Title :
Band-mixing effects and excitonic optical properties in GaAs quantum wire structures-comparison with the quantum wells
Author :
Suemune, Ikuo ; Coldren, Larry A.
Author_Institution :
Dept. of Electr. & Comput. Eng., California Univ., Santa Barbara, CA, USA
Abstract :
The excitonic properties in quantum-wire structures (QWS) are analyzed by taking into account the band-mixing effects in the valence band of the structure. The effective mass value in the wire direction at the zone center of the lowest heavy-hole-like subband is found to be as small as 0.027 m/sub 0/ for GaAs/AlGaAs QWS. This reduced effective mass and the related nonparabolicity of the subband structure play a significant role in determining the exciton properties. Using these results, the maximum excitonic contribution to the refractive index value is estimated to be 0.59, i.e. 17.4% of the bulk value for a GaAs/Al/sub 0.4/Ga/sub 0.6/As QWS with a 50 A*50 AA cross section. This value is six times larger than that in the 50-AA quantum well. With an electric field of 8*10/sup 4/ V/cm perpendicular to the heterointerface, a maximum refractive index change 30% larger than this value is estimated.<>
Keywords :
III-V semiconductors; effective mass (band structure); excitons; gallium arsenide; refractive index; semiconductor quantum wells; valence bands; GaAs quantum wire structures; GaAs-Al/sub 0.4/Ga/sub 0.6/As; III-V semiconductor; band-mixing effects; effective mass value; electric field; excitonic optical properties; heavy-hole-like subband; heterointerface; nonparabolicity; quantum wells; refractive index value; valence band; zone center; Absorption; Effective mass; Excitons; Gallium arsenide; Optical mixing; Optical refraction; Optical variables control; Oscillators; Refractive index; Wire;
Journal_Title :
Quantum Electronics, IEEE Journal of
