Analysis of AlGaAs/GaAs/InGaAs n-type step multiple quantum wells for the optimization of normal incident absorption
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Authors
Cheah, C.W.
Karunasiri, G.
Tan, L.S.
Subjects
Advisors
Date of Issue
2002
Date
Publisher
IOP Publishing
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Abstract
The response to normal incident radiation in n-type square quantum wells (QWs) is generally expected to be very small because, in the framework of the effective mass model, the parity selection rule of the envelope wavefunctions essentially forbids intersubband transitions induced by transverse electric polarized radiation. This problem can be overcome by employing an asymmetrical QW. In this paper, the effect of asymmetry, and the result of band mixing with the p-like valence and conduction bands due to the truncation of bulk crystal periodicity, of an n-type AlGaAs/GaAs/InGaAs step multiple QW, are analysed using a new 14-band k · p model with envelope function approximation. The structural and material parameters of the device are varied to study the probability density distributions of the ground state and first excited state wavefunctions, and their effect on the response of the device to transverse electric (TE) and transverse magnetic (TM) excitations. From the analysis, it is found that a step multiple QW optimized for absorption of TE mode radiation should have a wide GaAs step and a deep InGaAs well, subjected to the constraints of the material growth and fabrication process of the device. It is also found that, despite the efforts of improving the normal incidence absorption via step well optimization, the TE absorption as predicted using the 14-band k · p model remains less than 1% of the TM absorption.
Type
Article
Description
Series/Report No
Department
Physics
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NPS Report Number
Sponsors
Singapore Science and Technology Board
National University of Singapore
National University of Singapore
Funding
Singapore Science and Technology Board grant GR 6471, Project 4.
Format
10 p.
Citation
Cheah, C. W., G. Karunasiri, and L. S. Tan. "Analysis of AlGaAs/GaAs/InGaAs n-type step multiple quantum wells for the optimization of normal incident absorption." Semiconductor science and technology 17.9 (2002): 1028.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.