Diameter dependent optical emission properties of InAs nanowires grown on Si

Abstract

We report on the optical emission properties of catalyst-free, molecular beam epitaxy grown InAs nanowires (NW) on Si (111) using photoluminescence spectroscopy. InAs NW ensembles with similar density, length, and crystal structure (wurtzite-phase with stacking faults) but substantially different NW diameter (40–135 nm) are investigated, and the role of diameter on band-edge emission elucidated. Thick (>100 nm) as-grown NWs show relatively strong emission efficiency with emission up to >130 K, red-shift with temperature (T) and low-T band‐edge energy of ∼0.41 eV similar to bulk zincblende InAs. Reduction in NW diameter yields a characteristic blue‐shift (∼0.435 eV for 40-nm thin NWs), which is related to quantum confinement effects and confirmed by simulations.