Interfacial coupling enabled strong, asymmetric, and tunable thermoelectricity at graphene/MoS2 heterostructures

A comprehensive understanding of interfacial physics including electron/phonon transport and coupling at graphene/MoS2 heterojunctions is critical for thermoelectric conversion and sensing, yet remains insufficiently explored. Here, we comprehensively investigate its electrical transport, thermal transport, and thermoelectric properties using a well-designed micro-heater device and a photo-thermal Raman technique. Electrical transport measurements reveal opposite resistance dependence on gate voltage in individual MoS2 and graphene/MoS2 regions, based on which a low-voltage 0–1 logic device is demonstrated. The graphene/MoS2 heterojunction exhibits strong (maximum 1.03 mV/K in our experiment) and asymmetric thermoelectric characteristics, which are attributed to a synergistic mechanism involving interface energy filtering and graphene-doping. The thermoelectric response can be effectively tuned through modulation of interfacial Schottky barrier and electrical coupling. Additionally, we observe electrically tunable interfacial thermal conductance at the interface, which may arise from combined phonon coupling and electron–phonon interaction. Our study provides a promising platform for developing intelligent thermoelectric devices applications.