at the selenium K edge allowing x-ray transmission through glass. The resonant scattering peaks associated with the antiferroelectric phase were observed in two devices containing different materials. It was observed that the electric-field-induced antiferroelectric to ferroelectric transition coincides with the chevron to bookshelf transition in one of the devices. Observation of the splitting of the antiferroelectric resonant peaks as a function of applied field also confirmed that no helical unwinding occurs at fields lower than the chevron to bookshelf threshold. Resonant features associated with the four-layer ferrielectric liquid crystal phase were observed in a device geometry. Monitoring the electric field dependence of these ferrielectric resonant peaks showed that the chevron to bookshelf transition occurs at a lower applied field than the ferrielectric to ferroelectric switching transition.

  16. Micropatterned surfaces prepared using a liquid crystal projector-modified photopolymerization device and microfluidics.

    PubMed

    Itoga, Kazuyoshi; Yamato, Masayuki; Kobayashi, Jun; Kikuchi, Akihiko; Okano, Teruo

    2004-06-01

    A commercial liquid crystal device projector was modified for photopolymerization using its on-board intense light source and a precision optical control circuit. This device projects reduced images generated by a typical personal computer onto the stage where photopolymerization on a surface occurs. This all-in-one device does not require expensive photomasks and external light sources. However, light scattering and diffraction through glass substrates resulted in undesired reactions in areas corresponding to masked (black) domains in mask patterns, limiting pattern resolution. To overcome this shortcoming, two-step surface patterning was developed. First, three-dimensional microstructures of crosslinked silicone elastomer were fabricated with this device and adhered onto silanized glass substrate surfaces, forming microchannels in patterns on the glass support. Then, acrylamide monomer solution containing photoreactive initiator was flowed into these micromold channels and reacted in situ. The resultant polyacrylamide layer was highly hydrophilic and repelled protein adsorption. Cell seeding on these patterns in serum-supplemented culture medium produced cells selectively adhered to different patterns: cells attached and spread only on unpolymerized silanized glass surfaces, not on the photopolymerized acrylamide surfaces. This technique should prove useful for inexpensive, rapid prototyping of surface micropatterns from polymer materials.

  17. Electrically tunable liquid-crystal Fabry-Perot device for terahertz radiation

    NASA Astrophysics Data System (ADS)

    Li, Hui; Pan, Fan; Liu, Kan; Wu, Yuntao; Zhang, Yanduo; Xie, Xiaolin

    2015-11-01

    In this paper, we will present a smart structure based on an electrically controlled liquid crystal (LC) Fabry-Perot to achieve terahertz (THz) filter, which has extremely potential in THz communication. This proposed structure doesn't need any mechanical movements because of adapting LC as a key material to compose the Fabry-Perot device. The THz filter based on LC, which is smart, light and cheap, can be realized to solve that common problem of short of tunable devices in THz radiation. The chosen LC material is E7, which has very stable and good transmissions in THz range. Under the external applied voltage, the alignment of the nematic LC allows the refractive index of the device to be tuned. Because of this feature, the resonant peaks could be shifted by changing the applied voltage. Especially, when the alignment is changed from planar to phototropic, the maximum value of the shift could be realized. The simulation result of the proposed device could be got. And the optimal structural parameters could be also got. Numerical analyses results have shown that the proposed structure has a high narrow transmission band and very sharp edges. This THz filter is novel for compact and smart features, so this kind of proposed THz filter is very attractive in many applications, such as THz communication, and THz spectral imaging.

  18. Precision Control of Thermal Transport in Cryogenic Single-Crystal Silicon Devices

    NASA Technical Reports Server (NTRS)

    Rostem, K.; Chuss, D. T.; Colazo, F. A.; Crowe, E. J.; Denis, K. L.; Lourie, N. P.; Moseley, S. H.; Stevenson, T. R.; Wollack, E. J.

    2014-01-01

    We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than, even when the surface is fairly smooth, 510 nm rms, and the peak thermal wavelength is 0.6 microns. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order, the conductance is dominated by ballistic transport and is effectively set by the beam cross-sectional area. We have demonstrated a uniformity of +/-8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors.

  19. Optimization of liquid crystal devices based on weakly conductive layers for lensing and beam steering

    NASA Astrophysics Data System (ADS)

    Beeckman, Jeroen; Nys, Inge; Willekens, Oliver; Neyts, Kristiaan

    2017-01-01

    Liquid crystals are mostly known for their use in displays, but over the past decade these materials have been applied in a number of other devices such as tunable lenses or beam steering devices. A common technique to realize a gradual electric field profile as is required to obtain a gradual refractive index profile in these applications is the use of weakly conductive materials. The weakly conductive layers are able to spread the voltage profile which is applied through well-conductive electrodes at the side of the weakly conductive layer. The simulation and design of such structures is not trivial because two or three dimensional quasi-static electric field profiles need to be calculated. This is due to the fact that the resistivity of the conductive layers and the dielectric properties of the liquid crystal are coupled. An exact solution requires solving a number of coupled differential equations. In this paper, we develop a model to simulate the RC-effects with an approximate model.

  20. Precision control of thermal transport in cryogenic single-crystal silicon devices

    SciTech Connect

    Rostem, K.; Chuss, D. T.; Colazo, F. A.; Crowe, E. J.; Denis, K. L.; Lourie, N. P.; Moseley, S. H.; Stevenson, T. R.; Wollack, E. J.

    2014-03-28

    We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path ℓ is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than ℓ, even when the surface is fairly smooth, 5–10 nm rms, and the peak thermal wavelength is 0.6 μm. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order ℓ, the conductance is dominated by ballistic transport and is effectively set by the beam cross-sectional area. We have demonstrated a uniformity of ±8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors.

  1. Precise control of photoluminescence of silicon-vacancy color centers in homoepitaxial single-crystal diamond: evaluation of efficiency of Si doping from gas phase

    NASA Astrophysics Data System (ADS)

    Ralchenko, Victor; Sedov, Vadim; Saraykin, Vladimir; Bolshakov, Andrey; Zavedeev, Evgeny; Ashkinazi, Evgeny; Khomich, Andrew

    2016-09-01

    Ability to precisely control the Si-related color center abundance in diamond is important for the use of silicon-vacancy (SiV) defects with bright photoluminescence (PL) in quantum information technologies and optical biomarkers. Here, we evaluated the efficiency of Si incorporation in (100) plane of homoepitaxial diamond layers upon in situ doping by adding silane SiH4 in the course of diamond chemical vapor deposition in microwave plasma using CH4-H2 mixtures. Both the Si concentration in the doped samples, as determined by secondary ion mass spectrometry, and PL intensity of SiV centers at 738 nm wavelength, measured at excitation wavelength of 473 nm, demonstrate a linear increase with silane content in feed gas in the range. The incorporation efficiency f, defined as the ratio of Si concentration in diamond to that in gas, f = [Si/C]dia/[Si/C]gas is found to be (1.1 ± 0.5) × 10-3 for the silane concentrations explored, [SiH4/CH4] < 0.7 %; thus, the Si atoms are accommodated in (100) diamond face easier than nitrogen and phosphorus, but more difficult than boron. This finding allows a tailoring of the Si content and photoluminescence intensity of SiV centers in in situ doped CVD diamond.

  2. Diamond Tours

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On April 24, a group traveling with Diamond Tours visited StenniSphere, the visitor center at NASA John C. Stennis Space Center in South Mississippi. The trip marked Diamond Tours' return to StenniSphere since Hurricane Katrina struck the Gulf Coast on Aug. 29, 2005. About 25 business professionals from Georgia enjoyed the day's tour of America's largest rocket engine test complex, along with the many displays and exhibits at the museum. Before Hurricane Katrina, the nationwide company brought more than 1,000 visitors to StenniSphere each month. That contributed to more than 100,000 visitors from around the world touring the space center each year. In past years StenniSphere's visitor relations specialists booked Diamond Tours two or three times a week, averaging 40 to 50 people per visit. SSC was established in the 1960s to test the huge engines for the Saturn V moon rockets. Now 40 years later, the center tests every main engine for the space shuttle. SSC will soon begin testing the rocket engines that will power spacecraft carrying Americans back to the moon and on to Mars. For more information or to book a tour, visit http://www.nasa.gov/centers/stennis/home/index.html and click on the StenniSphere logo; or call 800-237-1821 or 228-688-2370.

  3. Electrical stimulation of non-classical photon emission from diamond color centers by means of sub-superficial graphitic electrodes

    PubMed Central

    Forneris, Jacopo; Traina, Paolo; Monticone, Daniele Gatto; Amato, Giampiero; Boarino, Luca; Brida, Giorgio; Degiovanni, Ivo P.; Enrico, Emanuele; Moreva, Ekaterina; Grilj, Veljko; Skukan, Natko; Jakšić, Milko; Genovese, Marco; Olivero, Paolo

    2015-01-01

    Focused MeV ion beams with micrometric resolution are suitable tools for the direct writing of conductive graphitic channels buried in an insulating diamond bulk, as already demonstrated for different device applications. In this work we apply this fabrication method to the electrical excitation of color centers in diamond, demonstrating the potential of electrical stimulation in diamond-based single-photon sources. Differently from optically-stimulated light emission from color centers in diamond, electroluminescence (EL) requires a high current flowing in the diamond subgap states between the electrodes. With this purpose, buried graphitic electrode pairs, 10 μm spaced, were fabricated in the bulk of a single-crystal diamond sample using a 6 MeV C microbeam. The electrical characterization of the structure showed a significant current injection above an effective voltage threshold of 150 V, which enabled the stimulation of a stable EL emission. The EL imaging allowed to identify the electroluminescent regions and the residual vacancy distribution associated with the fabrication technique. Measurements evidenced isolated electroluminescent spots where non-classical light emission in the 560–700 nm spectral range was observed. The spectral and auto-correlation features of the EL emission were investigated to qualify the non-classical properties of the color centers. PMID:26510889

  4. Electrical stimulation of non-classical photon emission from diamond color centers by means of sub-superficial graphitic electrodes

    NASA Astrophysics Data System (ADS)

    Forneris, Jacopo; Traina, Paolo; Monticone, Daniele Gatto; Amato, Giampiero; Boarino, Luca; Brida, Giorgio; Degiovanni, Ivo P.; Enrico, Emanuele; Moreva, Ekaterina; Grilj, Veljko; Skukan, Natko; Jakšić, Milko; Genovese, Marco; Olivero, Paolo

    2015-10-01

    Focused MeV ion beams with micrometric resolution are suitable tools for the direct writing of conductive graphitic channels buried in an insulating diamond bulk, as already demonstrated for different device applications. In this work we apply this fabrication method to the electrical excitation of color centers in diamond, demonstrating the potential of electrical stimulation in diamond-based single-photon sources. Differently from optically-stimulated light emission from color centers in diamond, electroluminescence (EL) requires a high current flowing in the diamond subgap states between the electrodes. With this purpose, buried graphitic electrode pairs, 10 μm spaced, were fabricated in the bulk of a single-crystal diamond sample using a 6 MeV C microbeam. The electrical characterization of the structure showed a significant current injection above an effective voltage threshold of 150 V, which enabled the stimulation of a stable EL emission. The EL imaging allowed to identify the electroluminescent regions and the residual vacancy distribution associated with the fabrication technique. Measurements evidenced isolated electroluminescent spots where non-classical light emission in the 560-700 nm spectral range was observed. The spectral and auto-correlation features of the EL emission were investigated to qualify the non-classical properties of the color centers.

  5. Modal liquid crystal devices in optical tweezing: 3D control and oscillating potential wells.

    PubMed

    Hands, Philip J W; Tatarkova, Svetlana A; Kirby, Andrew K; Love, Gordon D

    2006-05-15

    We investigate the use of liquid crystal (LC) adaptive optics elements to provide full 3 dimensional particle control in an optical tweezer. These devices are suitable for single controllable traps, and so are less versatile than many of the competing technologies which can be used to control multiple particles. However, they have the advantages of simplicity and light efficiency. Furthermore, compared to binary holographic optical traps they have increased positional accuracy. The transmissive LC devices could be retro-fitted to an existing microscope system. An adaptive modal LC lens is used to vary the z-focal position over a range of up to 100 mum and an adaptive LC beam-steering device is used to deflect the beam (and trapped particle) in the x-y plane within an available radius of 10 mum. Furthermore, by modifying the polarisation of the incident light, these LC components also offer the opportunity for the creation of dual optical traps of controllable depth and separation.

  6. Photo-aligned liquid crystal devices for high-peak-power laser applications

    NASA Astrophysics Data System (ADS)

    Marshall, K. L.; Dorrer, C.; Vargas, M.; Gnolek, A.; Statt, M.; Chen, S.-H.

    2012-10-01

    Liquid crystal (LC) optical elements have proven themselves as robust and cost-effective components for high-peakpowerlaser systems such as the 60-beam, 40-TW OMEGA Nd:glass laser system at the University of Rochester'sLaboratory for Laser Energetics. Although buffed nylon 6/6 alignment layers are the de facto standard for high-peak-power applications, photoalignment coatings based on coumarin materials have demonstrated exceptionally high near-IR laser-damage resistance. Using conventional photolithographic patterning techniques, high-resolution, photoaligned, nematic LC beam-shaper devices with a contrast ratio of 430:1, a pixel size of 10 μm, an interpixel resolution of 1.7 μm, and laser-damage resistance of 30 J/cm2 (1054-nm, 1-ns pulse) have been demonstrated. Recently, we have extended this photoalignment process to other existing and potential high-peak-power LC optical devices that have previously used buffed alignment coatings. In addition to fabricating photoaligned LC wave-plate prototypes that meet all optical and performance specifications of LC devices currently used on OMEGA, novel LC polarization converters with continuously varying radial or azimuthal polarization states have been fabricated using the same high-damage-threshold materials. These polarization converters have applications not only in high-peak-power lasers but also in microscopy, electron acceleration, and machining.

  7. Embedded Ag mesh electrodes for polymer dispersed liquid crystal devices on flexible substrate.

    PubMed

    Liu, Yanhua; Shen, Su; Hu, Jin; Chen, Linsen

    2016-10-31

    An embedded Ag mesh transparent conductive electrode (TCE) on flexible substrate, which is suitable for polymer dispersed liquid crystal (PDLC) device, is demonstrated. With the combination of soft ultra-violet nanoimprinting lithography and scrape technique, it offers parallel processing with high resolution (10000dpi), as well as remarkable simplicity and fully controllable flexibility to tailor the transmittance and sheet resistance. While being able to achieve maximum transmittance 60% in the on state and the minimum 0.1% in the off state, the PDLC smart window displays low sheet resistance (5.58 Ω/sq.) under low driven voltage (30V) safe for human. The main advantage of adoption of PDLC as an optically scattering element lies in the fact that there needs no mechanical part for in situ tunability. An enhancement factor of 50 of the diffraction intensity is observed experimentally. The embedded Ag mesh TCE for PDLC device has an environmentally-friendly additive manufacturing process inherently. Compared to existing solutions, the fabricated sample shows superior performance in both optoelectronic and mechanic characteristics. We envision that the embedded Ag mesh TCE will enable economically widen application of PDLC devices on flexible substrate.

  8. Modal liquid crystal devices in optical tweezing: 3D control and oscillating potential wells

    NASA Astrophysics Data System (ADS)

    Hands, Philip J. W.; Tatarkova, Svetlana A.; Kirby, Andrew K.; Love, Gordon D.

    2006-05-01

    We investigate the use of liquid crystal (LC) adaptive optics elements to provide full 3 dimensional particle control in an optical tweezer. These devices are suitable for single controllable traps, and so are less versatile than many of the competing technologies which can be used to control multiple particles. However, they have the advantages of simplicity and light efficiency. Furthermore, compared to binary holographic optical traps they have increased positional accuracy. The transmissive LC devices could be retro-fitted to an existing microscope system. An adaptive modal LC lens is used to vary the z-focal position over a range of up to 100 μm and an adaptive LC beam-steering device is used to deflect the beam (and trapped particle) in the x-y plane within an available radius of 10 μm. Furthermore, by modifying the polarisation of the incident light, these LC components also offer the opportunity for the creation of dual optical traps of controllable depth and separation.

  9. Superior electro-optic response in multiferroic bismuth ferrite nanoparticle doped nematic liquid crystal device

    PubMed Central

    Nayek, Prasenjit; Li, Guoqiang

    2015-01-01

    A superior electro-optic (E-O) response has been achieved when multiferroic bismuth ferrite (BiFeO3/BFO) nanoparticles (NPs) were doped in nematic liquid crystal (NLC) host E7 and the LC device was addressed in the large signal regime by an amplitude modulated square wave signal at the frequency of 100 Hz. The optimized concentration of BFO is 0.15 wt%, and the corresponding total optical response time (rise time + decay time) for a 5 μm-thick cell is 2.5 ms for ~7 Vrms. This might be exploited for the construction of adaptive lenses, modulators, displays, and other E-O devices. The possible reason behind the fast response time could be the visco-elastic constant and restoring force imparted by the locally ordered LCs induced by the multiferroic nanoparticles (MNPs). Polarized optical microscopic textural observation shows that the macroscopic dislocation-free excellent contrast have significant impact on improving the image quality and performance of the devices. PMID:26041701

  10. A low-power all-optical bistable device based on a liquid crystal layer embedded in thin gold films

    NASA Astrophysics Data System (ADS)

    Takase, Yuki; Tien Thanh, Pham; Fujimura, Ryushi; Kajikawa, Kotaro

    2014-04-01

    An all-optical bistable (AOB) resonator device composed of a 430-nm-thick liquid crystal (LC) layer embedded in two thin gold films (MLM) is reported in this paper. This device allows the use of the incident illumination at normal incidence, whereas the previous AOB devices based on twisted nematic (TN)-LC function only for illumination at oblique incidence. The fastest switching time was measured to be 1.8 ms, which is significantly faster than that of TN-LC. Because the MLM device operates free from electronic circuits, it is promising for two-dimensional optical data processing, random access optical memories, and spatial light modulators.

  11. Plasma, photon, and beam synthesis of diamond films and multilayered structures. Progress report, July 1, 1990--September 1992

    SciTech Connect

    Chang, R.P.H.

    1992-09-01

    In the area of nucleation, it was discovered that C{sub 70} thin films are perfect substitutes for diamond seeds in the growth of diamond films. This research, along with a careful study of diamond growth on carbon ion implanted single crystal copper, have clearly demonstrated that structured carbon is the best precursor for nucleation and growth of diamond films on non-diamond surfaces. In addition, by using fluorine chemistry during diamond growth, it has been shown that diamond films can grow on carbide substrates without the pretreatment of diamond seeding. The growth rates are higher and the film adhesion is much improved.

  12. Opalescent Diamonds Enriched in Hydrocarbon Fluids

    NASA Astrophysics Data System (ADS)

    Leung, I.; Tsao, C.

    2006-05-01

    We studied a large number of diamonds from Liaoning, China. These diamonds are not gem-quality, do not have sharp corners and sharp edges, they are not suitable for making cutting tools. Such industrial diamonds are usually crushed to form abrasives, thus, they might escape the scrutiny of researchers. In China, diamonds were routinely soaked in HF overnight to remove mud and other substances, and no oil and grease were used in the processing. It is not uncommon to see iridescence in pink, pale yellow and grey diamonds. The most common opalescent colors are alternating sharp bands of intense pink and indigo blue, and, less frequently, bands of yellow and blue-green, all may appear in the same diamond. As the bands have uniform thickness, their colors might not be due simply to optical effects, but rather, might be chemically related. We had chosen 10 diamonds to study their FT-IR spectra. Six of the crystals exhibited a group of hydrocarbons (HCs) peaks located just below 3000 cm-1, while all but one had a C-H stretch peak at 3107 cm-1. Two other diamonds had weak HCs peaks, but a very strong peak at 3107 cm-1. Two more diamonds had very weak HCs and C-H stretch peaks. To sum up, when a spectrum has strong HCs peaks, the C-H stretch peak is weak, and vice versa. There seems to be a chemical relationship between the substances represented by these peaks. Our observations indicate that hydrocarbon fluids might have been trapped during crystallization, but subsequently unmixed into well- organized thin bands. If fluids observed in the opalescent diamonds were soaked up in the mantle, then the amount of hydrocarbons existing in Earth's mantle might be quite appreciable in some environment.

  13. Ohmic contacts to semiconducting diamond

    NASA Astrophysics Data System (ADS)

    Zeidler, James R.; Taylor, M. J.; Zeisse, Carl R.; Hewett, C. A.; Delahoussaye, Paul R.

    1990-10-01

    Work was carried out to improve the electron beam evaporation system in order to achieve better deposited films. The basic system is an ion pumped vacuum chamber, with a three-hearth, single-gun e-beam evaporator. Four improvements were made to the system. The system was thoroughly cleaned and new ion pump elements, an e-gun beam adjust unit, and a more accurate crystal monitor were installed. The system now has a base pressure of 3 X 10(exp -9) Torr, and can easily deposit high-melting-temperature metals such as Ta with an accurately controlled thickness. Improved shadow masks were also fabricated for better alignment and control of corner contacts for electrical transport measurements. Appendices include: A Thermally Activated Solid State Reaction Process for Fabricating Ohmic Contacts to Semiconducting Diamond; Tantalum Ohmic Contacts to Diamond by a Solid State Reaction Process; Metallization of Semiconducting Diamond: Mo, Mo/Au, and Mo/Ni/Au; Specific Contact Resistance Measurements of Ohmic Contracts to Diamond; and Electrical Activation of Boron Implanted into Diamond.

  14. Crystal growth of hexaferrite architecture for magnetoelectrically tunable microwave semiconductor integrated devices

    NASA Astrophysics Data System (ADS)

    Hu, Bolin

    Hexaferrites (i.e., hexagonal ferrites), discovered in 1950s, exist as any one of six crystallographic structural variants (i.e., M-, X-, Y-, W-, U-, and Z-type). Over the past six decades, the hexaferrites have received much attention owing to their important properties that lend use as permanent magnets, magnetic data storage materials, as well as components in electrical devices, particularly those operating at RF frequencies. Moreover, there has been increasing interest in hexaferrites for new fundamental and emerging applications. Among those, electronic components for mobile and wireless communications especially incorporated with semiconductor integrated circuits at microwave frequencies, electromagnetic wave absorbers for electromagnetic compatibility, random-access memory (RAM) and low observable technology, and as composite materials having low dimensions. However, of particular interest is the magnetoelectric (ME) effect discovered recently in the hexaferrites such as SrScxFe12-xO19 (SrScM), Ba2--xSrxZn 2Fe12O22 (Zn2Y), Sr4Co2Fe 36O60 (Co2U) and Sr3Co2Fe 24O41 (Co2Z), demonstrating ferroelectricity induced by the complex internal alignment of magnetic moments. Further, both Co 2Z and Co2U have revealed observable magnetoelectric effects at room temperature, representing a step toward practical applications using the ME effect. These materials hold great potential for applications, since strong magnetoelectric coupling allows switching of the FE polarization with a magnetic field (H) and vice versa. These features could lead to a new type of storage devices, such as an electric field-controlled magnetic memory. A nanoscale-driven crystal growth of magnetic hexaferrites was successfully demonstrated at low growth temperatures (25--40% lower than the temperatures required often for crystal growth). This outcome exhibits thermodynamic processes of crystal growth, allowing ease in fabrication of advanced multifunctional materials. Most importantly, the

  15. The synthesis of high-quality diamond in combustion flames

    NASA Astrophysics Data System (ADS)

    Hirose, Yoichi; Amanuma, Shuji; Komaki, Kunio

    1990-12-01

    High-quality diamond with good crystallinity has been successfully synthesized on a substrate using an oxy-acetylene combustion flame in the atmosphere. The crystal grains under some conditions have good optical transparency. The deposition rate of transparent diamond depended strongly on substrate temperatures and the O2/C2H2 ratio and averaged ˜30 μm/h. The substrate temperature for the growth of optically transparent crystals was 500-750 °C, which is relatively low compared with other chemical vapor deposition methods. The optical transparency is attributed to the low defect densities in the crystals, as determined by transmission electron microscope, which results from the low substrate temperatures and moderate growth rates. Raman spectroscopy and x-ray diffraction data on the synthesized crystals were comparable with that of natural diamond. The synthesis conditions and corresponding diamond quality as well as emission spectrum analysis of the combustion flame during diamond synthesis are described.

  16. Anisotropic mechanical amorphization drives wear in diamond

    NASA Astrophysics Data System (ADS)

    Pastewka, Lars; Moser, Stefan; Gumbsch, Peter; Moseler, Michael

    2011-01-01

    Diamond is the hardest material on Earth. Nevertheless, polishing diamond is possible with a process that has remained unaltered for centuries and is still used for jewellery and coatings: the diamond is pressed against a rotating disc with embedded diamond grit. When polishing polycrystalline diamond, surface topographies become non-uniform because wear rates depend on crystal orientations. This anisotropy is not fully understood and impedes diamond’s widespread use in applications that require planar polycrystalline films, ranging from cutting tools to confinement fusion. Here, we use molecular dynamics to show that polished diamond undergoes an sp3-sp2 order-disorder transition resulting in an amorphous adlayer with a growth rate that strongly depends on surface orientation and sliding direction, in excellent correlation with experimental wear rates. This anisotropy originates in mechanically steered dissociation of individual crystal bonds. Similarly to other planarization processes, the diamond surface is chemically activated by mechanical means. Final removal of the amorphous interlayer proceeds either mechanically or through etching by ambient oxygen.

  17. Diamonds on Diamond: structural studies at extreme conditions on the Diamond Light Source.

    PubMed

    McMahon, M I

    2015-03-06

    Extreme conditions (EC) research investigates how the structures and physical and chemical properties of materials change when subjected to extremes of pressure and temperature. Pressures in excess of one million times atmospheric pressure can be achieved using a diamond anvil cell, and, in combination with high-energy, micro-focused radiation from a third-generation synchrotron such as Diamond, detailed structural information can be obtained using either powder or single-crystal diffraction techniques. Here, I summarize some of the research drivers behind international EC research, and then briefly describe the techniques by which high-quality diffraction data are obtained. I then highlight the breadth of EC research possible on Diamond by summarizing four examples from work conducted on the I15 and I19 beamlines, including a study which resulted in the first research paper from Diamond. Finally, I look to the future, and speculate as to the type of EC research might be conducted at Diamond over the next 10 years.

  18. Wavelength, temperature, and voltage dependent calibration of a nematic liquid crystal multispectral polarization generating device

    SciTech Connect

    Baba, Justin S; Boudreaux, Philip R

    2007-01-01

    Rapid calibration of liquid crystal variable retarder (LCVR) devices is critical for successful clinical implementation of a LC-based Mueller matrix imaging system being developed for noninvasisve skin cancer detection. For multispectral implementation of such a system, the effect of wavelength (), temperature (T), and voltage (V) on the retardance () required to generate each desired polarization state needs to be clearly understood. Calibration involves quantifying this interdependence such that for a given set of system input variables, T, the appropriate voltage is applied across a LC cell to generate a particular retardance. This paper presents findings that elucidate the dependence of voltage, for a set retardance, on the aforementioned variables for a nematic LC cell: 253 mv100 nm-dependence andd 10 mVC T-dependence. Additionally, an empirically derived model is presented that enables initial voltage calibration of retardance for any desired input wavelength within the calibration range of 460-905 nm. copyright 2007 Optical Society of America

  19. Diffraction based phase compensation method for phase-only liquid crystal on silicon devices in operation.

    PubMed

    Zhang, Zichen; Yang, Haining; Robertson, Brian; Redmond, Maura; Pivnenko, Mike; Collings, Neil; Crossland, William A; Chu, Daping

    2012-06-10

    A method to measure the optical response across the surface of a phase-only liquid crystal on silicon device using binary phase gratings is described together with a procedure to compensate its spatial optical phase variation. As a result, the residual power between zero and the minima of the first diffraction order for a binary grating can be reduced by more than 10 dB, from -15.98 dB to -26.29 dB. This phase compensation method is also shown to be useful in nonbinary cases. A reduction in the worst crosstalk by 5.32 dB can be achieved when quantized blazed gratings are used.

  20. On the fringing-field effect in liquid-crystal beam-steering devices.

    PubMed

    Apter, Boris; Efron, Uzi; Bahat-Treidel, Eldad

    2004-01-01

    A detailed simulation of the fringing-field effect in liquid-crystal (LC)-based blazed-grating structures has been carried out. These studies are aimed at clarifying the relationship between the width of the fringing-field-broadened phase profile of the blazed grating and the LC cell thickness. This fringing-field broadening of the blazed grating's phase profile is shown to affect mostly the 2pi phase-step zone (fly-back zone) of the blazed grating. The results of the simulations carried out on the blazed-grating structure indicate two main effects of the fringing field: (1) reduction in the attainable diffraction efficiency and (2) limitation of the maximum deflection angle of the device. Both effects are shown to be directly linked to the broadening of the fly-back zone, which is shown to be proportional to the LC cell thickness.

  1. Liquid crystal on silicon (LCOS) devices and their application to scene projection

    NASA Astrophysics Data System (ADS)

    Ewing, Teresa; Buck, Joseph; Serati, Steve; Linnenberger, Anna; Masterson, Hugh; Stockley, Jay

    2012-06-01

    Liquid Crystal on Silicon micro-displays are the enabling components on a variety of commercial consumer products including high-definition projection televisions, office projectors, camera view-finders, head-mounted displays and picoprojectors. The use and potential application of LCOS technology in calibrated scene projectors is just beginning to be explored. Calibrated LCOS displays and projectors have been built and demonstrated not only in the visible regime, but also in the SWIR, MWIR and LWIR. However, LCOS devices are not only capable of modulating the intensity of a broadband illumination source, but can also manipulate the polarization and/or phase of a laser source. This opens the possibility of both calibrated polarization displays and holographic projection displays.

  2. Impact of feature-size dependent etching on the optical properties of photonic crystal devices

    SciTech Connect

    Berrier, A.; Anand, S.; Ferrini, R.; Talneau, A.; Houdre, R.

    2008-05-01

    Feature size dependence in Ar/Cl{sub 2} chemically assisted ion beam etching of InP-based photonic crystals (PhCs) and its influence on the optical properties of PhC devices operating in the band gap are investigated. The analysis of the measured quality factors, the determined mirror reflectivities, and losses of one-dimensional Fabry-Perot cavities clearly demonstrates the importance of feature-size dependent etching. The optical properties show a dramatic improvement up to a hole depth of about 3.5 {mu}m that is primarily due to a significant reduction in extrinsic losses. However, beyond this hole depth, the improvement is at a lower rate, which suggests that extrinsic losses, although present, are not dominant.

  3. Computational chemistry modeling and design of photoswitchable alignment materials for optically addressable liquid crystal devices

    NASA Astrophysics Data System (ADS)

    Marshall, K. L.; Sekera, E. R.; Xiao, K.

    2015-09-01

    Photoalignment technology based on optically switchable "command surfaces" has been receiving increasing interest for liquid crystal optics and photonics device applications. Azobenzene compounds in the form of low-molar-mass, watersoluble salts deposited either directly on the substrate surface or after dispersion in a polymer binder have been almost exclusively employed for these applications, and ongoing research in the area follows a largely empirical materials design and development approach. Recent computational chemistry advances now afford unprecedented opportunities to develop predictive capabilities that will lead to new photoswitchable alignment layer materials with low switching energies, enhanced bistability, write/erase fatigue resistance, and high laser-damage thresholds. In the work described here, computational methods based on the density functional theory and time-dependent density functional theory were employed to study the impact of molecular structure on optical switching properties in photoswitchable methacrylate and acrylamide polymers functionalized with azobenzene and spiropyran pendants.

  4. Response measurement of single-crystal chemical vapor deposition diamond radiation detector for intense X-rays aiming at neutron bang-time and neutron burn-history measurement on an inertial confinement fusion with fast ignition

    SciTech Connect

    Shimaoka, T. Kaneko, J. H.; Tsubota, M.; Arikawa, Y.; Nagai, T.; Kojima, S.; Abe, Y.; Sakata, S.; Fujioka, S.; Nakai, M.; Shiraga, H.; Azechi, H.; Isobe, M.; Sato, Y.; Chayahara, A.; Umezawa, H.; Shikata, S.

    2015-05-15

    A neutron bang time and burn history monitor in inertial confinement fusion with fast ignition are necessary for plasma diagnostics. In the FIREX project, however, no detector attained those capabilities because high-intensity X-rays accompanied fast electrons used for plasma heating. To solve this problem, single-crystal CVD diamond was grown and fabricated into a radiation detector. The detector, which had excellent charge transportation property, was tested to obtain a response function for intense X-rays. The applicability for neutron bang time and burn history monitor was verified experimentally. Charge collection efficiency of 99.5% ± 0.8% and 97.1% ± 1.4% for holes and electrons were obtained using 5.486 MeV alpha particles. The drift velocity at electric field which saturates charge collection efficiency was 1.1 ± 0.4 × 10{sup 7} cm/s and 1.0 ± 0.3 × 10{sup 7} cm/s for holes and electrons. Fast response of several ns pulse width for intense X-ray was obtained at the GEKKO XII experiment, which is sufficiently fast for ToF measurements to obtain a neutron signal separately from X-rays. Based on these results, we confirmed that the single-crystal CVD diamond detector obtained neutron signal with good S/N under ion temperature 0.5–1 keV and neutron yield of more than 10{sup 9} neutrons/shot.

  5. Response measurement of single-crystal chemical vapor deposition diamond radiation detector for intense X-rays aiming at neutron bang-time and neutron burn-history measurement on an inertial confinement fusion with fast ignition.

    PubMed

    Shimaoka, T; Kaneko, J H; Arikawa, Y; Isobe, M; Sato, Y; Tsubota, M; Nagai, T; Kojima, S; Abe, Y; Sakata, S; Fujioka, S; Nakai, M; Shiraga, H; Azechi, H; Chayahara, A; Umezawa, H; Shikata, S

    2015-05-01

    A neutron bang time and burn history monitor in inertial confinement fusion with fast ignition are necessary for plasma diagnostics. In the FIREX project, however, no detector attained those capabilities because high-intensity X-rays accompanied fast electrons used for plasma heating. To solve this problem, single-crystal CVD diamond was grown and fabricated into a radiation detector. The detector, which had excellent charge transportation property, was tested to obtain a response function for intense X-rays. The applicability for neutron bang time and burn history monitor was verified experimentally. Charge collection efficiency of 99.5% ± 0.8% and 97.1% ± 1.4% for holes and electrons were obtained using 5.486 MeV alpha particles. The drift velocity at electric field which saturates charge collection efficiency was 1.1 ± 0.4 × 10(7) cm/s and 1.0 ± 0.3 × 10(7) cm/s for holes and electrons. Fast response of several ns pulse width for intense X-ray was obtained at the GEKKO XII experiment, which is sufficiently fast for ToF measurements to obtain a neutron signal separately from X-rays. Based on these results, we confirmed that the single-crystal CVD diamond detector obtained neutron signal with good S/N under ion temperature 0.5-1 keV and neutron yield of more than 10(9) neutrons/shot.

  6. Electrospray deposition device used to precisely control the matrix crystal to improve the performance of MALDI MSI

    PubMed Central

    Li, Shilei; Zhang, Yangyang; Liu, Jian’an; Han, Juanjuan; Guan, Ming; Yang, Hui; Lin, Yu; Xiong, Shaoxiang; Zhao, Zhenwen

    2016-01-01

    MALDI MSI has been recently applied as an innovative tool for detection of molecular distribution within a specific tissue. MALDI MSI requires deposition of an organic compound, known as matrix, on the tissue of interest to assist analyte desorption and ionization, in which the matrix crystal homogeneity and size greatly influence the imaging reproducibility and spatial resolution in MALDI MSI. In this work, a homemade electrospray deposition device was developed for deposition of matrix in MALDI MSI. The device could be used to achieve 1 μm homogeneous matrix crystals in MALDI MSI analysis. Moreover, it was found, for the first time, that the electrospray deposition device could be used to precisely control the matrix crystal size, and the imaging spatial resolution was increased greatly as the matrix crystals size becoming smaller. In addition, the easily-built electrospray deposition device was durable for acid, base or organic solvent, and even could be used for deposition of nanoparticles matrix, which made it unparalleled for MALDI MSI analysis. The feasibility of the electrospray deposition device was investigated by combination with MALDI FTICR MSI to analyze the distributions of lipids in mouse brain and liver cancer tissue section. PMID:27885266

  7. Continuously tunable devices based on electrical control of dual-frequency liquid crystal filled photonic bandgap fibers.

    PubMed

    Scolari, Lara; Alkeskjold, Thomas; Riishede, Jesper; Bjarklev, Anders; Hermann, David; Anawati, Anawati; Nielsen, Martin; Bassi, Paolo

    2005-09-19

    We present an electrically controlled photonic bandgap fiber device obtained by infiltrating the air holes of a photonic crystal fiber (PCF) with a dual-frequency liquid crystal (LC) with pre-tilted molecules. Compared to previously demonstrated devices of this kind, the main new feature of this one is its continuous tunability due to the fact that the used LC does not exhibit reverse tilt domain defects and threshold effects. Furthermore, the dual-frequency features of the LC enables electrical control of the spectral position of the bandgaps towards both shorter and longer wavelengths in the same device. We investigate the dynamics of this device and demonstrate a birefringence controller based on this principle.

  8. Integrated Multi-Color Light Emitting Device Made with Hybrid Crystal Structure

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang Hyouk (Inventor)

    2016-01-01

    An integrated hybrid crystal Light Emitting Diode ("LED") display device that may emit red, green, and blue colors on a single wafer. The various embodiments may provide double-sided hetero crystal growth with hexagonal wurtzite III-Nitride compound semiconductor on one side of (0001) c-plane sapphire media and cubic zinc-blended III-V or II-VI compound semiconductor on the opposite side of c-plane sapphire media. The c-plane sapphire media may be a bulk single crystalline c-plane sapphire wafer, a thin free standing c-plane sapphire layer, or crack-and-bonded c-plane sapphire layer on any substrate. The bandgap energies and lattice constants of the compound semiconductor alloys may be changed by mixing different amounts of ingredients of the same group into the compound semiconductor. The bandgap energy and lattice constant may be engineered by changing the alloy composition within the cubic group IV, group III-V, and group II-VI semiconductors and within the hexagonal III-Nitrides.

  9. Organic Crystal Growth Facility (OCGF) and Radiation Monitoring Container Device (RMCD) Groups in

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The primary payload for Space Shuttle Mission STS-42, launched January 22, 1992, was the International Microgravity Laboratory-1 (IML-1), a pressurized manned Spacelab module. The goal of IML-1 was to explore in depth the complex effects of weightlessness of living organisms and materials processing. Around-the-clock research was performed on the human nervous system's adaptation to low gravity and effects of microgravity on other life forms such as shrimp eggs, lentil seedlings, fruit fly eggs, and bacteria. Materials processing experiments were also conducted, including crystal growth from a variety of substances such as enzymes, mercury iodide, and a virus. The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Featured are activities of the Organic Crystal Growth Facility (OCGF) and Radiation Monitoring Container Device (RMCD) groups in the SL POCC during the IML-1 mission.

  10. Blue phase liquid crystal: strategies for phase stabilization and device development

    PubMed Central

    Rahman, M D Asiqur; Mohd Said, Suhana; Balamurugan, S

    2015-01-01

    The blue phase liquid crystal (BPLC) is a highly ordered liquid crystal (LC) phase found very close to the LC–isotropic transition. The BPLC has demonstrated potential in next-generation display and photonic technology due to its exceptional properties such as sub-millisecond response time and wide viewing angle. However, BPLC is stable in a very small temperature range (0.5–1 °C) and its driving voltage is very high (∼100 V). To overcome these challenges recent research has focused on solutions which incorporate polymers or nanoparticles into the blue phase to widen the temperature range from around few °C to potentially more than 60 °C. In order to reduce the driving voltage, strategies have been attempted by modifying the device structure by introducing protrusion or corrugated electrodes and vertical field switching mechanism has been proposed. In this paper the effectiveness of the proposed solution will be discussed, in order to assess the potential of BPLC in display technology and beyond. PMID:27877782

  11. Diamond Field Emission Source using Transfer Mold Technique Prepared by Diamond Powder Seeding

    NASA Astrophysics Data System (ADS)

    Tezuka, Sachiaki; Matsuba, Yohei; Takahashi, Kohro

    Diamond thin films fabricated by MPCVD (microwave plasma chemical vapor deposition) are available for use as a field emitter material, because of its high mechanical quality, thermal conductivity, chemical stability, environmental tolerance, and NEA (negative electron affinity). Diode and triode emitter arrays using P-doped polycrystalline diamond were manufactured on a SiO2/Si(100) substrate with reverse pyramids formed by the transfer mold technique. As the diamond nucleation process, spin-coat seeding with pure diamond powder dispersed in isoamyl acetate has been introduced in place of the bias method. SEM (scanning electron microscopy) images and Raman spectroscopy indicate that the crystal quality of the diamond thin film fabricated by spin-coat seeding is superior to that fabricated by the bias method. The diamond crystal completely grew on top of the diode emitter by the US (ultrasonic) treatment in a diamond powder solution before spin-coat seeding. The tip radius was smaller than 50 nm. The beginning voltage of the emission of the diode emitter is 3 V after the DC glow discharge treatment in H2, which is lower than that of an emitter array fabricated by the bias method, 40 V. On the other hand, the emission of the diamond triode emitter starts at a gate voltage of only 0.5 V, and the emission current of 50∼60 mA is obtained at a gate voltage of 2 V.

  12. Method for sputtering a PIN amorphous silicon semi-conductor device having partially crystallized P and N-layers

    DOEpatents

    Moustakas, Theodore D.; Maruska, H. Paul

    1985-07-09

    A high efficiency amorphous silicon PIN semiconductor device having partially crystallized (microcrystalline) P and N layers is constructed by the sequential sputtering of N, I and P layers and at least one semi-transparent ohmic electrode. The method of construction produces a PIN device, exhibiting enhanced electrical and optical properties, improved physical integrity, and facilitates the preparation in a singular vacuum system and vacuum pump down procedure.

  13. Observation of Transparency of Erbium-doped Silicon Nitride in Photonic Crystal Nanobeam Cavities

    DTIC Science & Technology

    2010-06-21

    Neu, and C. Becher, “Design of Photonic Crystal Microcavities in Diamond Films,” Opt. Express 16, 1632-1644 (2008). 9. M. Eichenfield, R. Camacho , J...effort to fabricate light emitting devices with Silicon complementary metal-oxide- semiconductor (Si-CMOS) compat- ible materials. One possible material

  14. Augmented reality with image registration, vision correction and sunlight readability via liquid crystal devices.

    PubMed

    Wang, Yu-Jen; Chen, Po-Ju; Liang, Xiao; Lin, Yi-Hsin

    2017-03-27

    Augmented reality (AR), which use computer-aided projected information to augment our sense, has important impact on human life, especially for the elder people. However, there are three major challenges regarding the optical system in the AR system, which are registration, vision correction, and readability under strong ambient light. Here, we solve three challenges simultaneously for the first time using two liquid crystal (LC) lenses and polarizer-free attenuator integrated in optical-see-through AR system. One of the LC lens is used to electrically adjust the position of the projected virtual image which is so-called registration. The other LC lens with larger aperture and polarization independent characteristic is in charge of vision correction, such as myopia and presbyopia. The linearity of lens powers of two LC lenses is also discussed. The readability of virtual images under strong ambient light is solved by electrically switchable transmittance of the LC attenuator originating from light scattering and light absorption. The concept demonstrated in this paper could be further extended to other electro-optical devices as long as the devices exhibit the capability of phase modulations and amplitude modulations.

  15. Diamond Provenance Through Shape, Colour, Surface Features and Value

    NASA Astrophysics Data System (ADS)

    Harris, J.

    2002-05-01

    The physical properties of diamond provide a possible means by which run-of-mine productions may be identified. Such properties as shape, the regularity and angularity of the crystal form, the level of transparency, colour, syngenetic inclusion content and surface feature characteristics, all as a function of diamond size, can classify diamond productions. In early work, up to 1500 diamonds in specific sizes ranging from just under 2mm up to 6mm were evaluated. Using this procedure, most of the diamonds from the main mines in southern Africa have now been classified. Within South Africa, the mine at Swartruggens is the only one to have measurable levels of cube-shaped diamonds and an absence of the spinel twin form of diamond, more commonly known as the macle. In Botswana, the proportion of cube related forms at Jwaneng is about four times that at Orapa. Whilst the common diamond colours, colourless, yellow and brown, occur in most mines, there is a marked change in the proportion of transparent green-coated diamonds with depth in mines such as Finsch and Jwaneng. Individual mines may also have very small proportions of distinctive diamond colours, such as pinks at the Argyle mine in Australia and blues in the Premier mine in South Africa. More recently, classification emphasis has shifted away from large numbers of diamonds examined and particular attention has been paid to surface features, which reflect changes to the diamond either whilst still in the kimberlite, or subsequently during transport to an alluvial source. A classification of diamonds at the Venetia mine, South Africa, for example, showed that the proportion of diamonds with the feature referred to as corrosion sculpture, was distinctive between kimberlite types within the mine. With alluvial diamonds, transport causes further defects, particularly a general increase in the proportion of diamonds with surface features referred to as percussion marks and edge abrasion. The above observational

  16. Effect of relative humidity on crystal growth, device performance and hysteresis in planar heterojunction perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Gangishetty, Mahesh K.; Scott, Robert W. J.; Kelly, Timothy L.

    2016-03-01

    Due to the hygroscopic nature of organolead halide perovskites, humidity is one of the most important factors affecting the efficiency and longevity of perovskite solar cells. Although humidity has a long term detrimental effect on device performance, it also plays a key role during the initial growth of perovskite crystals. Here we demonstrate that atmospheric relative humidity (RH) plays a key role during the formation of perovskite thin films via the sequential deposition technique. Our results indicate that the RH has a substantial impact on the crystallization process, and hence on device performance. SEM and pXRD analysis show an increase in crystallite size with increasing humidity. At low RH, the formation of small cubic crystallites with large gaps between them is observed. The presence of these voids adversely affects device performance and leads to substantial hysteresis in the device. At higher RH, the perovskite crystals are larger in size, with better connectivity between the crystallites. This produced efficient planar heterojunction solar cells with low hysteresis. By careful control of the RH during the cell fabrication process, efficiencies of up to 12.2% are reached using P3HT as the hole-transport material.Due to the hygroscopic nature of organolead halide perovskites, humidity is one of the most important factors affecting the efficiency and longevity of perovskite solar cells. Although humidity has a long term detrimental effect on device performance, it also plays a key role during the initial growth of perovskite crystals. Here we demonstrate that atmospheric relative humidity (RH) plays a key role during the formation of perovskite thin films via the sequential deposition technique. Our results indicate that the RH has a substantial impact on the crystallization process, and hence on device performance. SEM and pXRD analysis show an increase in crystallite size with increasing humidity. At low RH, the formation of small cubic crystallites

  17. Substantiation of Epitaxial Growth of Diamond Crystals on the Surface of Carbide Fe3AlC0.66 Phase Nanoparticles

    NASA Astrophysics Data System (ADS)

    Dzevin, Ievgenij M.; Mekhed, Alexander A.

    2017-03-01

    Samples of Fe-Al-C alloys of varying composition were synthesized under high pressures and temperatures. From X-ray analysis data, only K-phase with usual for it average parameter of elemental lattice cell, a = 0.376 nm, carbide Fe3C and cubic diamond reflexes were present before and after cooling to the temperature of liquid nitrogen.

  18. Diamond-bearing Rocks among Mantle Xenoliths in Kimberlites as Indicatory for the Chambers of Diamond-parental Carbonatite Magma

    NASA Astrophysics Data System (ADS)

    Litvin, Yuriy; Kuzyura, Anastasia

    2014-05-01

    may originate and evolve by: (1) metasomatic-magmatic stage resulted in partial carbonatization of mantle peridotite under attack of K-CO2-bearing metasomatic agents and generation of carbonate melts; (2) dissolving-magmatic stage when major and accessory minerals of peridotite host-rock, volatiles and carbon dissolve in carbonate melt whereas insoluble sulphide phases penetrate into melts; eventually, completely miscible peridotite-carbonatite-carbon magma parental for diamond and paragenetic minerals (hosting xenogenetic sulphide minerals and melts) are formed; (3) fraction-crystallization stage (in chamber consolidated into a self-dependent body) during natural cooling of parental magma up to solidus temperature; the cooling activates physicochemical control that is created by PT-phase relations for the parental magma composition, i.e., syngenesis phase diagram on a representative polythermal section of peridotite-eclogite-carbonatite-diamond system at 7 GPa under conditions of fractional crystallization (Litvin, 2013). Parental carbonatite melts, while compositionally evolve under fractional crystallization, are physicochemically capable to form diamond and sequentially minerals of peridotitic and eclogitic parageneses (presented as primary inclusions in diamonds). Paragenetic peridotite-eclogite transition in the course of ultrabasic-basic fractional evolution of parental melts is revealed in physicochemical experiments as the effect of 'peridotite-to-eclogite' tonnel (Litvin, 2013). Diamond-bearing peridotite and eclogite rocks and intimate mineral intergrowths with diamond are also formed in the chambers of diamond-parental carbonatite magmas under these physicochemical conditions. Diamond-free rocks among mantle xenoliths in kimberlites represent samples of the enclosing host-rocks for the chambers of diamond-parental carbonatite magma. Support: grant of the RF President #MK-1386.2013.5, RFBR grants 12-05-33044, 13-05-00835 and 14-05-00537.

  19. Diamond coated silicon field emitter array

    SciTech Connect

    S. Albin; W. Fu; A. Varghese; A. C. Lavarias; G. R. Myneni

    1999-07-01

    Diamond coated silicon tip arrays, with and without a self-aligned gate, were fabricated, and current-voltage characteristics of 400 tips were measured. Diamond films were grown uniformly on Si tips using microwave plasma after nucleation with 10 nm diamond suspension and substrate bias. An emission current of 57 ?A was obtained at 5 V from the ungated array tips separated from an anode at 2 ?m. In the case of the gated arrays with 1.5 ?m aperture, an emission current of 3.4 ?A was measured at a gate voltage of 80 V for an anode separation of 200 ?m. The turn-on voltages for these two types of devices were 0.2 and 40 V, respectively. Diamond coated Si tip arrays have potential applications in field emission based low voltage vacuum electronic devices and microsensors.

  20. Triphasic Tooling with Small Oriented Diamond Tip for Turning and Smoothing Lightweight Mirrors

    NASA Technical Reports Server (NTRS)

    Voronov, O. A.; Tompa, G. S.; Kear, B. H.; Veress, V.

    2004-01-01

    We are developing a new method for the growth of small diamond crystals at very high temperatures and pressures directly from a carbon melt. A prototype "Supercell" has been developed for this purpose. This system is capable of high rate crystal growth in relatively large working volumes. The resulting high quality diamond crystals will be incorporated into a triphasic diamond/titanium carbide/titanium composite tool, with an oriented diamond crystal at its tip. High pressure is needed to prevent degradation of diamond at high temperature, and to ensure the formation of a crack & composite structure. After grinding and polishing, the composite material will be joined to a steel holder, thus forming a diamond-tipped tool for turning and smoothing of a mirror surface. A properly oriented single-crystal diamond cuts and smoothes much better than a conventional polycrystalline diamond crystal. This is because the hardness depends on crystallographic orientation-the difference corresponds to 60-100 GPa on the Knoop scale. Our goal is to achieve surface roughness of about 1 nm, which will be accomplished by precision cutting and smoothing. The hardness of the functionally-graded diamond/titanium carbide/titanium composite tool varies from 100 GPa at its tip to 15 GPa at its base. Previous work has shown that the mass of machined material using an oriented-diamond tool is much larger than that for a standard diamond-metal composite tool.

  1. Spectroscopic analysis of H{sub 2}/CH{sub 4} microwave plasma and fast growth rate of diamond single crystal

    SciTech Connect

    Derkaoui, N.; Rond, C. Hassouni, K.; Gicquel, A.

    2014-06-21

    One of the best ways to increase the diamond growth rate is to couple high microwave power to the plasma. Indeed, increasing the power density leads to increase gas temperature the atomic hydrogen density in the plasma bulk, and to produce more hydrogen and methyl at the diamond surface. Experimental and numerical approaches were used to study the microwave plasma under high power densities conditions. Gas temperature was measured by optical emission spectroscopy and H-atom density using actinometry. CH{sub 3}-radical density was obtained using a 1D model that describes temperatures and plasma composition from the substrate to the top of the reactor. The results show that gas temperature in the plasma bulk, atomic hydrogen, and methyl densities at the diamond surface highly increase with the power density. As a consequence, measurements have shown that diamond growth rate also increases. At very high power density, we measured a growth rate of 40 μm/h with an H-atom density of 5 × 10{sup 17} cm{sup −3} which corresponds to a H{sub 2} dissociation rate higher than 50%. Finally, we have shown that the growth rate can be framed between a lower and an upper limit as a function depending only on the maximum of H-atom density measured or calculated in the plasma bulk. The results also demonstrated that increasing fresh CH{sub 4} by an appropriate injection into the boundary layer is a potential way to increase the diamond growth rates.

  2. [Study on the micro-infrared spectra and origin of polycrystalline diamonds from Mengyin kimberlite pipes].

    PubMed

    Yang, Zhi-Jun; Liang, Rong; Zeng, Xiang-Qing; Ge, Tie-Yan; Ai, Qun; Zheng, Yun-Long; Peng, Ming-Sheng

    2012-06-01

    The natural polycrystalline diamonds from the Mengyin kimberlite pipes can be classified as the euhedral faceted polycrystalline diamonds and anhedral rounded polycrystalline diamonds. The results of micro-FTIR spectra characterization of the polycrystalline diamonds show that the concentration of nitrogen is low, varying from 16.69 to 72.81 microgram per gram and is different among different diamond grains or position in polycrystalline diamonds. The euhedral faceted polycrystalline diamonds are Ia AB type and have higher concentration of A-center defects than B-center defects. Most of the anhedral rounded polycrystalline diamonds are Ia AB type and have higher content of B-center defects. A minority of the anhedral rounded polycrystalline diamonds have C-center, A-center and B-center defects simultaneously. The polycrystalline diamonds probably originated from the relatively deeper mantle and were not formed in diamond nucleation stage, but in the diamond growth period or some special conditions after the diamond grains were formed already. Furthermore, the euhedral faceted polycrystalline diamonds were formed slightly later and the anhedral rounded polycrystalline diamonds were formed obviously earlier than the diamond single crystals from the Mengyin kimberlite pipes.

  3. Numerical investigation of oxygen impurity distribution during multicrystalline silicon crystal growth using a gas flow guidance device

    NASA Astrophysics Data System (ADS)

    Teng, Ying-Yang; Chen, Jyh-Chen; Lu, Chung-Wei; Chen, Chi-Yung

    2012-12-01

    Oxygen is one of the most important types of impurities that can cause thermal donor or light-induced degradation in mc-Si solar cells. The objective of this study is to investigate the effect that installing a gas flow guidance device in a mc-Si crystal-growth furnace would have on the oxygen impurity distribution in the melt during the growth process. The installation of such a gas flow guidance device can enhance the gas flow near the free surface, which would allow the argon to carry a greater amount of evaporated SiO gas outside the furnace. Furthermore, the enhanced motion of the gas flow also improves heat transfer near the free surface, which would make the melt vortex separate more easily. The separated melt vortex, which is located near the central region of the melt-crystal interface, directs any oxygen impurity towards the central region of the melt-crystal interface. This is why the oxygen concentration can be reduced by installing the gas flow guidance device. The effectiveness of the gas flow guidance device depends on the vertical distance between it and the free surface (h) as well as the gap between the crucible sidewall and the tip of the device (d). The effect on the oxygen concentration in the melt is significant when smaller values for h and d are adopted.

  4. On possibility of diamond formations in radiation process

    NASA Technical Reports Server (NTRS)

    Fisenko, A. V.; Semjonova, L. F.; Bolsheva, L. N.; Grachjova, T. V.; Verchovsky, A. B.; Shukolyukov, Yu. A.

    1993-01-01

    The possibility of diamond formation in radiation processes was checked by studying diamond contents in carburanium sample. The diamonds were not found and this result is discussed. At present one possible process of formation of nanometer-size diamond crystals in some meteorites and Earth's diamonds (carbonado), the radiation mechanism, is suggested: the formation of diamonds from carbonaceous matter in tracks of U fragment fissions and heavy fragmentation due to the action of energetic particles of cosmic rays. Bjakov et. al. have carried out the calculations and shown that the volume of formed diamonds in carbonaceous chondrites by radiation processes corresponds to discovery of diamond volume in chondrites. The discovery by Ozima et. al. of the unsupported fission of Xe and Kr in carbonado supports the supposition that carbonado could be formed by radiation processes. The possibility of diamond formation in radiation processes leads to the study of diamond contents in Earth's samples enriched by uranium and carbon. The attempt to release the diamonds from carburanium was undertaken.

  5. Defect studies in 4H- Silicon Carbide PVT grown bulk crystals, CVD grown epilayers and devices

    NASA Astrophysics Data System (ADS)

    Byrappa, Shayan M.

    postulated fault vectors by macrostep overgrowth of surface outcrops, has revealed faults to be of four types of which one of the following are discussed in detail which is the Shockley faults. The fault vector were determined by taking into account the contrast from stacking faults in SWBXT undergoing phase shift as the X-ray wave fields cross the fault plane. The deflected dislocations onto the basal plane were responsible for the stacking faults and were observed to be detrimental to the devices grown on them as they replicate to the epilayer. In the wafers studied at different stages of the SiC crystal boule resulted in reduction of threading defects as they at certain stage get deflected out of the crystal causing drop of defects density. [2] A novel technique known as the Ray Tracing Simulation was used to determine the sense of c/c+a dislocations obtained via Grazing-Incidence X-ray Topography. Determination of the complete sense and burgers vector of these dislocations was very important to augment our proposed models on stacking faults associated with these defects. Orientation contrast mechanism in X- ray diffraction topography was previously determined to be the dominant factor in SiC by our group and the same principles were used for the simulation. The results were surmised after extensive comparison between experimental and simulation images for the c+2a defects. [3] With the BPD density down to a record level of few hundred per square centimeter in several wafers in multiple regions made it possible to observe the conversion of sessile Threading Edge Dislocations [TED] to glissile BPDs with this repeating multiple times. Previously the high density of Basal Plane Dislocations [BPD] prevented from discerning the details accurately in the SiC images taken by SWBXT. The contribution of SWBXT in accurately categorizing the nature of dislocations in SiC has enabled the crystal growth community to incorporate strategies to mitigate their influence. One of them has

  6. Cancer treatment with nano-diamonds.

    PubMed

    Gupta, Charu; Prakash, Dhan; Gupta, Sneh

    2017-01-01

    Diamond nano-particles find new and far-reaching applications in modern biomedical science and biotechnologies. Due to its excellent biocompatibility, nano-diamonds serve as versatile platforms that can be embedded within polymer-based microfilm devices. Nano-diamonds are complexed with a chemotherapeutic that enables sustained/slow release of the drug for a minimum of one month, with a significant amount of drug in reserve. This opens up the potential for highly localized drug release as a complementary and potent form of treatment with systemic injection towards the reduction of continuous dosing, and as such, attenuation of the often powerful side effects of chemotherapy. Nano-diamonds are quite economical, enabling the broad impact of these devices towards a spectrum of physiological disorders e.g. serving as a local chemotherapeutic patch, or as a pericardial device to suppress inflammation after open heart surgery. Nano-diamond patch could be used to treat a localized region where residual cancer cells might remain after a tumor is removed. Nano-diamonds can be used to explore a broad range of therapeutic classes, including additional small molecules, proteins, therapeutic antibodies, RNAi.

  7. 16 CFR 23.11 - Definition and misuse of the word “diamond.”

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... “diamond.” (a) A diamond is a natural mineral consisting essentially of pure carbon crystallized in the... “diamond” to describe or identify any object or product not meeting the requirements specified in the definition of diamond provided above, or which, though meeting such requirements, has not been...

  8. 16 CFR 23.11 - Definition and misuse of the word “diamond.”

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... “diamond.” (a) A diamond is a natural mineral consisting essentially of pure carbon crystallized in the... “diamond” to describe or identify any object or product not meeting the requirements specified in the definition of diamond provided above, or which, though meeting such requirements, has not been...

  9. 16 CFR 23.11 - Definition and misuse of the word “diamond.”

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... “diamond.” (a) A diamond is a natural mineral consisting essentially of pure carbon crystallized in the... “diamond” to describe or identify any object or product not meeting the requirements specified in the definition of diamond provided above, or which, though meeting such requirements, has not been...

  10. 16 CFR 23.11 - Definition and misuse of the word “diamond.”

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... “diamond.” (a) A diamond is a natural mineral consisting essentially of pure carbon crystallized in the... “diamond” to describe or identify any object or product not meeting the requirements specified in the definition of diamond provided above, or which, though meeting such requirements, has not been...

  11. 16 CFR 23.11 - Definition and misuse of the word “diamond.”

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... “diamond.” (a) A diamond is a natural mineral consisting essentially of pure carbon crystallized in the... “diamond” to describe or identify any object or product not meeting the requirements specified in the definition of diamond provided above, or which, though meeting such requirements, has not been...

  12. High-Current Cold Cathode Employing Diamond and Related Materials

    SciTech Connect

    Hirshfield, Jay L.

    2014-10-22

    The essence of this project was for diamond films to be deposited on cold cathodes to improve their emission properties. Films with varying morphology, composition, and size of the crystals were deposited and the emission properties of the cathodes that utilize such films were studied. The prototype cathodes fabricated by the methods developed during Phase I were tested and evaluated in an actual high-power RF device during Phase II. These high-power tests used the novel active RF pulse compression system and the X-band magnicon test facility at US Naval Research Laboratory. In earlier tests, plasma switches were employed, while tests under this project utilized electron-beam switching. The intense electron beams required in the switches were supplied from cold cathodes embodying diamond films with varying morphology, including uncoated molybdenum cathodes in the preliminary tests. Tests with uncoated molybdenum cathodes produced compressed X-band RF pulses with a peak power of 91 MW, and a maximum power gain of 16.5:1. Tests were also carried out with switches employing diamond coated cathodes. The pulse compressor was based on use of switches employing electron beam triggering to effect mode conversion. In experimental tests, the compressor produced 165 MW in a ~ 20 ns pulse at ~18× power gain and ~ 140 MW at ~ 16× power gain in a 16 ns pulse with a ~ 7 ns flat-top. In these tests, molybdenum blade cathodes with thin diamond coatings demonstrated good reproducible emission uniformity with a 100 kV, 100 ns high voltage pulse. The new compressor does not have the limitations of earlier types of active pulse compressors and can operate at significantly higher electric fields without breakdown.

  13. High average power diamond Raman laser.

    PubMed

    Feve, Jean-Philippe M; Shortoff, Kevin E; Bohn, Matthew J; Brasseur, Jason K

    2011-01-17

    We report a pulsed Raman laser at 1193 nm based on synthetic diamond crystals with a record output power of 24.5 W and a slope efficiency of 57%. We compared the performance of an anti-reflection coated crystal at normal incidence with a Brewster cut sample. Raman oscillation was achieved at both room temperature and under cryogenic operation at 77 K. Modeling of these experiments allowed us to confirm the value of Raman gain coefficient of diamond, which was found to be 13.5 ± 2.0 cm/GW for a pump wavelength of 1030 nm.

  14. 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.

  15. In situ observation of quasimelting of diamond and reversible graphite-diamond phase transformations.

    PubMed

    Huang, J Y

    2007-08-01

    Because of technique difficulties in achieving the extreme high-pressure and high-temperature (HPHT) simultaneously, direct observation of the structures of carbon at extreme HPHT conditions has not been possible. Banhart and Ajayan discovered remarkably that carbon onions can act as nanoscopic pressure cells to generate high pressures. By heating carbon onions to approximately 700 degrees C and under electron beam irradiation, the graphite-to-diamond transformation was observed in situ by transmission electron microscopy (TEM). However, the highest achievable temperature in a TEM heating holder is less than 1000 degrees C. Here we report that, by using carbon nanotubes as heaters and carbon onions as high-pressure cells, temperatures higher than 2000 degrees C and pressures higher than 40 GPa were achieved simultaneously in carbon onions. At such HPHT conditions and facilitated by electron beam irradiation, the diamond formed in the carbon onion cores frequently changed its shape, size, orientation, and internal structure and moved like a fluid, implying that it was in a quasimelting state. The fluctuation between the solid phase of diamond and the fluid/amorphous phase of diamond-like carbon, and the changes of the shape, size, and orientation of the solid diamond, were attributed to the dynamic crystallization of diamond crystal from the quasimolten state and the dynamic graphite-diamond phase transformations. Our discovery offers unprecedented opportunities to studying the nanostructures of carbon at extreme conditions in situ and at an atomic scale.

  16. Diamond Sheet: A new diamond tool material

    NASA Technical Reports Server (NTRS)

    Mackey, C. R.

    1982-01-01

    Diamond sheet is termed a diamond tool material because it is not a cutting tool, but rather a new material from which a variety of different tools may be fabricated. In appearance and properties, it resembles a sheet of copper alloy with diamond abrasive dispersed throughout it. It is capable of being cut, formed, and joined by conventional methods, and subsequently used for cutting as a metal bonded diamond tool. Diamond sheet is normally made with industrial diamond as the abrasive material. The metal matrix in diamond sheet is a medium hard copper alloy which has performed well in most applications. This alloy has the capability of being made harder or softer if specific cutting conditions require it. Other alloys have also been used including a precipitation hardened aluminum alloy with very free cutting characteristics. The material is suitable for use in a variety of cutting, surfacing, and ring type tools, as well as in such mundane items as files and sandpaper. It can also be used as a bearing surface (diamond to diamond) and in wear resistant surfaces.

  17. Differential optical spectropolarimetric imaging system assisted by liquid crystal devices for skin imaging

    NASA Astrophysics Data System (ADS)

    Aharon, Ofir; Abdulhalim, Ibrahim; Arnon, Ofer; Rosenberg, Lior; Dyomin, Victor; Silberstein, Eldad

    2011-08-01

    Skin cancer diagnosis depends not only on histopathological examination but also on visual inspection before and after the excision of suspected lesion. Neoplasm is accompanied with changes in birefringence of collagen, pleomorphicity, and hyperchromatic state of epithelial nuclei. These phenomena can be measured by spectral and polarization changes of light backscattered by the examined tissue. A new differential spectropolarimetric system is proposed using liquid crystal devices, one as a tunable filter and the other as a polarization rotator, both operating at wide spectral ranges from the visible to the near-infrared. Since collagen's fibrils texture orientation depends on its location in the skin and since it is not well organized, our system scans the bipolarization states by continuously rotating the linearly polarized light incident on a skin lesion, and collecting differential contrasts between sequenced images when simultaneously averaging the statistical readout of a video camera. This noninvasive method emphasizes areas on skin where the neoplasm, or tumor, minimizes the statistical polarization change of the scattered light from the lesion. The module can be considered as an assistant tool for epiluminescence microscopy. Images of skin tumors were captured in vivo before the patients having their surgery and compared to histopathological results.

  18. Design of tunable devices using one-dimensional Fibonacci photonic crystals incorporating graphene at terahertz frequencies

    NASA Astrophysics Data System (ADS)

    Bian, Li-an; Liu, Peiguo; Li, Gaosheng

    2016-10-01

    For the one-dimensional generalized Fibonacci photonic crystals incorporating graphene, we present many valuable properties and design the tunable devices accordingly with the help of the transfer matrix method in the frequency range of terahertz. For the common structure, all of dielectric layers are cladded by graphene, we design the high-Q tunable filter with double peaks by changing the Fibonacci distribution and chemical potential. In order to reduce the crosstalk of signals through this filter, a heterostructure based on the current structure and the one without graphene is utilized to separate the two peaks. Also, we fabricate the tunable switch by altering the parity of periodic number. Besides, through cladding the graphene on the one of the dielectrics only, we obtain other two kinds of cells. Combining these cells arbitrarily as the supercell to develop the periodic structure, the number of forbidden bands is increased in accordance with certain rules so that this structure with supercell is suitable as the multi-stop filter. If the active medium is introduced, the imaginary part of the complex permittivity of the material would be negative, which means the energy amplification. For our quasi-periodic structures with active medium, the functions of chemical potential, damping constant and reference wavelength are investigated.

  19. Laser writing of coherent colour centres in diamond

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Chen; Salter, Patrick S.; Knauer, Sebastian; Weng, Laiyi; Frangeskou, Angelo C.; Stephen, Colin J.; Ishmael, Shazeaa N.; Dolan, Philip R.; Johnson, Sam; Green, Ben L.; Morley, Gavin W.; Newton, Mark E.; Rarity, John G.; Booth, Martin J.; Smith, Jason M.

    2016-12-01

    Optically active point defects in crystals have gained widespread attention as photonic systems that could be applied in quantum information technologies. However, challenges remain in the placing of individual defects at desired locations, an essential element of device fabrication. Here we report the controlled generation of single negatively charged nitrogen-vacancy (NV‑) centres in diamond using laser writing. Aberration correction in the writing optics allows precise positioning of the vacancies within the diamond crystal, and subsequent annealing produces single NV‑ centres with a probability of success of up to 45 ± 15%, located within about 200 nm of the desired position in the transverse plane. Selected NV‑ centres display stable, coherent optical transitions at cryogenic temperatures, a prerequisite for the creation of distributed quantum networks of solid-state qubits. The results illustrate the potential of laser writing as a new tool for defect engineering in quantum technologies, and extend laser processing to the single-defect domain.

  20. Germanium: a new catalyst for diamond synthesis and a new optically active impurity in diamond

    NASA Astrophysics Data System (ADS)

    Palyanov, Yuri N.; Kupriyanov, Igor N.; Borzdov, Yuri M.; Surovtsev, Nikolay V.

    2015-10-01

    Diamond attracts considerable attention as a versatile and technologically useful material. For many demanding applications, such as recently emerged quantum optics and sensing, it is important to develop new routes for fabrication of diamond containing defects with specific optical, electronic and magnetic properties. Here we report on successful synthesis of diamond from a germanium-carbon system at conditions of 7 GPa and 1,500-1,800 °C. Both spontaneously nucleated diamond crystals and diamond growth layers on seeds were produced in experiments with reaction time up to 60 h. We found that diamonds synthesized in the Ge-C system contain a new optical centre with a ZPL system at 2.059 eV, which is assigned to germanium impurities. Photoluminescence from this centre is dominated by zero-phonon optical transitions even at room temperature. Our results have widened the family of non-metallic elemental catalysts for diamond synthesis and demonstrated the creation of germanium-related optical centres in diamond.