Electrically Tunable Enhanced Photoluminescence of\nSemiconductor Quantum Dots on Graphene

Abstract

Despite\nthe many fascinating discoveries of fundamental significance and device\napplications involving graphene, one area that has been lacking is\ngraphene-based displays and emissive devices. Since graphene by itself\nhas weak and wavelength-independent absorption and no emission in\nthe visible range, such devices must rely on synergistic combination\nwith other highly sensitive optical materials such as quantum dots.\nHowever, the well-known strong nonradiative energy transfer between\nemitters and quantum dots and graphene makes it impossible to create\nsuch devices due to strong emission quenching. Here we report the\nfirst demonstration of enhanced photoluminescence of quantum dots\nin close proximity to graphene field effect transistor devices, which\nare electrically and spectrally tunable. The enhanced emission originates\nfrom super-radiance between closely packed quantum dots placed close\nto single-layer graphene, which overcomes the strong nonradiative\nquenching observed earlier. Finite difference time domain simulations\nshed light on the regime in which such effects are likely to dominate.\nOur work opens up new avenues for research on novel displays, lasers,\nand emissive devices involving graphene–quantum dot hybrids\nas well as to study fundamental aspects of electrically tunable light–matter\ninteractions at the nanoscale.