Molecular-beam epitaxy growth of site-controlled InAs/GaAs quantum dots defined by soft photocurable nanoimprint lithography

Molecular-beam epitaxy grown InAs site-controlled quantum dots SCQDs have been demonstrated on GaAs substrates patterned with a dense array of 100 nm square nanopores in 200 nm pitch by soft photocurable nanoimprint lithography. The effects of different growth parameters, including GaAs buffer-layer thickness and arsenic overpressure, on SCQD formation are investigated. The buffer-layer thickness is found to be an influential factor affecting homogeneous quantum dot QD formation under a certain pore depth. After GaAs buffer-layer deposition with a suitable thickness, a single QD has been achieved in each patterned nanopore. Under an optimal arsenic overpressure, more uniformly distributed SCQDs have also been shown, confirmed by a narrower photoluminescence linewidth. Strong room-temperature photoluminescence indicates a high optical-quality QD layer on a defect-free interface. © 2010 American Vacuum Society. DOI: 10.1116/1.3414824