Local Stress-strain Structure in CVD Diamond Observed by Raman Peak-shift Mapping

2011 ◽  
Vol 1282 ◽  
Author(s):  
Yukako Kato ◽  
Hitoshi Umezawa ◽  
Tokuyuki Teraji ◽  
Shin-ichi Shikata
Keyword(s):  
Single Crystal ◽  
Strain Distribution ◽  
Local Stress ◽  
Peak Shift ◽  
Raman Peak ◽  
Stress Strain ◽  
Single Crystal Diamond ◽  
Shift Map ◽  
Raman Peak Shift ◽  
The Relationship

ABSTRACTSemiconductor epitaxial CVD single crystal diamond is considered a potential material for power devices because of its unique characteristics. In the discussion on the relationship between crystal quality and device performance, the atomic purity and defect concentration have been considered; however, the information on the local stress-strain distribution in a single crystal is not sufficient. In this paper, the local stress-strain distribution of the epitaxial CVD single crystal diamond is quantitatively examined using the birefringence and cathodoluminescence images and the Raman peak-shift map. From the Raman peak-shift map, the local stress-strain is estimated and the stress is found to range from -67 MPa to +160 MPa in the observed area.

CVD Diamond Dislocations Observed by X-ray Topography, Birefrengence Image and Cathodoluminesence mapping

2011 ◽  
Vol 1282 ◽  
Author(s):  
Yukako Kato ◽  
Hitoshi Umezawa ◽  
Hirotaka Yamaguchi ◽  
Tokuyuki Teraji ◽  
Shin-ichi Shikata
Keyword(s):  
Single Crystal ◽  
Strain Distribution ◽  
Local Stress ◽  
Cvd Diamond ◽  
Device Performance ◽  
Analysis Method ◽  
Power Devices ◽  
X Ray ◽  
Single Crystal Diamond ◽  
The Relationship

ABSTRACTSemiconductor epitaxial CVD single crystal diamond is considered a potential material for power devices because of its unique characteristics. In the discussion on the relationship between crystal quality and device performance, the atomic purity and defect concentration have been considered; however, the information on the local stress-strain distribution in a single crystal is not sufficient. In this paper, the dislocation analysis is shown for the suggestion of the established standard dislocation analysis method. The aggregation of mixed dislocations is observed by the analysis by using the birefringence image, cathodoluminescence image and x-ray topography.

Modelling Recovery and Recrystallisation Kinetics after Intercritical Deformation in 0.19 wt% C 1.5 wt% Mn Steel

2004 ◽  
Vol 467-470 ◽  
pp. 329-334 ◽  
Author(s):  
A. Smith ◽  
A. Miroux ◽  
Haiwen Luo ◽  
Jilt Sietsma ◽  
Sybrand van der Zwaag
Keyword(s):  
Stress Relaxation ◽  
Stress Distribution ◽  
Strain Distribution ◽  
Local Stress ◽  
Stress Strain ◽  
Simple Modification ◽  
Single Grain ◽  
Grain Model ◽  
Mn Steel ◽  
Kinetics Of

The softening kinetics of a 0.19 wt% C 1.5 wt% Mn steel deformed at two intercritical temperatures have been characterised using the stress relaxation technique. Recrystallisation of intercritical austenite has been modelled using a single grain model (Chen et al., 2002 [1]), whilst recovery of both intercritical austenite and ferrite has been modelled using a model in the literature [Verdier et al., 1999 [2]). The models are combined to predict the overall softening kinetics with a rule of mixtures formulation. Comparison of the model with experiment shows significant deviations. The reasons are discussed with reference to the mixture rule and to the local stress-strain distribution which exists in the deformed samples. A simple modification to the model is proposed which takes into account the effect of a local stress distribution in deformed austenite.

Reorientation of carbon nanotubes in polymer matrix composites using compressive loading

2005 ◽  
Vol 20 (4) ◽  
pp. 1026-1032 ◽  
Author(s):  
Michael J. Lance ◽  
Chun-Hway Hsueh ◽  
Ilia N. Ivanov ◽  
David B. Geohegan
Keyword(s):  
Strain Energy ◽  
Polymer Matrix Composites ◽  
Compressive Loading ◽  
Local Strain ◽  
Peak Shift ◽  
Raman Peak ◽  
Matrix Composites ◽  
Raman Peak Shift ◽  
Polarized Raman

Purified single-walled nanotubes (SWNTs) were dispersed in an epoxy polymer and subjected to uniaxial compressive loading. The orientation and stress in the nanotubes were monitored in situ using polarized Raman microscopy. At strains less than 2%, the nanotubes reorient normal to the direction of compression, thereby minimizing the local strain energy. Above 2% strain, the Raman peak shift reaches a plateau. A new analytical model, which approximates the SWNT reorientation by varying the aspect ratio of a representative spheroid, predicted the rotation behavior of nanotubes under load. The results of this model suggest that the observed plateau of the Raman peak shift is caused by both polymer yielding and interfacial debonding at the ends of nanotubes.

scholarly journals Influence of applied current density on the nanostructural and light emitting properties of n-type porous silicon

2015 ◽  
Vol 29 (15) ◽  
pp. 1550093 ◽  
Author(s):  
A. Cetinel ◽  
N. Artunç ◽  
G. Sahin ◽  
E. Tarhan
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Pore Diameter ◽  
Crystalline Silicon ◽  
Peak Shift ◽  
Raman Peak ◽  
Light Emitting ◽  
Nanocrystallite Size ◽  
Raman Peak Shift ◽  
Pore Depth

Effects of current density on nanostructure and light emitting properties of porous silicon (PS) samples were investigated by field emission scanning electron microscope (FE-SEM), gravimetric method, Raman and photoluminescence (PL) spectroscopy. FE-SEM images have shown that below 60 mA/cm 2, macropore and mesopore arrays, exhibiting rough morphology, are formed together, whose pore diameter, pore depth and porosity are about 265–760 nm, 58–63 μ m and 44–61%, respectively. However, PS samples prepared above 60 mA/cm 2 display smooth and straight macropore arrays, with pore diameter ranging from 900–1250 nm, porosity of 61–80% and pore depth between 63–69 μ m . Raman analyses have shown that when the current density is increased from 10 mA/cm 2 to 100 mA/cm 2, Raman peaks of PS samples shift to lower wavenumbers by comparison to crystalline silicon (c-Si). The highest Raman peak shift is found to be 3.2 cm -1 for PS sample, prepared at 90 mA/cm 2, which has the smallest nanocrystallite size, about 5.2 nm. This sample also shows a pronounced PL, with the highest blue shifting, of about 12 nm. Nanocrystalline silicon, with the smallest nanocrystallite size, confirmed by our Raman analyses using microcrystal model (MCM), should be responsible for both the highest Raman peak shift and PL blue shift due to quantum confinement effect (QCE).

scholarly journals Synthesis of cubic CdSe nanocrystals and their spectral properties

2017 ◽  
Vol 7 ◽  
pp. 184798041770174 ◽  
Author(s):  
Yukun Gao ◽  
PG Yin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Cadmium Selenide ◽  
Surface Effect ◽  
Peak Shift ◽  
Raman Peak ◽  
Cdse Nanocrystals ◽  
Transmission Electron ◽  
Raman Peak Shift

The cadmium selenide nanocrystals are prepared by colloidal chemistry under mild conditions. X-ray diffraction and high-resolution transmission electron microscopy measurements indicate that as-prepared cadmium selenide nanocrystals are zinc blende cubic structure. We carry out an analysis of quantum size effect in the Raman spectra of cadmium selenide nanocrystals performed by utilizing the chemical bond theory of Raman peak shift developed recently. It is revealed that the shifts of Raman peaks in cadmium selenide nanocrystals result from the overlapping of the quantum effect shifts and surface effect shifts. The sizes of the as-prepared cadmium selenide nanocrystals obtained by employing the Raman peak shift theory are in good agreement with the nanocrystal sizes determined by high-resolution transmission electron microscopy.

Residual Stress Measurements in PVD Coatings of Carbide Cutting Tools Directly in the Cutting Edge

2020 ◽  
Vol 404 ◽  
pp. 61-67
Author(s):  
Bernd Breidenstein ◽  
Nils Vogel ◽  
Marcel Dietrich ◽  
Harald Behrens ◽  
Jon M. Andersson
Keyword(s):  
Residual Stress ◽  
Cutting Tools ◽  
Peak Shift ◽  
Raman Microscopy ◽  
Cutting Edge ◽  
Raman Peak ◽  
X Ray ◽  
Stress Measurements ◽  
Bending Load ◽  
The Relationship

Residual stress measurements directly in the coated cutting edge are not possible with X-ray diffraction (XRD) due to the diameter of the X-ray beam. On the other hand, Raman microscopy enables measurements on the micrometer scale. Parameter variations in the PVD process were used to provide different residual stress states in (Al,Ti)N coatings on carbide cutting tools. They were examined by XRD in regions that can be reliably measured. The same area was then examined by Raman microscopy to determine the relationship of Raman peaks to the residual stress. Local high-resolution Raman measurements were then taken at the cutting edge and further influences on the Raman peak position besides residual stresses were excluded. In order to analyze the relationship between Raman peak shift and residual stress state, measurements were performed during a bending load. Finally, an outlook on further investigations is given.

Variations in the Raman peak shift as a function of hydrostatic pressure for various carbon nanostructures: A simple geometric effect

2003 ◽  
Vol 67 (3) ◽  
Author(s):  
J. Sandler ◽  
M. S. P. Shaffer ◽  
A. H. Windle ◽  
M. P. Halsall ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Carbon Nanostructures ◽  
Peak Shift ◽  
Raman Peak ◽  
Geometric Effect ◽  
Raman Peak Shift
Sign in / Sign up

Export Citation Format

Share Document