Arsenic Incorporation in InP Epilayers and Arsenide/InP Heterostructures Grown by Chemical Beam Epitaxy

1994 ◽  
Vol 340 ◽  
Author(s):  
V. Rossignol ◽  
A. H. Bensaoula ◽  
A. Freundlich ◽  
A. Bensaoula ◽  
G. Neu
Keyword(s):  
Quantum Wells ◽  
Flux Ratio ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Chemical Beam Epitaxy ◽  
X Ray Diffraction ◽  
Group V ◽  
Low Levels ◽  
Diffraction Patterns ◽  
Arsenic Incorporation

ABSTRACTLow levels of arsenic contamination have been previously reported (∼0.01%) in CBE grown InP by different groups. The level of As incorporation in InP is usually enhanced when arsenide(InGaAs, InAsP) / InP heterostructures are grown.In this work, optimal growth conditions to minimize the non-intentional As contamination during the growth of these heterostructures are discussed. The red shift of band-edge excitons in the low temperature photoluminescence spectra as well as the analysis of high resolution X-ray diffraction patterns of InAsP/InP multi-quantum wells suggest the presence of As in InP barriers. This contamination is consistent with the ratio of As/P partial pressure (As residual in the chamber: 10-9-10-8 Torr) and the As/P incorporation rates. We have studied the influence of the growth temperature, the group-V/III flux ratio and the growth rate on the level of the As incorporation.

High Indium Content Ingan Films and Quantum Wells.

1997 ◽  
Vol 482 ◽  
Author(s):  
W. Van Der Stricht ◽  
K. Jacobs ◽  
I. Moerman ◽  
P. Demeester ◽  
L. Considine ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Rotating Disk ◽  
Growth Conditions ◽  
Indium Content ◽  
X Ray ◽  
High Indium Content ◽  
Diffraction Patterns ◽  
Very High ◽  
Characterisation Techniques ◽  
Incorporation Efficiency

AbstractInGaN films and InGaN/GaN quantum wells with high indium content have been grown by MOVPE and characterised to evaluate the growth process and the indium incorporation efficiency. The characterisation techniques include photoluminescence, DC X-ray and TEM. The closed spaced vertical rotating disk reactor configuration results in a very high Indium incorporation for InGaN material, compared to other configurations. InGaN layers with an indium composition up to 56 % have been deposited which still exhibit very good optical properties (intense PL emission). The influence of various growth conditions on the InGaN composition and quality have been investigated to optimize the layer quality. TEM diffraction patterns have shown that the ternary InGaN layer can be chemically ordered. The In and Ga atoms occupy respectively the two simple hexagonal sublattice sites related by the glide mirrors and helicoidal axes of the P6 3mc symmetry group of the wurtzite GaN.

Sticking and Desorption Coefficients of As4 and As2 During Group V and Group III Controlled MBE Growth

1992 ◽  
Vol 263 ◽  
Author(s):  
Rouel Fernandez
Keyword(s):  
Activation Energy ◽  
Flux Ratio ◽  
Growth Conditions ◽  
High Energy ◽  
Controlled Growth ◽  
Sticking Coefficient ◽  
Group V ◽  
Mbe Growth ◽  
Group Iii ◽  
Sticking Coefficients

ABSTRACTReflection High Energy Electron Diffraction (RHEED) oscillations under arsenic and gallium-controlled Molecular Beam Epitaxy (MBE) growth conditions have been used to measure the sticking and desorption coefficients of As2 and As4. The coefficients are obtained from measurements of the arsenic incorporation rates. Comparisons are made with measurements obtained from desorption rates using modulated beam mass spectroscopy. The transition from gallium to arsenic-controlled growth is observed to occur after excess gallium atoms accumulate on the surface. The maximum intrinsic arsenic sticking coefficients occur when the maximum number of gallium atoms can be incorporated for a given arsenic flux. The intrinsic maximum arsenic sticking coefficients are found to be 0.75 and 0.50 for As2 and As4, respectively. During galliumcontrolled growth, the arsenic sticking coefficients are independent of substrate temperature as long as the sticking coefficient of gallium is equal to one. However, a temperature dependent maximum gallium-controlled arsenic sticking coefficient exists. It can be measured by the maximum Ga to As4 flux ratio that produces specular film surfaces. During gallium-controlled growth, the Ga to As flux ratios are shown to be equal to the gallium-controlled arsenic sticking coefficients. The activation energy for arsenic desorption during arsenic-controlled growth conditions was measured as -0.50 eV for independent As4 and As2 incident fluxes. During gallium-controlled growth with incident As4 fluxes, an activation energy for arsenic desorption of -0.70 eV was measured for the maximum gallium-controlled arsenic sticking coefficients.

scholarly journals Transcriptional regulation of SSA3, an HSP70 gene from Saccharomyces cerevisiae.

1990 ◽  
Vol 10 (6) ◽  
pp. 3262-3267 ◽  
Author(s):  
W R Boorstein ◽  
E A Craig
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Double Mutant ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Hsp70 Gene ◽  
Base Pairs ◽  
Double Mutant Strain ◽  
Low Levels ◽  
Necessary And Sufficient

The SSA3 gene of Saccharomyces cerevisiae, a member of the HSP70 multigene family, is expressed at low levels under optimal growth conditions and is dramatically induced in response to heat shock. Sequences coinciding with two overlapping heat shock elements, located 156 base pairs upstream of the transcribed region, were necessary and sufficient for regulation of heat induction. The SSA3 promoter was also activated in an ssa1ssa2 double-mutant strain. This increase in the expression of SSA3 was mediated via the same upstream activating sequences that activated transcription in response to heat shock.

High-resolution X-ray diffraction investigation of crystal perfection and relaxation of GaAs/InGaAs/GaAs quantum wells depending on MOVPE growth conditions

1997 ◽  
Vol 19 (2-4) ◽  
pp. 369-376 ◽  
Author(s):  
U. Zeimer ◽  
F. Bugge ◽  
S. Gramlich ◽  
I. Urban ◽  
A. Oster ◽  
...  
Keyword(s):  
High Resolution ◽  
Quantum Wells ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Perfection ◽  
Movpe Growth

Chemical Beam Epitaxy of III-V Semiconductor Heterostructures

1987 ◽  
Vol 102 ◽  
Author(s):  
W. T. Tsang
Keyword(s):  
Quantum Wells ◽  
Molecular Beam ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Chemical Beam Epitaxy ◽  
Group V ◽  
Group Iii ◽  
Group Iv Semiconductors ◽  
Gas Source Mbe

ABSTRACTThis paper reviews briefly some of the recent progress in chemical beam epitaxy (CBE) for the preparation of GaInAs(P)/InP and GaAs/AlGaAs quantum wells, superlattices, and heterostructure devices. Chemical beam epitaxy can be viewed as a chemical vapor deposition process but with the pressure inside the growth chamber sufficient, ow (< 10-4 torr) so that the transport of the gaseous reactants becomes molecular beam instead of via viscous flow. This not only eliminates the complicated gas phase reactions and the stagnant boundary layer above the substrate through which the reactants have to diffuse, but also allows for quick transitions of material compositions and dopings as those achievable by molecular beam epitaxy (MBE). For the growth of HI-V semiconductors, the group Inl elements are derived by the pyrolysis of organometallics (or inorganometallics such as dopant gases) on the heated substrate surface, while the group V elements are derived by the thermal decomposition of hydrides using a high temperature cracker. For the growth of group IV semiconductors, beams of inorganometallic compounds are used. Thus, both organometallic and inorganometallic compounds can be used as starting sources. There are two other alternatives: the gas source MBE (GSMBE), which uses group III elements evaporated from solid sources as in MBE and thermally decomposed hydrides, and the metalorganic MBE (MOMBE), which uses metalorganics as group III sources and group V elements evaporated from solid sources as in MBE. These other processes will not be reviewed here. Introd

X-Ray Scattering (Modeling and Experiment) of InxGa1-xAs/GaAs Multiple Quantum Wells

1987 ◽  
Vol 103 ◽  
Author(s):  
Jichai Jeong ◽  
J. C. Lee ◽  
M. A. Shahid ◽  
T. E. Schlesinger ◽  
A. G. Milnes
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Quantum Well Structures ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Good Agreement

ABSTRACTX-ray diffraction, transmission electron microscopy (TEM), and photoluminescence measurements have been made on strained InxGa1-xAs/GaAs quantum well structures. The well widths measured from TEM are 187, 115 and 69 Å for an interrupted growth, and 218, 126, 60 Å for a non-interrupted growth. In the measured x-ray diffraction patterns, the Pendellosung fringes due to GaAs barriers are modulated by a broad weak peak mostly coming from the thickest InxGa1-xAs well layer and is fairly symmetric for the noninterrupted sample. For the interrupted quantum well, the x-ray diffraction pattern is less symmetric, since there is further modulation by another broader and weaker peak. This results show that the In content in the InxGa1-xAs well layers are not well controlled for the interrupted quantum well. Using actual thickness measured from TEM, x-ray diffraction patterns are calculated and good agreement is obtained between the measured and the calculated x-ray diffraction patterns. The three strained InxGa1-xAs/Gaks quantum wells grown without interruption produce high intensity and narrow full-width at half-maximum (FWHIM) of 2.9 meV of the photoluminescence peak. The photoluminescence peaks for the interrupted quantum well are relatively broad and asymmetric, and have lower intensities, indicating that better quality InxGa1-xAs/GaAs quantum wells can be grown without interruption.

Direct Bandgap Quantum Wells on GaP

1996 ◽  
Vol 448 ◽  
Author(s):  
Jong-Won Lee ◽  
Alfred T. Schremer ◽  
Dan Fekete ◽  
James R. Shealy ◽  
Joseph M. Ballantyne
Keyword(s):  
Quantum Wells ◽  
Variable Temperature ◽  
Growth Conditions ◽  
Band Alignment ◽  
Type I ◽  
X Ray Diffraction ◽  
Direct Bandgap ◽  
Conduction Band Offset ◽  
Alloy Semiconductors ◽  
Lattice Matched

AbstractCurrently, there are no direct-bandgap alloy semiconductors that can be grown lattice-matched to GaP substrates. A strained layer of GaInP can be grown on GaP, however, with difficulties. First, GaInP is an indirect-bandgap material for In concentrations up to ∼30%. Second, the band alignment between GaInP and GaP is type-II for In concentrations up to ∼60%. The Mathews-Blakeslee critical thickness of GaInP layer on GaP is prohibitively small in the useful In concentration range. GaInP is known to grow in an ordered phase in certain growth conditions. By changing the growth conditions, a heterojunction of ordered GaInP and disordered GaInP can be grown. The conduction band offset going from a disordered GaInP phase to an ordered GaInP phase has been reported to be about 150 meV. Using a layer of ordered GaInP, a QW with type-I band alignment may be grown on GaP for a wider range of composition.We have grown a series of approximately 60 Å thick GaP/GaInP/GaP strained quantum wells of various compositions using OMVPE. Strong photoluminescence, which exhibited an unusual temperature dependence, has been observed on many samples. A study of the QW’s using X-ray diffraction, TEM, and variable temperature PL reveals behaviors consistent with direct bandgap GaInP quantum wells containing ordered and disordered domains.

Optimal Growth Conditions of AlGaAs/GaAs Quantum Wells by Flow-Rate Modulation Epitaxy

1989 ◽  
Vol 28 (Part 2, No. 2) ◽  
pp. L155-L158 ◽  
Author(s):  
Yoshiharu Yamauchi ◽  
Toshiki Makimoto ◽  
Yoshiji Horikoshi
Keyword(s):  
Quantum Wells ◽  
Flow Rate ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Rate Modulation

Transcriptional regulation of SSA3, an HSP70 gene from Saccharomyces cerevisiae

1990 ◽  
Vol 10 (6) ◽  
pp. 3262-3267
Author(s):  
W R Boorstein ◽  
E A Craig
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Double Mutant ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Hsp70 Gene ◽  
Base Pairs ◽  
Double Mutant Strain ◽  
Low Levels ◽  
Necessary And Sufficient

The SSA3 gene of Saccharomyces cerevisiae, a member of the HSP70 multigene family, is expressed at low levels under optimal growth conditions and is dramatically induced in response to heat shock. Sequences coinciding with two overlapping heat shock elements, located 156 base pairs upstream of the transcribed region, were necessary and sufficient for regulation of heat induction. The SSA3 promoter was also activated in an ssa1ssa2 double-mutant strain. This increase in the expression of SSA3 was mediated via the same upstream activating sequences that activated transcription in response to heat shock.

scholarly journals Low-temperature growth of GaSb epilayers on GaAs (001) by molecular beam epitaxy

2016 ◽  
Vol 24 (1) ◽  
Author(s):  
D. Benyahia ◽  
Ł. Kubiszyn ◽  
K. Michalczewski ◽  
A. Kębłowski ◽  
P. Martyniuk ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Molecular Beam Epitaxy ◽  
Low Temperature ◽  
Surface Morphology ◽  
Growth Temperature ◽  
Molecular Beam ◽  
Hole Concentration ◽  
Flux Ratio ◽  
X Ray Diffraction ◽  
Group V

Non-intentionally doped GaSb epilayers were grown by molecular beam epitaxy (MBE) on highly mismatched semi-insulating GaAs substrate (001) with 2 offcut towards [110]. The effects of substrate temperature and the Sb/Ga flux ratio on the crystalline quality, surface morphology and electrical properties were investigated by Nomarski optical microscopy, X-ray diffraction (XRD) and Hall measurements, respectively. Besides, differential Hall was used to investigate the hole concentration behaviour along the GaSb epilayer. It is found that the crystal quality, electrical properties and surface morphology are markedly dependent on the growth temperature and the group V/III flux ratio. Under the optimized parameters, we demonstrate a low hole concentration at very low growth temperature. Unfortunately, the layers grown at low temperature are characterized by wide FWHM and low Hall mobility.

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