Evidence for Non-Equilibrium Vacancy Concentrations Controlling Interdiffusion in III-V Materials

1998 ◽  
Vol 527 ◽  
Author(s):  
W.P. Gillin ◽  
O.M. Khreis ◽  
K.P. Homewood
Keyword(s):  
Thermal Equilibrium ◽  
Multiple Quantum Well ◽  
Flux Ratio ◽  
Growth Conditions ◽  
Background Concentration ◽  
Multiple Quantum ◽  
Single Experiment ◽  
Self Diffusion ◽  
Equilibrium Vacancy ◽  
Thin Source

ABSTRACTInterdiffusion and self-diffusion in III-V semiconductors has usually been assumed to operate through the diffusion of point defects, the concentrations of which are at thermal equilibrium values. We have studied the interdiffusion of multiple quantum well samples, grown under a range of growth conditions, each containing a thin source of vacancies. This has enabled simultaneous measurements of the interdiffusion coefficient, diffusion coefficient for vacancies and the concentration of those vacancies in a single experiment. We have shown that independent of growth conditions, within a wide window of III-V flux ratio and temperature, the diffusion at all temperatures is governed by a constant background concentration of vacancies.

Growth of Nonpolar (1100) Films and Heterostructures by Plasma-Assisted Molecular Beam Epitaxy

2004 ◽  
Vol 831 ◽  
Author(s):  
Oliver Brandt ◽  
Yue Jun Sun ◽  
Klaus H. Ploog
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Multiple Quantum Well ◽  
Growth Conditions ◽  
High Energy ◽  
Growth Direction ◽  
Desorption Kinetics ◽  
Multiple Quantum ◽  
Kinetics Of

ABSTRACTWe discuss the growth of M-plane GaN films and (In, Ga)N/GaN multiple quantum well (MQW) structures on LiAlO2(100) substrates by plasma-assisted molecular beam epitaxy. The adsorption and desorption kinetics of Ga on M-plane GaN is studied by reflection high-energy electron diffraction, allowing us to identify the optimum growth conditions with regard to surface morphology. Furthermore, we investigate the compositional profile of M-plane (In, Ga)N/GaN MQWs grown under conditions resulting in comparatively abrupt interfaces. The results demonstrate that significant In surface segregation occurs for the case of M-plane (In, Ga)N. The dependence of the transition energies of the M-plane MQWs on the actual well thickness reveals, however, that the structures are indeed free of electrostatic fields along the growth direction.

Molecular Beam Epitaxy of Cubic Group III-Nitrides on Free-Standing 3C-SiC Substrates

2006 ◽  
Vol 527-529 ◽  
pp. 1489-1492 ◽  
Author(s):  
Donat J. As ◽  
S. Potthast ◽  
J. Schörmann ◽  
S.F. Li ◽  
K. Lischka ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Multiple Quantum Well ◽  
Group Iii Nitrides ◽  
Growth Conditions ◽  
Multiple Quantum ◽  
Free Standing ◽  
X Ray ◽  
Group Iii ◽  
Cubic Gan

Cubic GaN, AlxGa1-xN/GaN and InyGa1-yN/GaN multiple quantum well (MQW) layers were grown by plasma assisted molecular beam epitaxy on 200 &m thick free standing 3C-SiC substrates. The influence of the surface roughness of the 3C-SiC substrates and the influence of metal coverage during growth are discussed. Optimum growth conditions of c-III nitrides exist, when a one monolayer Ga coverage is formed at the growing surface. The improvement of the structural properties of cubic III-nitride layers and multilayers grown on 3C-SiC substrates is demonstrated by 1 μm thick c-GaN layers with a minimum x-ray rocking curve width of 16 arcmin, and by c-AlGaN/GaN and c-InGaN/GaN MQWs which showed up to five satellite peaks in X-ray diffraction, respectively.

High Resolution X-ray Diffraction Characterization of [111]B Oriented InGaAs/GaAs Mqw Structures

1995 ◽  
Vol 39 ◽  
pp. 439-448
Author(s):  
A Sanz-Hervas ◽  
A Sacedón ◽  
E.J Abril ◽  
J.L Sanchez-Rojas ◽  
C. Villar ◽  
...  
Keyword(s):  
High Resolution ◽  
Quantum Well ◽  
Structural Information ◽  
Multiple Quantum Well ◽  
Growth Conditions ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Quantum Well Structures ◽  
X Ray

In this work we apply high-resolution X-ray diffractometry to the study of InGaAs/GaAs multiple quantum well structures on (001) and(lll)B GaAs substrates. The samples consisted of p-i-n diodes with a multiple quantum well embedded in the i-region and were simultaneously grown on (001) and (111)B substrates by molecular beam epitaxy. For the characterization we have used symmetric and asymmetric reflections at different azimuthal positions. The interpretation of the diffraction profiles has been possible thanks to our recently developed simulation model, which allows the calculation of any reflection regardless of the substrate orientation. X-ray results about composition and thickness are very similar in the samples simultaneously grown on both orientations as expected from our specific growth conditions. The information obtained from X-ray characterization is consistent with the results of photoluminescence and photocurrent measurements within the experimental uncertainty of the techniques. In (lll)B samples, X-ray diffractometry provides structural information which cannot be easily obtained from optical characterization techniques.

Optimizing growth conditions for GaN/AlxGa1−xN multiple quantum well structures

2000 ◽  
Vol 76 (7) ◽  
pp. 864-866 ◽  
Author(s):  
K. C. Zeng ◽  
J. Li ◽  
J. Y. Lin ◽  
H. X. Jiang
Keyword(s):  
Quantum Well ◽  
Multiple Quantum Well ◽  
Growth Conditions ◽  
Multiple Quantum ◽  
Quantum Well Structures

RESONANT TUNNELING STUDIES OF VARIABLY SPACED MULTIPLE QUANTUM WELL STRUCTURES IN THE AlGaAs SYSTEM

1987 ◽  
Vol 48 (C5) ◽  
pp. C5-457-C5-461
Author(s):  
C. J. SUMMERS ◽  
K. F. BRENNAN ◽  
A. TORABI ◽  
H. M. HARRIS ◽  
J. COMAS
Keyword(s):  
Quantum Well ◽  
Resonant Tunneling ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Quantum Well Structures

Thermoelectric Properties of PbSr(Se,Te)-Based Low Dimensional Structures

2000 ◽  
Vol 626 ◽  
Author(s):  
Harald Beyer ◽  
Joachim Nurnus ◽  
Harald Böttner ◽  
Armin Lambrecht ◽  
Lothar Schmitt ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Evaluation Method ◽  
Interband Transition ◽  
Multiple Quantum Well ◽  
Calculated Data ◽  
Multiple Quantum ◽  
Ir Transmission ◽  
Low Dimensional

ABSTRACTThermoelectric properties of low dimensional structures based on PbTe/PbSrTe-multiple quantum-well (MQW)-structures with regard to the structural dimensions, doping profiles and levels are presented. Interband transition energies and barrier band-gap are determined from IR-transmission spectra and compared with Kronig-Penney calculations. The influence of the data evaluation method to obtain the 2D power factor will be discussed. The thermoelectrical data of our layers show a more modest enhancement in the power factor σS2 compared with former publications and are in good agreement with calculated data from Broido et al. [5]. The maximum allowed doping level for modulation doped MQW structures is determined. Thermal conductivity measurements show that a ZT enhancement can be achieved by reducing the thermal conductivity due to interface scattering. Additionally promising lead chalcogenide based superlattices for an increased 3D figure of merit are presented.

Low-Temperature Operation of Green, Blue and UV InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes

2003 ◽  
Vol 764 ◽  
Author(s):  
X. A. Cao ◽  
S. F. LeBoeuf ◽  
J. L. Garrett ◽  
A. Ebong ◽  
L. B. Rowland ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Localized States ◽  
Multiple Quantum ◽  
Nonradiative Recombination ◽  
Light Emitting ◽  
Temperature Range ◽  
Green Leds

Absract:Temperature-dependent electroluminescence (EL) of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with peak emission energies ranging from 2.3 eV (green) to 3.3 eV (UV) has been studied over a wide temperature range (5-300 K). As the temperature is decreased from 300 K to 150 K, the EL intensity increases in all devices due to reduced nonradiative recombination and improved carrier confinement. However, LED operation at lower temperatures (150-5 K) is a strong function of In ratio in the active layer. For the green LEDs, emission intensity increases monotonically in the whole temperature range, while for the blue and UV LEDs, a remarkable decrease of the light output was observed, accompanied by a large redshift of the peak energy. The discrepancy can be attributed to various amounts of localization states caused by In composition fluctuation in the QW active regions. Based on a rate equation analysis, we find that the densities of the localized states in the green LEDs are more than two orders of magnitude higher than that in the UV LED. The large number of localized states in the green LEDs are crucial to maintain high-efficiency carrier capture at low temperatures.

High-Temperature High-Frequency Operation of Single and Multiple Quantum Well InGaAs Semiconductor Lasers

2000 ◽  
Author(s):  
William J. Siskaninetz ◽  
Hank D. Jackson ◽  
James E. Ehret ◽  
Jeffrey C. Wiemeri ◽  
John P. Loehr
Keyword(s):  
High Temperature ◽  
Quantum Well ◽  
Semiconductor Lasers ◽  
High Frequency ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
High Frequency Operation

Terahertz Radiators Based on Si~3C-SiC MQW IMPATT Diodes

2020 ◽  
Vol 10 (4) ◽  
pp. 501-506
Author(s):  
Monisha Ghosh ◽  
Arindam Biswas ◽  
Aritra Acharyya
Keyword(s):  
High Frequency ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Noise Performance ◽  
Rf Power ◽  
Drift Diffusion ◽  
Frequency Bands ◽  
Atmospheric Window ◽  
Lower Noise ◽  
Impatt Diodes

Aims:: The potentiality of Multiple Quantum Well (MQW) Impacts Avalanche Transit Time (IMPATT) diodes based on Si~3C-SiC heterostructures as possible terahertz radiators have been explored in this paper. Objective:: The static, high frequency and noise performance of MQW devices operating at 94, 140, and 220 GHz atmospheric window frequencies, as well as 0.30 and 0.50 THz frequency bands, have been studied in this paper. Methods: The simulation methods based on a Self-Consistent Quantum Drift-Diffusion (SCQDD) model developed by the authors have been used for the above-mentioned studies. Results: Thus the noise performance of MQW DDRs will be obviously better as compared to the flat Si DDRs operating at different mm-wave and THz frequencies. Conclusion:: Simulation results show that Si~3C-SiC MQW IMPATT sources are capable of providing considerably higher RF power output with the significantly lower noise level at both millimeter-wave (mm-wave) and terahertz (THz) frequency bands as compared to conventional flat Si IMPATT sources.

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