作者
Peng Li,Lixiang Liu,Sichao Du,Srikrishna Chanakya Bodepudi,Lingfei Li,Wei Liu,Runchen Lai,Xiaoxue Cao,Wenzhang Fang,Yingjun Liu,Xinyu Liu,Jianhang Lv,Muhammad Abid,Junxue Liu,Shengye Jin,Kaifeng Wu,Miao‐Ling Lin,Xin Cong,Ping‐Heng Tan,Haiming Zhu,Qihua Xiong,Xiaomu Wang,Weida Hu,Xiangfeng Duan,Bin Yu,Zhen Xu,Yang Xu,Chao Gao
摘要
Abstract Graphene with linear energy dispersion and weak electron–phonon interaction is highly anticipated to harvest hot electrons in a broad wavelength range. However, the limited absorption and serious backscattering of hot‐electrons result in inadequate quantum yields, especially in the mid‐infrared range. Here, we report a macroscopic assembled graphene (nMAG) nanofilm/silicon heterojunction for ultrafast mid‐infrared photodetection. The assembled Schottky diode works in 1.5–4.0 μm at room temperature with fast response (20–30 ns, rising time, 4 mm 2 window) and high detectivity (1.6 × 10 11 to 1.9 × 10 9 Jones from 1.5 to 4.0 μm) under the pulsed laser, outperforming single‐layer‐graphene/silicon photodetectors by 2–8 orders. These performances are attributed to the greatly enhanced photo‐thermionic effect of electrons in nMAG due to its high light absorption (~40%), long carrier relaxation time (~20 ps), low work function (4.52 eV), and suppressed carrier number fluctuation. The nMAG provides a long‐range platform to understand the hot‐carrier dynamics in bulk 2D materials, leading to broadband and ultrafast MIR active imaging devices at room temperature. image