Investigation of hydrogen adsorption on gallium nitride: A density functional theory study
Density functional theory (DFT) calculations were performed to investigate the effects of hydrogen (H) adsorption on polar GaN (0001) surfaces terminated with gallium (Ga) and nitrogen (N) atoms. We studied the effects of different coverage of H atoms on both terminations and found that the N-terminated surface adsorbs with much larger energies compared to the Ga-terminated surface. For a 0.25 monolayer (ML) coverage, the N-terminated surface has the largest adsorption energy of −2.63 eV, and the H atom transfers around 0.40e charge to the N atom based on Bader charge analysis. It was also observed that changes in the average adsorption energy is more dramatic, implying that the N-terminated surface is more sensitive to H adsorption.