Hot-Electron Photodetection with a Plasmonic Nanostripe Antenna
Hot-Electron Photodetection with a Plasmonic Nanostripe Antenna
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DOI：
10.1021/nl4044373
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发表时间：
2014-03-01
期刊：
影响因子：
10.8
通讯作者：
Brongersma, Mark L.
中科院分区：
文献类型：
--
作者：
Chalabi, Hamidreza;Schoen, David;Brongersma, Mark L.
平面金属氧化物金属结构可以作为光电探测器，不依赖于半导体中通常的电子空穴对的产生。相反，当入射光子能量超过氧化物势垒能量时，其中一种金属吸收的光可以产生热电子流。尽管这种器件具有制作方便、室温零偏压工作等优点，但其较低的功率转换效率限制了它的应用。在这里，我们演示了将其中一个金属触点重塑为等离子体条纹天线的好处。我们通过测量光电流的电压依赖性、光谱依赖性、条纹宽度依赖性和偏振依赖性，表明表面等离子体激元的激发可以导致光电流在条纹中有利的重新分布，从而增强光电流。我们还提供了一个根据结的电学和光学性质来量化光谱光电流的理论模型。该模型准确地估计了不同器件外量子效率的偏置依赖关系，并表明电场分布的空间和矢量特性对其运行都很重要。
Planar metal oxide metal structures can serve as photodetectors that do not rely on the usual electron hole pair generation in a semiconductor. Instead, absorbed light in one of the metals can produce a current of hot electrons when the incident photon energy exceeds the oxide barrier energy. Despite the desirable traits of convenient fabrication and room-temperature operation at zero bias of this type of device, the low power conversion efficiency has limited its use. Here, we demonstrate the benefits of reshaping one of the metallic contacts into a plasmonic stripe antenna. We use measurements of the voltage-dependence, spectral-dependence, stripe-width dependence, and polarization-dependence of the photocurrent to show that surface plasmon excitations can result in a favorable redistribution in the electric fields in the stripe that enhances the photocurrent. We also provide a theoretical model that quantifies the spectral photocurrent in terms of the electrical and optical properties of the junction. This model provides an accurate estimate of the bias dependence of the external quantum efficiency of different devices and shows that both the spatial and vectorial properties of the electric field distribution are important to its operation.