The enhanced responsivity and response speed of SnO2 visible-blind transparent photodetectors via the SiO2 passivation layer

Abstract

Recently, transparent ultraviolet (UV) photodetectors have gained wide attention for their giant potential in integrated transparent electronics applications. SnO₂ films as a common candidate for visible-blind transparent ultraviolet photodetectors have attracted increasing attention. In this work, high-performance visible-blind transparent UV photodetectors based on SnO₂ thin film and a SiO₂ passivation layer were successfully synthesized by the sol–gel spin coating method for the first time. The obtained SnO₂/SiO₂ hybrid device has a transmittance of nearly 80% in the visible band at 400–700 nm and demonstrates a high responsivity of 769 mA W⁻¹ and a detection sensitivity of 1.24 × 10¹⁴ Jones under UV light illumination. The UV-C/UV-A rejection ratio is greater than 10⁶, indicating that the device has good photo-selectivity. In addition, after the introdution of the SiO₂ layer, the response speed is 2 times higher than that of pure SnO₂. The presence of the SiO₂ layer reduces the exposed area of SnO₂, passivates the oxygen vacancies on the surface of SnO₂ and inhibits the surface chemical adsorption. The above results provide a new perspective for improving the performance of SnO₂ thin film for visible-blind transparent ultraviolet photodetectors.