Near-field photocurrent nanoscopy on bare and encapsulated graphene

Achim Woessner, Pablo Alonso-González, Mark B. Lundeberg, Yuanda Gao, Jose E. Barrios-Vargas, Gabriele Navickaite, Qiong Ma, Davide Janner, Kenji Watanabe, Aron W. Cummings, Takashi Taniguchi, Valerio Pruneri, Stephan Roche, Pablo Jarillo-Herrero, James Hone, Rainer Hillenbrand, Frank H.L. Koppens

    Research output: Contribution to journalArticleResearchpeer-review

    64 Citations (Scopus)

    Abstract

    Optoelectronic devices utilizing graphene have demonstrated unique capabilities and performances beyond state-of-the-art technologies. However, requirements in terms of device quality and uniformity are demanding. A major roadblock towards high-performance devices are nanoscale variations of the graphene device properties, impacting their macroscopic behaviour. Here we present and apply non-invasive optoelectronic nanoscopy to measure the optical and electronic properties of graphene devices locally. This is achieved by combining scanning near-field infrared nanoscopy with electrical read-out, allowing infrared photocurrent mapping at length scales of tens of nanometres. Using this technique, we study the impact of edges and grain boundaries on the spatial carrier density profiles and local thermoelectric properties. Moreover, we show that the technique can readily be applied to encapsulated graphene devices. We observe charge build-up near the edges and demonstrate a solution to this issue.
    Original languageEnglish
    Article number10783
    JournalNature Communications
    Volume7
    DOIs
    Publication statusPublished - 26 Feb 2016

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