The role of polarons in the broadening of photoluminescence lines observed in Cd1-xMnxTe layers grown by MBE

The mechanisms which cause emission line broadening of photoluminescence bands from Cd 1-x Mn x Te layers are discussed. For x<0.1, where the dominant exciton line is an exciton bound to a neutral acceptor, the linewidths can be accounted for using the alloy broadening theory of Schubert et al. (1984). For x>0.1, excitons are trapped principally at alloy fluctuations. However, the linewidth of such excitons cannot be accounted for by the alloy broadening theory of Baranovskii and Efros. It is shown that the observed linewidths are consistent with the formation of magnetic polarons, and the corresponding values of the polaron energies are estimated.