E-catalog        

Библиогр.: 39 назв.

The Au-assisted III-V nanowire growth is often preceded by the formation of pyramid-like pedestals under catalyst droplets during pre-growth annealing. In the present paper, we propose a kinetic step-flow model of the transition from the growth of pedestals to the formation of nanowires with constant diameters. In our model an atomic step at the pedestal sidewall appears when the edge of the 2D island growing at the liquid-solid interface under the droplet attains the triple phase line. The steps move along the sidewall downward to the pedestal base at the expense of adatoms attaching to the step edges from adjacent terraces. The analytical expressions for the step velocities yielding a set of equations for time-dependent positions of steps are obtained. It is shown that the transition to nanowire growth might take place as the result of the step bunching at the pedestal top when the upper terrace becomes shorter than a certain critical value at which the step-step repulsion is significant. The numerical simulations of the pedestal growth demonstrate a rapid transition to nanowire growth at low temperatures and the absence of such a transition at high temperatures, which is in accordance with the experimental observations.