Energetics of finite, clean and hydrogenated silicon nanotubes

The energetics and relative stability of infinite and finite, clean and hydrogenated open-ended Si nanotubes is investigated using the extended Brenner potential. The calculations show that the excess strain energy of infinite clean Si tubes is reduced when the tubes are hydrogenated on both sides of the tubular shell. For finite Si tubes the total energy exhibits a minimum which reflects a balance between the strain energy of the shell and the chemical energy of the open ends. If hydrogen atoms are chemisorbed on the outer surface of finite Si nanotubes, the tubes show a tendency to close their open ends. For very short, large-diameter tubes, topologically different structures are formed––hydrogenated silicon tori.