Lateral band-gap patterning and carrier confinement in InGaAs/GaAs quantum wells grown by molecular beam epitaxy on nonplanar dot patterns

Abstract

Two-dimensional (2D) lateral band-gap patterning and carrier confinement were observed in InGaAs/GaAs patterned quantum-well (QWL) dots grown by molecular beam epitaxy on prepatterned, nonplanar GaAs substrates. Growth of the strained QWL layers on craters of 0.2–5 μm diameters etched onto the substrate results in 2D lateral potential wells formed at the inside and outside regions of the craters due to preferential migration of Ga and In adatoms. Evidence for lateral carrier confinement and efficient radiative recombination in the resulting dot- and ring-shaped potential wells was provided by low-temperature cathodoluminescence spectroscopy and imaging. The results of this study indicate the feasibility of producing damage-free quantum dot and quantum ring heterostructures by growth of QWLs on patterned, nonplanar substrates.