Home  About us  Contact
 

Diamond Single Crystals (diamond + single_crystal)

Distribution by Scientific Domains
Physics and Astronomy75%

Selected Abstracts

High-temperature stability of Au/p-type diamond Schottky diode

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 6 2009
Tokuyuki Teraji
Abstract Rectification properties of Au Schottky diodes were investigated in high-temperature operation. These diodes were fabricated on a p-type diamond single crystal using the vacuum-ultraviolet light/ozone treatment. The ideality factor n of the Schottky diodes decreased monotonically with increasing measurement temperature whereas the Schottky barrier height ,b increased, and ,b reached 2.6 eV at 550 K with n of 1.1. Through high temperature heating at 870 K, the mean value of ,b at 300 K changed permanently from 2.2 eV to 1.1 eV. Decrease of ,b might originate from a dissolution of oxygen termination at the Au/diamond interface. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

In situ micro-Raman and X-ray diffraction study of diamonds and petrology of the new ureilite UAE 001 from the United Arab Emirates

METEORITICS & PLANETARY SCIENCE, Issue 7 2008
Dominik C. HEZEL
This is the first report of a meteorite in this country. The sample is heavily altered, of medium shock level, and has a total weight of 155 g. Bulk rock, olivine (Fo79.8,81.8) and pyroxene (En73.9,75.2, Fs15.5,16.9, Wo8.8,9.5) compositions are typical of ureilites. Olivine rims are reduced with Fo increasing up to Fo96.1,96.8. Metal in these rims is completely altered to Fehydroxide during terrestrial weathering. We studied diamond and graphite using micro-Raman and in situ synchrotron X-ray diffraction. The main diamond Raman band (LO = TO mode at ,1332 cm,1) is broadened when compared to well-ordered diamond single crystals. Full widths at half maximum (FWHM) values scatter around 7 cm,1. These values resemble FWHM values obtained from chemical vapor deposition (CVD) diamond. In situ XRD measurements show that diamonds have large grain sizes, up to >5 ,m. Some of the graphite measured is compressed graphite. We explore the possibilities of CVD versus impact shock origin of diamonds and conclude that a shock origin is much more plausible. The broadening of the Raman bands might be explained by prolonged shock pressure resulting in a transitional Raman signal between experimentally shock-produced and natural diamonds. [source]

Low-temperature electrical conductivity of heavily boron-doped diamond single crystals

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2007
V. D. Blank
Abstract Single crystal diamonds 0.2,0.7 cm large doped with boron concentration 1019,1020 cm,3 were grown by temperature gradient method on the seed under pressure P = 5.5 GPa, temperature T = 1650 K. Temperature dependence of electrical resistance had been measured in the range of 0.5,297 K. Boltzmann activation type of conductivity and Mott's VRH law observed in samples in the temperature ranges ,200,297 K and ,70,297 K respectively. The temperature rise of conductivity in the range of ,0.5,50 K for most heavily doped crystals was proportional to T1/2. This rule indicates the vicinity of the electronic system to metal,insulator transition. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Symmetry of platelet defects in diamond: new insights with synchrotron light

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2010
Alexei Bosak
Mapping of reciprocal space for Ia -type diamond single crystals with synchrotron radiation has uncovered a variety of diffuse scattering features, some of them have not been observed before. The main component of diffuse scattering in the form of diffuse rods corresponds to a set of platelets which join together blocks of diamond structure. The platelets are ordered structural entities with lattice periodicity , where is a unit-cell dimension of diamond. Intensity distribution along the rods has been measured and used for recognition of symmetry elements of the platelet structure. These findings, together with previously reported transmission electron microscopy (TEM) observations, provide strong constraints for atomistic modelling of the platelet structure. [source]