Effects of GaAlN barriers and of dimensionality on optical recombination processes in InGaN quantum wells and quantum boxes

We compare several InGaN-based low-dimensional systems, by time-resolved ph otoluminescence (PL), versus temperature (8 < T < 280 K). We investigate th e influence of growing or not an AlGaN barrier on top of the active layer. We address the differences between quantum wells and quantum boxes 5-10 nm in diameter and 2 nm in height. Our results are consistent with carrier loc alization on potential fluctuations with spatial extension much smaller tha n the size of the quantum boxes. Growing an AlGaN barrier reduces the carri er mobility between fluctuations, thus maintaining an effective PL dominate d by localized carriers up to room temperature. (C) 2001 American Institute of Physics.