Multilevel modeling of the influence of surface transport peculiarities on growth, shaping, and doping of Si nanowires

The growth, shaping, and doping of silicon nanowires in a catalyst-mediated CVD process are analyzed within the framework of a multilevel modeling procedure. At an atomistic level, surface transport processes and adsorption are considered by MC simulations. At the macroscopic level, numerical solutions of chemical kinetics equations are used to describe nanowire elongation growth and doping. Both atomistic and kinetic considerations complementing each other reveal the importance of surface transport and the role of low-mobility impurities present on the catalyst surface in the nanowire growth process. In particular, a controllable shaping and selective doping of nanowires is possible by means of well-directed effects on the surface transport of both silicon and impurity adatoms. Some nonlinear effects in the growth and doping caused by percolation-related phenomena are demonstrated.