A Theory of Growing Crystalline Nanorods - Mode I

TL;DR

This paper develops a theoretical model for the growth of crystalline nanorods in Mode I during physical vapor deposition, supported by kinetic Monte Carlo simulations, revealing how growth conditions influence nanorod dimensions.

Contribution

It provides closed-form theories for terrace lengths and nanorod diameter during Mode I growth, linking them to deposition parameters and validating with simulations.

Findings

Quasi-steady growth exists for each set of conditions.

Terrace lengths and diameters depend on deposition rate, temperature, and angle.

Theories are verified by kinetic Monte Carlo simulations.

Abstract

Nanorods grow in two modes through physical vapor deposition (PVD). In mode I, monolayer surface steps dictate the diameter of nanorods. In mode II, multiple-layer surface steps dictate the diameter, which is the smallest possible under physical vapor deposition [X. B. Niu et al., Phys. Rev. Lett 110, 136102 (2013) and F. Du & H. C. Huang, Phys. Rev. Materials. 1, 033401 (2017)]. This paper reports closed-form theories of terrace lengths and nanorod diameter during the growth in mode I, as a function of deposition conditions. The accompanying lattice kinetic Monte Carlo simulations verify the theories. This study reveals that (1) quasi-steady growth exists for each set of nanorod growth condition, (2) the characteristic length scales, including terrace lengths and nanorod diameter at the quasi-steady state, depend on the deposition conditions - deposition rate F, substrate temperature T, and incidence angle .