Top seeded solution growth of pure and Rh:KTiOPO4 single crystals and their optical and electrical characterization

In this paper we report the growth of pure and Rhodium ion incorporated KTiOPO4 (Rh:KTP) single crystals by top seeded solution growth (TSSG) technique with an improved seeding procedure. The optical transmission/absorption spectra of pure and Rh:KTP crystals in the UV-VIS region are discussed. It is shown that the presence of Rh ion increases the indirect energy gap (Eg) and shifts the lower absorption edge of KTP towards higher energy region. The ionic conductivity and dielectric properties of pure and Rh:KTP crystals were studied by means of impedance spectroscopy. The frequency and temperature dispersion behavior of dielectric constant and ionic conductivity of doped crystals are similar to pure KTP. Measured activation energies (Ea) from the ionic conductivity and dielectric loss spectra indicate the existence of superionic conduction behavior. Linear thermal expansion coefficients of pure and doped crystals along the polar axis were obtained using a thermo mechanical analyzer.