scholarly journals Optical and structural properties of the GaAs heterostructures grown using AlGaAs superlattice buffer layer on compliant Si(100) substrates with the preformed porous-Si (por-Si) layer.

2021 ◽  
Vol 2086 (1) ◽  
pp. 012046
Author(s):  
D Zolotukhin ◽  
P Seredin ◽  
A Lenshin ◽  
D Goloshchapov ◽  
Y Hudyakov ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Energy Shift ◽  
Sample Surface ◽  
Structural Quality ◽  
Photoluminescence Spectra ◽  
Porous Si ◽  
Crystalline Perfection ◽  
Growth Technique ◽  
Mocvd Growth ◽  
Xrd Study

Abstract 360 nm and 700 nm thick GaAs layers were grown by MO MOCVD growth technique directly on compliant Si (100) substrate and on supper-lattice (SL) AlGaAs buffer layer. The XRD study revealed better structural quality for the sample grown on SL / por-Si buffer. AFM study revealed a smoother sample surface with blocks of more regular rectangular shape and larger size as well. Photoluminescence spectra of the samples revealed an energy shift of PL maximum intensity for both samples. Sample grown on SL buffer also showed higher PL intensity corresponding to better crystalline perfection.

MOCVD growth of ZnO films on Si(111) substrate using a thin AlN buffer layer

2005 ◽  
Vol 284 (3-4) ◽  
pp. 459-463 ◽  
Author(s):  
L. Wang ◽  
Y. Pu ◽  
Y.F. Chen ◽  
C.L. Mo ◽  
W.Q. Fang ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Zno Films ◽  
Mocvd Growth ◽  
Aln Buffer

Structural Properties of InAs/AlSb Superlattices

1995 ◽  
Vol 379 ◽  
Author(s):  
B. Jenichen ◽  
H. Neuroth ◽  
B. Brar ◽  
H. Kroemer
Keyword(s):  
Buffer Layer ◽  
Peak Shift ◽  
Lattice Parameter ◽  
Structural Quality ◽  
Inhomogeneous Deformation ◽  
X Ray ◽  
Peak Broadening ◽  
Short Period ◽  
Intensity Ratios ◽  
Highly Correlated

ABSTRACTShort-period (InAs)6/(AlSb)6 superlattices (SL) with AlAs-like and InSb-like interfaces (IF) grown on a relaxed AlSb buffer layer are studied by X-ray reflectivity and diffractometry measurements. Reflectivity measurements reveal average IF roughnesses between 0.6 and 1.0 nm. Measurements of the diffuse scattering show that the roughness is highly correlated from layer to layer. Triple crystal area scans illustrate that the inhomogeneous deformation of the buffer layer leads to a certain symmetric peak broadening. In the case of AlAs-like IFs an additional broadening of the SL peaks reveals lattice parameter gradients over the superlattice. This asymmetric peak broadening may be attributed to a further relaxation of the superlattice, which is inhomogeneous with depth. The diffusion of As into the AlSb layers leads to a peak shift and modifies the intensity ratios of the different satellite reflections. The best structural quality is achieved for superlattices with InSb-like IFs.

Si2p Core Level Absorption and Photoemission Spectra of Porous Si

1992 ◽  
Vol 283 ◽  
Author(s):  
Hisao Nakashima ◽  
Koichi Inoue ◽  
Kenzo Maehashi
Keyword(s):  
Synchrotron Radiation ◽  
Electronic Structures ◽  
Energy Shift ◽  
Blue Shift ◽  
Photo Luminescence ◽  
High Energy ◽  
Core Level ◽  
Oxidation States ◽  
Porous Si ◽  
The Core

ABSTRACTSi2p core level absorption and photoemission spectra are taken for different porous Si layers using synchrotron radiation, toknow the electronic structures of porous Si. The core level absorption spectra show the high energy shift of the conduction band which correlates with the photo-luminescence blue shift. The oxidation states of porous Si are clarified from the photoemission spectra.

Influences of thickness and temperature of low temperature GaAs buffer layer on two-step MOVPE grown GaAs/Ge heterostructures

2020 ◽  
Vol 90 (2) ◽  
pp. 20301
Author(s):  
Ilkay Demir ◽  
Ahmet Emre Kasapoğlu ◽  
Hasan Feyzi Budak ◽  
Emre Gür ◽  
Sezai Elagoz
Keyword(s):  
Buffer Layer ◽  
Growth Parameters ◽  
Internal Quantum Efficiency ◽  
Optical Quality ◽  
Structural Quality ◽  
Atomic Step ◽  
Organic Vapor ◽  
Gaas Buffer Layer ◽  
Metal Organic ◽  
Low Temperature Gaas

We investigate influence of GaAs buffer layer (BL) growth parameters such as temperature and thickness on the structural, morphological, crystalline and optical quality of metal organic vapor phase epitaxy (MOVPE) grown heterostructures of GaAs on Ge. It was found that the optimal BL conditions significantly decrease the effects of anti-phase boundaries (APBs) even when grown on offcut Ge substrate by two-step growth technique with AsH3 pre-flow to promote double atomic step formation. It is observed that as the growth temperature increases, the growth rate of the GaAs BL increases, too. Improvement on the structural quality is observed up to BLs temperature of 535 °C, then it decreases. On the other hand, as the different thick BLs, 12, 25, 75 nm are considered, the epilayer grown on the 25 nm thick BL has shown the lowest full width at half maximum (FWHM) value, large photoluminescence peak intensity and internal quantum efficiency (IQE).

Structural quality of pseudomorphic Zn0.5Cd0.5Se layers grown on an InGaAs or InP buffer layer on (0 0 1) InP substrates

1997 ◽  
Vol 179 (1-2) ◽  
pp. 83-92 ◽  
Author(s):  
E. Snoeks ◽  
L. Zhao ◽  
B. Yang ◽  
A. Cavus ◽  
L. Zeng ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Structural Quality ◽  
Inp Substrates

scholarly journals Morphology and surface reconstructions of m-plane GaN

2002 ◽  
Vol 743 ◽  
Author(s):  
C. D. Lee ◽  
R. M. Feenstra ◽  
J. E. Northrup ◽  
L. Lymperakis ◽  
J. Neugebauer
Keyword(s):  
Molecular Beam Epitaxy ◽  
Low Temperature ◽  
Surface Morphology ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Structural Quality ◽  
Surface Reconstructions ◽  
Gan Buffer Layer

ABSTRACTM-plane GaN(1100) is grown by plasma assisted molecular beam epitaxy on ZnO(1100) substrates. A low-temperature GaN buffer layer is found to be necessary to obtain good structural quality of the films. Well oriented (1100) GaN films are obtained, with a slate like surface morphology. On the GaN(1100) surfaces, reconstructions with symmetry of c(2×2) and approximate “4×5” are found under N- and Ga-rich conditions, respectively. We propose a model for Ga-rich conditions with the “4×5” structure consisting of ≥ 2 monolayers of Ga terminating the GaN surface.

Tem Study of the Structure of Mbe GaAs Layers Grown at Low Temperature

1990 ◽  
Vol 198 ◽  
Author(s):  
Zuzanna Liliental-Weber
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Molecular Beam ◽  
Critical Thickness ◽  
Stacking Faults ◽  
Structural Quality ◽  
Crystalline Perfection ◽  
Transmission Electron ◽  
Low Temperature Gaas

ABSTRACTThe structural quality of GaAs layers grown at 200°C by molecular beam epitaxy (MBE) was investigated by transmission electron microscopy (TEM). We found that a high crystalline perfection can be achieved in the layers grown at this low temperature for thickness up to 3 μm. In some samples we observed pyramid-shaped defects with polycrystalline cores surrounded by microtwins, stacking faults and dislocations. The size of these cores increased as the growth temperature was decreased and as the layer thickness was increased. The upper surface of layers with pyramidal defects became polycrystalline at a critical thickness of the order of 3μm. We suggested that the low-temperature GaAs becomes polycrystalline at a critical thickness either because of a decrease in substrate temperature during growth or because strain induced by excess As incorporated in these layers leads to the formation of misoriented GaAs nuclei, thereby initiating polycrystalline growth. The pyramidal shape of the defects results from a growth-rate hierarchy of the low index planes in GaAs.

Improved MOCVD Growth of GaAs on Si

1987 ◽  
Vol 91 ◽  
Author(s):  
R.M. Lum ◽  
J.K. Klingert ◽  
B.A. Davidson ◽  
M.G. Lamont
Keyword(s):  
Buffer Layer ◽  
Rutherford Backscattering Spectrometry ◽  
Growth Parameters ◽  
Buffer Layers ◽  
Double Crystal ◽  
Gaas On Si ◽  
Mocvd Growth ◽  
Gaas Films ◽  
Gaas Buffer Layer ◽  
Direct Growth

ABSTRACTIn the direct growth of GaAs on Si by MOCVD the overall quality of the heteroepitaxial film is controlled to a large extent by the growth parameters of the initial GaAs buffer layer. We have investigated the structural properties of this layer using Rutherford Backscattering Spectrometry (RBS) and X-ray double crystal diffractometry. The crystallinity of the buffer layer was observed to improve with increasing layer thickness in the range 10–100nm, and then to rapidly degrade for thicker layers. High temperature (750°C) annealing of the buffer layers resulted in considerable reordering of all but the thicker (>200 nm) layers. Alteration of the usual GaAs/Si growth sequence to include an in-situ anneal of the buffer layer after growth interruption yielded GaAs films with improved structural, optical and electrical properties.

Effect of Buffer Design on AlGaN/AlN/GaN Heterostrucutres by MBE

2003 ◽  
Vol 798 ◽  
Author(s):  
Gon Namkoong ◽  
W. Alan ◽  
A. S. Brown ◽  
M. Losurdo ◽  
M. M. Giangregorio ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Buffer Layer ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Structural Quality ◽  
Epitaxial Layers ◽  
Etch Pit Density ◽  
Etch Pit ◽  
Sheet Charge ◽  
Aln Buffer

ABSTRACTThe effect of the buffer layers on the subsequent GaN epitaxial layers and electrical properties of AlGaN/AlN/GaN heterojunction structures nitrided at various temperatures was investigated. For AlN buffer layers, two different growth conditions of AlN buffer layers were introduced to avoid Al droplets. We found that etch pit density and structural quality of GaN epitaxial layer strongly depends on the growth conditions of AlN buffer layers. When using a double buffer layer (low temperature GaN on high temperature AlN) for 200 °C nitridation, the etch pit density was measured to high 107 cm-2 in GaN epitaxial layers. Furthermore, we observed that electrical properties of AlGaN/AlN/GaN heterostructures depend on growth conditions of buffer layers and nitridation temperatures. The mobility in Al0.33Ga0.67N/AlN/GaN structures grown on single AlN buffer layers for 200 °C nitridation were 1300 cm2/Vs at a sheet charge of 1.6×1013 cm-2. Using the double buffer layer for 200 °C nitridation, the mobility increased to 1587 cm2/Vs with a sheet charge of 1.25×1013 cm-2.

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