Effect of non-metal atom adsorption on the electronic, magnetic, optical and HER properties of a Ga 2 O 3 monolayer: a first-principles study

First-principles calculations have been carried out to explore the structural, magnetic, electronic, optical and HER properties of non-metal-adatom-functionalized Ga₂O₃ monolayers. All adatoms lead to enhanced metallicity, a wider optical absorption region, better HER activity and lower work function of the Ga₂O₃ monolayer. In particular, the B-adsorbed Ga₂O₃ monolayer and P-adsorbed Ga₂O₃ monolayer with -2% strain in the Y direction demonstrate extraordinary HER performance (their H adsorption free energies are -0.019 and -0.043 eV, respectively). The Se-adsorbed Ga₂O₃ monolayer exhibits ultrahigh ultraviolet and visible-light absorption capacity, attributed to its unique Se adsorption structure and strongly enhanced metallicity. Our calculations provide an effective method to modulate the structural, magnetic, optoelectronic and HER properties of a Ga₂O₃ monolayer for device applications.