Woessner Achim, Alonso-González Pablo, Lundeberg Mark B, Gao Yuanda, Barrios-Vargas Jose E, Navickaite Gabriele, Ma Qiong, Janner Davide, Watanabe Kenji, Cummings Aron W, Taniguchi Takashi, Pruneri Valerio, Roche Stephan, Jarillo-Herrero Pablo, Hone James, Hillenbrand Rainer, Koppens Frank H L
ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Barcelona, Spain.
CIC nanoGUNE, 20018 Donostia-San Sebastian, Spain.
Nat Commun. 2016 Feb 26;7:10783. doi: 10.1038/ncomms10783.
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.
利用石墨烯的光电器件已展现出超越现有技术的独特能力和性能。然而，对器件质量和均匀性的要求很高。高性能器件面临的一个主要障碍是石墨烯器件特性的纳米级变化，这会影响其宏观行为。在此，我们展示并应用非侵入式光电纳米显微镜来局部测量石墨烯器件的光学和电学性质。这是通过将扫描近场红外纳米显微镜与电学读出相结合来实现的，从而能够在几十纳米的长度尺度上进行红外光电流映射。利用这项技术，我们研究了边缘和晶界对空间载流子密度分布以及局部热电性质的影响。此外，我们表明该技术可以很容易地应用于封装的石墨烯器件。我们观察到边缘附近的电荷积累，并展示了针对此问题的解决方案。
