High-Detectivity β-Ga₂O₃ Microflake Solar-Blind Phototransistor for Weak Light Detection

This letter reports a high-performance solar-blind phototransistor based on N2-annealed β-Ga2O3microflake for weak light detection. The phototransistor exhibits an ultra-low dark current of 27 fA, a high external quantum efficiency of 8.36 x 107%, a photo-to-dark-current ratio of 1.08 x 107, a low power consumption of 2.92 pW, and a narrow-band response with a cut off wavelength of 263 nm. In addition, the spectral selectivity can be well modulated by the gate bias and reaches a maximum R240/R400ratio of 2.4 x 104. Especially, an ultra-high responsivity (R) of 1.71 x 105A/W and a record-high detectivity (D*) of 1.19 x 1018Jones have been achieved under 254nm illumination of 4.1 μW/cm2. The superior weak-light-detection performance of the device makes it one of the best Ga2O3detectors towards solar-blind photodetection application.