Molecular dynamic simulation of structural stability of carbon and silicon composite nanowires

In the field of electronic and computational technology, silicon nanowires (SiNWs), as one-dimensional semiconductor materials, possess superior and distinctive photovoltaic and electronic characteristics. Their application in microelectronic circuits has greatly facilitated the development of advanced fields, including aerospace and quantum computation. However, the stability of SiNWs decreases in a thermal environment, highlighting the enhancement of their thermal stability as a critical research focus. In this paper, structural models of SiNWs coated with carbon nanotubes (CNTs) of different sizes were constructed. The thermal stability of these composite nanowires during heating from 300 to 3000 K was investigated by molecular dynamics simulation. The CNTs exhibited shell contraction and folding at temperatures above 500 K, which enhanced protection and induced the formation of new carbon–carbon bonds. As a result, several isolated Si atoms reassembled into diamond clusters, thereby increasing the crystallization rate. The number of diamond clusters initially increased and then decreased with increasing temperature, and there is a significant peak in systems with a larger CNT folding diameter. The CNTs with the smallest diameter exhibit the highest stability at room temperature, while larger systems exhibit higher thermal stability due to the folding of CNTs. These findings contribute to the development of CNT-SiNW composites with optimal thermal stability.