Emergence of Photoswitchable States in a Graphene–Azobenzene–AuPlatform.

The perfect transmission of chargecarriers through potential barriers in graphene (Klein tunneling)is a direct consequence of the Dirac equation that governs the low-energycarrier dynamics. As a result, localized states do not exist in unpatternedgraphene, but quasibound states canoccur for potentialswith closed integrable dynamics. Here, we report the observation ofresonance states in photoswitchable self-assembled molecular(SAM)-graphenehybrid. Conductive AFM measurements performed at room temperaturereveal strong current resonances, the strength of which can be reversiblygated on- and off- by opticallyswitching the molecular conformation of the mSAM. Comparisons of thevoltage separation between current resonances (∼70–120mV) with solutions of the Dirac equation indicate that the radiusof the gating potential is ∼7 ± 2 nm with a strength ≥0.5eV. Our results and methods might provide a route toward opticallyprogrammablecarrier dynamics and transport in graphene nanomaterials. [ABSTRACT FROM AUTHOR]