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Proceedings Paper

Fermi-level pinning of GaAs at room temperature directly determined by the amplitude of photoreflectance spectra
Author(s): YauHuei Chen; RuyMing Chen
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Paper Abstract

Photoreflectance (PR) measurements on an n-GaAs epitaxial layer as a function of the intensity of pumping light are reported. Based on the thermionic emission theory and current-transport theory, the pinning position of surface Fermi level can be determined from the dependence of the PR signal on the pumping light intensity. Experiments demonstrated that the PR amplitude depends upon the optical excitation intensity I as ln((gamma) I), which is normally the case experimentally and theoretically. From the analysis of the dependence on the amplitude of PR on optical excitation intensity, the surface Fermi level of GaAs at room temperature about 0.72 +/- 0.02 eV below conduction band was evaluated easily and directly. This result is consistent with those accurately reported results using PR to characterize samples with specially designed complex surface-intrinsic-doped structures for obtaining a uniform Franz-Keldysh oscillations and derived the built-in electric fields then evaluated the Fermi level pinning position indirectly.

Paper Details

Date Published: 11 July 2000
PDF: 7 pages
Proc. SPIE 4078, Optoelectronic Materials and Devices II, (11 July 2000); doi: 10.1117/12.392170
Show Author Affiliations
YauHuei Chen, National Taipei Univ. of Technology (Taiwan)
RuyMing Chen, National Taipei Univ. of Technology (Taiwan)

Published in SPIE Proceedings Vol. 4078:
Optoelectronic Materials and Devices II
Yan-Kuin Su; Pallab Bhattacharya, Editor(s)

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