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 Cubic InGaN Grown by MOCVD

1999 ◽  
Vol 4 (S1) ◽  
pp. 239-243
Author(s):  
J.B. Li ◽  
Hui Yang ◽  
L.X. Zheng ◽  
D.P. Xu ◽  
Y.T. Wang
Keyword(s):  
Room Temperature ◽  
Emission Peak ◽  
Buffer Layers ◽  
Cubic Phase ◽  
Yellow Luminescence ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Cubic Gan ◽  
Pl Emission

We report on the growth of high-quality cubic phase InGaN on GaAs by MOCVD. The cubic InGaN layers are grown on cubic GaN buffer layers on GaAs (001) substrates. The surface morphology of the films are mirror-like. The cubic nature of the InGaN films is obtained by X-ray diffraction (XRD) measurements. The InGaN layers show strong photoluminescence (PL) at room temperature. Neither emission peak from wurtzite GaN nor yellow luminescence is observed in our films. The highest In content as determined by XRD is about 17% with an PL emission wavelength of 450 nm. The FWHM of the cubic InGaN PL peak are 153 meV and 216 meV for 427 nm and 450 nm emissions, respectively. It is found that the In compositions determined from XRD are not in agreement with those estimated from PL measurements. The reasons for this disagreement are discussed.

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.

Growth of CuInGaSe2 Films by RF Sputtering Using CuInGaSe2 Single Phase Target

2013 ◽  
Vol 372 ◽  
pp. 571-574
Author(s):  
Kenji Yoshino ◽  
Takahiro Tokuda ◽  
Akira Nagaoka ◽  
Kenichiro Miseki ◽  
Rie Mori ◽  
...  
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Rf Sputtering ◽  
Diffraction Peak ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
High Quality ◽  
Homogeneous Surface ◽  
X Ray

CuIn0.8Ga0.2Se2 thin film is grown at room temperature by RF sputtering using high quality of CuIn0.8Ga0.2Se2 single phase target. A (112) diffraction peak is dominant with no secondary phases such as selenide materials in the X-ray diffraction pattern. A flat and homogeneous surface can be obtained in the sample.

Cubic InGaN Grown by Mocvd

1998 ◽  
Vol 537 ◽  
Author(s):  
J.B. Li ◽  
Hui Yang ◽  
L.X. Zheng ◽  
D.P. Xu ◽  
Y.T. Wang
Keyword(s):  
Room Temperature ◽  
Emission Peak ◽  
Buffer Layers ◽  
Cubic Phase ◽  
Yellow Luminescence ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Cubic Gan ◽  
Pl Emission

AbstractWe report on the growth of high-quality cubic phase InGaN on GaAs by MOCVD. The cubic InGaN layers are grown on cubic GaN buffer layers on GaAs (001) substrates. The surface morphology of the films are mirror-like. The cubic nature of the InGaN films is obtained by X-ray diffraction (XRD) measurements. The InGaN layers show strong photoluminescence (PL) at room temperature. Neither emission peak from wurtzite GaN nor yellow luminescence is observed in our films. The highest In content as determined by XRD is about 17% with an PL emission wavelength of 450 nm. The FWHM of the cubic InGaN PL peak are 153 meV and 216 meV for 427 nm and 450 nm emissions, respectively. It is found that the In compositions determined from XRD are not in agreement with those estimated from PL measurements. The reasons for this disagreement are discussed.

Characterization of Cubic GaN Films Using An AlN/GaN Ordered Alloy on GaAs (100) by RF-MBE

2002 ◽  
Vol 743 ◽  
Author(s):  
Junichi Shike ◽  
Atsushi Shigemori ◽  
Koichi Ishida ◽  
Kiyoshi Takahashi ◽  
Ryuhei Kimura
Keyword(s):  
Buffer Layer ◽  
X Ray Diffraction ◽  
High Quality ◽  
Nucleation Layer ◽  
X Ray ◽  
Cubic Gan

ABSTRACTHigh quality cubic GaN films were successfully grown on an AlN/GaN ordered alloy by RF-MBE. AlN/GaN ordered alloy is here employed instead of a AlGaN nucleation layer formed by nitridation of an AlGaAs buffer layer. Dominant cubic GaN epilayer (1.0 μm) growth was confirmed by insitu RHEED observations, AFM, TEM, PL and X-ray diffraction measurements.

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.

High Quality Hydrothermal ZnO Crystals

1998 ◽  
Vol 537 ◽  
Author(s):  
M. Suscavage ◽  
M. Harris ◽  
D. Bliss ◽  
P. Yip ◽  
S.-Q. Wang ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Liquid Helium ◽  
Room Temperature ◽  
Surface Preparation ◽  
Critical Factor ◽  
High Quality ◽  
Rocking Curve ◽  
X Ray ◽  
Oxide Crystals

AbstractZinc Oxide crystals have historically been grown in hydrothermal autoclaves with a basic mineralizer; however, doubts have been raised about the quality of such crystals because they have often exhibited large x-ray rocking curve widths and low photoluminescence (PL) yield with large linewidths. Several ZnO crystals were grown hydrothermally and sliced parallel to the c-plane. This resulted in opposite surfaces (the C+ and C-) exhibiting pronounced chemical and mechanical differences. Different surface treatments were investigated and compared by PL both at room temperature and liquid helium temperatures, and by double axis X-ray rocking curve measurements. The high quality of hydrothermally-grown ZnO is substantiated by the narrow rocking curve widths and sharp PL peaks obtained. A critical factor in obtaining these results was found to be surface preparation.

scholarly journals Experimental Investigations of the Interaction of SO2 with MgO

1999 ◽  
Vol 590 ◽  
Author(s):  
Andrea Freitag ◽  
J. A. Rodriguez ◽  
J. Z. Larese
Keyword(s):  
High Resolution ◽  
Film Thickness ◽  
Room Temperature ◽  
Temperature Programmed Desorption ◽  
Experimental Investigations ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Temperature Programmed ◽  
X Ray Absorption

ABSTRACTHigh resolution adsorption isotherms, temperature programmed desorption (TPD), x-ray diffraction (XRD) and x-ray absorption near edge spectroscopy (XANES) methods were used to investigate the interaction of SO2 with high quality MgO powders. The results of these investigations indicate that when SO2 is deposited on MgO in monolayer quantities at temperatures near 100K both SO3 and SO4 species form that are not removed by simply pumping on the pre-dosed samples at room temperature. TPD and XANES studies indicate that heating of pre-dosed MgO samples to temperatures above 350 °C is required for full removal of the SO3/SO4 species. XANES measurements made as a function of film thickness indicate for coverages near monolayer completion that the SO4 species form first.

Low-temperature crystal structure of RS-thiocamphor

2004 ◽  
Vol 219 (9) ◽  
Author(s):  
E. Louise R. Robins ◽  
Michela Brunelli ◽  
Asiloé J. Mora ◽  
Andrew N. Fitch
Keyword(s):  
Crystal Structure ◽  
Phase Transitions ◽  
Low Temperature ◽  
Room Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Two Phase ◽  
X Ray ◽  
Low Temperature Crystal Structure

AbstractDSC and high-resolution powder X-ray diffraction measurements in the range 295 K–100 K show that RS-thiocamphor undergoes two phase transitions. The first, at around 260 K on cooling, is from the room-temperature body-centred-cubic phase to a short-lived intermediate. At 258 K the low-temperature form starts to appear. The crystal structure of the latter is orthorhombic, space group

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