Phase transition impact on electronic and optical properties of Fe-doped MoSe2 monolayer via N2O adsorption

Electronic and optical properties of Fe-doped MoSe₂ monolayer with (without) N₂O gas adsorption are reported in this paper. The impact of N₂O gas adsorption on both the properties (electronic, optical) is significantly observed as compared to their pristine MoSe2 monolayer (ML) counterpart. The adsorption energy (Eads) is −0.40 eV for N₂O/Fe-doped MoSe₂ ML followed by charge transfer of 8.00e for the electronic property. Similarly, for Fe-doping on MoSe₂ ML a phase transition from semiconducting to metallic (2H →1T) behavior, is displayed from the band structure analysis. Later, after N₂O gas adsorption, semiconducting (2H) behavior is regained due to high electron affinity of Fe-atom, as analyzed from its band structure. Moreover, the work function is modulated from 5.73 eV for pristine MoSe₂ ML, to 4.12 eV for Fe–MoSe₂ ML and 4.06 eV for N₂O/Fe-doped MoSe₂ ML post gas adsorption respectively. Further, the imaginary part (ε₂) of dielectric constant is shifted from 2.38 to 6.83 arbitrary unit (a.u.) from pristine to N₂O/Fe-doped MoSe₂ ML, respectively. Noticeably, the refractive index is altered from 1.54 to 6.6 a.u. while absorption index is varied from 1.07 to 0.00 a.u. showing its potential ability to absorb light in the visible region. Lastly, this nature is again confirmed from orbital and molecular level interaction in total density of states plots. This increases its utility to be used for different photovoltaic applications such as photo detectors and display devices.