Interface defects and impurities at the growth zone of Au-catalyzed GaAs nanowire from first principles

The defects and impurities at the interface of a Au-catalyzed GaAs nanowire have been studied by the first-principles method. The interface is modeled by Au layers on the GaAs ((111) over bar) substrate with both Ga- and As-terminations. From the energetics of interface defects and impurities, we find that a highly ordered As-terminated interface is expected under As-rich growth, but mixed Ga- and As-terminations are expected under Ga-rich growth. Comparing the interface defects and impurities to their bulk species, we expect the interface to be a sink for Au impurities in the GaAs nanowire. Based on DFT results, we estimate that materials transport by impurity diffusion through a liquid nanoparticle is sufficient for sustained GaAs growth. ((c) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)