Browsing by Author "MEI, WN"

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BINDING-ENERGIES AND EXTERNAL-FIELD EFFECTS OF THE A-EXCITON STATES IN CDS
(1990-03-26)
DAI, CM
;
PEI, JH
;
MEI, WN
;
CHUU, DS
;
電子物理學系
FINITE-CONICAL-WELL MODEL FOR VERTICALLY ADSORBED DIATOMIC-MOLECULES
(1995-05-15)
SHIH, YT
;
CHUU, DS
;
MEI, WN
;
電子物理學系
;
光電工程研究所
GROUND-STATES OF SHALLOW DONOR IMPURITIES ON ANISOTROPIC SEMICONDUCTOR SURFACES
(1988-03-01)
HUANG, WJ
;
CHOU, WC
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CHUU, DS
;
HAN, CS
;
MEI, WN
HYDROGENIC IMPURITY STATES IN QUANTUM DOTS AND QUANTUM WIRES
(1992-08-15)
CHUU, DS
;
HSIAO, CM
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MEI, WN
;
電子物理學系
;
Department of Electrophysics
The energies of hydrogenic impurity states with an impurity atom located at the center of a quantum dot and on the axis of a quantum-well wire are studied. These two systems are all assumed to have an infinite confining potential. In the case of the quantum dot, the impurity eigenfunctions are expressed in terms of Whittaker functions and Coulomb scattering functions. The calculated ground-state energy of the impurity approaches the correct limit of three-dimensional hydrogen atom as the radius of the quantum dot becomes very large. In the case of the quantum-well wire, analytical solutions can be obtained if we divide the space into a two-dimensional subspace (perpendicular to the axis of the quantum-well wire) and a one-dimensional subspace (parallel to the axis of the quantum-well wire). The calculated ground-state energy of the quantum-well wire approaches the ground-state energy of the shallow-impurity atom located on the surface as the radius of the wire becomes infinite. Variations of the state energies with the radius of the quantum dot and the quantum-well wire are obtained.
QUANTUM CONFINEMENT EFFECT ON THE IMPURITY STATES OF A SPHERICAL CONFINING SYSTEM
(1992-03-01)
HSIAO, CM
;
MEI, WN
;
CHUU, DS
;
電子物理學系
;
Department of Electrophysics
Whittaker function and scattering Coulomb wave function are used to calculate the eigen-energies of an impurity in a spherical confining system. Variation of the state energies with the radii of the confining system is obtained.
RENORMALIZED FREQUENCY-SHIFT OF SUPERRADIANT EXCITONS IN THIN SEMICONDUCTOR-FILMS
(1992-08-17)
LEE, YC
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CHUU, DS
;
MEI, WN
;
電子物理學系
;
Department of Electrophysics
The radiative frequency shift of an exciton in a thin semiconductor film, like its radiative level width, is shown to be superradiatively enhanced. Unlike the latter, however, a finite frequency shift can only be obtained after proper renormalization for the correlated system. The shift is found to be inversely proportional to the square of the factor k0d and proportional to the film thickness T; k0 = E(qn)/H(BAR)c, E(qn) being the exciton energy gap and d the lattice constant of the semiconductor. Therefore, the coherent frequency shift can be observed experimentally if one varies the thickness, or the exciton energy gap E(qn) by imposing high pressure.