Koepfli Stefan M, Baumann Michael, Gadola Robin, Nashashibi Shadi, Koyaz Yesim, Rieben Daniel, Güngör Arif Can, Doderer Michael, Keller Killian, Fedoryshyn Yuriy, Leuthold Juerg
ETH Zurich, Institute of Electromagnetic Fields (IEF), Zurich, Switzerland.
EPFL, Photonic Systems Laboratory (PHOSL), Lausanne, Switzerland.
Nat Commun. 2024 Aug 27;15(1):7351. doi: 10.1038/s41467-024-51599-w.
Photodetection in the near- and mid-infrared spectrum requires a suitable absorbing material able to meet the respective targets while ideally being cost-effective. Graphene, with its extraordinary optoelectronic properties, could provide a material basis simultaneously serving both regimes. The zero-band gap offers almost wavelength independent absorption which lead to photodetectors operating in the infrared spectrum. However, to keep noise low, a detection mechanism with fast and zero bias operation would be needed. Here, we show a self-powered graphene photodetector with a > 400 GHz frequency response. The device combines a metamaterial perfect absorber architecture with graphene, where asymmetric resonators induce photothermoelectric directional photocurrents within the graphene channel. A quasi-instantaneous response linked to the photothermoelectric effect is found. Typical drift/diffusion times optimization are not needed for a high-speed response. Our results demonstrate that these photothermoelectric directional photocurrents have the potential to outperform the bandwidth of many other graphene photodetectors and most conventional technologies.
近红外和中红外光谱中的光探测需要一种合适的吸收材料，该材料要能够满足各自的目标，同时理想情况下还要具有成本效益。石墨烯具有非凡的光电特性，可为同时适用于这两种光谱范围的材料基础。零带隙提供几乎与波长无关的吸收，这使得光电探测器能够在红外光谱中工作。然而，为了保持低噪声，需要一种具有快速和零偏置操作的探测机制。在此，我们展示了一种频率响应大于400 GHz的自供电石墨烯光电探测器。该器件将超材料完美吸收体结构与石墨烯相结合，其中非对称谐振器在石墨烯通道内诱导光热电流方向的光电流。发现了与光热效应相关的准瞬时响应。高速响应不需要典型的漂移/扩散时间优化。我们的结果表明，这些光热电流方向的光电流有可能超越许多其他石墨烯光电探测器和大多数传统技术的带宽。
