▎ 摘　　要

Ultranarrow graphene nanoribbons (GNRs) with atomically precise structures are considered a promising class of materials for the realization of optoelectronic and photonic devices with improved functionalities. Here we report the optoelectronic characterization of a field-effect transistor device made of a layer of bottom-up synthesized GNRs contacted with multilayer graphene electrodes, showing high photoresponsivity of 5 x 10(5) A/W for small incident power in the visible-UV range. Our results show that combining the properties of intrinsic graphene with that of semiconducting GNRs is a viable route to realize novel devices for optoelectronic and sensing applications.