EXCITON DIFFUSION DYNAMICS IN QUANTUM NANOSTRUCTURES ON V-GROOVE PATTERNED SUBSTRATES

Time-resolved photoluminescence (PL) measurements were performed for t wo different quantum nanostructures on V-groove patterned substrates; SiGe/Si quantum wells (QWs) on V-grooved Si substrates and AlGaAs spon taneous vertical quantum wells on V-grooved GaAs substrates. Anomalous behaviours of the PL, such as the decrease of the decay time of the S iGe (111) QWs and the (111)A AlGaAs layer, were fully explained by tak ing the exciton diffusion towards the bottom of the V-groove into acco unt, showing that the exciton diffusion driven by the spatial nonunifo rmity of the alloy compositions and/or geometry of the substrates is a key to controlling the PL properties of the nanostructures. (C) 1998 Academic Press Limited.