Determination of Trion and Exciton Lineshapes in Modulation-Doped Quantum Wells

TL;DR

This paper studies how a two-dimensional electron gas influences the optical lineshapes of excitons and trions in CdTe quantum wells, highlighting the role of electron scattering and distribution in spectral features.

Contribution

It introduces a model including electron scattering effects to accurately describe reflectivity spectra of quantum wells with varying electron concentrations.

Findings

High energy tail of exciton and trion resonances depends on electron concentration.

Electron scattering is essential for accurate spectral modeling.

Electron distribution affects resonance lineshapes in time-resolved experiments.

Abstract

We investigate the effect of a two dimensional electron gas on the linear optical properties of CdTe quantum wells. We evidence experimentally the high energy tail of the exciton and charged exciton resonances which depends on electron concentration. Based on that, we show that the scattering of electrons with excitons and charged excitons is needed to be included in the matrix transfer calculations to describe the reflectivity spectra. We demonstrate by time-resolved reflectivity experiments the importance of electron distribution in the resonance lineshapes.