Substrate temperature dependent dielectric and ferroelectric properties of (100) oriented lead-free Na$_{0.4}$K$_{0.1}$Bi$_{0.5}$TiO$_3$ thin films grown by pulsed laser deposition

TL;DR

This study investigates how substrate temperature affects the structural, dielectric, and ferroelectric properties of lead-free NKBT0.1 thin films grown by pulsed laser deposition, identifying optimal conditions for high-performance ferroelectric devices.

Contribution

It provides new insights into the influence of substrate temperature on NKBT0.1 thin films, highlighting the optimal deposition temperature of 700°C for enhanced ferroelectric properties.

Findings

Higher deposition temperatures increase grain size, dielectric constant, and remnant polarization.

Films at 700°C show low dielectric loss and high dielectric constant.

Optimal ferroelectric performance achieved at 700°C deposition temperature.

Abstract

Pb-free ferroelectric thin films are gaining attention due to their applicability in memory, sensor, actuator, and microelectromechanical system. In this work, Na$_{0.4}$K$_{0.1}$Bi$_{0.5}$TiO$_3$ (NKBT0.1) ferroelectric thin films were deposited on Pt(111)/Ti/SiO$_2$/Si substrates using the pulsed laser deposition technique at various substrate temperatures (600-750 $^\circ$C). The comprehensive structural, microstructural, and ferroelectric properties characterizations depicted that the grain size, dielectric constant, and remnant polarization increased with higher deposition temperatures. The influence of higher substrate temperatures on the control of (100)-preferential orientations was observed, indicating the importance of deposition conditions. Significantly, films deposited at 700 deg C exhibited reduced dielectric loss of 0.08 (at 1kHz), high dielectric constant of 673, and remnant polarization of 17 microC/cm2 at room temperature. At this deposition temperature, a maximum effective piezoelectric coefficient of 76 pm/V was availed. Based on the structural analysis, dielectric properties, and ferroelectric behavior, the optimal deposition temperature for the NKBT0.1 thin films was 700 $^\circ$C. This study contributes to the understanding of the influence of substrate temperature on the structural and ferroelectric properties of Pb-free NKBT0.1 thin films, providing insights for the development of high-performance ferroelectric devices.