High yield preparation of (100)_c-oriented (K,Na)NbO₃ thick films by hydrothermal method using amorphous niobium source

Abstract

(K,Na)NbO₃ thick films were prepared at 240 °C on (100)_cSrRuO₃//(100)SrTiO₃ substrates by hydrothermal method. Film thickness increased using an amorphous niobium source instead of conventionally used crystalline one and have the maximum thickness at 0.5 mmol of input mass of niobium source within the range of 0.02–7.5 mmol in case of the 20 h deposition. The yield of (K,Na)NbO₃ films from 0.5 mmol amorphous niobium source becomes 20 times higher than that from conventionally used a 2 mmol crystalline niobium source. In addition, crystal structure, surface morphology, dielectric constant, and ferroelectric and piezoelectric properties of these films were almost independent of the kinds of niobium sources and their input mass within the limitation of the present results.