MBE Growth and Characterization of InSb/AlxIn1−xSb Strained Layer Structures

1996 ◽  
Vol 450 ◽  
Author(s):  
K. J. Goldammer ◽  
W. K. Liu ◽  
W. Ma ◽  
M. B. Santos ◽  
R. J. Hauenstein ◽  
...  
Keyword(s):  
Quantum Wells ◽  
High Mobility ◽  
Structural Quality ◽  
Electron Systems ◽  
X Ray Diffraction ◽  
Mbe Growth ◽  
Gaas Substrates ◽  
Layer Structures

ABSTRACTThree types of structures were fabricated using molecular beam epitaxy. High-resolution x-ray diffraction measurements demonstrated the high structural quality of InSb/AlxIn1−xSb superlattices grown on InSb and GaAs substrates. Hall effect data revealed the effect of substrate temperature on autocompensation in InSb δ-doped with Si. Two-dimensional electron systems with a high mobility were realized in InSb quantum wells with AlxIn1−xSb barriers δ-doped with Si.

MBE Growth and Characterization of CdTe, ZnTe Epilayers and CdTe/ZnCdTe Superlattices on GaAs Substrates

1992 ◽  
Vol 263 ◽  
Author(s):  
A.E. Milokhin ◽  
I.E. Trofimov ◽  
M.V. Petrov ◽  
F.F. Balakirev ◽  
V.D. Kuzmin ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Buffer Layer ◽  
Lattice Constant ◽  
Strong Influence ◽  
High Crystalline Quality ◽  
Mbe Growth ◽  
X Ray ◽  
Gaas Substrates

Semiconductor heterostuctures ZnxCd1−xTe/CdTe were found to be of interest recently due to their potential practical usage. The reason for this is the beautiful variety of electrical heterostucture properties which arise from the strong influence of elastic deformation distribution. Thin epilayer films and superlattices ZnxCd1−xTe/CdTe were prepared on GaAs semi-isolator substrates by MBE technology with RHEED oscillation measurements of the deposited layers. X-ray measurements have shown high crystalline quality of the samples.We have performed Raman scattering studies of ZnxZnxCd1−xTe/CdTe structures. The data obtained were interpreted as a proff of the pseudomorphous growth model. That is, ZnxCd1−xTe/CdTe SLS keeps the lattice constant of the buffer layer.

Normal Incidence Photoresponse as a Function of Well Width in P-Type GaAs/AlGaAs Multi-Quantum Wells

1996 ◽  
Vol 450 ◽  
Author(s):  
G. J. Brown ◽  
M. A. Capano ◽  
S. M. Hegde ◽  
K. Eyink ◽  
F. Szmulowicz
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Normal Incidence ◽  
Light Hole ◽  
Structural Quality ◽  
Hole State ◽  
X Ray Diffraction ◽  
Optimization Study ◽  
P Type

ABSTRACTWe have performed an optimization study of the mid-infrared photoresponse of p-type GaAs/AlGaAs Quantum Well Infrared Photodetectors (QWIPs) designed for normal incidence detection. In these p-type quantum wells, normal incidence absorption is allowed (by the dipole selection rules for optical transitions) especially for transitions from the heavy-hole ground state to the second light-hole state. Previous theoretical modeling predicted that this transition will produce the strongest bound-to-continuum infrared absorption when the second light-hole state is located very near the top of the GaAs quantum well. For AlGaAs barrier layers with 30% aluminum, our modeling showed that a well width between 45Å and 50Å would optimize the normal incidence photoresponse of this p-type QWIP. In this work, photore^oonse spectra are reported for well widths ranging from 40Å to 65Å. A series of samples were tudied in which only the GaAs well width was varied in two monolayer increments, from 11 to 20 monolayers. Photoluminescence and X-ray diffraction measurements were used to verify the composition, well width, and structural quality of each sample. This study verified that the spectral range of the normal incidence photoresponse is narrower, as predicted by theory, for well widths in which the second light-hole state approaches the top of the valence band well.

MBE Growth and Optical Characterization of InGaN/AlGaN Multiquantum Wells

1996 ◽  
Vol 449 ◽  
Author(s):  
R. Singh ◽  
W.D. Herzog ◽  
D. Doppalapudi ◽  
M.S. ÜnlÜ ◽  
B.B. Goldberg ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Electron Cyclotron Resonance ◽  
Temperature Cycling ◽  
Cross Sectional ◽  
Luminescence Microscopy ◽  
Mbe Growth ◽  
Transmission Electron ◽  
Ingan Quantum Wells

ABSTRACTWe report the growth of InGaN/AIGaN MQWs on c-plane sapphire by electron cyclotron resonance assisted molecular beam epitaxy (ECR-MBE). Two types of structures were investigated; one employing a GaN and the other a A1GaN barrier layer. The first structure consists of five periods of 80 Å thick In0.09Ga0.91N wells separated by 90 Å thick GaN barriers. The second structure consists of|seven periods of 120 Å thick In0.35Ga0.65N wells and Al0.1Ga0.9N barriers. The substrate temperature was kept constant during the growth of both the wells and the barriers, thus avoiding the need for any temperature cycling during the growth, which may lead to interfacial contamination. The films were characterized by cross sectional transmission electron microscopy (TEM), room temperature photoluminescence (PL) and sub-micron resolution luminescence microscopy. TEM images show sharp and abrupt interfaces, thus confirming the high interfacial quality of the MQW structures. Both structures exhibit strong RT luminescence emission peaking at 387 nm (FWHM = 16nm) for the In0.09Ga0.91N/GaN structure and at 463 nm (FWHM = 28nm) for the In0.35Ga0.65N/A10.1Ga0 9N structure. The high resolution luminescence microscopy studies reveal that the radiative recombination for the InGaN quantum wells is 60–70 times more efficient than for the underlying GaN film.

Mbe Growth of Strained-Layer InSb/InAlSb Structures

1990 ◽  
Vol 198 ◽  
Author(s):  
C.R. Whitehouse ◽  
C.F. Mcconville ◽  
G.M. Williams ◽  
A.G. Cullis ◽  
S.J. Barnett ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Critical Thickness ◽  
Multiple Quantum ◽  
Material System ◽  
X Ray Diffraction ◽  
Mbe Growth ◽  
X Ray ◽  
Strained Layer ◽  
Transmission Electron ◽  
Layer Structures

ABSTRACTThe MBE growth and related materials characterisation of InSb/InAlSb strained-layer structures is described. Band-gap considerations and critical thickness calculations are presented and indicate that this material system should offer considerable device potential. Detailed structural studies, performed using both transmission electron microscopy and X-ray diffraction, confirm the growth of high quality multiple quantum-wells, and 2K photoluminescence has shown corresponding energy upshifted transitions.

MBE Growth of 2.3μm InGaAsSb/AlGaAsSb Strained Multiple Quantum Well Diode Lasers

2013 ◽  
Vol 552 ◽  
pp. 389-392 ◽  
Author(s):  
Tian Cheng Zhang ◽  
Qin Fei Ni ◽  
Xue Zhen Liu ◽  
Bin Yu ◽  
Yu Xia Wang ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Multiple Quantum Well ◽  
Energy Band Structure ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Mbe Growth ◽  
One Dimensional ◽  
X Ray ◽  
Growth Quality

2.3 μm InGaAsSb/AlGaAsSb lasers with multiple quantum wells(MQWs) have been demonstrated.The growth temperature of quantum wells is 440°C,and the growth quality of InGaAsSb/AlGaAsSb MQWs is examined by X-ray diffraction and Photoluminescence(PL) at room temperature.The energy band structure of MQWs was calculated by one-dimensional finite-difference method(1D-FDM)

Characterization of epitaxial SrTiO3/YBa2Cu3O7 layers deposited on (001) MgO by laser ablation

1993 ◽  
Vol 8 (11) ◽  
pp. 2780-2784 ◽  
Author(s):  
P. Scardi ◽  
L. Lutterotti ◽  
L. Correra ◽  
S. Nicoletti
Keyword(s):  
Laser Ablation ◽  
Critical Current ◽  
Ybco Film ◽  
Structural Quality ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Columnar Grains

We discuss the results obtained for SrTiO3/YBa2Cu3O7 layers deposited on (001) MgO substrates by UV pulsed laser ablation. Different samples were prepared to study both the growth of a thin (55 nm) layer of SrTiO3 on MgO and the successive epitaxy of a 220 nm YBa2Cu3O7 (YBCO) film on the SrTiO3 layer. An x-ray diffraction (XRD) texture analysis is reported for the bilayers together with resistivity versus temperature and critical current density (Jc) measurements of the superconducting films. The results show that YBCO grains grow with c-axis normal to the surface; the main in-plane orientations are [100] MgO // [100] SrTiO3 // [100] YBCO ([010] YBCO). The XRD line broadening analysis suggests that YBCO columnar grains grow along the whole thickness of the film, also evidencing dislocations and/or faulting separated by a mean distance of 80 nm. The values obtained for the critical current of the superconductor demonstrate the effectiveness of the SrTiO3 intermediate layer in improving the structural quality of the YBCO film.

Growth and Characterization of Zn1-xMnxSe1-ySy Epilayers and Related Heterostructures

1996 ◽  
Vol 452 ◽  
Author(s):  
F. S. Flack ◽  
N. Samarth ◽  
F. Semendy
Keyword(s):  
Quantum Wells ◽  
Energy Gap ◽  
Spin Fluctuations ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Double Crystal ◽  
Wide Range ◽  
Confining Layers

AbstractWe describe the growth of (Zn,Mn)(S,Se) epitaxial layers of high structural quality on (100) GaAs substrates. Double crystal x-ray diffraction (DCXRD) measurements indicate that quaternary epilayers nearly lattice-matched with GaAs are characterized by DCXRD curves with a foil width at half maximum in the range 30 – 60 arc seconds. Photoluminescence (PL) spectroscopy is employed to map the variation of the energy gap of the quartenary alloys over a wide range of alloy compositions. Finally, temperature dependent PL is used to examine the viability of (Zn,Mn)(S,Se) alloys as confining layers for ZnSe and (Zn,Cd)Se quantum wells. While efficient exciton confinement is demonstrated through the observation of robust PL from such quantum wells up to high temperatures, the renormalization of the quartenary band gap by spin fluctuations leads to a rapid decrease in confinement with increase in temperature.

Structural Characterization of Bulk AlN Single Crystals Grown from Self-Seeding and Seeding by SiC Substrates

2006 ◽  
Vol 527-529 ◽  
pp. 1521-1524 ◽  
Author(s):  
Balaji Raghothamachar ◽  
Rafael Dalmau ◽  
Michael Dudley ◽  
Raoul Schlesser ◽  
Dejin Zhuang ◽  
...  
Keyword(s):  
Growth Conditions ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
Free Standing ◽  
X Ray ◽  
Highly Strained ◽  
Defect Densities ◽  
High Defect Densities

Using a combination of synchrotron white beam x-ray topography (SWBXT) and high resolution x-ray diffraction (HRXRD), the structural quality of AlN crystals grown by various sublimation-based techniques have been non-destructively analyzed. Spontaneously nucleated AlN crystals are characterized by very low defect densities but their size is small. Self-seeding results in nucleation of multiple grains of different orientations, a few of which are of good quality while most are highly strained. Using readily available commercial 4H and 6H-SiC substrates, several growth runs have been carried out using different growth conditions to obtain thick AlN layers, either attached to the seed or free-standing. While attached layers are typically cracked and highly strained, crack-free free-standing layers can be obtained by delamination or SiC decomposition. X-ray characterization reveals these crystals have good purity but moderately high defect densities.

Characterization of Natural and Synthesized FeTiO3 Crystals With RBS/PIXE/XRD

1997 ◽  
Vol 07 (03n04) ◽  
pp. 265-275
Author(s):  
R. Q. Zhang ◽  
S. Yamamoto ◽  
Z. N. Dai ◽  
K. Narumi ◽  
A. Miyashita ◽  
...  
Keyword(s):  
Single Crystals ◽  
Ion Beam ◽  
Pressure Control ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beam Analysis ◽  
Ppm Level

Natural FeTiO 3 (illuminate) and synthesized FeTiO 3, single crystals were characterized by Rutherford backscattering spectroscopy combined with channeling technique and particle-induced x-ray emission (RBS-C and PIXE). The results obtained by the ion beam analysis were supplemented by the x-ray diffraction analysis to identify the crystallographic phase. Oriented single crystals of synthesized FeTiO 3 were grown under the pressure control of CO 2 and H 2 mixture gas using a single-crystal floating zone technique. The crystal quality of synthesized FeTiO 3 single crystals could be improved by the thermal treatment but the exact pressure control is needed to avoid the precipitation of Fe 2 O 3 even during the annealing procedure. Natural FeTiO 3 contains several kinds of impurities such as Mn , Mg , Na and Si . The synthesized samples contain Al , Si and Na which are around 100 ppm level as impurities. The PBS-C results of the natural sample imply that Mn impurities occupy the Fe sublattice in FeTiO 3 or in mixed phase between ilmenite and hematite.

Characterization of WC-Co Coatings Using HP/HVOF Process

1996 ◽  
Author(s):  
S.Y. Hwang ◽  
B.G. Seong ◽  
M.C. Kim
Keyword(s):  
Wear Resistance ◽  
X Ray Diffraction ◽  
High Carbon ◽  
Properties Of Coatings ◽  
X Ray ◽  
Hvof Process ◽  
Number Of Passes ◽  
Oxygen Fuel

Abstract To maintain surface roughness of process rolls in cold rolling steel plants, WC-Co coatings have been known to be effective ones. In this study, a high pressure/high velocity oxygen fuel (HP/HVOF) process was used to obtain WC-Co coatings. To get the best quality of coatings, WC-Co coatings are sprayed with numerous powders made by various processes. These powders include agglomerated sintered powders, fused-crushed powders, extra high carbon WC-Co powders and (W2C, WC)-Co powders. After spraying, properties of coatings such as hardness, wear resistance. X-ray diffraction, and microstructures were analyzed. For coatings produced by agglomerated-sintered powders, hardness of the coating increased as power levels and the number of passes were increased. In case of the coatings produced by fused-crushed powders, a very low deposition rate was obtained due to a low flowablity of the powders. In addition, the WC-Co coatings sprayed with extra carbon content of WC-Co did not show improved hardness and wear resistance. Also, some decomposition of WC was observed in the coating. Finally, the coatings produced by (W2C, WC)-Co powders produced higher hardness and lower wear resistance coating.

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