Growth and characterization of KTiOPO4 single crystals

Large size potassium titanyl phosphate (KTP) crystals were grown by spontaneous nucleation technique from the K6P4O13 flux modified with the addition of MoO3. MoO3 suppressed the multinucleation. A cooling rate of 0.2 K h−1 yielded large crystals. Growth mechanism was revealed by optical microscopy. Etching experiments showed typical etch pits with hollow core and dislocation density in the range of 1500–20000 cm−2. Hardness measurements showed anisotropy and a decrease in hardness index with applied load.