Regensburg 2010 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 52: Heterostructures

HL 52.8: Vortrag

Donnerstag, 25. März 2010, 12:00–12:15, H17

Si and Be incorporation into GaAs nanowires — •Maria Hilse, Manfred Ramsteiner, Steffen Breuer, Lutz Geelhaar, and Henning Riechert — Paul-Drude-Institut für Festkörperelektronik, Berlin

As catalyst seeds are suspected to introduce impurities into nanowires (NWs), a much higher purity is expected for NWs grown by mechanisms that do not require any foreign material. Therefore, it is particularly important to investigate the doping, which is a prerequisite for the fabrication of devices, of NWs prepared by such mechanisms. A further requirement for controlled doping is the incorporation of dopants on the particular lattice sites of the desired electrical activity. We studied the incorporation of Si and Be into GaAs NWs grown on Si(111) by molecular beam epitaxy. The formation of these NWs was induced by Ga droplets that developed under the appropriate growth conditions on the native silicon oxide. Concerning the NW morphology, no influence was observed for Si doping but high Be doping concentrations cause a kinking and tapering of the NWs. The incorporation of the dopant atoms on the different lattice sites of GaAs was investigated by resonant Raman scattering. As expected, Be was found to be incorporated dominantly as an acceptor on Ga-sites leading to p-type conductivity. For Si doping, however, both donors on Ga sites and acceptors on As sites have been observed with similar abundance, leading to strong self-compensation and a resulting p-type conductivity.