Effects of Low-Temperature Grown GaAs Intermediate Layers on the Crystalline Quality of GaAs-on-Si Epilayers

1994 ◽  
Vol 340 ◽  
Author(s):  
T.C. Chong ◽  
C.C. Phua ◽  
W.S. Lau ◽  
L.S. Tan
Keyword(s):  
Low Temperature ◽  
Deep Level ◽  
Crystalline Quality ◽  
X Ray Diffraction ◽  
Nucleation Layer ◽  
X Ray ◽  
Peak Intensity ◽  
Intermediate Layers ◽  
Lt Gaas

ABSTRACTThe incorporation of low-temperature (LT) GaAs intermediate layers grown at 230°C had been shown to have the effects of improving the crystalline quality of GaAs epilayers on Si. The use of this LT-GaAs intermediate layer between the GaAs nucleation layer and the GaAs overlayer has improved the photoluminescence (PL) peak intensity by about five times, and reduced the GaAs (004) X-ray diffraction full width at half maximum (FWHM) by 59 arcsecs. The PL results were subsequently confirmed by cathodoluminescence images. The dominant deep level electron trap in the LT-GaAs epilayer grown on Si substrate was the same as that found in LT-GaAs epilayer grown on GaAs substrate.

The Effect of Low Temperature GaAs Nucleation on the Growth of GaN on Silicon (001) During MOVPE Process

1997 ◽  
Vol 482 ◽  
Author(s):  
L. X. Zheng ◽  
J. W. Liang ◽  
H. Yang ◽  
J. B. Li ◽  
Y. T. Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Atomic Layer ◽  
X Ray Diffraction ◽  
High Quality ◽  
Nucleation Layer ◽  
X Ray ◽  
Cubic Gan ◽  
Low Temperature Gaas

AbstractHigh quality cubic GaN was grown on Silicon (001) by metalorganic vapor phase epitaxy (MOVPE) using a GaAs nucleation layer grown at low temperature. The influence of various nucleation conditions on the GaN epilayers' quality was investigated. We found that the GaAs nucleation layer grown by atomic layer epitaxy (ALE) could improve the quality of GaN films by depressing the formation of mixed phase. Photoluminescence (PL) and X-ray diffraction were used to characterize the properties of GaN epilayers. High quality GaN epilayers with PL full width at half maximum (FWHM) of 130meV at room temperature and X-ray FWHM of 70 arc-min were obtained by using 10–20nm GaAs nucleation layer grown by ALE.

scholarly journals X-ray diffraction analysis of kaolin M1 and M2 via the Williamson–Hall and Warren–Averbach methods

2021 ◽  
pp. 174751982098472
Author(s):  
Lalmi Khier ◽  
Lakel Abdelghani ◽  
Belahssen Okba ◽  
Djamel Maouche ◽  
Lakel Said
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Mechanical Resistance ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Mullite Phase

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

Evaluation of the Crystalline Quality of Strongly Curved 3C-SiC∕Si Epiwafers Through X-Ray Diffraction Analyses

2010 ◽  
Author(s):  
M. Zielinski ◽  
S. Jiao ◽  
T. Chassagne ◽  
A. Michon ◽  
M. Nemoz ◽  
...  
Keyword(s):  
Crystalline Quality ◽  
X Ray Diffraction ◽  
X Ray

Improvement of the Crystalline Quality of β-Ga2O3 Films by High-Temperature Annealing

2012 ◽  
Vol 725 ◽  
pp. 273-276
Author(s):  
Motoki Takahara ◽  
Suguru Funasaki ◽  
Jyun Kudou ◽  
Isao Tsunoda ◽  
Kenichiro Takakura ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Crystalline Quality ◽  
High Temperature Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Si Doped ◽  
Scanning Electron

For the purpose of improving the crystalline quality of undoped and Si doped β-Ga2O3 films, high temperature annealing at 900°C was performed. The crystalline quality of the films investigated using scanning electron microscopy and X-ray diffraction. Also the conductivity of the films is compared before and after the annealing. After the 900°C annealing, the XRD peaks intensity corresponding to β-Ga2O3 is increased. This result indicates that the crystalline quality improves by the high temperature annealing.

scholarly journals The use of Raman and XPS spectroscopy to study the cathode material of LiFePO4/C

2020 ◽  
Vol 85 (8) ◽  
pp. 1047-1054
Author(s):  
Vadym Galaguz ◽  
Oleksandr Korduban ◽  
Eduard Panov ◽  
Sergiy Malovanyi
Keyword(s):  
Sample Surface ◽  
X Ray Diffraction ◽  
Peak Intensity Ratio ◽  
X Ray ◽  
Synthesis Conditions ◽  
A Value ◽  
Peak Intensity ◽  
Reduction Of Iron ◽  
Carbon Coated

Using Raman spectroscopy and X-ray photoelection spectroscopy, synthesized lithium iron(II) phosphate (LiFePO4) and carbon coated nanocomposites LiFePO4/?, synthesized by annealing LiFePO4 with glucose for 1 and 12 h at 700?C, have been investigated. According to XPS data, the synthesis conditions of LiFePO4/? nanocomposite (700?C, 1 h) facilitate the reduction of iron, Fe3+ ?Fe2+, on the sample surface. Also according to C1s spectra, sp2C-sp2C is the main bond type in the samples under investigation. Contributions relating to C?O, C=O, C?O?C, O?C=O functional groups are also present. According to X-ray diffraction analysis, a 12-h synthesis of LiFePO4/C nanocomposite leads to the formation of impurities. According to Raman spectra, the annealing time does not affect the quality of carbon coating: the peak intensity ratio of bands D and G has a value of 1.06 for the material annealed for 1 h and 1.04 for LiFePO4/? nanocomposite after annealing for 12 h.

HVPE Growth of GaN Layers on Cleaved β-Ga2O3 Substrates

2016 ◽  
Vol 674 ◽  
pp. 302-307 ◽  
Author(s):  
V.I. Nikolaev ◽  
A.I. Pechnikov ◽  
S.I. Stepanov ◽  
V.M. Krymov ◽  
V.N. Maslov ◽  
...  
Keyword(s):  
Deposition Time ◽  
Substrate Surface ◽  
Vapour Phase ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
Nucleation Layer ◽  
Vapour Phase Epitaxy ◽  
X Ray ◽  
Gan Film

GaN epitaxial layers were successfully grown by hydride vapour phase epitaxy (HVPE) on β-Ga2O3 substrates produced by cleaving. The initial stages of GaN epitaxial growth on β-Ga2O3 were studied by scanning electron microscopy (SEM) and x-ray diffraction analysis (XRD). The nucleation and the transition from the nucleation layer to a continuous GaN film were studied. It was found that the growth starts with formation of small crystallites on the substrate surface. As the growth continues, crystallites transform into pyramidal islands which increase in size and merge together. It was found that the structural quality of the GaN layers rapidly improves with increasing thickness. The full width at half maximum of x-ray ω rocking curves for (0002) peak decreased from 1370 to 540 arcsec as the deposition time was increased from 30 to 120 sec. This corresponds to the variation of the nominal layer thickness from 250 nm to 1000 nm.

STUDY OF Al0.065Ga0.935Sb AVALANCHE PHOTODETECTORS FOR 1.55 μm OF WAVELENGTH BY LIQUID PHASE EPITAXY AT LOW TEMPERATURE

2002 ◽  
Vol 09 (05n06) ◽  
pp. 1741-1745 ◽  
Author(s):  
J. MARTÍNEZ-JUÁREZ ◽  
J. OLVERA ◽  
T. DÍAZ ◽  
F. DE ANDA ◽  
A. ESCOBOSA
Keyword(s):  
Liquid Phase ◽  
Low Temperature ◽  
Carrier Concentration ◽  
Liquid Phase Epitaxy ◽  
Donor Concentration ◽  
X Ray Diffraction ◽  
Avalanche Multiplication ◽  
X Ray ◽  
Avalanche Photodetectors

We report the results of a study of Al 0.065 Ga 0.935 Sb avalanche photodetectors grown on n-GaSb substrates. The devices have been fabricated from layers with the structure p-Al 0.13 Ga 0.87 Sb/n-Al 0.065 Ga 0.935 Sb:Te/n-GaSb (substrate) grown by liquid phase epitaxy (LPE) with a composition matched to detect light of 1.55 μm. The heterostructures were grown from Ga-rich solutions at 400°C. Just after their growth, the structures were subjected to baking processes inside the growth chamber. The baking time was varied and its influence on the breakdown voltages of the junctions was observed. Breakdown voltages up to 12 V, very low net donor concentration in the active layer (1E15 cm -3), and avalanche multiplication factors of around 50 have been obtained. The carrier concentration was determined by the C–V method. Photoluminescence and X-ray diffraction measurements were carried out to investigate the properties of the LPE-grown ternary layers, to determine the band gap and to estimate the quality of epitaxial layers. The photoresponses of the detectors are also presented.

Crystalline Quality Evaluation of 6H-SiC Bulk Crystals Grown from Si-Ti-C Ternary Solution

2005 ◽  
Vol 483-485 ◽  
pp. 13-16 ◽  
Author(s):  
Kazuhiko Kusunoki ◽  
Kazuhito Kamei ◽  
Y. Ueda ◽  
S. Naga ◽  
Y. Ito ◽  
...  
Keyword(s):  
Grown Crystal ◽  
Seed Crystal ◽  
Solution Growth ◽  
Crystalline Quality ◽  
Ternary Solution ◽  
Bulk Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Koh Etching

The growth of 6H-SiC crystal from Si-Ti-C ternary solution was conducted under the temperature gradient and the crystalline quality evaluations of the grown crystals were carried out. 6H-SiC(0001) on-axis pvt-grown crystal was used as a seed crystal. Micropipes in the seed crystal were terminated during the solution growth and 28mm􀊷28mm self-standing micropipe-free SiC crystals were obtained. The quality of the grown crystals was investigated by SIMS, high-resolution x-ray diffraction and molten KOH etching. The content of residual impurities in the SiC were very low. The X-ray 􀐢-rocking curves of the solution grown SiC showed single peak with high peak intensity ,while that of the seed crystal showed several peaks due to the misoriented domains. Moreover, it was found that the number of etch-pit in the grown crystal is much less than that in the seed crystal and it decreases with the increase of the growth thickness. These results indicate that the crystalline quality of grown crystal was significantly improved during the solution growth.

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