Model-simulation of light-induced defect creation in hydrogenated amorphous silicon

The processes of light-induced defect creation in hydrogenated amorphous silicon consist of self-trapping of holes in a weak Si-Si bond adjacent to a Si-H bond, nonradiative recombination of self-trapped holes with electrons, the Si-H bond switching towards the weak Si-Si bond, and hydrogen-hopping or -tunneling along the weak Si-Si bond. The Si-H bond switching and hydrogen movements are treated by Monte-Carlo computer simulation in a simple cubic lattice. From the result of <r(2)> vs t in which r and t designate diffusion distance of hydrogen and diffusion time, respectively, the density of light-induced defects is estimated in a good agreement with the observed density.