Impact of N‐Doping on MoSe2 Monolayer for PH3, C2N2, and HN3 Gas Sensing: A DFT Study

Abstract In this research, the different characteristics of MoSe 2 and N‐doped MoSe 2 monolayers were studied using density functional theory calculations. The negative cohesive energy (−5.216 eV for MoSe 2 and −5.333 eV for N‐MoSe 2 ) verified their energetical stability. The variation of structural, electronic, and optical properties of MoSe 2 and N‐MoSe 2 via adsorption of PH 3 , C 2 N 2 , and HN 3 gases are studied. The N‐doping results in a stronger adsorbent‐gas interaction, resulting in maximum adsorption energy of −0.036, −0.033, and −0.198 eV for the selected gases. The MoSe 2 and N‐MoSe 2 monolayers showed a direct band gap of 1.48 eV and 1.09 eV, respectively. However, upon interaction with the gases, a notable shift in the band gap of both adsorbents is observed. N‐MoSe 2 showed semiconductor‐to‐conductor transition via C 2 N 2 and HN 3 adsorption. The sensitivity of MoSe 2 for the selected gases has improved remarkably via N‐doping. Also, HN 3 gas can be easily detected by the N‐MoSe 2 monolayer due to the greater changes in work function (0.45 eV). The absorption coefficient of both adsorbents is over 10 5 cm −1 order in the UV region, which suffers a mild peak shifting due to gas adsorption. This study suggests that N‐MoSe 2 can be a potential candidate for selected gas sensing.