Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India.
Nanoscale. 2018 Apr 26;10(16):7685-7693. doi: 10.1039/c7nr09061g.
The weak light-matter interaction in graphene can be enhanced with a number of strategies, among which sensitization with plasmonic nanostructures is particularly attractive. This has resulted in the development of graphene-plasmonic hybrid systems with strongly enhanced photodetection efficiencies in the visible and the IR, but none in the UV. Here, we describe a silver nanoparticle-graphene stacked optoelectronic device that shows strong enhancement of its photoresponse across the entire UV spectrum. The device fabrication strategy is scalable and modular. Self-assembly techniques are combined with physical shadow growth techniques to fabricate a regular large-area array of 50 nm silver nanoparticles onto which CVD graphene is transferred. The presence of the silver nanoparticles resulted in a plasmonically enhanced photoresponse as high as 3.2 A W-1 in the wavelength range from 330 nm to 450 nm. At lower wavelengths, close to the Van Hove singularity of the density of states in graphene, we measured an even higher responsivity of 14.5 A W-1 at 280 nm, which corresponds to a more than 10 000-fold enhancement over the photoresponse of native graphene.
在石墨烯中，弱的光物质相互作用可以通过多种策略来增强，其中等离子体纳米结构的敏化特别有吸引力。这导致了石墨烯等离子体混合系统的发展，这些系统在可见光和红外光范围内具有很强的光电探测效率，但在紫外光范围内没有。在这里，我们描述了一种银纳米粒子-石墨烯堆叠光电设备，该设备在整个紫外光谱范围内显示出强烈的光响应增强。该器件制造策略具有可扩展性和模块化。自组装技术与物理阴影生长技术相结合，在其上转移 CVD 石墨烯，以在 50nm 的银纳米粒子上制造出规则的大面积阵列。银纳米粒子的存在导致光响应高达 3.2A W-1，在 330nm 至 450nm 的波长范围内。在较低的波长下，接近石墨烯中态密度的范霍夫奇异点，我们测量到在 280nm 处的响应率甚至更高，为 14.5A W-1，这比本征石墨烯的光响应增强了 10000 多倍。
