New luminescence band due to nitrogen impurities in gallium oxide powders

Abstract

In this study, we show the new luminescence aspects about gallium oxide powders by intra-bandgap photoluminescence (PL) measurement. In contrast to the generally accepted results of the earlier works done by many researchers, the nitrogen impurity is found to obviously play an important role on the ultraviolet (UV) region luminescence properties of gallium oxides. It is observed for the first time that the nitrogen-induced luminescence center leads to the new UV emission band around 3.47 eV with narrow line-width from both α- and β-Ga 2O 3. This demonstrates that α- and β-Ga 2O 3, despite the different crystal structure, have the same nitrogen-induced luminescence mechanism. It is also found that the nitrogen in gallium oxides acts as a shallow donor whose ionization energy is 12–15 meV.