Comparison of Be-doped GaAs nanowires grown by Au- and Ga-assisted molecular beam epitaxy

Abstract

We report on the growth, structural and electrical characterizations of Be-doped GaAs nanowires (NWs) grown by the Au- and Ga-assisted vapour-liquid-solid techniques using molecular beam epitaxy. The growth rate of Be-doped GaAs NWs grown by the Au-assisted technique is observed to be lower as compared to the growth rate of undoped GaAs NWs grown under identical conditions. However, no effect on either the growth rate or the morphology of NWs has been observed for Be-doped GaAs NWs grown by the Ga-assisted technique with the same Be flux as used for the Au-assisted technique. Electrical characterization reveals that the Ga-assisted grown NWs show more consistent, symmetric current-voltage (I-V) characteristics with higher electrical current than the Au-assisted grown NWs. Finally, we show that ohmic contacts to Be-doped Ga-assisted NWs can be achieved either by post-annealing the metal-contacted NW or increasing the doping concentration during the NW growth. © 2013 Elsevier B.V. All rights reserved.