Electronic Structure of Boron Doped HOPG: Selective Observation of Carbon and Trace Dope Boron by Means of X-ray Emission and Absorption Spectroscopy

抄録

We have measured the soft X-ray absorption and emission spectra of near B-K and C-K absorption edges of highly oriented pyrolytic graphite (HOPG) doped with a small amount (0.32 at.%) of boron (B), including incident/takeoff angle dependence. The main peak intensities at the B-K edge around 182 eV were almost independent on the change of takeoff angle. On the other hand, the satellite peak around 185 eV becomes larger as the takeoff angle becomes smaller. Based on this result, unlike the previous assignment of the main peak predicted from the quantum chemical calculation (π orbitals), it is reasonable to attribute the main peak to the σ orbitals. The takeoff angle dependence of the B-K emission is similar to the angle dependency of the C-K emission of undoped HOPG. Based on this and the theoretical consideration, it is presumable that the doped B atom does not intercalate between the layers of HOPG; it replaces the C atom of the hexagonal network structure and has a wave function similar to that of C atoms (sp² type hybridized orbital). [DOI: 10.1380/ejssnt.2018.122]