Na 0.5 K 0.5 NbO 3 thin films for voltage controlled acoustoelectric device applications

Perovskite Na0.5K0.5NbO3 (NKN) thin films have been prepared on Y+36° cut single crystal quartz substrates using the pulsed laser ablation technique. X-ray diffraction θ–2θ and ω-scan data demonstrate almost perfectly c-axis oriented film textures with narrow mosaic broadening. Radio frequency dielectric spectroscopy showed that the films possess relatively high dielectric permittivities, low dielectric losses, and low frequency dispersions. Capacitance–voltage (C–V) measurements for a 2 μm slot NKN/quartz interdigital capacitor yield 23.1% tunability by applying 40 V bias at 1 MHz, while C–V hysteresis indicates polarization reversal. The considerable voltage tunability with superior crystallinity in piezoelectric NKN films on quartz substrates suggests their potential use for novel voltage tunable acoustoelectric devices.