Rhodium-repaired Ga-defect in GaN, exhibiting extremely strong SOF2 molecule selectivity at room temperature: A DFT study

GaN is an emerging 2D material with a wide direct bandgap and high carrier concentration. By using computational methods to introduce Ga defects in GaN, we have made a structure with extremely high chemical activity. After that, Ag, Pt, and Rh are used to repair Ga defects to reasonably suppress the overactive defect sites. In this way, the Ga defect GaN repaired by metal atoms was made. We used density functional theory for dispersion correction for calculation. Specifically, the Perdew–Berke–Ernzerhof generalized gradient approximation method was used. Through the analysis of geometric structure, adsorption energy, electron transfer, deformation charge density, density of states, and band structure, it was screened that Rh@GaN could effectively adsorb SOF2 (adsorption energy −0.78 eV) and be accompanied by a high electron transfer (0.186e). Finally, through the analysis of recovery time and sensitivity, it is verified that Rh@GaN can adsorb SOF2 with high selectivity at room temperature and can generate up to 191.75% response signal to SOF2.