Terahertz photoluminescence from GaAs doped with shallow donors at interband excitation

Abstract

We report on the observation of efficient generation of terahertz radiation at continuous-wave interband excitation of n-GaAs at low temperatures. The radiative transitions, accompanying relaxation and trapping of photoexcited electrons to localized donor states or to empty states in impurity subband, lead to the emission of terahertz photons with a relatively high external quantum yield up to 0.3%.