Size control of InP nanowires by in situ annealing and its application to the formation of InAsP quantum dots

Abstract

We carried out in-situ annealing of InP Nanowires (NWs) in a metal-organic vapor phase epitaxial (MOVPE) growth reactor to control and reduce the tip size of InP NWs. InP NWs were grown by selective-area (SA) MOVPE on partially masked (111)A InP substrates, and annealing was successively applied in tertiarybutylphosphine (TBP) ambient. Initially, InP NWs had a hexagonal cross-section with {11-2} facets vertical to the substrates; they became tapered, and edges were rounded by annealing. By appropriately selecting the annealing temperature and initial NW diameter, the tip size of the NW was reduced and NWs with a tip size of 20nm were successfully formed. Subsequently, a thin InAsP layer was grown on the annealed NWs and their photoluminescence was investigated at low temperatures. The characterization results indicated the formation of InAsP quantum dots (QDs) emitting in the telecom band. Our approach is useful for reducing the size of NWs and for the controlled formation of InAsP QDs embedded in InP NWs in photonic devices compatible with telecom bands.