Highly (111)-oriented PbTiO₃ prepared by rf planar magnetron sputtering and their optical properties

Perovskite type PbTiO₃ films with highly [111] preferred orientation were synthesized successfully on the amorphous sapphire substrates by rf planar magnetron sputtering with an element target. Studies reveal that the film has a good alignment in the growth direction and a grain size approximately 180 nm. The mechanism of film growth was studied and the results manifested that an interfacial layer formed as self-buffer layer. This transition layer released the intrinsic stress, so that the film with excellent structure could be grown on amorphous substrates. The refractive index at room temperature was determined in the wavelength range 400-2500 nm from the transmittance at normal incidence. The dispersion was found to fit the individual dipole oscillator model very well, and the minimum refractive index of the film is deduced as 2.51.