Angular dependence of X-ray-excited valence-band photoelectron spectra of diamond

Abstract

Angle-resolved valence-band X-ray photoelectron spectra from (110) single-crystal diamond surfaces are reported and discussed. Comparison of the spectra from polished, oxidatively eroded and heated (ca. 1070 K) surfaces enabled the O 2s and O 2p contributions to the spectra to be positively identified. The marked angular dependence of the relative intensities and energies of the major intrinsic valence-band components is attributed to the sampling of different portions of the Brillouin zone at different angles of photoelectron emission, as a result of wavevector-conserving direct transitions, in accordance with theoretical expectations. The angle-integrated valance-band profile obtained by summation is compared with previous experimental work and with calculated densities-of-states.