Growth of PbI2 single crystal by the top seed vertical zone melting method

PbI₂ is a type of syntectic compound, and its single crystal is one of the room temperature semiconductor nuclear radiation detector materials. A new method for the growth of the PbI₂ single crystal is proposed in this article, which was named the top seed vertical zone melting method (TSVZMM), directly from the synthesis of polycrystal with analytically pure lead and iodine, by controlling the decomposition and stratification of the melt and the stoichiometry of the PbI₂ crystal. Impurities in the crystal and the coagulating droplets of lead were eliminated during the PbI₂ crystal growth process from the top to bottom by TSVZMM. The PbI₂ single crystal was successfully grown with the size of Φ15 mm×15 mm, an infrared transmittance of more than 40%, a resistivity of 2×10¹² Ω cm magnitude and stoichiometry close to its theoretical value.