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Intensity analysis of boron and nitrogen K‐edge spectra for hexagonal boron nitride by EELS
Author(s) -
Saito S.,
Higeta K.,
Ichinokawa T.
Publication year - 1986
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1986.tb02751.x
Subject(s) - boron , spectral line , chemistry , atomic physics , exciton , boron nitride , atomic orbital , k edge , electron , spectroscopy , physics , condensed matter physics , organic chemistry , quantum mechanics , astronomy
SUMMARY Boron and nitrogen K‐edge spectra for hexagonal boron nitride (h‐BN) were measured by electron energy loss spectroscopy (EELS) at orientations of a momentum transfer q parallel and perpendicular to the c‐axis in order to investigate anisotropic unoccupied states π* and σ*, separately. Differences between intensity profiles for B K and N K spectra are attributed to different transition probabilities at B K and N K edges from Is states to the π* and σ* states. The intensity of the first peak at q ∥ c in the B K spectrum, which is ascribed to the transition from B‐1s to the Q — 2 state in the π* band, is 10 times as large as that in the N K spectrum. Quantitative calculation of transition probabilities for B K and N K spectra at q ∥ c shows that the contribution of B‐2p z orbital to the Q — 2 state is 1–7 times as large as that of N‐2p z . This value suggests that the enhanced peak in the B K spectrum is explained by means of single electron excitations, disregarding the electron‐electron interactions for the exciton reported by several workers. The contributions of 2p x and 2p y orbitals of B and N atoms to σ* states are also estimated by intensity analysis of B K and N K spectra at q⊥c .