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

TL;DR

This study investigates the optical properties of self-assembled CdTe quantum dots, revealing how inter-shell energy splitting varies with layer width and demonstrating exciton cascade emissions.

Contribution

It provides new insights into how the inter-shell splitting in CdTe quantum dots depends on the layer width, using photoluminescence measurements.

Findings

Inter-shell splitting increases with CdTe layer width.

Sequential filling of s-, p-, and d-shells observed.

Radiative cascade occurs between multi-exciton states.

Abstract

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.