单层石墨烯具有较低的固有光吸收效率，且材料中含有较多的缺陷，导致仅依靠石墨烯本身很难制备高性能的光电器件。通过石墨烯与半导体材料复合形成异质结构的方法可以克服这一瓶颈。本工作中利用石墨烯/砷化镓高迁移率异质晶体管结构制备了毫米波光电探测器，有效地提升了二维电子气特性，大幅度提高了器件在室温条件下的毫米波响应和探测能力。实验证明，400 mV的偏置电压下，该器件在25 GHz波段的获得了20.6V?W^-1响应率，响应时间为9.8 μs，噪声等效功率为3.2×10^-10 W?Hz^-1/2。在太赫兹波0.12 THz下响应率仍然达到了4.6V?W^-1，响应时间为10 μs，噪声等效功率为1.4×10^-9 W?Hz^-1/2。该工作展示了石墨烯/砷化镓异质结构毫米波太赫兹探测器的巨大应用前景。

The low intrinsic absorption and the existence of the inherent defects hamper the monoatomic layer graphene from being a high-performance photoelectric material， which leads to the strategy to form heterostructure by combining graphene with semiconductor materials. In this work， a graphene/GaAs heterostructure based photodetector has been designed and fabricated， in which the two-dimensional electron gas are enhanced to improve the photoresponse ability at the band of sub-millimeter and Terahertz （THz） wave ranging from 20 GHz to 0.12 THz. Under 25 GHz radiation， the responsivity of photodetector at room temperature （RT） reaches 20.6V?W^-1， with the response time of 9.8 μs and the noise equivalent power （NEP） of 3.2×10¹⁰ W?Hz^-1/2 under a bias of 400 mV. At 0.12 THz， the responsivity is determined to be 4.6 V?W^-1， with the response time of 10 μs. And a NEP of 1.4×10^-9 W?Hz^-1/2 can be achieved under the bias of 400 mV. These results exhibit great application potential for the graphene/GaAs heterostructure based THz photodetectors.