Inhomogeneous broadening of exciton lines in magneto-optical reflection from CdTe/CdMgTe quantum wells

Abstract:A spectroscopic method is proposed to determine parameters of homogeneous and inhomogeneous broadening for excitons confined in semiconductor quantum wells with free carriers. By measuring the optical reflectivity of modulation doped CdTe/(Cd,Mg)Te single quantum wells in high magnetic fields the homogeneous and inhomogeneous broadening of the exciton lines was determined. The method is based on the difference in reflectivity of light with opposite circular polarizations measured for experimental conditions of full polarization of a two-dimensional electron gas. The analysis is based on a phenomenological model which allows to distinguish between the two broadening mechanisms.