Crystal Growth of α-HgI2 by the Temperature Difference Method for High Sensitivity X-ray Detection

α-HgI 2 is a promising material for room temperature X-ray detection. A facile temperature difference method is designed to grow 4 × 4 × 2 mm 3 α-HgI 2 bulk crystal from KI aqueous solution. Characterization results indicate the as-grown high quality crystals are single-crystalline and possess a standard bandgap ( E g = 2.16 eV at 300 K) and high electrical resistivity (10 10 Ω·cm). Utilizing the as-grown crystal, moreover, a photoconductive type prototype X-ray detector is fabricated. The detector behaves at high X-ray sensitivity, which is improved by one order of magnitude in comparison with previous results from solution grown α-HgI 2 . In addition to α-HgI 2, the crystal growth of other halides materials which are used for X-ray detection, e.g., PbI 2, HgBr 2, BiI 3, may also benefit from the presented temperature difference method.