Influence of excitation energy on carrier dynamics in GaAs-Al_0.46Ga_0.54As superlattice

摘要

The efficiency of carrier collection into the active region in GaAs-Al_xGa_1-xAs quantum well structures is of considerable interest for the development of heterostructure lasers which should operate at room temperature. In order to gain access to a quantitative understanding of the capture and of the emission processes in these structures, we report an experimental study of the photoluminescence (PL) properties, after both picosecond and continuous-wave laser excitation, of a GaAs-Al_0.46Ga_0.54As superlattice (SL) heterostructure grown by molecular beam epitaxy. We show that the temperature dependence of the integrated PL intensity observed under both direct and indirect excitation in this SL containing a thicker quantum well in the structure centre, reveals much information about the mechanism of carrier emission processes.