First-principles study on adsorption of oxygen on H-terminated armchair silicene nanoribbon

This work systematically studies the electronic and optical properties of H-terminated armchair silicene nanoribbon (HASiNR) for oxygen (O-2) adsorption using first-principles calculations. The results show that the most stable site for O-2 adsorption is the edge of the ribbon, which possesses relatively low adsorption energy of -2.46eV, indicating good stability. Particularly, the adsorption energy decreases gradually with the increase of the oxygen concentration. It was also found that the direct bandgap of HASiNR can be effectively tuned by changing the adsorption concentration of O-2 gas. Additionally, the analysis of the density of states shows that the adsorption of O-2 on HASiNR is chemisorption due to the apparent charge transfer from the ribbon to O-2 gas. Besides, the work function, absorption coefficient and refractive index of the HASiNR are sensitive to O-2 gas adsorption. Therefore, our studies prove that oxygen gas adsorption allows the HASiNR to modulate its electronic and optical properties.