Hybrid graphene tunneling photoconductor with interface engineering towards fast photoresponse and high responsivity

Hybrid graphene photoconductor/phototransistor has achieved giant photoresponsivity, but its response speed dramatically degrades as the expense due to the long lifetime of trapped interfacial carriers. In this work, by intercalating a large-area atomically thin MoS₂ film into a hybrid graphene photoconductor, we have developed a prototype tunneling photoconductor, which exhibits a record-fast response (rising time ~17 ns) and a high responsivity (~3 × 10⁴ A/W at 635 nm illumination with 16.8 nW power) across the broad spectral range. We demonstrate that the photo-excited carriers generated in silicon are transferred into graphene through a tunneling process rather than carrier drift. The atomically thin MoS₂ film not only serves as tunneling layer but also passivates surface states, which in combination delivers a superior response speed (~3 orders of magnitude improved than a device without MoS₂ layer), while the responsivity remains high. This intriguing tunneling photoconductor integrates both fast response and high responsivity and thus has significant potential in practical applications of optoelectronic devices.