Specific features in the temperature dependence of photoluminescence from CdTe/ZnTe size-quantized islands and ultrathin quantum wells

A study has been carried out of the temperature dependences of luminescence spectra on a large number of CdTe/ZnTe structures differing in average thi ckness, [L-z] = 0.25-4 monolayers (ML), and CdTe layer geometry (continuous , island type). The influence of geometric features in the structure of ult rathin layers on linewidth, the extent of lateral localization of excitons, their binding energy, and exciton-phonon coupling is discussed. It is show n that in island structures there is practically no lateral exciton migrati on. The exciton-phonon coupling constant in a submonolayer structure has be en determined, Gamma(ph) = 53 meV, and it is shown that in structures with larger average thicknesses Gamma(ph) is considerably smaller. Substantial l ateral exciton migration was observed to occur in a quantum well with [L-z] = 4 ML, and interaction with acoustic phonons was found to play a noticeab le part in transport processes. It has been established that the depth of t he exciton level in a quantum well and structural features of an ultrathin layer significantly affect the temperature dependences of integrated photol uminescence intensity. (C) 1999 American Institute of Physics. [S1063-7834( 99)03204-9].