title: Catalytic role of gold nanoparticle in GaAs nanowire growth: a density functional theory study.
abstract: The energetics of Ga, As, and GaAs species on the Au(111) surface (employed as a model for Au nanoparticles) is investigated by means of density functional calculations. Apart from formation of the compound Au(7)Ga(2), Ga is found to form a surface alloy with gold with comparable ΔH ~ -0.5 eV for both processes. Dissociative adsorption of As(2) is found to be exothermic by more than 2 eV on both clean Au(111) and AuGa surface alloys. The As-Ga species formed by reaction of As with the surface alloy is sufficiently stable to cover the surface of an Au particle in vacuo in contact with a GaAs substrate. The results of the calculations are interpreted in the context of Au-catalyzed growth of GaAs nanowires. We argue that arsenic is supplied to the growth zone of the nanowire mainly by impingement of molecules on the gold particle and identify a regime of temperatures and As(2) partial pressures suitable for Au-catalyzed nanowire growth in molecular beam epitaxy.
authors.affiliation: Fakultät für Physik and Center for Nanointegration (CENIDE), Universität Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany. Peter.Kratzer@uni-due.de
authors.forename: Peter
authors.initials: P
authors.lastname: Kratzer
authors.forename: Sung
authors.initials: S
authors.lastname: Sakong
authors.forename: Volker
authors.initials: V
authors.lastname: Pankoke
mesh_terms: D001152:Arsenicals / Q000737:chemistry*; D002384:Catalysis; D005708:Gallium / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D053770:Nanowires / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D001152:Arsenicals; C043055:gallium arsenide; D006046:Gold; D005708:Gallium