Photoreftectance characterization of LEC-SI GaAs and Fe-InP

Abstract

The amplitude dependence of the photoreflectance signal upon intensity of the pumping beam has been measured for SI-GaAs and SI-InP and it is explained by the difference in the surface Fermi level in the two materials. When a pump beam with photon energy less than the bandgap is used in SI-GaAs a simple relationship exists between the amplitude of the photoreflectance signal and the trapped surface charge. The effect of several chemical treatments or of a ZnSe cap layer on the surface trap density in SI-GaAs has been determined.