Study of the dielectric properties near the band gap by VEELS: gap measurement in bulk materials

Measuring the band gap of bulk materials by valence electron energy loss spectroscopy (VEELS) is not straightforward. Mathematical procedures used to recover the single scattering distribution from raw data introduce artefacts in the signal, which complicate the gap measurement. In this work, we propose a method to overcome this and measure the direct band gap energy with an accuracy of ±0.1 eV. The method is tested on six crystalline wide-band gap materials: MgO, Ga2O3, SrTiO3, ZnO, BN and GaN.