Institute of Photonics, Vienna University of Technology , Gußhausstraße 27-29, 1040 Vienna, Austria.
AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany.
Nano Lett. 2016 Nov 9;16(11):7107-7112. doi: 10.1021/acs.nanolett.6b03374. Epub 2016 Oct 11.
With its electrically tunable light absorption and ultrafast photoresponse, graphene is a promising candidate for high-speed chip-integrated photonics. The generation mechanisms of photosignals in graphene photodetectors have been studied extensively in the past years. However, the knowledge about efficient light conversion at graphene p-n junctions has not yet been translated into high-performance devices. Here, we present a graphene photodetector integrated on a silicon slot-waveguide, acting as a dual gate to create a p-n junction in the optical absorption region of the device. While at zero bias the photothermoelectric effect is the dominant conversion process, an additional photoconductive contribution is identified in a biased configuration. Extrinsic responsivities of 35 mA/W, or 3.5 V/W, at zero bias and 76 mA/W at 300 mV bias voltage are achieved. The device exhibits a 3 dB bandwidth of 65 GHz, which is the highest value reported for a graphene-based photodetector.
具有可调谐电吸收和超快光响应的石墨烯是高速片上集成光子学的理想候选材料。在过去的几年中，人们广泛研究了石墨烯光电探测器中光信号的产生机制。然而，关于在石墨烯 p-n 结处高效光转换的知识尚未转化为高性能器件。在这里，我们展示了一种集成在硅槽波导上的石墨烯光电探测器，它作为双栅极在器件的光学吸收区域中形成 p-n 结。在零偏压下，光热电效应是主要的转换过程，而在偏置配置中则确定了额外的光电导贡献。在零偏压下，器件实现了 35 mA/W 或 3.5 V/W 的外量子响应率，在 300 mV 偏置电压下实现了 76 mA/W 的外量子响应率。该器件的 3 dB 带宽为 65 GHz，这是报道的基于石墨烯的光电探测器中的最高值。
