MOCVD of KNbO₃ Ferroelectric Films and their Characterization

Abstract

KNbO 3 in the form of films is a highly acclaimed material due to its potential application in surface acoustic wave (SAW), and nonlinear optic devices. Single-source powder flash evaporation MOCVD of epitaxial KNbO 3 films was accomplished, for the first time, with potassium tert-butoxide and niobium heteroligand complex, Nb(O i Pr) 4 (thd) used as volatile metal±or-ganic precursors. The microstructure of the films was found to be dependent on the substrate used (MgO or SrTiO 3 ) and deposition temperature. A new approach to reach cation stoichiometry of deposited films deficient in potassium, consisting of a post-deposition annealing with a KNbO 3 /K 3 NbO 4 powder mixture, was proposed. The device quality of the films was verified by high second harmonic generation (SHG) output. The effect of the oxygen non-stoichiometry of films on the phase transition temperature was proven.

Strain‐Induced High Polarization of a KNbO3 Thin Film on a Single Crystalline Rh Substrate

“…Romanov et al . synthesized epitaxial KNO films on a SrTiO 3 substrate using a metal‐organic chemical vapor deposition method, but they showed only the second harmonic generation characteristics without any ferroelectric properties. Xiao et al .…”

Effect of Pyrolysis Temperature on K0.5Na0.5NbO3 Thick Films Derived from Polyvinylpyrrolidone‐Modified Chemical Solution

“…As a result, it is difficult to fabricate KNN films with saturated polarization–electric field ( P – E ) hysteresis loops and high piezoelectric properties, especially the films derived from the chemical solution deposition (CSD) method 6,7 . Adding an excess amount of the volatile constituents to the precursor solution is an effective method that has been used to obtain the required stoichiometry in the deposited films 7–10 . Unfortunately, the resulting ferroelectric properties are far from satisfactory.…”

Ferroelectric properties in KNbO3 thin films probed by optical second harmonic generation

“…2 Metalorganic compounds of potassium and niobium are used as volatile precursors. 2 Metalorganic compounds of potassium and niobium are used as volatile precursors.…”