Plasmonic hot-carriers, which are induced by plasmons at metal surfaces, can be used to convert photon energy into excited carriers over a subwavelength region and provide a new means to realize photodetection within the sub-band-gap region of semiconductor materials. However, the barrier height of the metal–semiconductor junction affects the behavior of the plasmon-induced hot-carriers and limits the electrical response of photodetection. High electrical responsivity, achieved by manipulating the barrier height using plasmon-induced hot electrons, is desired to broaden the possible applications. Here we report a plasmonic channel-coupled nanogap structure, where the barrier height of the metal–semiconductor junction is altered upon the excitation of plasmon-induced hot-carriers. The structure consists of semiconductor channels and metal slabs forming nanogaps, which sustain coupled plasmons and confine light to the semiconductor–metal interfaces. In contrast to conventional Schottky barriers and ohmic contacts, in which plasmon-induced hot-carriers and the generation of electron–hole pairs by photoabsorption cause an increase in the photocurrent, the generation of plasmon-induced hot-carriers at the resonant wavelength results in an increase in the junction barrier height and a decrease in the photocurrent induced by photoabsorption. By modifying the barrier height, the plasmon resonance can be monitored from the electrical response with a high spectral resolution and a large modulation.

中文翻译：

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通道耦合纳米间隙结构中的等离子热载流子，用于金属-半导体势垒调制和光谱选择性等离子监测

由金属表面的等离激元引起的等离激元热载流子可用于将光子能量转换为亚波长区域上的激发载流子，并提供了一种在半导体材料的子带隙区域内实现光检测的新手段。但是，金属-半导体结的势垒高度会影响等离激元诱导的热载流子的行为，并限制光电检测的电响应。期望通过使用等离激元感应的热电子来操纵势垒高度来实现高电响应性，以拓宽可能的应用范围。在这里，我们报告了等离激元通道耦合的纳米间隙结构，其中金属-半导体结的势垒高度会随着等离激元引起的热载流子的激发而改变。该结构由形成纳米间隙的半导体通道和金属平板组成，这些纳米间隙维持耦合的等离激元并将光限制在半导体与金属的界面上。与常规的肖特基势垒和欧姆接触不同，在传统的肖特基势垒和欧姆接触中，等离激元诱导的热载流子和通过光吸收产生的电子-空穴对引起光电流的增加，而在共振波长处等离激元诱导的热载流子的产生导致结势垒高度的增加和光吸收引起的光电流的减少。通过修改势垒高度，可以以高光谱分辨率和大调制率从电响应中监测等离振子共振。与常规的肖特基势垒和欧姆接触不同，在传统的肖特基势垒和欧姆接触中，等离激元诱导的热载流子和通过光吸收产生的电子-空穴对引起光电流的增加，而在共振波长处等离激元诱导的热载流子的产生导致结势垒高度的增加和光吸收引起的光电流的减少。通过修改势垒高度，可以以高光谱分辨率和大调制率从电响应中监测等离振子共振。与常规的肖特基势垒和欧姆接触不同，在传统的肖特基势垒和欧姆接触中，等离激元诱导的热载流子和通过光吸收产生的电子-空穴对引起光电流的增加，而在共振波长处等离激元诱导的热载流子的产生导致结势垒高度的增加和光吸收引起的光电流的减少。通过修改势垒高度，可以以高光谱分辨率和大调制度从电响应中监测等离子体共振。在共振波长处等离激元诱导的热载流子的产生导致结势垒高度的增加和由光吸收引起的光电流的减小。通过修改势垒高度，可以以高光谱分辨率和大调制率从电响应中监测等离振子共振。在共振波长处等离激元诱导的热载流子的产生导致结势垒高度的增加和由光吸收引起的光电流的减小。通过修改势垒高度，可以以高光谱分辨率和大调制率从电响应中监测等离振子共振。