Growth of High-Quality Perovskite KTa1-xNbxO3 Thin Films by RF Magnetron Co-Sputtering

Abstract

In this study, we demonstrate the growth of high-quality KTa1-xNbxO3 (KTN) thin films by using multi-target radio frequency (RF) magnetron co-sputtering with KTaO3, KNbO3, and K2CO3 targets. KTaO3 and KNbO3 targets were used to control the Ta/Nb ratio while the K2CO3 target was used to supply excess potassium (K) to compensate for the K deficiency. Through careful control of the RF powers applied to each target, high-quality perovskite KTN (x = 0.53) thin films were grown on various single crystal substrates. Variable temperature Raman spectroscopy revealed that the KTN thin films exhibit a ferroelectric phase at room temperature with a Curie temperature of ~403 K. The optical constants n and k of the KTN thin film were also similar to those reported for single KTN crystals. These results present a simple route toward fabricating high-quality perovskite KTN thin films with desired structural and optical properties for various device applications utilizing the RF magnetron co-sputtering method.