title: The Role of Surface Passivation in Controlling Ge Nanowire Faceting.
abstract: In situ transmission electron microscopy observations of nanowire morphologies indicate that during Au-catalyzed Ge nanowire growth, Ge facets can rapidly form along the nanowire sidewalls when the source gas (here, digermane) flux is decreased or the temperature is increased. This sidewall faceting is accompanied by continuous catalyst loss as Au diffuses from the droplet to the wire surface. We suggest that high digermane flux and low temperatures promote effective surface passivation of Ge nanowires with H or other digermane fragments inhibiting diffusion and attachment of Au and Ge on the sidewalls. These results illustrate the essential roles of the precursor gas and substrate temperature in maintaining nanowire sidewall passivation, necessary to ensure the growth of straight, untapered, ⟨111⟩-oriented nanowires.
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States.
authors.forename: A D
authors.initials: AD
authors.lastname: Gamalski
authors.affiliation: IBM Research Division, T. J. Watson Research Center , Yorktown Heights, New York 10598, United States.
authors.forename: J
authors.initials: J
authors.lastname: Tersoff
authors.affiliation: Department of Materials Science and Engineering, University of California Los Angeles , Los Angeles, California 90095, United States.
authors.forename: S
authors.initials: S
authors.lastname: Kodambaka
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States.
authors.forename: D N
authors.initials: DN
authors.lastname: Zakharov
authors.affiliation: IBM Research Division, T. J. Watson Research Center , Yorktown Heights, New York 10598, United States.
authors.forename: F M
authors.initials: FM
authors.lastname: Ross
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States.
authors.forename: E A
authors.initials: EA
authors.lastname: Stach
keywords: Nanowire; diffusion; in situ transmission electron microscopy; surface passivation