Interface-Engineered Ultrawide-Bandgap TiN/β-Ga2O3 Schottky Diodes for Radiation-Hard X-ray Detection and Imaging

초록

High-performance X-ray detectors capable of reliable operation under harsh environments are vital for applications spanning medical diagnostics, industrial inspection, security screening, and space exploration. Ultrawide bandgap semiconductors have emerged as promising candidates for next-generation radiation sensors due to their intrinsic robustness and superior electrical properties. Among them, monoclinic beta-gallium oxide (beta-Ga2O3), with its ultrawide bandgap (similar to 4.8 eV), high density (6.44 g/cm(3)), strong chemical/thermal stability, and high theoretical breakdown field (similar to 8 MV/cm), offers unique advantages for radiation detection. In this work, TiN/beta-Ga2O3 Schottky barrier diodes (SBDs) exhibit low leakage, reduced specific on-resistance (R-on,R-sp), and enhanced breakdown performance. Deep-level transient spectroscopy (DLTS) identifies three dominant electron traps: two associated with intrinsic Ga-site defects or unintentional impurities and a third linked to Ga-site defect complexes. Their capture cross-sections (10(-13) to 10(-20) cm(2)) reveal deep donor-like behavior that affects reverse leakage and breakdown voltage, providing insight into defect-limited transport mechanisms in beta-Ga2O3 devices. The TiN/beta-Ga2O3 SBDs further demonstrate excellent radiation hardness and operational stability, establishing them as strong candidates for advanced X-ray detection. The detector shows stable photocurrent responses proportional to the dose rate and tube voltage, while scan-based imaging using KWU and SJU phantoms produces clear grayscale and 3D reconstructions, validating reliable image formation. These results highlight the promise of TiN/beta-Ga2O3 devices for next-generation, high-reliability X-ray imaging and radiation monitoring systems.

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