Delayed luminescence induced by intersubband optical excitation in a charge transfer double quantum well structure

Abstract

Photoluminescence processes in a novel GaAs double quantum well (DQW) structure were studied and found to be controlled by a 10 μm mid-infrared (MIR) light. In this DQW structure, photogenerated electron-hole pairs are normally separated into different wells and their radiative recombination is inhibited. However, when a MIR light pulse is supplied to induce an electron intersubband transition, electrons are efficiently transferred to the hole-rich well, resulting in a significant enhancement of luminescence. By time shifting the MIR pulse with respect to the light pulse for interband excitation, we demonstrated the generation of a delayed photoluminescence. Device potentials of this MIR to near-infrared conversion are discussed.