On the reversibility of hydrogen effects on the properties of amorphous silicon carbide

Abstract

We performed a theoretical investigation on the effects of hydrogenation and dehydrogenation in the structural properties of amorphous silicon carbide (a-SiC). The calculations were carried out combining interatomic potentials with free volume Monte Carlo simulations. Our prototype amorphous silicon carbide systems contained as much as 85 000 atoms, allowing for a good statistical sampling. We addressed the role of hydrogen on the local and mid-range order of the material. We found that carbon atoms segregate, forming small clusters, embedded in an extensive silicon network. Ring statistics showed that hydrogenation increases the concentration of micro-voids in the structure and reduces its mid-range order. On the other hand, dehydrogenation recovers most of the original structural order.