Nanoscale band gap spectroscopy on ZnO and GaN-based compounds with a monochromated electron microscope

Monochromated low-loss EELS (electron energy-loss spectroscopy) is explored as an analytical technique for nanoscale mapping of the electronic band gap energy on arsenic-implanted ZnO, CdZnO, and InGaN compounds. Its accuracy is confirmed independently with Raman spectroscopy. From a ternary compound, the relationship between the band gap energy and the chemical composition is determined, a powerful application of low-loss EELS. The effects of electron beam delocalization are discussed using examples from In₀․₂₅Ga₀․₇₅N quantum wells.