Optically induced charge storage and current generation in InAs quantum dots

Abstract

We report on optically induced charge storage effects and current generation in self-assembled InAs quantum dots embedded in an InP matrix. Illumination with photons of energy higher than about 0.86 eV efficiently loads the dots with a maximum of about 1 hole/dot. The spectral response at lower photon energy is strongly enhanced at elevated temperatures. We present a detailed balance model for the dots and discuss the thermally assisted optical excitation processes pertinent to hole accumulation. We also show that these processes make the dots act as nanometer-scaled temperature-dependent current generators.