多层石墨烯具有超宽的光谱吸收范围及独特的光电性能, 是制作下一代光电探测器件的理想材料。 以石墨烯的带间隧穿理论为基础, 提出了一个多层石墨烯纳米带结构的光电探测器模型, 纳米带的两端与源极和漏极相连, 夹在半导体基质和上下栅极之间。 利用这个模型, 建立了多层石墨烯纳米带探测器的光电转换机制, 讨论了上栅极电压不同时探测器的工作原理, 研究了源-漏极间光电流及暗电流与入射光能量的关系, 探讨了探测器的偏置电压, 耗尽层长度以及带隙取值对暗电流的影响, 并分析了不同参数下探测器响应率以及探测率随入射光能量的变化关系。 结果表明, 探测器的响应率随纳米带层数的增加而增加, 受带隙, 耗尽层长度和偏置电压的影响, 最大的响应率约为103 A·W-1; 通过限制上栅压, 带隙等变量可以控制系统暗电流, 增大探测器的探测率, 最高探测率约为109 cm·Hz1/2·W-1。 多层石墨烯纳米带结构可以增强探测器对入射光的吸收, 提高探测器的灵敏度以及对弱光的探测能力, 实现对太赫兹到远红外波段入射光的有效探测, 探测性能远高于许多量子结构和窄带半导体结构的光电探测器。

Multilayer graphene, with wide absorption spectrum and unique photoelectric properties, is an ideal material to make the next generation of photoelectric detector. Taking graphene interband tunneling theory as the foundation, a photoelectric detector model with the structure of multilayer graphene nanoribbons was proposed. Nanoribbons which contacted with source and drain electrode at the end were sandwiched between the semiconductor substrate and the top and back gate. Using this model, a photoelectric conversion mechanism of multilayer graphene nanoribbon detector was established. It discussed the working principle of the detector at different top gate voltage, studied the relationship between the source-drain current and the incident light energy, researched the influence of the bias voltage, the length of depletion and the values of band gap on the dark current, and analyzed the change of detector responsibility and detectivity with the incident light energy under the different parameters. The results show that, the responsibility of detector increases with the layers of nanoribbons, and are affected by the band gap, the length of depletion and the bias voltage. The maximum responsibility up to 103 A·W-1; By limiting on the top gate voltage, the band gap and other variables can control the dark current of system and increase the detectivity, the detectivity up to a maximum value of 109 cm Hz1/2·W-1. The structure of multilayer graphene nanoribbons can enhance the absorption of the incident light, improve the sensitivity of the detector and the detection capability of weak light, and realize the detection from THz to far infrared wavelength of incident light. The detection performance is far better than that of many quantum structures and narrow-band semiconductor structure of photoelectric detector.