Excitonic Emission Modulation in GaSe/MoS₂ Van Der Waals Heterostructure Via Plasmonic Control of Interlayer Charge Transfer

2D van der Waals (vdW) semiconductors attract attention for their unique optoelectronic properties and emerging applications, as they exhibit unexplored phenomena in ultrathin films. Beyond their stable excitonic characteristics at room temperature, efforts focus on enhancing light-matter interactions by integrating hybrid structures due to their absolute thinness. Here, a method for controlling excitonic emission by suppressing interlayer charge transfer in 2D vdW heterojunctions using plasmonic hybridization is presented. This is achieved by stacking multilayer (ML)-GaSe and monolayer (1L)-MoS₂ on a plasmonic Ag film. At the edge of this device, the plasmonic Purcell effect significantly enhanced the radiative emission of excitons from both GaSe and MoS₂. In contrast, interlayer charge transfer occurrs at the center due to the absence of plasmonic enhancement, resulting in exciton quenching. The work demonstrates the potential to manipulate charge transfer between layers in vdW heterojunctions through plasmonic interactions.