The role of morphology in stability of Si nanowires

Abstract

By means of ab initio calculations we have investigated the morphology and stability of nonhydrogenated, free standing, single crystal silicon nanowires oriented along ⟨001⟩, ⟨011⟩, ⟨111⟩, and ⟨112⟩ axes and with diameters ranging from 2 to 5 nm. Different shapes and facet reconstructions have been carefully considered in order to provide a surface without any atoms with two dangling bonds and, eventually, to select the morphology more stable in energy. We have found the ⟨011⟩-oriented silicon nanowires to display the lowest total energy and we also discuss how our results support recent experimental observations.