Plasmonic enhanced silicon pyramids for internal photoemission Schottky detectors in the near-infrared regime
Plasmonic enhanced silicon pyramids for internal photoemission Schottky detectors in the near-infrared regime
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DOI：
10.1364/optica.2.000335
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发表时间：
2015-04-20
期刊：
影响因子：
10.4
通讯作者：
Levy, Uriel
中科院分区：
文献类型：
--
作者：
Desiatov, Boris;Goykhman, Ilya;Levy, Uriel
我们展示了一种纳米级宽带硅等离子体肖特基探测器，它具有高响应率和改善的信噪比，工作在亚带隙区域。响应性通过使用金字塔形状的等离子体聚集器来增强。由于金字塔的横截面很大，光线从与其底部对应的大面积收集，集中在金字塔的纳米尖端，被金属吸收，并产生热电子。利用内部光电发射过程，这些电子穿过肖特基势垒，以光电流的形式被收集起来。硅技术的使用与高收集效率和纳米尺度的限制相结合，使硅金字塔成为在构建改进的光电探测器中发挥核心作用的理想材料。此外，由于有源面积小，与平板探测器相比，暗电流显著降低，从而获得了改善的信噪比。我们的测量显示出在宽光谱范围内的高响应度，在1064 nm的波长下达到了约30 mA/W的记录高点，同时将暗电流保持在接近100nA的低水平。最后，这种探测器还可以以像素阵列的形式构造，因此可以用作焦平面探测器阵列。(C)2015年美国光学学会
We demonstrate a nanoscale broadband silicon plasmonic Schottky detector with high responsivity and improved signal to noise ratio operating in the sub-bandgap regime. Responsivity is enhanced by the use of pyramidally shaped plasmonic concentrators. Owing to the large cross-section of the pyramid, light is collected from a large area which corresponds to its base, concentrated toward the nano apex of the pyramid, absorbed in the metal, and generates hot electrons. Using the internal photoemission process, these electrons cross over the Schottky barrier and are collected as a photocurrent. The combination of using silicon technology together with the high collection efficiency and nanoscale confinement makes the silicon pyramids ideal for playing a central role in the construction of improved photodetectors. Furthermore, owing to the small active area, the dark current is significantly reduced as compared with flat detectors, and thus an improved signal to noise ratio is obtained. Our measurements show high responsivities over a broad spectral regime, with a record high of about 30 mA/W at the wavelength of 1064 nm, while keeping the dark current as low as similar to 100 nA. Finally, such detectors can also be constructed in the form of a pixel array, and thus can be used as focal plane detector arrays. (C) 2015 Optical Society of America