Valerie Demange

Abstract:

Environmental-friendly lead-free oxides in the K-Nb-O (KN), K-Ta-Nb-O (KTN) and K-Na-Nb-O (KNN) systems have attracted great interest for various applications in microelectronics, electro-optics and photocatalysis. In this work, KN, KTN and KNN thin films were grown on different substrates and electrodes by pulsed laser deposition which allows the control of both composition and structural properties, which strongly impacts the morphology and the physical behavior. The influence of deposition parameters, such as temperature, target composition or target-substrate distance was studied with adopting a phase diagram approach. Thin films of pure phases (KNbO3, K4Nb6O17, K6Nb10O30, KNb3O8, K3Nb7O19) were analysed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, precession electron diffraction, energy dispersive X-ray spectrometry and piezoresponse force microscopy.
In this study, we evidenced i) the first synthesis of thin films of K6Nb10O30, KNb3O8, K3Nb7O19 phases; ii) the epitaxial growth of all these phases on SrTiO3 (100) and (110); iii) the nanostructuration of some compounds under the form of nanorods, nanowires or nanosheets; iv) the synthesis of a new form of the well-known KNbO3 perovskite phase.