  This study provides a new insight into the processes which occur when thin
film hydrogenated amorphous silicon is subjected to UV laser irradiation in the
presence of oxygen. It achieves this by observing the effects of subjecting the
films to progressively increasing laser radiation doses. This reveals that an
array of nuclei is first created, leading to the formation of a well-defined
crystalline network, consistent with the structure of silicon oxide. Further
irradiation results in the formation of cone-like structures on the crystalline
network, due to silicon-oxygen bond breakage and migration of the resultant
silicon-rich material. Eventually the cone-like structures become the dominant
features, but remain interconnected by nanowire remnants of the original
crystalline structure.
