Synthesis and Characterization of Single Crystals of Cadmium Iodide as Gamma-ray Radiation Sensor

Single crystals of Cadmium iodide have been grown by solution method and characterized by X-ray Diffraction (XRD) to determine the structural parameters and miller planes which are responsible for X-ray diffraction. The Crystals were subjected to UV spectroscopy to determine the optical band gap. The value of optical band gap was found to be 3.22 eV, well matched with the value reported in the literature. The presence of well-defined reflections with low FWHM confirms the good crystalline quality of single crystals. Single crystals of cadmium iodide have been chosen to design a radiation sensor as it has high absorption coefficient, wide band gap, and high resistivity. These are the required parameters for a compound semiconductor to act as a radiation sensor at room temperature. Single crystals were exposed to low dose of gamma radiation emitted by the source Cobalt-60 to explore their usage in detecting high energy gamma radiations at room temperature. It was observed that on irradiation the optical band gap decreased but there was no variation in the peak positions of XRD, although the intensity of XRD peaks decreased. The results have been explained in terms of structural defects produced due to gamma irradiation.