Plasmonic harvesting of hot carriers (HCs) in metal–semiconductor (M–S) junctions has stimulated intensive research activities for sub-bandgap photodetection, in particular the development of silicon-based infrared photodetectors. Here, a copper–silicon heterojunction was investigated both theoretically and experimentally in comparison to the commonly used gold–silicon ones. A 1-order-of-magnitude higher responsivity and a longer cutoff wavelength over 2000 nm were observed in experiments in the sub-bandgap wavelength range of silicon with a copper–silicon junction. A phenomenological model was developed to analyze the dynamic processes of HCs and attributed the advanced photodetection performance of copper–silicon devices to the relatively higher electron density of state above the Fermi level and the higher ejection probability. Such a complementary metal–oxide–semiconductor-compatible and low-cost HC photodetection platform shows promising potential in silicon-based optoelectronic applications.

中文翻译：

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CMOS 兼容的宽带热载流子光电探测与铜硅纳米结

金属-半导体 (M-S) 结中热载流子 (HC) 的等离子体收集刺激了对子带隙光电探测的密集研究活动，特别是硅基红外光电探测器的开发。在这里，与常用的金硅异质结相比，从理论上和实验上研究了铜硅异质结。在具有铜硅结的硅的亚带隙波长范围内的实验中观察到 1 个数量级的更高响应度和超过 2000 nm 的更长截止波长。开发了一个现象学模型来分析 HC 的动态过程，并将铜硅器件的先进光电探测性能归因于费米能级以上相对较高的电子态密度和较高的弹射概率。