Graphene has been demonstrated to be a promising material for optoelectronics and photodetection devices because of its ultra-broadband optical absorption and high carrier mobility. However, its integration with optoelectronic systems has been limited by the zero-bandgap and the lack of a gain mechanism. Herein, we demonstrate a novel photodetector based on the graphene nanoribbons (GRNs) with a sizable bandgap. Utilizing trapping charge at the interface between SiO₂ and light-doped silicon, an ultrahigh gain of 22,400 has been obtained. Our devices show an enhanced photoresponsivity (~ 800 AW⁻¹) while the response speed is still fast (up to 10 μs). This photoresponsivity is about two orders of magnitude higher compared to that of a previous graphene-based photodetector. The photodetector exhibits a wide-range tunability via source-drain bias and back gate voltage. Our work addresses key challenges for the photodetectors and potentially provides the desired pathway toward practical application of graphene photodetectors that can be externally manipulated by an electric field with fast response speed and high sensitivity.

石墨烯因其超宽带光吸收和高载流子迁移率而被证明是光电子和光电检测设备的有前途的材料。但是，其与光电系统的集成受到零带隙和缺乏增益机制的限制。在本文中，我们展示了一种基于带隙较大的石墨烯纳米带（GRN）的新型光电探测器。利用SiO ₂和轻掺杂硅之间的界面处的捕获电荷，获得了22,400的超高增益。我们的设备显示出增强的光响应性（〜800 AW ^-1），而响应速度仍然很快（最高10μs）。与以前的基于石墨烯的光电检测器相比，该光敏性大约高两个数量级。光电探测器通过源极-漏极偏置和背栅电压表现出宽范围的可调性。我们的工作解决了光电探测器的关键挑战，并可能为石墨烯光电探测器的实际应用提供理想的途径，该石墨烯光电探测器可以通过电场以快速响应速度和高灵敏度从外部进行操纵。