Origin of Short Period Oscillation near GaAs Band-Gap Energy in Photoreflectance

Abstract

We investigated the origin of the short-period oscillation (SPO) in photoreflectance (PR) spectra of selectively doped GaAs samples. In the PR spectra of the samples the SPO are separated into two distinct signals. The intensity of the lower-energy signal decreases rapidly as the temperature is lowered. Therefore, we conclude that the short-period oscillation is due to the hole-ionized acceptor (h-A(-)) pair modulation and the free exciton modulation in the cap layer. (C) 1997 Elsevier Science Ltd.