Van der Waals light sources and photodetectors based on energy transfer between tunneling electrons and excitons

We introduce a platform for nanoscale light emission and detection based on energy transfer (ET) between tunneling electrons and excitons in van der Waals (vdW) heterostructures. In contrast to conventional charge injection approaches, we use near-field electromagnetic coupling to generate or detect excitons in optically active materials that lie outside the electronic conduction path. We show that tunneling electrons can efficiently excite excitons via ET, with efficiencies exceeding photon-mediated coupling by up to four orders of magnitude [1,2]. This mechanism enables electroluminescence not only from TMD monolayers but also various quantum emitters (CdSe, CsPbBr3, dye mol.) with simple drop-casting onto graphene-hBN-gold tunnel junctions. Moreover, we demonstrate exciton generation at sub-bandgap voltages via multi-electron tunneling processes, revealing nonlinear excitation pathways enabled by resonant LDOS enhancement [3]. Additionally, we show that the principle of ET can be used for exciton-polariton generation on CrSBr [4]. On detector applications, we exploit a WS₂ antenna layer to enhance the photoresponse of a MoSe₂-based photodetector via exciton-mediated ET, achieving responsivity gains of over 18× without altering the electronic architecture [5]. Together, these results establish tunneling-driven ET as a universal mechanism for electrically controlled exciton dynamics, offering new design principles for integrated, efficient vdW optoelectronic components.