Electronic Impact of Inclusions in Diamond

2009 ◽  
Vol 1203 ◽  
Author(s):  
Erik M. Muller ◽  
John Smedley ◽  
Balaji Raghothamachar ◽  
Mengjia Gaowei ◽  
Jeffrey W. Keister ◽  
...  
Keyword(s):  
Charge Trapping ◽  
Secondary Phase ◽  
Surface Region ◽  
Phase Region ◽  
Electron Trapping ◽  
Near Surface ◽  
X Ray ◽  
Photoconductive Gain ◽  
Single Crystal Diamond ◽  
Topography Data

AbstractX-ray topography data are compared with photodiode responsivity maps to identify potential candidates for electron trapping in high purity, single crystal diamond. X-ray topography data reveal the defects that exist in the diamond material, which are dominated by non-electrically active linear dislocations. However, many diamonds also contain defects configurations (groups of threading dislocations originating from a secondary phase region or inclusion) in the bulk of the wafer which map well to regions of photoconductive gain, indicating that these inclusions are a source of electron trapping which affect the performance of diamond X-ray detectors. It was determined that photoconductive gain is only possible with the combination of an injecting contact and charge trapping in the near surface region. Typical photoconductive gain regions are 0.2 mm across; away from these near-surface inclusions the device yields the expected diode responsivity.

scholarly journals Anomalous Grazing X-ray Reflectometry for Determining the Number Density of Atoms in the Near-Surface Region

1996 ◽  
Vol 37 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Masatoshi Saito ◽  
Eiichiro Matsubara ◽  
Yoshio Waseda
Keyword(s):  
Surface Region ◽  
Number Density ◽  
Near Surface ◽  
X Ray

Revealing the mechanism of the early stages of Ni–W RABiTS oxidation

2010 ◽  
Vol 25 (12) ◽  
pp. 2362-2370 ◽  
Author(s):  
Andrey V. Blednov ◽  
Oleg Yu. Gorbenko ◽  
Dmitriy P. Rodionov ◽  
Andrey R. Kaul
Keyword(s):  
Internal Oxidation ◽  
Photoelectron Spectroscopy ◽  
Oxidation Mechanism ◽  
Surface Oxidation ◽  
Surface Region ◽  
Near Surface ◽  
Precise Position ◽  
X Ray ◽  
Early Stages ◽  
Phase And Chemical Composition

The early stages of surface oxidation of biaxially textured Ni–W tapes were studied using thermodynamic calculations along with experimental tape oxidation at low P(O2). Tape phase and chemical composition, surface morphology, and roughness were examined using x-ray diffraction (XRD), energy-dispersive x-ray analysis (EDX), secondary ion mass spectroscopy (SIMS), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). For a Ni0.95W0.05 alloy tape, the precise position of the tape oxidation line in P(O2)–T coordinates was established. This line includes a break at T ≈ 650 °C that originates from the change of the W oxidation mechanism from internal oxidation to oxidation on a free surface accompanied by segregation of the alloy components in the tape near-surface region. The surface roughness of a polished tape increased drastically during internal oxidation of W; further tape oxidation did not affect the integral roughness parameters, but introduced numerous small (˜;100 nm) features on the tape surface comprising NiO precipitates.

scholarly journals Microstructure and Mechanical Properties of Ti + N Ion Implanted Cronidur30 Steel

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 427 ◽  
Author(s):  
Jie Jin ◽  
Wei Wang ◽  
Xinchun Chen
Keyword(s):  
Mechanical Properties ◽  
Ion Implantation ◽  
Photoelectron Spectroscopy ◽  
Structural Modification ◽  
Surface Region ◽  
Grazing Incidence ◽  
Bearing Steel ◽  
Near Surface ◽  
X Ray ◽  
Ion Implanted

In this study, Ti + N ion implantation was used as a surface modification method for surface hardening and friction-reducing properties of Cronidur30 bearing steel. The structural modification and newly-formed ceramic phases induced by the ion implantation processes were investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and grazing incidence X-ray diffraction (GIXRD). The mechanical properties of the samples were tested by nanoindentation and friction experiments. The surface nanohardness was also improved significantly, changing from ~10.5 GPa (pristine substrate) to ~14.2 GPa (Ti + N implanted sample). The friction coefficient of Ti + N ion implanted samples was greatly reduced before failure, which is less than one third of pristine samples. Furthermore, the TEM analyses confirmed a trilamellar structure at the near-surface region, in which amorphous/ceramic nanocrystalline phases were embedded into the implanted layers. The combined structural modification and hardening ceramic phases played a crucial role in improving surface properties, and the variations in these two factors determined the differences in the mechanical properties of the samples.

X-Ray diagnostics of 2D deformation profiles in crystals with periodically distorted near-surface region

1992 ◽  
Vol 130 (2) ◽  
pp. 263-271 ◽  
Author(s):  
T. E. Goureev ◽  
A. Yu. Nikulin ◽  
P. V. Petrashen
Keyword(s):  
Surface Region ◽  
Near Surface ◽  
X Ray

In situinvestigation of the non-linear optical crystal rubidium titanyl arsenate, RbTiOAsO4, under applied electric field using X-ray imaging

2007 ◽  
Vol 40 (3) ◽  
pp. 505-512 ◽  
Author(s):  
D. Walker ◽  
P. A. Thomas ◽  
P. Pernot-Rejmánková ◽  
J. Baruchel
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Surface Region ◽  
Uniform Field ◽  
Linear Optics ◽  
Near Surface ◽  
X Ray ◽  
Non Linear ◽  
Linear Optical ◽  
Section Topography

Recent work on the non-linear optical single-crystal rubidium titanyl arsenate (RbTiOAsO4, RTA) has shown that it exhibits behaviour consistent with a ferroelectric semiconductor under large applied electric fields, with the development of a non-uniform field in the near-surface region. To confirm aspects of the proposed model, the behaviour of 001 slices of initially single-domain RTA, patterned with periodic Ag electrodes of spacing 38 µm, as for periodic poling in non-linear optics, were investigated using synchrotron X-ray section topography with the electric field appliedin situwhile under X-ray illumination at the ID19 topography beamline of the ESRF, Grenoble. The results of white-beam section topography as both a function of crystal to film distance, and under DC voltage are reported, confirming that there is a bending of the planes in the near-surface region. The strain in the near-surface region was examined directly using high-resolution monochromatic X-ray section topography. This revealed an extensive strain of 3 (±1) × 10−4at 1 kV, indicating that the electrostrictive coefficient, γ3333, in RTA is positive in sign.

THE SURFACE STRUCTURE OF A LOW Pd Cu/Pd-(110) CRYSTAL ALLOY

1994 ◽  
Vol 01 (04) ◽  
pp. 569-571 ◽  
Author(s):  
M. BOWKER ◽  
M. NEWTON ◽  
S.M. FRANCIS ◽  
M. GLEESON ◽  
C. BARNES
Keyword(s):  
Surface Structure ◽  
Surface Region ◽  
Single Scattering ◽  
Alloy Surface ◽  
High Concentration ◽  
Near Surface ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Layer 2

X-ray photoelectron diffraction studies of this alloy surface have been carried out and indicate that there is a significant expansion of the lattice in the near-surface region due to the high concentration of Pd in layer 2. Preliminary single scattering calculations lend support to this proposal for the surface structure, and place this expansion in the subsurface mainly between layers 2 and 3.

X-RAY SCATTERING STUDIES OF CHARGE STRIPES IN La2-xSrxNiO4 (x=0.20-0.33)

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1633-1640 ◽  
Author(s):  
P. D. HATTON ◽  
M. E. GHAZI ◽  
S. B. WILKINS ◽  
P. D. SPENCER ◽  
D. MANNIX ◽  
...  
Keyword(s):  
Correlation Length ◽  
Surface Region ◽  
Crystalline Lattice ◽  
X Rays ◽  
Near Surface ◽  
X Ray ◽  
X Ray Scattering ◽  
Charge Stripe ◽  
A Charge ◽  
Ray Scattering

The La 2-x Sr x NiO 4 system is isostructural with the high T C superconducting cuprate La 2-x Sr x CuO 4 and is a prototypical system for the understanding of strongly correlated electron-phonon coupling, and the resultant effects on material properties. X-ray scattering studies have been performed on La5/3Sr1/3NiO4 that demonstrate the two-dimensional nature of these charge stripes. Such studies, demonstrate the very high correlation length of the stripes (~ 2000 Å) at low temperatures. We have undertaken a series of experiments measuring the wavevector and charge stripe correlation length on a variety of crystals with the compositions La 2-x Sr x NiO 4 (x=0.20, 0.25, 0.275, 0.30 and 0.33) using ~10 keV X-rays. The results demonstrate that for x=0.275, and above, the charge stripes are highly correlated in a well-ordered crystalline lattice. Measurements of the incommensurability, ε, as a function of temperature for the series revealed that it is commensurate and temperature independent for the x=0.33 sample. For other compositions it is incommensurate and also temperature dependent. However for the x=0.20 and 0.25 crystals a much reduced correlation length was observed suggestive of a charge stripe glass. However, such experiments are sensitive to such charge ordering only in the near (top few micron) surface region. High energy X-rays however can probe the charge stripe ordering within the bulk of the single crystal by utilising the dramatic increase in penetration depth. We have used 130 keV X-rays and demonstrate that in La5/3Sr1/3NiO4 the charge stripes are far less correlated in the bulk than in the near surface region. This reduced correlation length (~300 Å), consistent with neutron scattering measurements, is indicative of a charge stripe glass, reminiscent of that observed below x=0.25, in the near surface region.

Characterization of Reactive Ion Etch Damage in GaAs by Triple Crystal X-Ray Diffraction

1993 ◽  
Vol 324 ◽  
Author(s):  
Victor S. Wang ◽  
Richard J. Matyi ◽  
Karen J. Nordheden
Keyword(s):  
Bias Voltage ◽  
Diffuse Scattering ◽  
Reciprocal Lattice ◽  
Surface Region ◽  
Perfect Crystal ◽  
X Ray Diffraction ◽  
Reciprocal Lattice Point ◽  
Near Surface ◽  
X Ray ◽  
Imperfect Crystal

AbstractTriple crystal x-ray diffraction (TCXD) is a non-destructive structural characterization tool capable of the separation and direct observation of the dynamic (perfect crystal) and the kinematic (imperfect crystal) components of the total intensity diffracted by a crystal. Specifically, TCXD can be used to measure the magnitude of the diffuse scattering arising from defects in the crystal structure in the immediate vicinity of a reciprocal lattice point. In this study, the effects of BC13 reactive ion etching (RIE) on the near-surface region of GaAs were investigated by analyzing the changes in the diffuse scattering using both the symmetric 004 reflection as well as the highly asymmetric and more surface sensitive 113 reflection. While the results from the 004 reflections revealed little difference between the unetched and the BC13-etched samples, maps of the diffracted intensity around the 113 reflections showed an unexpected and reproducible decrease in the extent of the diffuse scattering in the transverse direction (perpendicular to the < 113 > direction) as the RIE bias voltage was increased. This decrease suggests that the degree of etch damage induced in the GaAs near-surface region is reduced with increasing bias voltage and ion energy. Additionally, the symmetry and orientation of the kinematic scattering was altered. Possible mechanisms for these results willbe discussed.

Microstructure and Oxidation of a Cast Nickel Aluminide Alloy

2002 ◽  
Vol 753 ◽  
Author(s):  
D. Y. Lee ◽  
M. L. Santella ◽  
I. M. Anderson ◽  
G. M. Pharr
Keyword(s):  
Nickel Aluminide ◽  
Volume Fraction ◽  
Surface Region ◽  
Oxidation Products ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Multivariate Statistical ◽  
Near Surface ◽  
X Ray ◽  
Spectrum Imaging

ABSTRACTSpecimens of the cast Ni3Al alloy IC221M were annealed in air at 900°C to examine the effects of oxidation and thermal aging on the microstructure. The alloy is comprised of a dendritically solidified γ-γ′ matrix containing γ+Ni5Zr eutectic colonies in the interdendritic regions. Microstructures of aged specimens were examined by optical microscopy and energy dispersive X-ray (EDX) spectrum imaging in the scanning electron microscope (SEM). Two primary changes in the microstructures were observed: (1) there is considerable homogenization of the cast microstructures with aging, and (2) the volume fraction of the γ+Ni5Zr eutectic decreases. Oxidation products were identified using x-ray diffraction and EDX spectrum imaging with multivariate statistical analysis (MSA). During the initial stages of oxidation, the first surface oxide to form is mostly NiO with small amounts of Cr2O3, ZrO2, NiCr2O4, and θ-Al2O3. Initially, oxidation occurs primarily in the interdendritic regions due to microsegregation of alloying elements during casting. With further aging, a continuous film of α-Al2O3 forms immediately beneath the surface that eventually evolves into a double layer of α-Al2O3 and NiAl2O4. Although these oxides are constrained to the near surface region, others penetrate to greater depths facilitated by oxidation of the γ+Ni5Zr eutectic colonies. These oxides appear in the microstructure as long, thin spikes of ZrO2 surrounded by a thin sheath of Al2O3.

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