A molecular dynamics study of the Si-nanowire@carbon-nanotube nanocomposite with sp3 interfacial bonding

Molecular dynamics (MD) simulations are performed to study the mechanical properties of nanocomposite of carbon nanotube (CNT) encapsulating a Si16-fullerene-linked nanowires (Si16NW). It is found that Si16NW is not coaxial with CNT. Instead, it is adsorbed and hence closer to one side of the internal wall of CNT by forming strong sp3 bonds. These sp3 bonds can greatly enhance the limit of CNT against torsional and bending deformation. Due to the protection of CNT, the encapsulated Si16NW can maintain its configuration at relatively high torsional angle. The axial Young's modulus of the freestanding Si16NW is found to be more than that of bulk Si and much larger than that of the Si nanowires of similar size. Furthermore, the interfacial sp3 bonds resulted in a strong enhancement of axial maximum strength of encapsulated Si16NW. However, it is interesting that filling Si16NW into (13, 0) CNT does not enhance the axial tensile strength and elastic modulus of the host CNT.