Optimizing the Synthesis of Zinc-rich Gallium Zinc Oxynitrides by Combining Co-Precipitation and Moisture-Assisted Nitridation: Optimizing the Synthesis of Zinc-rich Gallium Zinc Oxynitrides by Combining Co-Precipitation and Moisture-Assisted Nitridation

ZnO-co-doped GaN is a promising catalyst for photocatalytic overall water splitting in the visible light range. The conventional high-temperature synthesis has the drawback that only low amounts of Zn2+ ions can be incorporated into the GaN:ZnO matrix due to a substantial loss of volatile Zn metal during the nitridation of the binary oxides in flowing NH3. By applying moisture-assisted nitridation of a co-precipitated GaZn precursor under milder conditions it was possible to significantly reduce the Zn loss during nitridation. Using a GaZn precursor with a high Zn content, GaN:ZnO nanoparticles containing high amounts of Zn were obtained. The bandgap was found to decrease nearly linearly with increasing Zn content. Concomitantly, the defect density and structural disorder increased with increasing Zn content.