Spectroscopy of self-assembled quantum rings

摘要

A summary is presented of optical spectroscopy measurements on self-assembled quantum rings. The rings are unusual quantum dots, having a pronounced hole in the centre, and can be self-assembled during growth using a modified Stranski-Krastanow procedure. We embed the quantum rings in a capacitor-like structure which enables us to load the quantum rings with electrons and to apply a vertical electric field. The results of these experiments, performed on a large number of individual quantum rings at low temperature, reveal pronounced Coulomb interactions and an excitonic Stark effect. Additionally, we have applied a magnetic field, primarily to probe the form of the lateral wave functions, but we find that this too yields insights into the Coulomb interactions. Model calculations are used to interpret these results.