Estudo das propriedades térmicas de nanofios de silício

Abstract

In this work we present the results of the study of thermal stability of silicon nanowires (SiNWs), carried out by computational simulation using Monte Carlo methods. The study focuses on cylindrical nanowires grown in the [001], [110] and [111] directions with diameters up to 6nm. For the case of nanowires in the [001] direction, hollow structures have been studied. These hollow structures present a fixed 5nm external diameter and variable internal diameters. Hydrogen passivated nanowires, grown in the [111] direction, have also been studied. The Tersoff potential has been inplemented to describe the Si-Si and Si-H interactions. For the nonpassivated nanowires, the calculations show that the nanowires grown in the [110] direction are the most stable ones, with the nanowires grown in the [001] direction being determined to melt at the lower temperatures. Passivated nanowires, grown at [111] direction, are seen to melt at lower temperatures when compareted to the non-passivated nanowires with similar diameters and grown at the same direction. A fit of the melting temperatures, as a function of the diameter of the nanowires, show that the surface to bulk ratio has a great influence on the melting temperature of the Si nanowires. This study was performed using the "mcsim"code, by Prof. Dr. Ricardo Andreas Sauerwein, of the Santa Maria Federal University.