Exciton energy structure and population dynamics in a wide CdTe/CdZnTe quantum well are studied by spectrally-resolved pump-probe spectroscopy. Multiple excitonic resonances in reflectance spectra are observed and identified by solving numerically three-dimensional Schr\"odinger equation. The pump-probe reflectivity signal is shown to be dominated by the photoinduced nonradiative broadening of the excitonic resonances, while pump-induced exciton energy shift and reduction of the oscillator strength appear to be negligible. This broadening is induced by the reservoir of dark excitons with large in-plane wave vector, which are coupled to the the bright excitons states. The dynamics of the pump-induced nonradiative broadening observed experimentally is characterised by three components: signal build up on the scale of tens of picoseconds (i) and bi-exponential decay on the scale of one nanosecond (ii) and ten nanosecons (iii). Possible mechanisms of the reservoir population and depletion responsible for this behaviour are discussed.
@article{arxiv.2304.07135,
title = {Exciton dynamics in CdTe/CdZnTe quantum well},
author = {A. V. Mikhailov and A. S. Kurdyubov and E. S. Khramtsov and I. V. Ignatiev and B. F. Gribakin and S. Cronenberger and D. Scalbert and M. R. Vladimirova and R. André},
journal= {arXiv preprint arXiv:2304.07135},
year = {2023}
}