Electroreflectance of surface-intrinsic-n(+)-type-doped GaAs by using a large modulating field

Abstract

It is known that electroreflectance of surface-intrinsic-n(+)-type-doped GaAs has exhibited many Franz-Keldysh oscillations to enable the application of fast Fourier transform to separate the heavy- and light-hole transitions. However, each peak still contains two components, which belong to F+deltaF/2 and F-deltaF/2, respectively, where F is the electric-field strength in the undoped layer and deltaF is the modulating field of applied ac voltage (V-ac). In order to resolve the heavy- and light-hole transitions, deltaF was kept much smaller than F in the previous works. In this work, we have used a larger V-ac and, hence, a larger deltaF, to further separate the peaks. The peaks can be divided into two groups which belong to F+deltaF/2 and F-deltaF/2, respectively. The peak belonging to the heavy-hole transition and F-deltaF/2 can be singled out to compare with the Airy function theory. (C) 2003 American Institute of Physics.