A broadband UV-visible photodetector based on a Ga2O3/BFO heterojunction

In this work, a well-operated broadband UV-visible photodetector based on a Ga2O3/BiFeO3 (Ga2O3/BFO) heterojunction is fabricated and characterized. Under the ultraviolet (UV) light illumination with an intensity of 100 μW·cm−2 at 254 nm in UVC waveband, at a biasing voltage of 2 V, an ultra-low dark current (Idark) of 0.12 pA, a high photo-to-dark current ratio (PDCR) of 1.0 × 105, a responsivity (R) of 12.0 mA·W−1, a specific detectivity (D*) of 6.1 × 1012 Jones, an external quantum efficiency (EQE) of 5.9%, and a UVC/visible rejection ratio (R235/R600) of 4.47 × 103 are achieved. In addition, the rise time and decay time are 0.25 s and 0.04 s, respectively. Meanwhile, the potential of the device as a self-powered photodetector is proved, and the principle of energy-band diagram is analysed for the fabricated heterojunction device. The results show that the Ga2O3/BFO heterojunction is a potential candidate for preforming desired broadband UV-visible photodetection.