Effects of oxidation on the electronic and optical properties of GaN(0001) surface: First principles study

Abstract

Surface oxidation often affects the electronic and optical properties of materials. In fact, controlled oxidation can make materials richer in electronic properties. And, it is necessary to deeply understand the oxidation mechanism of GaN (0001) surface, which has significant application prospects in the field of light-emitting diodes and photodetectors. Using first-principle calculations, we systematically investigated the effect of oxidation on the structure, electronic, and optical properties of GaN(0001) surfaces. It is noted that oxidation is an exothermic process, and oxygen atoms are preferentially adsorbed at the H-top sites. Meanwhile, some interesting phenomena appeared after surface oxidation, such as electron transfer from the GaN(0001) surface to O atoms and geometric deformation of the surface structure. Furthermore, oxidation enhances the visible light absorption area by as much as 87.07%. These results suggest that surface oxidation can be a source of novel optoelectronic properties of GaN(0001) surfaces and facilitate its application in optoelectronic devices.