Pulsed X‐Ray Detector Based on Vertical p‐NiO/<i>β</i>‐Ga₂O₃ Heterojunction Diode

Gallium Oxide (Ga 2 O 3 ) devices have shown great potential for radiation detection. However, developing Ga 2 O 3 detectors for pulsed radiation monitoring is still challenging, which requires high response sensitivity ( R ), low noise, high time resolution, and linear outputs. Herein, a vertical p‐NiO/ β‐ Ga 2 O 3 heterojunction diode (HJD) is fabricated and its performance in X‐ray detection is analyzed. Benefiting from the high quality of the p‐n heterojunction, the HJD exhibits a low‐leakage current density of less than 1.73 × 10 −7 A cm −2 at 100 V and features a high R of 7.92 μC Gy −1 cm −2 , a low noise equivalent dose rate of 9.14 × 10 −12 Gy −1 Hz −0.5 at an X‐ray dose rate of 0.383 Gy s −1 , and good linear outputs to X‐ray dose rates from 0.0383 to 1.149 Gy s −1 . The conductive process of the HJD detector is dominated by the tunneling mechanism, which leads to a longer response time associated with the trapping and releasing process of the deep‐level traps under the continuous X‐ray illumination. However, the pulsed X‐ray response property shows no significant influence from the slow trapping/releasing process of the traps. As a result, pulsed X‐ray radiation detection with a 50 ns full width is achieved, and the time resolution of the detector is characterized to be 3.31 ns by a 20 ps laser source.