February 29th at 12.00

TASC seminar room

First-Principle investigations of intrinsic and Si-doped GaAs nanowires

Nahid Gaderi

Abstract:
High quality GaAs nanowires (NWs) are nowadays experimentally grown on different substrates, regularly shaped and nicely oriented. At variance with the bulk phase, they show a prevalence of wurzite structure with respect to zincblende and a p-type behavior with respect to the possible amphoteric behavior upon Si incorporation. motivated by these recent experimental findings we investigate by first principles pseudopotential calculations the structural stability and electronic properties of GaAs nanowire. The nature of Si dopants in GaAs nanowire and the relative stability of donor and acceptor have been also studied. Our results show that, on the basis of formation energy only, Si dopants have amphoteric behaviour in GaAs nanowires and segregates at the surface of the wire. We also examined the nanowires size effect on the stability of dopant configurations.