Department of Electrical Engineering and Computer Science and ∥Department of Mechanical Engineering, Vanderbilt University , Nashville, Tennessee 37212, United States.
Department of Physics and Astronomy and §Interdisciplinary Graduate Program in Materials Science, Vanderbilt University , Nashville, Tennessee 37235, United States.
Nano Lett. 2015 Nov 11;15(11):7440-4. doi: 10.1021/acs.nanolett.5b02866. Epub 2015 Oct 6.
Recently, there has been much interest in the extraction of hot electrons generated from surface plasmon decay, as this process can be used to achieve additional bandwidth for both photodetectors and photovoltaics. Hot electrons are typically injected into semiconductors over a Schottky barrier between the metal and semiconductor, enabling generation of photocurrent with below bandgap photon illumination. As a two-dimensional semiconductor single and few layer molybdenum disulfide (MoS2) has been demonstrated to exhibit internal photogain and therefore becomes an attractive hot electron acceptor. Here, we investigate hot electron-based photodetection in a device consisting of bilayer MoS2 integrated with a plasmonic antenna array. We demonstrate sub-bandgap photocurrent originating from the injection of hot electrons into MoS2 as well as photoamplification that yields a photogain of 10(5). The large photogain results in a photoresponsivity of 5.2 A/W at 1070 nm, which is far above similar silicon-based hot electron photodetectors in which no photoamplification is present. This technique is expected to have potential use in future ultracompact near-infrared photodetection and optical memory devices.
最近，人们对表面等离激元衰减产生的热电子的提取产生了浓厚的兴趣，因为这一过程可用于实现光电探测器和光伏电池的额外带宽。热电子通常通过金属和半导体之间的肖特基势垒注入半导体，从而在带隙以下的光子激发下产生光电流。作为二维半导体，单层和少数层二硫化钼 (MoS2) 已被证明具有内部光增益，因此成为一种有吸引力的热电子受体。在这里，我们研究了由与等离子体天线阵列集成的双层 MoS2 组成的器件中的基于热电子的光电检测。我们证明了源于将热电子注入 MoS2 的亚带隙光电流以及光放大，其产生的光增益为 10(5)。大的光增益导致在 1070nm 处的光响应率为 5.2A/W，远高于没有光放大的类似硅基热电子光电探测器。该技术有望在未来的超紧凑近红外光电探测和光学存储器件中得到应用。
