Noise suppression and enhanced energy resolution in NiO/β-Ga₂O₃ radiation detectors

In this Letter, we investigated the noise sources in NiO/β-Ga₂O₃ p-n heterojunctions and demonstrated the field management for noise suppression to enhance radiation detection performance. Combining TCAD simulations and experimental electrical analysis, we identified two primary noise sources, including shot noise originating from carrier density fluctuations and non-uniform carrier drift velocities, and flicker noise associated with localized carrier trapping centers. To mitigate these noise contributions, we developed a large-area (1 × 1 mm²) NiO/β-Ga₂O₃ p-n heterojunction detector incorporating an amorphous high-k dielectric BaTiO₃ layer as the field-plate (FP) structure. By effectively redistributing the electric field, the FP implementation minimizes field crowding at device edges, reduces leakage current, and enhances carrier transport uniformity, thereby leading to significant background noise suppression. Consequently, the detector achieves an improved energy resolution of 4.3% for α-particle detection, surpassing the previously reported Ga₂O₃ radiation detectors. These findings deepen the fundamental understanding of noise mechanisms in β-Ga₂O₃ devices and demonstrate a robust field-engineering strategy for achieving low-noise and high-energy-resolution radiation detectors.