Resonant soft-x-ray emission study in relation to the band structure of cBN

Abstract

The resonant soft-x-ray emission ͑SXE͒ and its total photon yield ͑TPY͒ spectra were measured at the B 1s and N 1s edges of cubic boron nitride ͑cBN͒ using undulator radiation. The band-gap energy was found to be about 6.2 eV, which is in good agreement with other experiments. It was found that the emission from the high symmetry point in the SXE spectrum is enhanced when the same high symmetry point in the TPY spectrum is excited. The line shapes in both the SXE and N 1s TPY spectra were consistent with the calculated partial density of states, though the total bandwidth was not well reproduced. On the other hand, the exciton effect was found to be strong in the B 1s TPY spectra.

Linear and nonlinear optical properties of group-III nitrides

“…4 In all the compounds studied here the valence bands are dominated by the 2p bonding states of nitrogen at the top of the valence band. In the absence of the metal d states, the LDOS's of N 2s bonding states in AlN and BN are much higher than those of the electronic states of metal 60 ͑see Figs. 1 and 2͒.…”

Band-gap measurements of bulk and nanoscale hematite by soft x-ray spectroscopy

“…49 Loss of intensity at the VB maximum is observed when the excitation is tuned to the lowest point of the CB because indirect band-gap excitations are forbidden. 50 For direct-gap semiconductors, an opposite trend is found.…”

Surface studies of (111) facets of cBN mini-crystals

“…Recently, Agui et al 14 used soft x-ray emission and total photon yields from scraped cBN surfaces to show that the B 1s core level and the conduction band maximum should be separated by 194.2 eV. If we use this as a reference, the Fermi level of the three pinned facets should be 3.5 eV above the valence band maximum.…”