▎ 摘　　要

Graphene-semiconducting light absorber hybrid photodetectors have attracted increasing attention because of their ultrahigh photoconductive gain and superior sensitivity. However, most graphene-based hybrid photodetectors reported previously have shown a relatively long response time (on the order of seconds) caused by numerous long-lived traps in these hybrid systems, which greatly restricts device speed. In this work, graphene-thieno[3,4-b]thiophene/benzodithiophene polymer hybrid photodetectors fabricated on self-assembled-monolayer (SAM)-functionalized SiO2 substrates are demonstrated with a maximum responsivity of similar to 1.8 x 10(5) A W-1 and a relatively short photocurrent response time of similar to 7.8 ms. The fast and highly sensitive device characteristics provide great potential in low-light imaging applications. The hybrid photodetector on the SAM-coated SiO2 substrate shows better performance in responsivities and response times as compared with those of the device on the bare SiO2 substrate. The improved responsivities are attributed to a significant increase in carrier mobility in graphene channels by introducing SAM-modified substrates. In addition, SAM functionalization is capable of effectively removing multiple surface traps and charged impurities between graphene sheets and SiO2 substrates, which prevents the long-lived trapping of photocarriers at graphene/SiO2 interfaces and remarkably decreases device response time.