Kinetics of germanium nanowire growth by the vapor-solid-solid mechanism with a Ni-based catalyst

The kinetics of vapor-solid-solid (VSS) Ge nanowire growth using a Ni-based catalyst were investigated to probe the rate-limiting step for this complex nanoscale crystal growth process. The effects of key parameters such as temperature and precursor partial pressure on the nanowire growth rate were studied in order to gain detailed insights into the growth kinetics. Two different regimes were observed for VSS growth of Ge nanowires as function of temperature. At higher temperatures (345 °C–375 °C), kinetics data suggest that mass transport of germane precursor to the catalyst surface is rate limiting. At lower temperatures (<345 °C), either surface reaction of the GeH4 precursor on the catalyst or incorporation of Ge into the nanowire across the wire/catalyst interface is rate limiting