摘要： The bandgap, surface Fermi level, and surface state density of a series of GaAs 1−x Sb x surface intrinsic-n + structures with GaAs as substrate are determined for various Sb mole fractions x by the photoreflectance modulation spectroscopy. The dependence of the bandgap on the mole composition x is in good agreement with previous measurements as well as predictions calculated using the dielectric model of Van Vechten and Bergstresser in Phys. Rev. B 1 , 3551 (1970). For a particular composition x, the surface Fermi level is always strongly pinned within the bandgap of GaAs 1−x Sb x and we find its variation with composition x is well described by a function E F =0.70−0.192x for 0≦x≦0.35, a result which is notably different from that reported by Chouaib [Appl. Phys. Lett. 93 , 041913 (2008)]. Our results suggest that the surface Fermi level is pinned at the midgap of GaAs and near the valence band of the GaSb. 出版者： American Institute of Physics 出版日期： 2012-05-28 出處： Applied physics letters, 2012-05, Vol.100 (22), p.222104-222104-4 資源來源： AIP Publishing 版權： 2012 American Institute of Physics 識別號： ISSN: 0003-6951 識別號： EISSN: 1077-3118 識別號： DOI: 10.1063/1.4724097 識別號： CODEN: APPLAB
