title: Self-catalyzed GaAs nanowires on silicon by hydride vapor phase epitaxy.
abstract: Gold-free GaAs nanowires on silicon substrates can pave the way for monolithic integration of photonic nanodevices with silicon electronic platforms. It is extensively documented that the self-catalyzed approach works well in molecular beam epitaxy but is much more difficult to implement in vapor phase epitaxies. Here, we report the first gallium-catalyzed hydride vapor phase epitaxy growth of long (more than 10 μm) GaAs nanowires on Si(111) substrates with a high integrated growth rate up to 60 μm h-1and pure zincblende crystal structure. The growth is achieved by combining a low temperature of 600 °C with high gaseous GaCl/As flow ratios to enable dechlorination and formation of gallium droplets. GaAs nanowires exhibit an interesting bottle-like shape with strongly tapered bases, followed by straight tops with radii as small as 5 nm. We present a model that explains the peculiar growth mechanism in which the gallium droplets nucleate and rapidly swell on the silicon surface but then are gradually consumed to reach a stationary size. Our results unravel the necessary conditions for obtaining gallium-catalyzed GaAs nanowires by vapor phase epitaxy techniques.
authors.affiliation: Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut Pascal, F-63000 Clermont-Ferrand, France.
authors.forename: Zhenning
authors.initials: Z
authors.lastname: Dong
authors.forename: Yamina
authors.initials: Y
authors.lastname: André
authors.forename: Vladimir G
authors.initials: VG
authors.lastname: Dubrovskii
authors.forename: Catherine
authors.initials: C
authors.lastname: Bougerol
authors.forename: Christine
authors.initials: C
authors.lastname: Leroux
authors.forename: Mohammed R
authors.initials: MR
authors.lastname: Ramdani
authors.forename: Guillaume
authors.initials: G
authors.lastname: Monier
authors.forename: Agnès
authors.initials: A
authors.lastname: Trassoudaine
authors.forename: Dominique
authors.initials: D
authors.lastname: Castelluci
authors.forename: Evelyne
authors.initials: E
authors.lastname: Gil