Size-selected compound semiconductor quantum dots by nanoparticle conversion

Abstract

We have developed a novel technology, called nanoparticle conversion, for producingcompound semiconductor quantum dots (QDs) in which the dot size, surface density,position, and the materials system are all independently controlled. Nanoparticleconversion also lends itself to spatially controlled positioning of QDs. To demonstrate thistechnology we report the formation of InP QDs using nanoparticle conversion. We haveproduced QDs on substrates of different types by converting randomly and lithographicallypositioned nanoparticles into compound semiconductors in a chemical vapour depositionsystem. Electron microscopy and atomic force microscopy measurements reveal that themorphology of these QDs is similar to that of QDs produced by other techniques.Photo- and cathodoluminescence measurements show that the converted nanoparticlesexhibit properties and behaviours typical of semiconductor QDs. These includequantum confinement, free-to-bound recombination and blinking. Production ofmulti-component QDs like InP, GaN, and InAsP on various substrates like Si,SiO2, and sapphire show that this technology can produce a wide variety of differenttypes of QD on different substrates with minimal need for process optimization.