Growth and anisotropic optoelectronic properties of a two-inch CsPbBr3 crystal by the vertical Bridgman method

Abstract

CsPbBr₃ crystals exhibit high photoelectric absorption, large carrier mobility, long carrier lifetimes, and notable stability at room temperature. With an intermediate bandgap of 2.3 eV, they allow the fabrication of stable photonic devices and show good application prospects in the field of nuclear radiation detection. Through the adjustment of the polycrystalline raw material synthesis, crucible shape design, and multiple growths, a high-quality CsPbBr₃ crystal of Φ 50 mm × 80 mm with uniform and crack-free appearance was successfully grown by the vertical Bridgman method. The FWHM of the different crystalline planes was characterized by XRD rocking curves, which showed that the (010) plane has a narrower half peak width and higher crystallinity. Detectors with an Au/CsPbBr₃/Au structure were fabricated by magnetron sputtering with Au electrodes of 2 mm in diameter, and the resistivity of the (100) crystal plane and (010) crystal plane was 2.5 × 10⁹ Ω cm and 7.8 × 10⁹ Ω cm, respectively. Under a 5 V bias, UV lamp bands and X-ray irradiation tests revealed that devices with the (010) plane had higher switching ratios and sensitivity, resulting in higher signal-to-noise ratios at lower X-ray doses.