Growth and Characterization of Pure and Cd-Doped Zinc Tris-Thiourea Sulfate (ZTS) Single Crystals

Single crystals of pure and Cd-doped zinc tris-thiourea sulfate (ZTS) were grown for frequency conversion applications by a low temperature solution growth method, allowing slow evaporation of the water solvent at a constant temperature. The solubility of ZTS was found to increase with the concentration of Cd in the aqueous solution. The optical transparency was found to increase in the Cd-doped crystals as compared to that in the undoped crystals. The doping of Cd was confirmed quantitatively by the atomic absorption spectroscopy and qualitatively by Fourier transform infrared spectroscopy. From the powder x-ray diffraction study, it was found that the lattice constants (a, b and c) decrease with the concentration of Cd in ZTS, but the change in the crystal symmetry and space group has not been reported. A␣change in growth habit of Cd-doped crystals has been observed. Thermo-gravimetric and differential thermal analysis was employed to learn the thermal stability of the grown crystals, and 2 mol% Cd-doped ZTS crystal was found to thermally stable up to 230 °C. The second harmonic generation (SHG) efficiency measurement reveals improvement in the SHG efficiency, as 4 mol% Cd-doped ZTS crystal has 1.36 times more SHG efficiency as compared to the pure ZTS crystal.