▎ 摘　　要

Graphene has attracted intensive attentions due to its significant optoelectronic performances. Photovoltaic effect and photo-thermoelectric effect make graphene to be a hot choice in ultra-wide spectrum band photodetection. Thinking of serious influences such as chemical pollution and mechanical damages of CVD grown and exfoliated graphene caused by transfer and exfoliation processes, the epitaxial graphene on SiC single crystal wafer shows intrinsic and better performances. Here, high quality epitaxial graphene has been successfully synthesized by thermal decomposition of Si-terminated, semi-insulating on-axis oriented 4H-SiC (0001) wafer. Photon response of the graphene has been investigated by employing a metal-graphene-metal photodetector. The largest photo-current value obtained under 780 nm laser illumination and 10 V bias voltage is up to 2.2 x 10(-7) A, which is almost 30 times greater than the dark current. While under 0.05 mW/cm(2) irradiance, the highest values of responsivity and EQE are 4.48 x 10(-2) A/W and 8.13%, respectively. This type of fabricated graphene based photodetector has shown steady and outstanding photo detection performances.