Model of hydrogenated amorphous silicon

Abstract

Computer models of hydrogenated amorphous silicon have been constructed by adding hydrogen atoms to broken bonds in periodic random-network models of pure amorphous silicon. The atomic coordinates of 12 examples containing 10-13 at.% have been determined by minimizing a valence-force potential supplemented by a repulsion between H atoms and Si atoms other than those that are bonded to each other. Radial distribution functions and structure factors have been computed for three sets of force constants. The computed neutron scattering is in good agreement with recent diffraction data, and this is taken as support for the assumption that most of the hydrogen in this material is covalently bound to silicon atoms in a random network.