Investigation of Sensing Properties of NOx Adsorbed Gas Molecules on Fe-Doped MoSe₂ Monolayer

In this paper, the authors explore the impact of NO
_x
(NO, NO
₂
, N
₂
O) gas molecule’s adsorption on the sensing properties of Fe-doped MoSe
₂
monolayer. Formation and binding energy confirm the electronic stability for pristine and doped monolayers. In terms of electronic parameters of interest, the sensing is adsorption energy, charge transfer, recovery time, the density of states (TDOS), conductivity, and sensitivity. Firstly, the adsorption energy (E
_ads
) is analyzed in the sequence of 1.37, 2.00, 0.07 eV. Secondly, the study of charge transfer is in order of 3.67e, 5.91e, 5.90e. It is observed that charge transfer aligns with the trend of adsorption energy. Third, recovery time as a parameter of reusability of Fe-doped MoSe
₂
monolayer by a detachment of gas molecules is estimated. The N
₂
O gas molecule takes minimum time for separation with a value of 0.15 pico sec. Fourth, adsorbed systems’ density of states (DOS) (NO/Fe-doped MoSe
₂
, NO
₂
/Fe-doped MoSe
₂
, N
₂
O/Fe-doped MoSe
₂
) accounts for the population of electrons present in different energy levels showing impurities in the Fermi level region. These impurities arouse to asymmetrical nature of the TDOS inducing magnetic domains in it. Fifth, conductivity as an application of modulated bandgap is studied, and NO
₂
gives the highest conductivity of 0.49. Lastly, sensitivity as a practical sensing parameter concludes the three adsorbed configurations with a maximum sensing response of 89.69% for NO
₂
gas molecules. Therefore, analyzing three NO
_x
gas molecules regarding electronic properties concludes that the Fe-doped MoSe
₂
monolayer more suitably senses NO
₂
gas molecules