There is an emerging need for high-sensitivity solar-blind deep ultraviolet (DUV) photodetectors with an ultra-fast response speed. Although nanoscale devices based on Ga 2 O 3 nanostructures have been developed, their practical applications are greatly limited by their slow response speed as well as low specific detectivity. Here, the successful fabrication of two-/three-dimensional (2D/3D) graphene (Gr)/PtSe 2 /β-Ga 2 O 3 Schottky junction devices for high-sensitivity solar-blind DUV photodetectors is demonstrated. Benefitting from the high-quality 2D/3D Schottky junction, the vertically stacked structure, and the superior-quality transparent graphene electrode for effective carrier collection, the photodetector is highly sensitive to DUV light illumination and achieves a high responsivity of 76.2 mA/W, a large on/off current ratio of ~ 10 5 , along with an ultra-high ultraviolet (UV)/visible rejection ratio of 1.8 × 10 4 . More importantly, it has an ultra-fast response time of 12 s and a remarkable specific detectivity of ~ 10 13 Jones. Finally, an excellent DUV imaging capability has been identified based on the Gr/PtSe 2 /β-Ga 2 O 3 Schottky junction photodetector, demonstrating its great potential application in DUV imaging systems.

In this paper a convenient and universal strategy for preparing nanoring arrays of different compositions based on a colloidal‐crystal‐template strategy is reported. Large‐area arrays of polystyrene, magnetite, Au, Si, magnetite nanoparticle/polystyrene and Au/polystyrene double‐layer composite nanorings are prepared. Many kinds of nanoring structures, including Fe3O4 nanoparticle/polystyrene and Au/polystyrene double‐layer nanorings, can be released from the substrates, resulting in free‐standing composite nanorings, which might be used as self‐assembly building blocks and ultrasensitive bio‐ and chemical sensors.

A high-performance self-powered photodetector based on a MoS2/GaAs heterojunction was demonstrated, which demonstrated a high responsivity, specific detectivity, fast response speeds, as well as high polarization sensitivity.

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A self-driven photodetector based on WS2/GaAs type-II Zener heterojunction is fabricated, which shows a broadband response spectrum from 200 to 1550 nm beyond the limitation of the bandgaps with a high responsivity and specific detectivity.