Effects of Se implantation on the compositional disordering of GaAs-AlAs superlattices

1985 ◽  
Vol 56 ◽  
Author(s):  
T. NAKAMURA ◽  
S. KOMIYA ◽  
T. INATA ◽  
S. MUTO ◽  
S. HIYAMIZU
Keyword(s):  
Thermal Diffusion ◽  
Raman Spectra ◽  
Low Dose ◽  
Phonon Frequency ◽  
Gaas Layer ◽  
Probable Mechanism ◽  
Subsequent Annealing ◽  
Alas Layer

AbstractThe LO phonon frequency evaluated from Raman spectra identifies two compositional disordering mechanisms in GaAs-AlAs superlattices. For a high Se dose, the LO phonons of the Al0.5Ga0.5As alloy are observed from the asimplanted samples. That means the compositional disordering occurred just by Se implantation. The probable mechanism for this disordering is the implantation of Ga atoms into the AlAs layer and of Al atoms into the GaAs layer. The superlattices implanted at a low dose are disordered by the subsequent annealing. The mechanism is the enhanced interdiffusion of both Ga and Al atoms between the GaAs and AlAs layers by Se thermal diffusion.

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 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 spectroscopy for the evaluation of the radiobiological sensitivity of normal human breast cells at different time points after irradiation by a clinical proton beam

The Analyst ◽  
2019 ◽  
Vol 144 (6) ◽  
pp. 2097-2108 ◽  
Author(s):  
M. Lasalvia ◽  
G. Perna ◽  
P. Pisciotta ◽  
F. P. Cammarata ◽  
L. Manti ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Proton Beam ◽  
Raman Spectra ◽  
Low Dose ◽  
Human Breast ◽  
Time Points ◽  
Normal Human Breast ◽  
Breast Cells ◽  
Normal Human ◽  
Radiobiological Effects

Radiobiological effects occurring in normal human breast cells exposed to a low dose of a clinical proton beam are detectable by means of Raman spectra and the ratiometric analysis of Raman peak intensities.

Anisotropic properties and Raman spectra of a LiNa5Mo9O30 single crystal grown by the TSSG method

CrystEngComm ◽  
2020 ◽  
Vol 22 (44) ◽  
pp. 7716-7722
Author(s):  
Xiaoli Du ◽  
Zeliang Gao ◽  
Fuan Liu ◽  
Xiaojie Guo ◽  
Xiangmei Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Raman Spectrum ◽  
Single Crystal ◽  
Thermal Diffusion ◽  
Raman Spectra ◽  
Transmission Spectrum ◽  
Anisotropic Properties ◽  
Polarized Raman

Single crystal LiNa5Mo9O30 with 52 × 44 × 8 mm3 was successfully grown using the TSSG method. The transmission spectrum, thermal diffusion, thermal conductivity, and polarized Raman spectrum of a-cut configurations were systematically investigated.

The Recrystallization Properties of Poly-GexSi1-xON SiO2/Si

1997 ◽  
Vol 472 ◽  
Author(s):  
N. Jiang ◽  
J.R. Ma ◽  
M. Wu ◽  
X.D. Huang ◽  
S.L. Gu ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Raman Spectra ◽  
Annealing Process ◽  
Subsequent Annealing ◽  
Damage Distribution ◽  
Grain Sizes ◽  
Longitudinal Pattern

ABSTRACTIn this paper, we have developed a new way to recrystallize the poly-GeSi on SiO2. 300nm poly-GeSi was grown by RTP/VLP-CVD on SiO2/Si, and then amorphized by 180 keV-Si+ ion implantation with dose of 2×10'4 cm'2. An amorphized region with the damage distribution was formed. After subsequent annealing process, the comparison between the XRD scans and Raman spectra of poly-GeSi and poly-Si indicated that the annealed poly-GeSi was more recrystallized than the poly-Si in the same conditions, this was the inducement of Ge in the annealing process. The segregation of Ge atoms in the heavy damaged region would enhance this inducement. The XTEM showed the longitudinal pattern of GeSi grains which meant the longitudinal sizes were much greater than the horizontal sizes. After annealing process, the final GeSi grain sizes were greater than the poly-Si grain sizes processed in SSIC with the same implantation conditions.

scholarly journals Комбинационное рассеяние света в сферических нанокристаллах InSb, ионно-синтезированных в пленках оксида кремния

2019 ◽  
Vol 53 (4) ◽  
pp. 502
Author(s):  
И.Е. Тысченко ◽  
В.А. Володин ◽  
В.П. Попов
Keyword(s):  
Raman Spectra ◽  
Quantum Confinement ◽  
Phonon Frequency ◽  
Ion Beam ◽  
Quantum Confinement Effect ◽  
Confinement Effect ◽  
Bulk Crystals ◽  
High Frequencies ◽  
Surface Phonon ◽  
Ion Beam Synthesis

AbstractThe Raman spectra of SiO_2 films containing InSb spherical nanocrystals produced by ion-beam synthesis are studied. TO- and LO-like modes in the spectra of the InSb nanocrystals are detected at frequencies of 187 and 195 cm^–1, respectively. The shift of these modes to high frequencies with respect to the corresponding frequencies in InSb bulk crystals is analyzed from the viewpoint of the influence of the quantum-confinement effect, strains in nanocrystals, the surface phonon frequency, and scattering at the frequency corresponding to stretched anion–cation modes at the surface of polar spherical nanocrystals. The position of the 195-cm^–1 mode corresponds to LO phonons in InSb nanocrystals hydrostatically compressed in the SiO_2 matrix at pressures of about 10 kbar. The 187-cm^–1 mode corresponds to resonance at the Fröhlich frequency.

Investigation of Temperature and Composition Dependence of Relaxor Ferroelectric (1-x)PZN :xPT Using Micro-Raman Spectroscopy

1998 ◽  
Vol 547 ◽  
Author(s):  
S. Gupta ◽  
R.S. Katiyar ◽  
A. S. Bhalla
Keyword(s):  
Raman Spectra ◽  
Composition Dependence ◽  
Phonon Frequency ◽  
Soft Mode ◽  
Relaxor Ferroelectric ◽  
Frequency Range ◽  
Multiple Phase ◽  
Integrated Intensity ◽  
Frequency Position ◽  
Raman Modes

AbstractMicro-Raman spectra of relaxor ferroelectric (RFE) in the (1-x)Pb(Zn1/3Nb2/3)O3 :xTiO3 solid solution series have been measured as a function of temperature (70-580K) and composition (x = 0.02, 0.085, and 0.11). Micro-Raman spectra have been recorded in frequency range of 30-1000cm-1 and have been analyzed for all the Raman modes observed in terms of integrated intensity, phonon width and phonon frequency position. No soft mode like behavior is observed in the measured frequency range. We do observe two multiple phase transitions at 67°C (340K) and 147°C (420K) for the composition ≤ 0.91PZN:09PT, but both the transitions are slightly diffused in nature.

Behavior Of The Potential N-Type Dopants P And As In Diamondafter Low Dose Ion Implantation

1996 ◽  
Vol 442 ◽  
Author(s):  
H. Hofsäss ◽  
M. Dalmer ◽  
M. Restle ◽  
C. Ronning ◽  
K. Bharuth-Ram ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Electron Emission ◽  
Room Temperature ◽  
Low Dose ◽  
Subsequent Annealing ◽  
Low Doses ◽  
Emission Channeling

AbstractWe have studied the lattice sites of P and As impurities in natural IIa diamond after room temperature ion implantation at very low doses of 1011 P/cm2 and ≤ 1013 As/cm2 and subsequent annealing. We implanted radioactive 33P and 73Se/73As probe atoms and used the sensitive emission channeling technique to determine the impurity lattice sites. In this technique the channeling effects of emitted decay electrons are measured for different crystal axes. By comparison with calculated electron emission distributions the fractions of emitter atoms on different lattice sites can be quantitatively determined. After annealing of the implanted samples above 900°C we find high substitutional fractions of 70 ± 10 % for 33P and 55 ± 5 % for 73As.

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

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