Broadband high photoresponse from pure monolayer graphene photodetector

By Yongzhe Zhang, Tao Liu, Bo Meng, Xiaohui Li, Guozhen Liang, Xiaonan Hu, Qi Jie Wang

Graphene has attracted large interest in photonic applications owing to its promising optical properties, especially its ability to absorb light over a broad wavelength range, which has lead to several studies on pure monolayer graphene-based photodetectors. However, the maximum responsivity of these photodetectors is below 10 mA W(-1), which significantly limits their potential for applications. Here we report high photoresponsivity (with high photoconductive gain) of 8.61 A W(-1) in pure monolayer graphene photodetectors, about three orders of magnitude higher than those reported in the literature, by introducing electron trapping centres and by creating a bandgap in graphene through band structure engineering. In addition, broadband photoresponse with high photoresponsivity from the visible to the mid-infrared is experimentally demonstrated. To the best of our knowledge, this work demonstrates the broadest photoresponse with high photoresponsivity from pure monolayer graphene photodetectors, proving the potential of graphene as a promising material for efficient optoelectronic devices.