IDENTIFICATION OF RADIATIVE RECOMBINATION CHANNELS IN QUANTUM-DOT STRUCTURES

The photoluminescence properties of (In,Ca)As quantum dots formed in s itu in a GaAs matrix by molecular beam epitaxy and metal-vapor deposit ion are studied. In both cases, besides states created by the quantum dots and the so-called wetting layer, the photoluminescence spectra co ntain bands associated with the recombination of nonequilibrium carrie rs localized in two-dimensional (In,Ga)As islands with thicknesses of several monolayers. Differences are observed in tile capture and relax ation of carriers at quantum dots and islands. (C) 1996 American Insti tute of Physics.