Electron diffraction radial distribution function analysis of amorphous boron carbide synthesized by ion beam irradiation and chemical vapor deposition

Abstract

Amorphous boron carbide (a-BxC) networks consist of light elements, and their low atomic scattering factors makes structural analysis by x-ray diffraction difficult. Electron diffraction has an advantage of detecting the light elements, because of the strong interaction between the matter and electrons. We prepared a-BxC by ion beam technologies and plasma-enhanced chemical vapor deposition, and characterized their structures via atomic pair-distribution functions derived from electron diffraction intensity profiles. It was found that a pentagonal pyramid is the most favorable cluster in a-B4C generated by ion irradiation, while C[sbnd]C homonuclear bonds were formed in the deposited a-BxC thin film. X-ray photoemission spectroscopy revealed that the a-BxC thin film possesses more carbon than B4C, which is responsible for the formation of the homonuclear bonds.