Liquid-phase precipitation growth rates

The mechanism for VLS was proposed by Wagner in 1964. Under deposition conditions, the catalyzer has to form a liquid solution with the desired material. It should also have a low vapor pressure and be chemically inert. In the process, the vapor diffuses into the liquid catalyzer and, as the concentration becomes too high, the growth species precipitate to form the nanowire. The liquid phase is a preferential condensation site, and this causes a higher growth rate of the VLS with respect to the VS. Furthermore, by controlling the dimension and dispersion of the catalyzer, control can be achieved over the diameter of the nanowire. 

At low concentrations of the liquid phase, the elimination of isolated pores is continued at a reduced rate, due to the solution precipitation and grain-shape accommodation. If the volume fraction of the liquid is sufficiently high, the filling of the isolated pores could be discontinuous [95, 100]. In this case, grain growth, rather than grain-shape accommodation, is responsible for the filling of the pores. 

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