Formation of self-assembled GaAs quantum dots via droplet epitaxy on misoriented GaAs(111)B substrates

Abstract

Self-assembled GaAs quantum dots (QDs) have been grown on misoriented GaAs(111)B substrates using droplet epitaxy. Different droplet deposition temperatures, arsenization temperatures and times as well as postcrystallization annealing temperatures have been investigated, while the amount of deposited Ga was kept constant at two monolayers. Atomic force microscopy measurements reveal that unusually low Ga deposition and arsenization temperatures in comparison to the (100) and (111)A surfaces are necessary to obtain droplet/QD densities in the order of 108 cm−2. The formation of droplets and their crystallization result in QDs with approximately circular symmetry regardless of the anisotropy introduced by the miscut. Crystallized GaAs QDs show the thermal resistance comparable to those observed on (100) and (111)A. When the QDs are embedded in Al0.3Ga0.7 As, a spectrally broad luminescence around 790 nm can be observed.