The effect of short-range H re-bonding in creating metastable defects in amorphous hydrogenated material was studied by using a tight-binding molecular dynamics model which took account of both electronic and structural energies. The formation energy of defects that were created by transferring H from Si-H sites to weak Si-Si bond sites was found to scale linearly with the Si-Si bond length. This H re-bonding mechanism could account for several features of thermally generated and light-induced defects. It was suggested that bond-length disorder could be the predominant factor in controlling the defect density of amorphous hydrogenated material.

Q.Li, R.Biswas: Physical Review B, 1995, 52[15], 10705-8