Here, an engineered tunneling layer enhanced photocurrent multiplication through the impact ionization effect was proposed and experimentally demonstrated on the graphene/silicon heterojunction photodetectors. With considering the suitable band structure of the insulation material and their special defect states, an atomic layer deposition (ALD) prepared wide-bandgap insulating (WBI) layer of AlN was introduced into the interface of graphene/silicon heterojunction. The promoted tunneling process from this designed structure demonstrated that can effectively help the impact ionization with photogain not only for the regular minority carriers from silicon, but also for the novel hot carries from graphene. As a result, significantly enhanced photocurrent as well as simultaneously decreased dark current about one order were accomplished in this graphene/insulation/silicon (GIS) heterojunction devices with the optimized AlN thickness of ~15 nm compared to the conventional graphene/silicon (GS) devices. Specifically, at the reverse bias of −10 V, a 3.96-A W⁻¹ responsivity with the photogain of ~5.8 for the peak response under 850-nm light illumination, and a 1.03-A W⁻¹ responsivity with ∼3.5 photogain under the 365 nm ultraviolet (UV) illumination were realized, which are even remarkably higher than those in GIS devices with either Al₂O₃ or the commonly employed SiO₂ insulation layers. This work demonstrates a universal strategy to fabricate broadband, low-cost and high-performance photo-detecting devices towards the graphene-silicon optoelectronic integration.

在这里，提出了一种通过碰撞电离效应增强光电流倍增的工程隧道层，并在石墨烯/硅异质结光电探测器上进行了实验证明。考虑到绝缘材料合适的能带结构及其特殊的缺陷态，将原子层沉积（ALD）制备的氮化铝宽带隙绝缘（WBI）层引入石墨烯/硅异质结的界面。这种设计结构所促进的隧穿过程表明，不仅可以有效地帮助来自硅的常规少数载流子的光增益碰撞电离，还可以有效地帮助来自石墨烯的新型热载流子。因此，与传统的石墨烯/硅 (GS) 器件相比，这种石墨烯/绝缘体/硅 (GIS) 异质结器件具有约 15 nm 的优化 AlN 厚度，显着增强了光电流并同时降低了大约一个数量级的暗电流。具体而言，在 -10 V 的反向偏压下，3.96-A W^-1响应率在 850 nm 光照射下的峰值响应为 ~5.8，在365 nm 紫外 (UV) 光照下实现了 1.03-A W ^-1响应率和~ 3.5 光增益，甚至显着高于GIS 设备中的那些具有 Al ₂ O ₃或常用的 SiO ₂绝缘层。这项工作展示了制造宽带、低成本和高性能光电检测器件以实现石墨烯-硅光电集成的通用策略。