Tuning of electron occupancy in luminescence of single InP/GaInP quantum dot

Abstract

Summary form only given. Macro- as well as micro-photoluminescence studies of InP/GaInP quantum dots (QDs) fabricated via the Stranski-Krastanow growth mode always show multiple luminescence lines, with an unexpected spectral width even for an individual QD. The origin of this unusual behavior has been debated and until now no clear picture has emerged. We have recently developed a new spectroscopic tool in which we can follow the luminescence of a single QD during the application of an electric field via a transparent Schottky barrier on the surface of the GaInP barrier material. This enables us to follow the evolution of each of the peaks as function of applied bias, with respect to (i) spectral shifts, (ii) intensities and (iii) line-widths. We will present experimental data and computer simulation results which show that during optical illumination with intensities such that luminescence is detected, a condition very close to flat-band is obtained and an open-circuit voltage corresponding to the Schottky-barrier height is detected.