Narrow emission linewidths of positioned InAs quantum dots grown on pre-patternedGaAs(100) substrates

Abstract

We report photoluminescence measurements on a single layer of site-controlled InAs quantumdots (QDs) grown by molecular beam epitaxy (MBE) on pre-patterned GaAs(100) substrateswith a 15 nm re-growth buffer separating the dots from the re-growth interface. A processfor cleaning the re-growth interface allows us to measure single dot emission linewidths of80 µeV under non-resonant optical excitation, similar to that observed for self-assembled QDs. Thedots reveal excitonic transitions confirmed by power dependence and fine structure splittingmeasurements. The emission wavelengths are stable, which indicates the absence of afluctuating charge background in the sample and confirms the cleanliness of the re-growthinterface.