Low-bias visible photodetection realized by graphite nanostructures grown on silicon nanoporous pillar array

A graphite nanostructure (nano-graphite) with the morphology of nanoparticles and nanowires which are composed of graphite nanocrystallites (nc-graphite) was grown on silicon nanoporous pillar array (Si-NPA) by a simple chemical vapor deposition method. The structural characterizations disclosed a complex interface configuration made of nc-graphite, nc-Ni (pre-deposited on Si-NPA as catalyst for nc-graphite growth), nc-NiO₂, and nc-Si. The designed nano-graphite/Si-NPA exhibits strong light absorption and sensitive photoresponsivity under low-bias potential in the visible region of 400–800 nm. For example, it shows a switching ratio of 75, a photoresponsivity of ~?0.16 AW^?1 and a rise/fall time of 12.24/5.66 s with an ultralow bias of 0.1 mV under the visible illumination of 5 mWcm^?2. The high switching ratio and responsivity were ascribed to the complexity of the interface nanostructures and the formation of a thick and compact graphite nanofilm. The results illustrate that nano-graphite/Si-NPA might be a promising candidate material for fabricating high-performance low-power Si-based visible photodetectors.