| Summary: | 碩士 === 中原大學 === 物理學系 === 88 === By controlling the crystal growth temperature and vapor transport rate, the growth and characterization of mercuric iodide single crystals from physical vapor transport are studied. The crystal structure and surface morphology for the as-grown α-HgI2 crystals for different conditions are discussed by optical microscopy, SEM, and XRD. In the physical properties measurement, the temperature dependence of band gap deduced from photoconductivity spectra is measured, and the comparison of photoconductivity with photoluminescence spectra are made. In the samples with rough surface morphology and bad crystal quality, the persistent photoconductivity (PPC) at low temperature is observed. From the temperature dependence of PPC decay time, the activation energy is evaluated of about a few meV, and its origin may be related to the band tail from the relaxation of lattice structure.
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