Dependence of Surface Facet Period on the Diameter of Nanowires

Axial heterostructured silicon nanowires with varying n- and p-doping were synthesized using a vapor-liquid-solid approach. The nanowire sidewalls exhibit periodic nanofaceting in the silicon deposited directly on the sidewalls when diborane dopant gas is introduced during growth. For such nanofaceting, a model predicting the distance between facets (the facet period) is developed. For a nanowire structure, an extra energy cost term arising from the formation of apexes between facets is considered, and the facet size is predicted to decrease as the wire diameter increases. It is found that the model fits the experimental data well, and the fitted parameters in the model lie within the ranges of their expected values.