Top-Seeded Solution Growth, Morphology, and Properties of a Polar Crystal Cs2TeMo3O12

Single crystals of the polar hexagonal tungsten oxide (HTO) material Cs2TeMo3O12 with dimensions up to 20 x 20 x 16 mm(3) were grown successfully through a top-seeded solution growth (TSSG) method using a TeO2-MoO3 mixture as a self-flux. The Cs2TeMo3O12 crystals grown from a solution with a low concentration exhibit {0002}, {10 (1) over bar0}, and {10 (1) over bar(1) over bar} facets, which are in good accordance with the predicted growth morphology based upon the Bravais-Friedel and Donnay-Harker (BFDH) methods. However, the crystals grown from solution with a high concentration show additional {10 (1) over bar(2) over bar} facets, which are not predicted. Crystals grown by using the [0001]-oriented seed have more regular shapes as compared with those grown by using the [2 (1) over bar(1) over bar0]-oriented seed. Cs2TeMo3O12 crystallizes in the polar hexagonal space group P6(3) (no. 173). The result of the high-resolution X-ray diffraction indicates that the full-width at half-maximum (fwlun) of the rocking curve is 18.96 ''. Thermal analysis and powder X-ray diffraction demonstrate that Cs2TeMo3O12 melts incongruently at 494.95 degrees C. Optical measurements indicate that the Cs2TeMo3O12 crystal has a broad transmission window range from 0.43 to 5.38 mu m. In addition, polarization measurements indicate that although Cs2TeMo3O12 is polar, the material is not ferroelectric.