PHOTOREFLECTION STUDY ON THE SURFACE ELECTRIC-FIELD OF DELTA-DOPED GAAS GROWN BY MOLECULAR-BEAM EPITAXY

Abstract

Photoreflectance spectroscopy has been used to study the surface electric-field strength and the surface potential of delta-doped GaAs. Franz-Keldysh oscillations in the reflectance spectra were clearly observed and the oscillation periods were used to calculate the internal electric fields of the delta-doped samples. Based on the measured results and the self-consistent calculation, a surface potential of 0.6 eV is obtained.