VEELS spectra in the band-gap energy domain, after subtraction of the zero loss tail, showing how a fit with a square root function (E − E_g)^1/2 can lead to a measurement of the bandgap. Intensity below this E_g energy can have different origins, such as the presence of surface defects quoted by the authors in the case of c-GaN (courtesy of Erni and Browning [90] for left figure and Lazar et al. [89] for right figure).