Macroscopic assembled graphene nanofilms based room temperature ultrafast mid-infrared photodetectors
Macroscopic assembled graphene nanofilms based room temperature ultrafast mid-infrared photodetectors
复制标题
基于宏观组装石墨烯纳米膜的室温超快中红外光电探测器
DOI：
10.1002/inf2.12309
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发表时间：
2022-03-18
期刊：
影响因子：
22.7
通讯作者：
Gao, Chao
中科院分区：
文献类型：
--
作者：
Peng, Li;Liu, Lixiang;Gao, Chao
石墨烯具有线性能量色散和弱的电子-声子相互作用，有望在较宽的波长范围内获得热电子。然而，热电子的有限吸收和严重的后向散射导致量子产额不足，特别是在中红外范围内。在这里，我们报道了一种用于超快中红外光探测的宏观组装石墨烯(NMAG)纳米膜/硅异质结。组装的肖特基二极管在室温下工作在1.5-4.0微米，在脉冲激光下具有快速响应(20-30 ns，上升时间，4 mm(2)窗口)和高探测率(1.5-4.0微米范围内1.6×10(11)到1.9×10(9)琼斯)，性能比单层石墨烯/硅光探测器高2-8个数量级。这些性能归因于nMAG的高吸光度(约40%)、长载流子弛豫时间(约20ps)、低功函数(4.52 eV)和抑制载流子数波动，从而大大增强了电子的光热效应。NMAG提供了一个远程平台来了解块状2D材料中的热载流子动力学，从而在室温下开发出宽带和超快的MIR主动成像设备。
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 mu m at room temperature with fast response (20-30 ns, rising time, 4 mm(2) window) and high detectivity (1.6 x 10(11) to 1.9 x 10(9) Jones from 1.5 to 4.0 mu m) 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 (similar to 40%), long carrier relaxation time (similar to 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.