Stabilizing the Ferroelectric Phase of KNO3 Thin Films Using Substrate Electrodes

In this study, polarization–voltage (P–V) and current density–voltage (J–V) measurements were utilized to investigate the effect of nickel (Ni), 304 austenitic stainless steel (SS) and tantalum (Ta) substrate electrodes on the ferroelectric phase stability of KNO3 thin films. P–V loops and J–V switching peaks were obtained to suggest the intriguing possibility of attaining ferroelectric phase stability in KNO3 films by means of an appropriate substrate electrode. SS substrate electrode stabilized the ferroelectric phase to room temperature (28°C) while Ni substrate electrodes stabilized the phase close to room temperature. On the other hand, Ta substrate electrodes severely degraded the ferroelectric phase of the deposited films. A strong agreement was found between the appearance of the P–V hysteresis loop and the occurrence of the J–V switching peaks confirming polarization switching to be responsible for the observed ferroelectric properties exhibited by the thin film samples.