ABSTRACT
Photodetectors with ultrahigh sensitivity based on the composite made with all carbon-based materials consisting of graphite quantum dots (QDs), and two dimensional graphene crystal have been demonstrated. Under light illumination, remarkably, a photocurrent responsivity up to 4 × 10(7)â AW(-1) can be obtained. The underlying mechanism is attributed to the spatial separation of photogenerated electrons and holes due to the charge transfer caused by the appropriate band alignment across the interface between graphite QDs and graphene. Besides, the large absorptivity of graphite QDs and the excellent conductivity of the graphene sheet also play significant roles. Our result therefore demonstrates an outstanding illustration for the integration of the distinct properties of nanostructured carbon materials with different dimensionalities to achieve highly efficient devices. Together with the associated mechanism, it paves a valuable step for the further development of all carbon-based, cheap, and non-toxic optoelectronics devices with excellent performance.
ABSTRACT
The high sensitivity of photodetector in the UV range based on the composite consisting of a single SnO(2) nanowire and NiO nanoparticles has been demonstrated. The underlying mechanism is attributed to the formation of p-NiO and n-SnO(2) heterojunction on the nanowire surface. The enhanced space charge region owing to the existence of p-n heterojunction increases the surface electric field, which will improve the separation of photogenerated electrons and holes, and the photoresponse gain will be greatly enhanced. This work shows a new approach that by decorating suitable p-type nanoparticles on n-type nanowires, the photoresponse gain can be enhanced drastically. Our result should be useful for creating novel high efficiency photodetectors.
