Photoreflectance spectra of a GaAs/GaAs and of an InGaAs/InP multiple quantum well structures grown with molecular beam epitaxy

Photoreflectance (PR) is a contactless form of electroreflectance in which the electromodulation is caused by the electron-hole pairs created by the modulating light. In particular, PR is becoming an important tool for studying semiconductor heterostructures. Franz-Keldysh oscillations are observed in the photoreflectance spectrum of a GaAs/GaAs structure. The surface field and the ionised dopant concentration are determined. In the photoreflectance spectra of a multiple quantum well structure InP transitions from the valence subbands into the conduction subbands are clearly resolved and energy levels are determined.