Study of the stability of hydrogenated amorphous silicon using tight-binding molecular dynamics

We have developed a tight-binding molecular dynamics (TBMD) approach for simulating the Si-H bonds in hydrogenated amorphous silicon (a-Si:H) systems. Using our approach, it has been possible to generate the structure models of a-Si:H with different hydrogen concentrations. The calculated radial distribution function (RDF) of our models agree with experimental results. We have also calculated the total average energy per silicon atom in our models and found it to be minimum when the hydrogen concentration is in the range of 8-14%. This minimum implies that the a-Si:H models are most stable in this hydrogen concentration range, which agrees very well with the experimental results.