Buried Quantum Well Structure Fabricated by in Situ EB Lithography

1991 ◽  
Vol 236 ◽  
Author(s):  
H. Kawanishi ◽  
Y. Sugimoto ◽  
T. Ishikawa ◽  
N. Tanaka ◽  
H. Hidaka
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Gaas Surface ◽  
Photoluminescence Intensity ◽  
Positive Type ◽  
Quantum Well Structures ◽  
Lithography Process ◽  
Order Of Magnitude ◽  
Processed Sample

AbstractBuried quantum well structures have been fabricated in GaAs/AIGaAs system using an in situ lithography process. The process utilizes an ultrathin oxide layer formed in situ on a GaAs surface as a mask against Cl2 gas etching. An electron beam (EB)-induced Cl2 gas etching is used to locally remove the oxide mask for positive-type lithography. For negativetype lithography, the oxide mask is selectively formed on a GaAs surface by EB-stimulated oxidation. Subsequent Cl2 gas etching results in the formation of isolated quantum wells. After removing the oxide mask, overgrowth using molecular beam epitaxy is successfully carried out on the patterned surface. The cathodoluminescence image of the buried quantum well demonstrates the high quality of the resulting structure formed by this “in situ EB lithography” process. The photoluminescence intensity from the quantum well of the processed sample is proved to be the same order of magnitude compared with that from a successively grown sample, showing that the use of the oxide mask causes no serious degradation in the processed interface.

scholarly journals In-situ photo-modulated reflectance study on the interface of Al and GaAs surface quantum well

2004 ◽  
Vol 53 (10) ◽  
pp. 3521
Author(s):  
Yuan Xian-Zhang ◽  
Miao Zhong-Lin
Keyword(s):  
Quantum Well ◽  
Gaas Surface

Evidence of Sequential Carrier Escape in III-V p-i-n Multi-Quantum Well Solar Cells

2007 ◽  
Vol 1031 ◽  
Author(s):  
Andenet Alemu ◽  
Jose A. H. Coaquira ◽  
Alex Freundlich
Keyword(s):  
Activation Energy ◽  
Solar Cells ◽  
Quantum Well ◽  
Quantum Wells ◽  
Effective Potential ◽  
Radiative Recombination ◽  
Energy Levels ◽  
Photoluminescence Intensity ◽  
Carrier Escape ◽  
Multi Quantum Well

AbstractSeveral InAsP/InP p-i-n Multi-Quantum Well (MQW) solar cells, only differing by their MQW region composition and geometry, were investigated. For each sample, the Arrhenius plot of the temperature related variation of the photoluminescence intensity was used to deduce the radiative recombination activation energy. The electron and holes confinement energy levels in the quantum wells and the associated effective potential barriers seen by each carrier were theoretically calculated. Carrier escape times were also estimated for each carrier. The fastest escaping carrier is found to display an effective potential energy barrier equal to the experimentally determined photoluminescence activation energy. This not only shows that the temperature related radiative recombination extinction process is driven by the carrier escape mechanism but also that the carriers escape process is sequential. Moreover, a discrepancy in device performance is directly correlated to the nature of the fastest escaping carrier.

Photoluminescence Fatigue in Laterally-Ordered (GaP)2/(InP)2 Short-Period-Superlattices (SPS) Grown by Molecular Beam Epitaxy

1993 ◽  
Vol 325 ◽  
Author(s):  
X. C. Liu ◽  
S. Q. Gu ◽  
E. E. Reuter ◽  
S. G. Bishop ◽  
A. C. Chen ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Quantum Well ◽  
Quantum Wells ◽  
Lower Energy ◽  
Molecular Beam ◽  
Continuous Illumination ◽  
Exciting Light ◽  
Quantum Well Structures ◽  
Short Period ◽  
Short Period Superlattices

AbstractSpontaneously laterally ordered (GaP)2/(InP)2 short period superlattices (SPS) grown by Molecular Beam Epitaxy (MBE) on nominal (100) GaAs substrates have been studied by photoluminescence (PL) spectroscopy. The samples studied included SPS comprising 110 pairs of (GaP)2/(InP)2 (total thickness σ90 nm) and multiquantum well structures in which quantum wells comprising 12 pairs of (GaP)2/(InP)2 SPS layers (thickness σ10 nm) are alternated with lattice-matched GaInP random alloy barrier layers. The 5K PL spectra include a σ1760 meV nearband edge band, and a much broader, lower energy (σ1670 meV) luminescence band that exhibits an unusual fatiguing behavior; its intensity diminishes monotonically during continuous illumination by the exciting light. This fatigued PL state is metastable at low temperatures. In the quantum well structure, although the relative intensity of the lower energy band is significantly weaker in comparison to the higher one, the fatiguing behavior still exists. However the fatiguing rate is slower in quantum well structures than that observed in the thick SPS film.

A THEORETICAL AND EXPERIMENTAL STUDY OF ELECTRONIC CONFINEMENT, COUPLING, AND TRANSLAYER INTERACTION IN NOBLE-METAL QUANTUM-WELL STRUCTURES

1994 ◽  
Vol 08 (18) ◽  
pp. 1075-1096 ◽  
Author(s):  
W. E. MCMAHON ◽  
T. MILLER ◽  
T.-C. CHIANG
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Noble Metal ◽  
Experimental Studies ◽  
Surface States ◽  
Double Quantum ◽  
Multilayer Systems ◽  
Quantum Well Structures ◽  
Double Quantum Well ◽  
Bloch Electrons

Noble-metal multilayer systems have been grown and examined with angle-resolved photoemission. Surface states, and single and double quantum wells have been studied experimentally; the results can be explained with a simple theoretical model based upon Bloch electrons. In this paper, we will present our model and then give a description of some experimental studies which utilize the model. In particular, we will consider double-quantum-well systems which can be used to examine basic aspects of electronic confinement, layer–layer coupling, and translayer interaction through a barrier.

Optical Gain Spectra in InGaN/GaN Quantum Wells with the Compositional Fluctuations

1998 ◽  
Vol 537 ◽  
Author(s):  
Takeshi Uenoyama
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Optical Gain ◽  
Inhomogeneous Broadening ◽  
Localized States ◽  
Quantum Well Structures ◽  
Potential Fluctuation ◽  
Quantum Disk ◽  
Gain Spectra

The compositional fluctuations of the In content were found in InGaN/GaN quantum wells and it caused the localized states by the potential fluctuation. We have evaluated the optical gain of GaN based quantum well structures with localized states. The localized states are treated as the subband states of the quantum disk-like dots in the well. It was found that the inhomogeneous broadening played an important role in the optical gain and that it should be reduced to use the benefit of the localized states for laser oscillations.

AES and EELFS Studies of Initial Stages of Growth of GaAs/InAs/GaAs Heterostructures.

1988 ◽  
Vol 144 ◽  
Author(s):  
F. D. Schowengerdt ◽  
F. J. Grunthaner ◽  
John K. Liu
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Growth Parameters ◽  
High Energy ◽  
Model Calculations ◽  
Mbe Growth ◽  
Quantum Well Structures ◽  
Stages Of Growth ◽  
Double Heterostructures ◽  
Composition And Structure

ABSTRACTWe report on a systematic study of the composition and structure of GaAs/InAs/GaAs quantum wells using Auger Electron Spectroscopy (AES), Extended Energy Loss Fine Structure (EELFS), and Reflection High Energy Electron Diffraction (RHEED) techniques. Double heterostructures with InAs thickness ranging from 2 to 10 monolayers, capped by 2 to 10 monolayers of GaAs, were grown by MBE using a variety of techniques, including those employing sequential, interrupted, and delayed shutter timing sequences. AES peak ratios are compared with model calculations to monitor compositional development of the multilayers. The AES results are correlated with RHEED measurements to determine MBE growth parameters for optimal control of the stoichiometry and surface morphology. EELFS was used to monitor strain in the buried InAs layers. The AES results show departure from smooth laminar growth of layers of stoichiometric InAs on GaAs at temperatures below 420 C and above 470 C. AES results on the quantum well structures suggest floating InAs layers on top of the GaAs and/or facet formation in the GaAs layers. The EELFS results, when compared to bulk InAs, indicate the presence of strain in the buried InAs quantum well.

In Situ Flux Transient Monitoring and Correction During MBE Growth of Quantum Well Structures

1993 ◽  
Vol 300 ◽  
Author(s):  
F. G. Celii ◽  
Y.-C. Kao ◽  
A. J. Katz
Keyword(s):  
Quantum Well ◽  
Multiple Quantum Well ◽  
Effusion Cell ◽  
Multiple Quantum ◽  
Group V ◽  
Quantum Well Structures ◽  
Group Iii ◽  
Tunneling Diode ◽  
Partial Pressures

ABSTRACTShutter closure during MBE deposition causes source overheating and results in flux transients. These transients are particularly detrimental to the thickness and compositional accuracy of thin quantum well layers. In this paper, we document the effects of flux transients on growth of multiple quantum well (MQW) and resonant tunneling diode (RTD) structures, and demonstrate rudimentary transient correction by employing real-time flux detection.Reflection mass spectrometry (REMS) provides a convenient in situ method for MBE flux monitoring. The Group III partial pressures can be detected in the presence of Group V overpressure, and REMS is compatible with wafer rotation. We used REMS to characterize In, Al and Ga flux transients as a function of shutter closed time, cell flux and substrate temperature. Overshoot magnitudes up to 30% were observed. We verified the correspondence of REMS signal transients and effusion cell flux transients using GaAs/AlGaAs and InGaAs/lnAlAs MQW and test structures. We also successfully demonstrated flux transient correction by cell temperature ramping during MQW and RTD growth.

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