ULTRATHIN CDSE QUANTUM-WELLS

We report a survey of samples containing ultrathin layers of CdSe embe dded in ZnSe or 2nS(0.06)Se(0.94) matrices. CdSe single quantum wells (SQW) with well widths in the range 0.3-3 ML show several bands in the photon energy range from 1.7 to 2.4 eV. Similar bands have been attri buted recently to self-organised quantum dots. Temperature-dependent p hotoluminescence (PL) shows that the bands in our samples vanish, with out significant peak shift, at moderately high temperatures. Prelimina ry time-resolved PL shows that they also have relatively long lifetime s (ca. 30-250 ns). In all samples, the SQW exciton band lying at highe r energies shows line narrowing with increasing temperature. Variation s due to quantum-well thickness induce a correlation between the lumin escence peak energy and the optical bandwidth which may be used to sys tematise our observations. (C) 1998 Elsevier Science B.V. All rights r eserved.