LOCALIZATION AND THERMAL ESCAPE OF EXCITONS IN ULTRATHIN ZNSE ZNS SINGLE QUANTUM-WELLS LINKED TO INTERFACIAL ZNSE QUANTUM SLABS/

UItrathin ZnSe/ZnS single quantum well structures have been grown by m olecular beam epitaxy, on GaP substrates with high Miller indices. The optical properties of pseudomorphic ZnSe/ZnS single quantum wells hav e been investigated by conventional optical methods. Power-dependence and temperature-dependence measurements show that structural disorder plays an important role in ZnSe/ZnS ultrathin single quantum wells. Th e luminescence emission is the collective response of a group of local potentials with quantum dotlike characteristics. Consequently, the lu minescence peak is the convolution of individual narrow lines. In addi tion, the luminescence spectra are dominated by a thermal escape of ca rriers when investigating the temperature dependence. (C) 1998 America n Institute of Physics. [S0021-8979(98)07111-4].