“All three in one”: An excellent bismuth-based oxide hard X-ray detector unveiling ultra-high sensitivity, ultra-low dark current and ultra-low detection limit

Abstract

Currently, ongoing endeavors are under way for developing X-ray detection materials with high sensitivity and low detection limit used for medical diagnosis, industrial inspection and beyond. Presenting a groundbreaking solution, we originally propose the utilization of bismuth-based oxide crystals for X-ray detection. Specifically, we highlight the exceptional capabilities of Bi₁₂SiO₂₀ (BSO) crystal as an exemplary oxide X-ray detector. Benefiting from its large absorption coefficient, high resistivity (2.5 × 10¹³ Ω·cm), high ion activation energy (1.5 eV) and excellent carrier transport property (μτ = 7.5 × 10^-3 cm²·V⁻¹), the BSO X-ray detector exhibits an ultrahigh sensitivity of 2.1 × 10⁴ μC·Gy⁻¹·cm⁻² under 120 keV hard X-ray, surpassing all previously reported all-inorganic bismuth-based perovskites materials. The specific detectivity (9.91 × 10⁸ μC·Gy⁻¹·cm⁻¹·A^-1/2) outperforms all known perovskite materials. Notably, the BSO X-ray detector achieves an ultralow detection limit of 1.4 nGys⁻¹ owing to its low dark current (0.85 nA/cm² at 10000 V/cm). These achievements not only establish BSO as an excellent hard X-ray detection material, but also pave a new avenue for exploring high-performance X-ray detectors within bismuth-based oxide crystals.