Photocurrent anisotropy in compositional modulated superlattice of long-range ordered Ga0.5In0.5P |
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Authors: | Takashi Kita Akira Fujiwara Hiroshi Nakayama Taneo Nishino |
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Affiliation: | (1) Department of Electrical and Electronics Engineering, Faculty of Engineering, Kobe University, 1-1 Rokkodai, 657 Kobe, Japan |
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Abstract: | Photocurrent anisotropy of long-range ordered Ga0.5In0.5P alloys has been sys-tematically investigated. The ordered Ga0.5In0.5P is a compositional modulated superlattice of Ga0.5+η/2In0.5-η/2P and Ga0.5-η/2In0.5+η/2P monolayer planes, where η is a long-range order parameter. The photocurrent edge of the 110] polarization is lower than
that of the
. The observed anisotropy in the photocurrent spectra is due to a crystal-field splitting at the valence-band maximum in ordered
Ga0.5In0.5P. The anisotropy shows a continous variation as a function of η. In order to make clear the effects of the valence-band splitting
on the polarized photocurrent spectra, we performed theoretical calculations in which a distribu-tion of η in the epitaxial
film and an order-parameter dependence of oscillator strength were considered. From these calculations, it is found that oscillator
strength is a key parameter in the anisotropic character. The calculated results moderately agree with the measured data.
Furthermore, the epitaxial thickness dependence of the anisotropic character in photocurrent was investigated. |
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Keywords: | GaInP ordering photocurrent superlattice |
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