Transparent, low dark current, fast response ultraviolet and short-wavelength blue photons photodetector based on Graphene/SrTiO3 single crystal

Ultraviolet light and short-wavelength blue photons (UV-SWB) can cause damage to the human body under excessive exposure. Strontium titanate (SrTiO 3 ), which is a crucial perovskite oxide with a direct energy band gap of ∼3.2 eV, has great potential for UV-SWB photodetection . In this work, UV-SWB photodetector with high transparency based on Graphene/SrTiO 3 heterojunction was fabricated by graphene transfer method. The Graphene/SrTiO 3 photodetector exhibits an ultra-low dark current of 6 pA at a 30 V bias. The response spectrum of the Graphene/SrTiO 3 photodetector was 220–410 nm, covering the UV-SWB band. Under 385 nm light irradiation, the photodetector exhibits a response of 3.4 mA/W, a detectivity of 1.5 × 10 10 Jones, a response time of 186 ms, and a light-to-dark current ratio of 10 3 magnitude at a 30 V bias. In addition, the transmittance of the photodetector in the visible light band reaches 80 %, which has excellent visualization performance. The excellent performance of Graphene/SrTiO 3 photodetector is attributed to the high crystal quality of SrTiO 3 wafer and the van der Waals interface constructed by Graphene/SrTiO 3 reduces the bulk defect density and interfacial state density, which could be beneficial the separation and transport of photogenerated carriers in the active layer and heterojunction . This study has important reference value for the design and manufacture of UV-SWB photodetectors.