Indium Composition Dependence of Raman Spectroscopy and Photocurrent of InxGa1−xAs Strained Layers Grown by Using MOCVD

ABSTRACTThe rate of solid-phase epitaxial regrowth has been studied using time-resolved reflectivity in three different types of SiGe/Si epilayers amorphized by ion implantation. In two of these cases, the alloy epilayer contained either 12% or 20% Ge, and the amorphization depth was greater than the thickness (2000 Å) of the SiGe alloy layer. Time-resolved reflectivity measurements showed that the rate of regrowth was not constant in these two cases, but first decreased after passing the SiGe/Si interface, and then increased. The minimum regrowth rate occurred closer to the SiGe/Si interface in the epilayers with the larger Ge atomic fraction. In the third type of sample, the alloy epilayer thickness was ∼7μm, so that the initial epilayer (15% Ge) had the lattice constant of the bulk alloy. Furthermore, amorphization and regrowth occurred entirely within the relaxed alloy layer. In this case, the regrowth rate was constant. The composition dependence of the regrowth-rate transient in the strained layers is discussed in the context of a ‘critical-thickness’ model of strain relaxation.

Download Full-text

Optical Studies of InP/GaAs/InP Single Strained Layers

MRS Proceedings ◽

10.1557/proc-281-203 ◽

1992 ◽

Vol 281 ◽

Author(s):

Dan Hessman ◽

Mats-Erik Pistol ◽

Janos Olajos ◽

Werner Seifert ◽

Xiao Liu ◽

...

Keyword(s):

Raman Spectroscopy ◽

Spectral Shape ◽

Type Ii ◽

Photoluminescence Excitation ◽

Optical Studies ◽

Excitation Spectra ◽

Optical Techniques ◽

Strained Layers

ABSTRACTSingle strained layers of GaAs grown on InP have been studied using different optical techniques. Absorption has been measured on these structure which are believed to be type II. The absorption is found to increase slowly close to the threshold and the spectral shape is very similar to photoluminescence excitation spectra. No sharp excitonic peaks were found. The absorption has been modelled using K.p-theory including strain and confinement. The agreement with experiments is good with respect to the shape of the spectra but differs a factor of three with respect to the magnitude of the absorption. The strain and composition of the samples have been measured by a combination of photoluminescence and Raman spectroscopy.

Download Full-text

Thermal Stability of Thin Virtual Substrates for High Performance Devices

MRS Proceedings ◽

10.1557/proc-0913-d02-05 ◽

2006 ◽

Vol 913 ◽

Author(s):

Sarah H Olsen ◽

Steve J Bull ◽

Peter Dobrosz ◽

Enrique Escobedo-Cousin ◽

Rimoon Agaiby ◽

...

Keyword(s):

Thermal Stability ◽

Raman Spectroscopy ◽

Layer Thickness ◽

Critical Thickness ◽

Great Promise ◽

Initial Growth ◽

Strained Si ◽

Strained Layers ◽

Wide Range ◽

The Impact

AbstractDetailed investigations of strain generation and relaxation in Si films grown on thin Si0.78Ge0.22 virtual substrates using Raman spectroscopy are presented. Good virtual substrate relaxation (>90%) is achieved by incorporating C during the initial growth stage. The robustness of the strained layers to relaxation is studied following high temperature rapid thermal annealing typical of CMOS processing (800-1050 °C). The impact of strained layer thickness on thermal stability is also investigated. Strain in layers below the critical thickness did not relax following any thermal treatments. However for layers above the critical thickness the annealing temperature at which the onset of strain relaxation occurred appeared to decrease with increasing layer thickness. Strain in Si layers grown on thin and thick virtual substrates having identical Ge composition and epilayer thickness has been compared. Relaxation through the introduction of defects has been assessed through preferential defect etching in order to verify the trends observed. Raman signals have been analysed by calibrated deconvolution and curve-fitting of the spectra peaks. Raman spectroscopy has also been used to study epitaxial layer thickness and the impact of Ge out-diffusion during processing. Improved device performance and reduced self-heating effects are demonstrated in thin virtual substrate devices when fabricated using strained layers below the critical thickness. The results suggest that thin virtual substrates offer great promise for enhancing the performance of a wide range of strained Si devices.

Download Full-text

Mid-infrared emission in InxGa1−xAs/GaAs T-shaped quantum wire lasers and its indium composition dependence

Infrared Physics & Technology ◽

10.1016/j.infrared.2018.01.009 ◽

2018 ◽

Vol 89 ◽

pp. 218-222 ◽

Cited By ~ 5

Author(s):

Said Ridene

Keyword(s):

Quantum Wire ◽

Composition Dependence ◽

Infrared Emission ◽

Mid Infrared ◽

Indium Composition

Download Full-text

Spectroscopic investigations of polycrystalline InxSb20−xAg10Se70 (0 ⩽ × ⩽ 15) multicomponent chalcogenides

Materials Science-Poland ◽

10.1515/msp-2016-0114 ◽

2016 ◽

Vol 34 (4) ◽

pp. 794-799 ◽

Cited By ~ 1

Author(s):

Rita Sharma ◽

Shaveta Sharma ◽

Praveen Kumar ◽

Ravi Chander ◽

R. Thangaraj ◽

...

Keyword(s):

Raman Spectroscopy ◽

Physical Properties ◽

Solid Solutions ◽

Composition Dependence ◽

Alloy Composition ◽

Alloy System ◽

Indium Content ◽

Structural Modifications ◽

System A ◽

Phase Quantification

AbstractThe composition dependence of physical properties of chalcogenides has recently been studied for their phase change properties and energy conversion. In the present work, we report the structure, composition, optical and Raman spectroscopy results for bulk polycrystalline InxSb20−xAg10Se70 (0 ⩽ × ⩽ 15) samples. The phase quantification and composition have been studied by using XRD and EDX techniques. The alloy composition up to 5 at.% of indium resulted in crystallization of AgSbSe2, while further increase in In content favored the formation of another chalcopyrite AgInSe2 phase yielding the solid solutions for this alloy system. A decrease in band gap up to x = 5 followed by its increase with an increase in indium concentration has been observed. The variations in shape and position of characteristic Raman bands has been used for understanding the structural modifications of the network with the variation in indium content.

Download Full-text

Defect morphology in thick relaxed layers of InGaAs on GaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176472 ◽

1990 ◽

Vol 48 (4) ◽

pp. 668-669

Author(s):

R H Dixon ◽

P Kidd ◽

P J Goodhew

Keyword(s):

Electron Microscopy ◽

Surface Morphology ◽

Growth Conditions ◽

X Ray Diffraction ◽

Double Crystal ◽

Strained Layers ◽

Good Surface ◽

Transmission Electron ◽

Device Structures ◽

Surface Morphologies

Thick relaxed InGaAs layers grown epitaxially on GaAs are potentially useful substrates for growing high indium percentage strained layers. It is important that these relaxed layers are defect free and have a good surface morphology for the subsequent growth of device structures.3μm relaxed layers of InxGa1-xAs were grown on semi - insulating GaAs substrates by Molecular Beam Epitaxy (MBE), where the indium composition ranged from x=0.1 to 1.0. The interface, bulk and surface of the layers have been examined in planar view and cross-section by Transmission Electron Microscopy (TEM). The surface morphologies have been characterised by Scanning Electron Microscopy (SEM), and the bulk lattice perfection of the layers assessed using Double Crystal X-ray Diffraction (DCXRD).The surface morphology has been found to correlate with the growth conditions, with the type of defects grown-in to the layer (e.g. stacking faults, microtwins), and with the nature and density of dislocations in the interface.

Download Full-text