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

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.