TY - JOUR

T1 - Record pure zincblende phase in GaAs nanowires down to 5 nm in radius

AU - Gil, Evelyne

AU - Dubrovskii, Vladimir G.

AU - Avit, Geoffrey

AU - André, Yamina

AU - Leroux, Christine

AU - Lekhal, Kaddour

AU - Grecenkov, Jurij

AU - Trassoudaine, Agnès

AU - Castelluci, Dominique

AU - Monier, Guillaume

AU - Ramdani, Reda M.

AU - Robert-Goumet, Christine

AU - Bideux, Luc

AU - Harmand, Jean Christophe

AU - Glas, Frank

PY - 2014/7/9

Y1 - 2014/7/9

N2 - We report the Au catalyst-assisted synthesis of 20 μm long GaAs nanowires by the vapor-liquid-solid hydride vapor phase epitaxy (HVPE) exhibiting a polytypism-free zincblende phase for record radii lower than 15 nm down to 5 nm. HVPE makes use of GaCl gaseous growth precursors at high mass input of which fast dechlorination at the usual process temperature of 715 °C results in high planar growth rate (standard 30-40 μm/h). When it comes to the vapor-liquid-solid growth of nanowires, fast solidification at a rate higher than 100 μm/h is observed. Nanowire growth by HVPE only proceeds by introduction of precursors in the catalyst droplets from the vapor phase. This promotes almost pure axial growth leading to nanowires with a constant cylinder shape over unusual length. The question of the cubic zincblende structure observed in HVPE-grown GaAs nanowires regardless of their radius is at the heart of the paper. We demonstrate that the vapor-liquid-solid growth in our conditions takes place at high liquid chemical potential that originates from very high influxes of both As and Ga. This yields a Ga concentration systematically higher than 0.62 in the Au-Ga-As droplets. The high Ga concentration decreases the surface energy of the droplets, which disables nucleation at the triple phase line thus preventing the formation of wurtzite structure whatever the nanowire radius is.

AB - We report the Au catalyst-assisted synthesis of 20 μm long GaAs nanowires by the vapor-liquid-solid hydride vapor phase epitaxy (HVPE) exhibiting a polytypism-free zincblende phase for record radii lower than 15 nm down to 5 nm. HVPE makes use of GaCl gaseous growth precursors at high mass input of which fast dechlorination at the usual process temperature of 715 °C results in high planar growth rate (standard 30-40 μm/h). When it comes to the vapor-liquid-solid growth of nanowires, fast solidification at a rate higher than 100 μm/h is observed. Nanowire growth by HVPE only proceeds by introduction of precursors in the catalyst droplets from the vapor phase. This promotes almost pure axial growth leading to nanowires with a constant cylinder shape over unusual length. The question of the cubic zincblende structure observed in HVPE-grown GaAs nanowires regardless of their radius is at the heart of the paper. We demonstrate that the vapor-liquid-solid growth in our conditions takes place at high liquid chemical potential that originates from very high influxes of both As and Ga. This yields a Ga concentration systematically higher than 0.62 in the Au-Ga-As droplets. The high Ga concentration decreases the surface energy of the droplets, which disables nucleation at the triple phase line thus preventing the formation of wurtzite structure whatever the nanowire radius is.

KW - chemical potential

KW - crystal structure

KW - GaAs

KW - HVPE

KW - Nanowire

KW - VLS

UR - http://www.scopus.com/inward/record.url?scp=84904015856&partnerID=8YFLogxK

U2 - 10.1021/nl501239h

DO - 10.1021/nl501239h

M3 - Article

VL - 14

SP - 3938

EP - 3944

JO - Nano Letters

JF - Nano Letters

SN - 1530-6984

IS - 7

ER -