Abstract
We present a polarization-resolved photoluminescence excitation study of the absorption spectrum of a -shell neutral exciton in a single CdTe/ZnTe quantum dot. We find that the fine structure of the -shell exciton is completely analogous to the fine structure of the -shell exciton, including the selection rules and the effects of a magnetic field applied in Faraday and Voigt configurations. The energy spectrum of the -shell exciton is found to be well described by introducing respective isotropic and anisotropic constants of the exchange interaction between a -shell electron and a -shell hole. The typical values of these exchange constants averaged over several randomly selected quantum dots yield meV and meV. Additionally, we demonstrate that the nonresonant relaxation of the -shell exciton conserves the exciton spin to a very high degree for both bright and dark exciton configurations.
- Received 5 January 2016
- Revised 29 February 2016
DOI:https://doi.org/10.1103/PhysRevB.93.195311
©2016 American Physical Society