Growth and crystallography of bismuth tri-iodide crystals grown by vapor transport

摘要

A single crystal of bismuth tri-iodide (BiI(sub 3)) of dimensions 1.2 (times) 1.2 (times) 0.4 cm(sup 3) has been grown by physical vapor transport. The lattice parameters of the hexagonal crystal and its polycrystaleme powder precursor were measured by x-ray diffraction (XRD) and were in agreement, indicating that the vapor phase growth and sublimation purification processing at temperatures below 330(degree)C did not significantly affect the stoichiometry. X-ray rocking measurements of the single crystal showed low angle boundaries of the order of 0.05(degree). In tests as gamma radiation detectors, neither melt grown nor vapor grown crystals were satisfactory, but the vapor grown crystals were promising. Several observations suggest that better performance may be achievable with purer bismuth tri-iodide.