Planar Dual-Layer System for Ultra-Broadband Absorption and Hot-Carrier Photodetection in Longwave Near-Infrared Band
Planar Dual-Layer System for Ultra-Broadband Absorption and Hot-Carrier Photodetection in Longwave Near-Infrared Band
复制标题
用于长波近红外波段超宽带吸收和热载流子光电探测的平面双层系统
DOI：
10.1109/jstqe.2021.3069495
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发表时间：
2021
影响因子：
4.9
通讯作者：
Li Xiaofeng
中科院分区：
文献类型：
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作者：
Zhang Cheng;Liu Tingting;Li Liang;Wu Shaolong;Wang Chinhua;Li Xiaofeng
超宽带和完美的光吸收通常是通过引入金属纳米结构来实现的，但这种结构对制造的要求非常严格。这将是非常有用的，如果这可以实现平面系统，这通常不具有这样的能力来操纵光。在这里，我们从理论上推导了一个简单的平面双层系统的临界光耦合条件，该系统由吸收基板上的无损介电膜组成，以实现所需的宽带和强光吸收。我们通过数值预测和实验观察到了平面双层体系在长波近红外（LW-NIR, 1.1 - 2.5 μm）波段上的超宽带、强、偏振不敏感和广角吸收。从理论（结合电磁模拟、第一性原理计算和蒙特卡罗方法）和实验两方面进一步探讨了双层系统在宽带热载子光探测中的应用。结果表明，该平面器件的响应率和探测率比基于传统金属纳米结构的器件提高了一个数量级。这种简单的平面系统在大面积和无光刻热光伏、光电探测、热发射等方面显示出巨大的潜力。
Ultra-broadband and perfect optical absorption is usually realized by introducing metallic nanostructures, which however have stringent requirements on fabrication. It would be highly useful if this can be realized by planar systems, which do not normally have such a capability in manipulating the light. Here, we theoretically deduce the critical optical coupling conditions in a simple planar dual-layer system consisted of a lossless dielectric film on an absorptive substrate to enable the desired broadband and strong optical absorption. We numerically predict and experimentally observe an ultra-broadband, strong, polarization-insensitive, and wide-angle absorption across the longwave near-infrared (LW-NIR, 1.1 – 2.5 μm) band from the planar dual-layer system. The application of the dual-layer system in broadband hot-carrier photodetection is further explored from both theory (by combining electromagnetic simulations, first-principles calculations and Monte Carlo approach) and experiment perspectives. Results show that the responsivity and detectivity of the planar device can even be an order of magnitude higher than those based on the conventional metallic nanostructures. Such a simple planar system shows great potentials in large-area and lithography-free thermo-photovoltaics, photodetections, thermal emitters, etc.