Adsorption of NO and NO₂ on MoSeS/GaN heterojunction: a first-principles study

The adsorption behaviors of gas molecules such as Cl-2, CO, NO, NO2 and SO2 on MoSSe/GaN, as well as their adsorption energies, charge transfer and adsorption distances are investigated based on the first-principles calculation. The large adsorption energies of Cl-2, NO, NO2 and SO2 on MoSSe/GaN indicate that the gas molecules have strong interaction forces with MoSSe/GaN. Probing the changes in the electronic structure, the adsorption of NO and NO2 on MoSSe/GaN introduces magnetism into their systems and reduces the band gaps. The magnetism mainly originates from the O atoms in NO and NO2, while the decrease of the band gap is due to the hybridization of orbitals near the bottom of the conduction band and the top of the valence band with the p orbitals of Ga atoms in MoSSe/GaN. This suggests that MoSSe/GaN can be applied to detect NO and NO2 gas molecules and has potential as a semiconductor gas sensor for these gases.