Incorporation of the dopants Si and Be into GaAs nanowires

We studied the doping with Si and Be of GaAs nanowires (NWRs) grown by molecular beam epitaxy. Regarding the NW morphology, no influence was observed for Si doping but high Be doping concentrations cause a kinking and tapering of the NWRs. We investigated local vibrational modes by means of resonant Raman scattering to determine the incorporation sites of the dopant atoms. For Si doping, both donors on Ga sites and acceptors on As sites have been observed. Be was found to be incorporated as an acceptor on Ga sites. However, at high doping concentration, Be is also incorporated on interstitial sites.