Indium selenide (InSe) has gained extensive research attention due to its unique structure and broad tunable optical response in the visible to near-infrared range. However, InSe has a low optical absorption rate due to its intrinsic indirect bandgap nature and is easily affected by ambient air and water vapor, thus limiting its photoelectric performance. In this work, we significantly enhanced the photoelectric performance of the InSe photodetector by taking advantage of the synergetic effect of both surface plasmon resonance (SPR) and surface engineering. The former is induced by an array of gold nanoparticles (Au NPs) placed under the InSe channel, while the latter is realized by a 20 nm In layer deposited on the InSe layer surface. The responsivity of such an In/InSe/Au NP-based photodetector reaches 15.2 A/W at 637 nm, 3 orders of magnitude higher than that of the In/InSe photodetector and 4 orders of magnitude higher than the original InSe photodetector. The response speed achieves 1.75 ms, representing a three-order-of-magnitude improvement over the original InSe photodetector. This enhancement can be attributed to the increased surface charge transfer and the localized SPR, which couples with the out-of-plane polarized InSe bandgap excitons, enhancing the light–matter interaction of InSe. Raman spectroscopy and photoluminescence (PL) spectroscopy analyses confirmed significant surface charge transfer at the In–InSe interface and enhanced PL due to the presence of Au NPs. Therefore, our work provides an effective pathway for improving the optical properties of InSe, taking an important step toward its practical application in optoelectronic devices.

中文翻译：

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协同表面等离子共振和表面工程诱导的高性能 InSe 光电探测器


硒化铟（InSe）由于其独特的结构和在可见光到近红外范围内广泛的可调谐光学响应而获得了广泛的研究关注。然而，InSe由于其固有的间接带隙性质而具有较低的光吸收率，并且容易受到环境空气和水蒸气的影响，从而限制了其光电性能。在这项工作中，我们利用表面等离子体共振（SPR）和表面工程的协同效应，显着增强了InSe光电探测器的光电性能。前者是由放置在 InSe 通道下的金纳米颗粒 (Au NP) 阵列引起的，而后者是通过沉积在 InSe 层表面上的 20 nm In 层实现的。这种基于In/InSe/Au NP的光电探测器的响应度在637 nm处达到15.2 A/W，比In/InSe光电探测器高3个数量级，比原始InSe光电探测器高4个数量级。响应速度达到1.75 ms，比原来的InSe光电探测器提高了三个数量级。这种增强可归因于表面电荷转移的增加和局域SPR，它与面外偏振InSe带隙激子耦合，增强了InSe的光-物质相互作用。拉曼光谱和光致发光 (PL) 光谱分析证实了 In-InSe 界面上显着的表面电荷转移，并且由于 Au 纳米颗粒的存在而增强了 PL。因此，我们的工作为提高InSe的光学性能提供了有效途径，为其在光电器件中的实际应用迈出了重要一步。