▎ 摘　　要

The geometries, electronic structures and optical behaviors of intrinsic and alkaline-earth-metals adsorbed g-GaN system have been investigated using first-principle calculations. The results show that the process of alkaline-earth-metals adsorption on g-GaN is exothermic and all the alkaline-earth-metals adsorption systems are steady. Meanwhile, the most stable position of g-GaN with different alkaline-earth-metals is not the same. The band structures of alkaline-earth-metals adsorbed g-GaN denote semiconductor behaviour; whereas, the band structures of alkaline-earth-metals adsorbed g-GaN reveal an impurity energy level between the VBM and CBM. Importantly, the work function of Sr adsorbed g-GaN is 54.39% lower than that of intrinsic g-GaN, which has tremendous application in field emission nanodevices. More importantly, several absorption peaks for alkalineearth-metals adsorbed g-GaN appear located at 1.5-2.9 eV, which cover the visible light area, thus, the alkalineearth-metals adsorbed g-GaN system can be used for visible light catalytic. Adsorption of alkaline-earth-metal can expand the application of g-GaN in optoelectronic devices.