標題: Analysis of GaAs/GaSb/GaAs structures under optical excitation considering surface states as an electron reservoir
作者: Hsieh, Hong-Wen
Yen, Shun-Tung
電子工程學系及電子研究所
Department of Electronics Engineering and Institute of Electronics
關鍵字: carrier density;conduction bands;Fermi level;gallium arsenide;gallium compounds;III-V semiconductors;semiconductor quantum wells;surface states;valence bands
公開日期: 15-May-2009
摘要: We present a self-consistent model for the analysis of the carrier distribution, the band profile, and the transition energy of type-II aligned GaAs/GaSb/GaAs structures under optical excitation. The model considers the surface states as an electron reservoir, associated with pinning of the conduction band Fermi level at the midgap. In our model, the optical generated holes in the GaSb quantum well causes a potential well on one side of the GaSb layer, which can efficiently accommodate the optically generated electrons. Accordingly, we derive a relation connecting the excitation power to the carrier density. Using the relation and the effective triangular potential approximation, we obtain a simple formula for the transition energy shift as a function of the excitation power, which follows the cube-root rule quite well. The calculation allows the determination of the band offset of a type-II heterointerface by comparison with data from photoluminescence measurement. The result suggests the unstrained valence band offset of GaSb/GaAs to lie between 0.5 and 0.55 eV. We also present a simplified model for analyzing the electronic and optical properties of type-II heterostructures without the need of a self-consistent calculation.
URI: http://dx.doi.org/10.1063/1.3129616
http://hdl.handle.net/11536/7232
ISSN: 0021-8979
DOI: 10.1063/1.3129616
期刊: JOURNAL OF APPLIED PHYSICS
Volume: 105
Issue: 10
結束頁: 
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