Effects of external perturbations on the optical properties of semiconductor microstructures.
Item
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Title
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Effects of external perturbations on the optical properties of semiconductor microstructures.
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Identifier
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AAI9405578
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identifier
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9405578
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Creator
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Qiang, Hao.
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Contributor
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Adviser: Fred H. Pollak
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Date
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1993
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Condensed Matter | Physics, Optics | Physics, Electricity and Magnetism
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Abstract
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Semiconductor microstructures have become more and more important because they have generated many types of novel devices. Optical spectroscopy is one of the most powerful tools in studying semiconductor microstructures. In this thesis, modulation spectroscopy (MS) and time resolved photoluminescence (PL) spectroscopy have been used to study the effects of external perturbations, such as temperature, electric field and uniaxial stress, on the optical properties of semiconductor microstructures.;Temperature dependence of the MS line shape, exciton transition energy and linewidth of quantum well (QW) structures have been studied. We report the experimental evidence of the reduced exciton-phonon interaction in reduced dimensional systems.;Electric field effects in semiconductor microstructures are quite different from the bulk semiconductor materials. Effects of homogeneous electric field controlled by external bias have been studied in QW and coupled double QW (CDQW) structures. Pseudomorphic InGaAs high electron mobility transistors (HEMT) with huge built-in inhomogeneous electric field have also been studied.;Uniaxial stress is a very powerful tool for tuning the electronic band structures. Deformation potentials of AlGaAs ternary alloy materials of several Al compositions have been measured. QW structures of different material systems such as unstrained GaAs/AlGaAs, biaxially compressed InGaAs/GaAs, and biaxially tensioned GaAs/Si systems have been studied under large in-plane uniaxial stress (up to 10 {dollar}\sim{dollar} 20 kbar). Both the energy dependence and polarization behavior are quite different for light and heavy hole features. Phenomena related to the piezoelectric field have been observed for the low symmetry (110) stress axis. Different screening to the generated electric field has been observed among different material systems such as between InGaAs/GaAs and GaAs/AlGaAs systems. Preliminary experimental results of the growth directional stress configuration were also discussed.;Uniaxial stress influence on the dynamical properties has been studied using time resolved PL spectroscopy. Relaxation processes of free holes in a bulk {dollar}n\sp+{dollar}-GaAs sample, excitons in an intrinsic GaAs/Si QW structure and free carriers in a {dollar}p\sp+{dollar}-GaAs/Si QW structure have been studied.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
