Abstract

We present various optical characterization methods of GaAs/AlGaAs multi-quantum-well structures employing tunable pulsed and cw lasers as well as incoherent light sources. The samples we examined were molecular-beam eptiaxy (MBE) grown, with layer thicknesses ranging from 20 to 250 Å. The inhomogeneity along the MBE-growth direction in terms of the impurity species and the well layer thicknesses can be revealed by utilizing the wavelength-dependent beam penetration depth changes into the sample. In one of the samples, the GaAs well layer thickness near the sample surface was found to be two monolayers (5.65 Å) smaller than those inside the sample toward the substrate material. We also discuss the potential usefulness of the high-lying energy states above the AlGaAs barrier energy gap in characterizing superlattice samples.

© 1986 Optical Society of America