Narrow optical gap ferroelectric Bi2ZnTiO6 thin films deposited by RF sputtering

Abstract

This work reports the deposition of single phase Bi₂ZnTiO₆ thin films onto Pt/Si-based substrates using the RF-sputtering method and the respective structural, morphological, optical and local ferroelectric characterization. The thin film grows in the polycrystalline form with tetragonal P4mm symmetry identified by X-ray diffraction. The lack of a spatial inversion centre was confirmed by the second harmonic generation. A narrow indirect optical gap of 1.48 eV was measured using optical diffuse reflectance. The ferroelectric domain reversal was further demonstrated through piezo-response force microscopy. This work demonstrates a practical method to fabricate the BZT perovskite phase, without resorting to high pressure and temperature conditions necessary to synthetize the bulk form, with outstanding optical and ferroelectric properties.