Optical Detection of Multiple-Trapping Relaxation in Disordered Crystalline Semiconductors

Abstract

Relaxation of optically excited carriers within localized continuum states in heavily doped crystalline GaAs is directly observed by picosecond luminescence experiments. The relaxation within localized states takes place via thermally activated multiple trapping. Saturation of the relaxation is observed at high temperatures and for small trap densities. The results demonstrate that heavily doped crystalline semiconductors can serve as a simple model for amorphous materials.