Photoluminescence Properties of In-Plane Ultrahigh-Density InAs Quantum Dots on GaAsSb/GaAs(001) for Solar Cell Applications

Abstract

In-plane ultrahigh-density InAs quantum dots (QDs) were grown on GaAsSb/GaAs(OOl) for intermediated-band solar cell applications. Photoluminescence (PL) spectra under 785-nm-light excitation were originated from the type-II transition between the QD electron ground states (GS) and the GaAsSb valence band and did not changed at different measurement positions. It can be explained by a GS filling effect due to tunneling between QDs. For 860-nm-light excitation, PL spectra were obtained at a shorter wavelength region and depended on the measurement position. These PL spectra were composed into some crossed transitions, which were attributed to localized excitons between QD electron excited states and GaAsSb valence band.