OBSERVATION OF GROWTH STEPS AND GROWTH HILLOCKS ON THE (100), (210), (011) AND (101) FACES OF FLUX GROWN KTIOPO4 (KTP)

The as-grown crystal forms, which occur naturally on flux grown potassium titanyl phosphate KTiOPO4 (KTP) were investigated by optical microscopy. Growth spirals and growth steps have been identified on all crystal forms. No indications of a two-dimensional nucleation mechanism could be found. Although many dislocations with a screw component outcrop occur on all the faces of KTP, only one or a few growth spirals per face were visible. Slope angles of growth hillocks, step heights and step distances were determined on faces adjacent to optically clear, inclusion-free growth sectors. This resulted in step heights of 1 to 10 nm for all faces in the proximity of the centre of the growth spirals. At some distance from the step generator on {011} macrosteps are formed, which leads to inclusion formation parallel to this face.