Semiconductor radiation detectors have broad and surging applications in homeland security， medical imaging， and fundamental scientific research. Recently， the all-inorganic perovskite CsPbBr3 has attracted considerable attention owing to its suitable bandgap （~2.3 eV）， high effective atomic number （65.9）， high density （4.85 g·cm-3）， high resistivity （>109 Ω·cm）， and excellent carrier transport properties （μτ on the order of 10-3 cm2·V-1）， making it a promising candidate for next-generation room-temperature semiconductor radiation detectors. Specifically， CsPbBr3 crystals can be synthesized via either solution-growth or melt-growth techniques. Solution-based methods are typically carried out at relatively low temperatures and feature simple fabrication procedures and low cost. However， the size of solution-grown CsPbBr3 crystals is generally limited to the centimeter scale. In comparison， melt-growth techniques are currently the most widely used methods for producing large-size CsPbBr3 crystals. Nevertheless， melt growth is typically carried out at high temperatures using high-purity raw materials. Moreover， due to the relatively low thermal conductivity of CsPbBr3， together with the structural phase transitions during the cooling process， defects such as twins and cracks are readily generated， severely deteriorating the single-crystal quality and detector performance.
In this work， the growth process of CsPbBr3 crystals was systematically investigated using the vertical Bridgman method. Based on optimized growth parameters， including the temperature gradient and cooling rate， a high-quality large-volume CsPbBr3 crystal with dimensions ofø40 mm×7 cm was successfully grown using zone-refined CsPbBr3 polycrystals. The optical properties of the as-grown CsPbBr3 crystals were systematically characterized. UV-Vis-NIR measurement revealed a high optical transmittance of up to 80% and a bandgap of 2.27 eV. Photoluminescence （PL） measurement showed a strong emission peak at 531 nm， while time-resolved photoluminescence （TRPL） spectra exhibited decay lifetimes of 2.26 and 38.62 ns， respectively. To evaluate the electrical properties， γ-ray detection performance， and charge transport properties， an asymmetric Au/CsPbBr3/EGaIn planar device was fabricated. The CsPbBr3 detector exhibited a high resistivity of up to 6.12×109 Ω·cm determined by current-voltage （I-V） test. Owing to the asymmetric Schottky-type configuration， the dark current was effectively suppressed to 4.4 nA at -100 V， which was approximately two orders of magnitude lower than that measured at 100 V. In addition， the device exhibited a large ON/OFF ratio of 2 300 under a bias of -10 V using a white LED as the illumination source during current-time （I-t） test. The detector was subsequently evaluated using various γ-ray sources under a hole-dominant collection mode， achieving energy resolutions （ERs） of 10.0%， 5.5%， and 1.6% at room temperature for 241Am （59.5 keV）， 57Co （122 keV）， and 137Cs （662 keV） γ-rays， respectively. Carrier transport properties， particularly high carrier mobility and long carrier lifetime， are critical for improving charge collection efficiency and radiation detection performance. Using a 241Am γ-ray source， the hole mobility of CsPbBr3 was determined to be 24.41 cm2·V-1·s-1 via time-of-flight （TOF） measurement， while the hole mobility-lifetime product was extracted to be 4.17×10-3 cm2·V-1 based on the Hecht equation. This work presents a reliable growth process for producing high-quality large-volume perovskite CsPbBr3 with superior radiation detection performance， which may facilitate their scalable fabrication and practical applications.
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