Manipulation of trions to enhance the excitonic emission in monolayer p-MoS and its hetero-bilayer by reverse charge injection.

Monolayer 2D transition metal dichalcogenides (TMDs) are known for their direct bandgaps and pronounced excitonic effects, which facilitate efficient light absorption and high photoluminescence (PL). In this study, we report a significant enhancement in PL emission from monolayers of p-type molybdenum disulfide (p-MoS), fabricated on conductive substrates-such as indium tin oxide (ITO) and gold (Au). We attribute this behaviour to the reverse injection of charge carriers from substrates to p-MoS and the subsequent localization of electrons and holes in the substrate and p-MoS, respectively.