SEM studies of domains in KTIOPO₄ crystals

Domain structures of as-grown and electrically poled KTiOPO₄ (KTP) crystals were studied on polished polar and nonpolar surfaces by SEM method. The results demonstrate different contrast origin of domains and domain boundaries. It is shown that opposite in sign pyroelectric potentials for C^- and C^- domains is the reason for the domain contrast in a "Fast" electron scanning mode, whilst domain boundaries are revealed due to a converse piezoelectric effect. It is assumed that in a "Slow" regime asymmetric electron processes in KTP ferroelectrics define the domain contrast both on polar and nonpolar surfaces. It is proposed to use the developed method for testing periodic domain patterns of KTP optical frequency doublers.