Raman Scattering Spectroscopy of GeSi/Si Strained Layer Superlattice

1993 ◽  
Vol 298 ◽  
Author(s):  
Zhang Rong ◽  
Zheng Youdou ◽  
Gu Shulin ◽  
Hu Liqun
Keyword(s):  
Raman Scattering ◽  
Frequency Shift ◽  
Raman Spectra ◽  
Strain Distribution ◽  
Phonon Frequency ◽  
New Method ◽  
Raman Scattering Spectroscopy ◽  
Scattering Measurements ◽  
Optic Phonon ◽  
Strained Layer Superlattice

AbstractRaman scattering measurements have been carried out on Si1-xGex/Si SLS. It is found that the Ge–Ge optic phonon frequency shift is proportional to strain in the SiGe film, and the Ge–Ge strain shift coefficient is 408cm−1. Based on these study a new method for analyzing the Raman spectra of SiGe/Si SLS has been proposed. Using the new method we can obtain the composition of the alloy sublayers as well as the strain in SLS. The strain distribution in the SiGe/Si SLS has been discussed, and strain in both SiGe and Si sublayers of the SLS have been calculated.

Raman Study of Strain and Confinement Effects in Si/Ge Strained Layer Superlattices Under Hydrostatic Pressure

1991 ◽  
Vol 220 ◽  
Author(s):  
Zhifeng Sui ◽  
Irving P. Herman ◽  
Joze Bevk
Keyword(s):  
Hydrostatic Pressure ◽  
Raman Scattering ◽  
Optical Phonon ◽  
Phonon Frequency ◽  
Optical Phonons ◽  
Biaxial Strain ◽  
Strained Layer ◽  
Strained Layer Superlattice ◽  
Raman Study ◽  
Strained Layer Superlattices

ABSTRACTThe effects of strain and confinement on optical phonons in a Si12Ge4 strained layer superlattice grown by MBE on c-Si (001) were studied as a function of hydrostatic pressure (T = 295 K) using Raman scattering. The change of phonon frequency with pressure, dω/dP, for the principal quasi-confined LO mode in the Ge layers is found to be significantly smaller than that for bulk crystalline Ge because the magnitude of biaxial strain decreases in the Ge layers with added pressure and because the Grüneisen parameter of the confined mode is smaller than that of the Γ-point optical phonon. More generally, it is noted that the magnitude of biaxial strain in many strained layer superlattices initially decreases with the application of hydrostatic pressure, making the structures more stable.

scholarly journals Discrimination of Falsified Erectile Dysfunction Medicines by Use of an Ultra-Compact Raman Scattering Spectrometer

Pharmacy ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 3
Author(s):  
Tomoko Sanada ◽  
Naoko Yoshida ◽  
Kazuko Kimura ◽  
Hirohito Tsuboi
Keyword(s):  
Raman Scattering ◽  
Raman Spectra ◽  
Principal Component ◽  
Detection Methods ◽  
Score Plot ◽  
Raman Scattering Spectroscopy ◽  
Standard Product ◽  
Destructive Analysis ◽  
Falsified Medicines ◽  
Non Destructive

Substandard and falsified medicines are often reported worldwide. An accurate and rapid detection method for falsified medicines is needed to prevent human health hazards. Raman scattering spectroscopy has emerged as a non-destructive analysis method for the detection of falsified medicines. In this laboratory study, Raman spectroscopy was performed to evaluate the applicability of the ultra-compact Raman scattering spectrometer (C13560). Principal component analysis (PCA) was also performed on the Raman spectra. This study analyzed tadalafil (Cialis), vardenafil (Levitra), and sildenafil (Viagra) tablets. We tested the standard product and products purchased from the internet (genuine or falsified). For Cialis and Levitra, all falsified tablets were identified by the Raman spectra and PCA score plot. For Viagra, the Raman spectra of some falsified tablets were almost comparable to the standard tablet. The PCA score plots of falsified tablets were dispersed, and some plots of falsified tablets were close to the standard tablet. In conclusion, C13560 was useful for the discrimination of falsified Cialis and Levitra tablets, whereas some falsified Viagra tablets had Raman spectra similar to that of the standard tablet. The development of detection methods that can be introduced in various settings may help prevent the spread of falsified products.

Raman Scattering and Photoluminescence Studies of Zn1-xMnxO Nanowires via Vapor Phase Growth

2005 ◽  
Vol 475-479 ◽  
pp. 3525-3530 ◽  
Author(s):  
Y.Q. Chang ◽  
Yi Zhi Chen ◽  
D.P. Yu ◽  
Z.L. Fang ◽  
G.H. Li ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Raman Spectra ◽  
Vapor Phase ◽  
Phonon Frequency ◽  
Quantum Confinement Effect ◽  
Phase Growth ◽  
Vapor Phase Growth ◽  
Band Emission ◽  
Near Band Emission ◽  
Photoluminescence Studies

In this paper, we investigated the Raman scattering and photoluminescence of Zn1-xMnxO nanowires synthesized by the vapor phase growth. The changes of E2(High) and A1(LO) phonon frequency in Raman spectra indicate that the tensile stress increases while the free carrier concentration decreases with the increase of manganese. The Raman spectra exited by the different lasers exhibit the quantum confinement effect of Zn1-xMnxO nanowires. The photoluminescence spectra reveal that the near band emission is affected by the content of manganese obviously. The values of IUV/G decrease distinctly with the manganese increase also demonstrate that more stress introduced with the more substitution of Mn for Zn.

Raman Scattering and Superconductivity of Alkali-Fullerene Materials

1992 ◽  
Vol 270 ◽  
Author(s):  
J. S. Lannin ◽  
M. G. Mitch ◽  
W. Bacsa ◽  
S. J. Chase
Keyword(s):  
Thin Films ◽  
Raman Scattering ◽  
Raman Spectra ◽  
Solid Solutions ◽  
Thick Films ◽  
Ultrathin Film ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Scattering Measurements ◽  
Different Thickness

ABSTRACTRaman scattering measurements in alkali—fullerene alloys in ultrathin and thin films provide evidence for variations in electron—phonon coupling. For x — 3similar behavior of Rb3 C60 films of different thickness support substantial electron—phonon induced damping of specific Hg(i) modes derived from intramolecular modes of C60. In 400A thick films a reduction of induced scattering from Raman inactive C60 modes substantiates the importance ofHg(2), but not Hg(3) modes for phonon—mediated superconductivity. In contrast to RbxC60 and KxC60 ultrathin film solid solutions, similar Raman spectra for NaxC60 indicate substantially reduced coupling consistent with the absence of superconductivity in this system.

Annealing of High Dose Implanted GaAs with Halogen Lamps

1983 ◽  
Vol 23 ◽  
Author(s):  
Y.I. Nissim ◽  
B. Joukoff ◽  
J. Sapriel ◽  
P. Henoc
Keyword(s):  
Raman Scattering ◽  
Raman Spectra ◽  
Quartz Plate ◽  
Gaas Surface ◽  
High Dose ◽  
Surface Degradation ◽  
Surface Protection ◽  
Scattering Measurements ◽  
Halogen Lamps

ABSTRACTHalogen lamps are used to anneal implanted GaAs. Surface protection is obtained by mouting the substrate in a sandwiched configuration between a silicon and a quartz plate. Raman scattering measurements are carried out to follow simultaneously lattice reconstruction and surface degradation due to Arsenic loss. The evolution of the Raman spectra is compared to a T.E.M. analysis carried out on the same samples.

On a new method in spectroscopy : laser-induced frequency shift of self-excited ion oscillations

1992 ◽  
Vol 2 (7) ◽  
pp. 1367-1372
Author(s):  
R. C. Bobulescu ◽  
M. A. Brǎtescu ◽  
C. Stǎnciulescu ◽  
G. Musa
Keyword(s):  
Frequency Shift ◽  
New Method ◽  
Spectroscopy Laser

Raman scattering measurements of vibrational and rotational distributions in expanding nitrogen

1993 ◽  
Author(s):  
WALTER GILLESPIE ◽  
DANIEL BERSHADER ◽  
SURENDRA SHARMA ◽  
STEPHEN RUFFIN
Keyword(s):  
Raman Scattering ◽  
Scattering Measurements

scholarly journals Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Osiekowicz ◽  
D. Staszczuk ◽  
K. Olkowska-Pucko ◽  
Ł. Kipczak ◽  
M. Grzeszczyk ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Temperature Effect ◽  
Band Gap ◽  
Raman Spectra ◽  
Quantum Interference ◽  
Optical Band Gap ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Resonant Raman

AbstractThe temperature effect on the Raman scattering efficiency is investigated in $$\varepsilon$$ ε -GaSe and $$\gamma$$ γ -InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.

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