Sharp photoluminescence lines of InAs quantum dot embedded in GaAs mesa

Abstract

Sharp photoluminescence (PL) lines were observed in a single InAs quantum dot embedded in a micro-sized mesa of GaAs. These lines are in groups which conform to the conventional PL spectra. Power and temperature dependence of PL were measured to study the energy level structure. Clear state filling was observed in each sharp PL line by increasing the excitation power density. With the increase of the temperature, the PL intensity of these lines became gradually very weak successively from the higher energy side. These results suggest that most of the PL lines observed in our experiments come from the excited states of excitons confined in InAs quantum dots. Level filling and the relaxation process of excitons are discussed.