Paria Debadrita, Vadakkumbatt Vaisakh, Ravindra Pramod, Avasthi Sushobhan, Ghosh Ambarish
Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India.
Department of Physics, Indian Institute of Science, Bangalore 560012, India.
Nanotechnology. 2021 May 10;32(31). doi: 10.1088/1361-6528/abf96c.
Light-matter interaction in graphene can be engineered and substantially enhanced through plasmonic sensitization, which has led to numerous applications in photodetection, sensing, photocatalysis and spectroscopy. The majority of these designs have relied on conventional plasmonic materials such as gold, silver and aluminum. This limits the implementation of such devices to the ultraviolet and visible regimes of the electromagnetic spectrum. However, for many practical applications, including those relevant to security and defense, the development of new strategies and materials for sensing and detection of infra red (IR) light is crucial. Here we use surface enhanced Raman spectroscopy (SERS), for direct visualization and estimation of enhanced light-matter interaction in graphene in the mid-IR regime, through sensitization by an unconventional plasmonic material. Specifically, we fabricate a hybrid device consisting of a single layer graphene and a two-dimensional array of nanodiscs of aluminum doped zinc oxide (AZO), which is a highly doped semiconductor, exhibiting plasmonic resonance in the mid-IR. We find that the enhancement in the SERS signal of graphene is of similar magnitude to what has been achieved previously in the visible using conventional plasmonic materials. Our results establish the potential of such hybrid systems for graphene-based optical and optoelectronic applications in the mid-IR.
石墨烯中的光与物质相互作用可通过等离子体敏化进行调控并显著增强，这已在光探测、传感、光催化和光谱学等众多领域得到应用。这些设计大多依赖于金、银和铝等传统等离子体材料。这将此类器件的应用限制在了电磁频谱的紫外和可见光区域。然而，对于许多实际应用，包括与安全和国防相关的应用，开发用于红外（IR）光传感和探测的新策略和材料至关重要。在此，我们利用表面增强拉曼光谱（SERS），通过一种非传统等离子体材料的敏化作用，直接可视化并估算中红外波段石墨烯中增强的光与物质相互作用。具体而言，我们制备了一种混合器件，它由单层石墨烯和二维铝掺杂氧化锌（AZO）纳米盘阵列组成，AZO是一种高掺杂半导体，在中红外波段表现出等离子体共振。我们发现，石墨烯的SERS信号增强幅度与此前在可见光波段使用传统等离子体材料所达到的幅度相似。我们的结果确立了此类混合系统在中红外波段基于石墨烯的光学和光电子应用中的潜力。
