Effect of scattering angle on energy loss near-edge structure of h-BN

Angular dependence of the B-K edge in hexagonal BN (h-BN) has been quantitatively characterized using transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) in terms of the ratio of π* and σ* peaks. The dependence of the peak ratio on the scattering angle has been observed with two different values of the collection angle, 0.78 and 4.2 mrad. Under these conditions, the peak ratio of π*/σ* decreases with the increase of the scattering angle up to as much as the Bragg angle. As the angle approaches the fundamental reflection, the peak ratio re-increases, which may be attributable to the elastic scattering effect on the Bragg reflection. A change of the peak ratio in energy-loss spectra has been confirmed by the calculated peak ratio estimated by DV-Xα method.