Single crystals of ZnWO4 were grown successfully in the [100], [010] and [001] directions using the Czochralski method. Seed crystals of ZnWO4 were obtained from single crystal growth using platinum wires from the melt by capillary action. The effect of the growth parameters, such as the rotation speed, pulling rate and diameter of the grown crystals, were examined. The ZnWO4 crystals had a cleavage plane of (010). The dislocation density on the (010) plane at the center of the crystal was lower than near the edge. The higher dislocation density at the edge of the crystals was attributed to the thermal gradient in the growing crystals. The etch pit arrangement revealed the (100) slip plane to be most active during crystal growth. The formation of cracks in the grown crystals during the cooling process was prevented by annealing. The hardness, thermal expansion coefficients and dielectric constants of the crystals were evaluated.

Keywords: Single crystal growth, Czochralski method, ZnWO4, scintillator materials.