Coexistence of type-I and type-II band lineups in Cd(Te,Se)/ZnSe quantum-dot structures

Abstract

The authors report on transmission electron microscopy, cathodoluminescence, and time resolved photoluminescence studies of thin Cd(Te,Se) layers in a ZnSe matrix, grown by molecular beam epitaxy. All observations confirm strain-induced self-assembly of quantum dots (QD's), induced primarily by the 14% lattice mismatch between CdTe and ZnSe. The emission spectrum of the structure is the superposition of a relatively narrow luminescence line originating from CdSe-enriched type-I QD's and a broad band attributed to the emission of an ultrathin ZnTeSe/ZnSe layer with type-II band lineup, formed in between the QD's. © 2006 American Institute of Physics.