Environmental Friendly Potassium Sodium Niobate Based Thin Films from Solutions

We present the synthesis of ~250 nm thick K0.5Na0.5NbO3 thin films on platinized silicon substrates from alkoxide-based solutions with the stoichiometric composition and with the 5 or 10 mole % potassium acetate excess. The films crystallized into a pure perovskite phase, but depending on the amount of the alkali excess in solutions, they consisted of ~50 nm or of ~200 nm large grains. The fine-grained film from the solution with the 5 mole % alkali excess had the dielectric permittivity and losses of 610 and 1.5 %, respectively, and exhibited a ferroelectric polarisation–electric field dependence at room temperature.