Twin superlattice-induced large surface recombination velocity in GaAs nanostructures
Semiconductor nanowires (NWs) often contain a high density of twin defects that form a twin superlattice, but its effects on electronic properties are largely unknown. In this work, nonadiabatic quantum molecular dynamics simulation shows unique surface electronic states at alternating (111)A and (111)B sidewall surfaces of a twinned [111]-oriented GaAs NW, which act as effective charge-recombination centers. The calculated large surface recombination velocity quantitatively explains recent experimental observations and offers microscopic understanding of the underlying surface-recombination processes.