Quantum confinement phenomena in ultrathin GaAs nanowires

In this contribution we present our recently developed “reverse-reaction-growth” scheme in molecular beam epitaxy to fabricate 1D GaAs nanowires (NWs) with diameters down to 7 nm. We observe the presence of strong quantum confinement phenomena, opening the path towards a true 1D NW platform. The introduction of crystal defects in the NW effectively leads to bright and spectrally sharp crystal phase quantum dots (CPQDs). By directly correlated transmission electron microscopy, cathodoluminescence, and photoluminescence spectroscopy, we examine the microscopic nature and properties of these CPQDs. We identify individual twin defects (single monolayer inclusions of wurtzite in a zincblende crystal) as the predominant source for CPQD emission.