ON THE USE OF PHOTOLUMINESCENCE SPECTROSCOPY TO INVESTIGATE ONE MONOLAYER ISLAND DISTRIBUTIONS IN QUANTUM-WELLS

Photoluminescence spectroscopy can advantageously be used to determine the smoothness of quantum well interfaces. In analyzing the spectra one should take into account a possible distribution of islands which will modify the line shape of exciton transitions. In the present paper, the roughness of a single GaAs/GaAlAs quantum well is described by an island structure of different thickness. Depending on the ratio of the lateral extension of the exciton to the area of islands, a distribution of exciton energies is obtained. In the case of large islands a peak structure, corresponding to discrete thickness parameters is found; whereas in the opposite case a Gaussian distribution is derived. The model for the probability distribution of exciton energies is used to calculate luminescence spectra. © 1992.