Ground and excited state energy trend in InAs InGaAs quantum dots monitored by scanning photoluminescence spectroscopy

This paper presents a temperature-dependent scanning photoluminescence spectroscopic study of the ground and excited states on InAs quantum dots (QDs) inserted into In0.15Ga0.85As GaAs quantum wells. It is shown that structures exhibit a long-range spatial variation of the QD electronic states across the wafer. The observed trend of the ground state energy is attributed to the QD size variation and applied to explore multiple excited state energy shift versus ground state energy. Experimental results are compared with the electronic energy level dependence versus QD size predicted theoretically earlier on the basis of the eight-band k•p approximation.