Self-Powered Ultraviolet Photodetector Based on β-Ga2O3/WO3 NPs Heterojunction With Low Noise and High Visible Rejection

Self-powered ultraviolet (UV) photodetectors (PDs) have attracted numerous interests for high-performance and low power consumption, making wireless and independent operation possible. Herein, the solution processed tungsten oxide (WO ₃ ) nanoparticles (NPs) were employed to construct $\boldsymbol {\beta }$ -Ga ₂ O ₃ /WO ₃ planar heterojunction PD. The formation of type-II $\boldsymbol {\beta }$ -Ga ₂ O ₃ /WO ₃ heterointerface generated typical photovoltaic effect enabling self-powered work manner. Importantly, the fabricated $\boldsymbol {\beta }$ -Ga ₂ O ₃ /WO ₃ NPs PD demonstrated record low noise with dark current of 6.5 fA and prominent spectral selectivity with rejection ratio ( ${R}_{265} / {R}_{400}$ ) of $5.3\,\,\times10$ ⁴ , as well as excellent photodetection properties with photo-to-dark current ratio of $6.4\,\,\times10$ ⁵ , ON/OFF switching ratio of $2.7\,\,\times10$ ⁴ , responsivity of 4.1 mA/W, detectivity of $9.0\,\,\times10$ ¹² Jones and rise/decay time of 168/171 ms at 0 V. Besides, the narrower bandgap and UVB spectral response of WO ₃ NPs extended the detectable wavelength to 310 nm realizing broadband photodetection. The low-cost manufacture process and high self-powered performances pave the way of $\boldsymbol {\beta }$ -Ga ₂ O ₃ /WO ₃ NPs PD in next-generation nanodevices.