Tuning the inter-shell splitting in self-assembled CdTe quantum dots

We present photoluminescence studies of highly excited single self–assembled CdTe quantum dots under continuous–wave and pulsed excitations. We observe appearance of emission bands related to sequential filling of s–, p-- and d–shells. We analyze the inter-shell splitting for five samples, in which the dots were formed from a strained CdTe layer of different width. We find that with increasing the CdTe layer width the inter-shell splitting increases. In a time resolved measurement, we observe a radiative cascade between transitions involving one, two, and more than two excitons.