ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Crystallite size-driven optical and mechanical behaviour of sol–gel synthesized pure PZT thin films on alumina

Sreelalitha K, Sambasivaiah B, Lakshmi M, and Pavan Kumar N

Department of Physics, Aditya College of Engineering, Madanapalle, India

E-mail: sreelalithak@gmail.com

Received: 25 September 2025  Accepted: 1 December 2025

Abstract:

Spectral and mechanical characteristics of sol–gel synthesized Lead Zirconate Titanate (PZT) thin films on alumina substrates were evaluated using optical analysis and nanoindentation techniques. The stochimetrically prepared PZT [Pb(Zr_0.52Ti_0.48)O₃] solutions were treated at room temperature and at 125 °C and then spin coated on alumina substrate. The spin coater was used in double mode and coated PZT thin films were analysed to study the effect of the temperature on various properties. The well-ordered pure Perovskite structure of PZT thin films was confirmed using X-ray diffraction (XRD). Solution temperature influenced crystallite size, dislocation density and strain. Optical analysis confirmed direct band transitions. As thickness increases from 1.73 to 3.37 µm, the band gap value decreases from 3.51 to 3.34 eV. Nanoindentation analysis showed that both Young’s modulus and hardness enhanced with increasing crystallite size, aligning with the inverse Hall–Petch effect. The values of young’s modulus vary from 117.1 to 210.9 GPa, and hardness varies from 9.2 to 12.1 GPa with crystallite size variation of 30–42 nm.

Keywords: PZT thin films; Nano Indentation; Crystallite size; Band gap; Young’s modulus; Hardness

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04574-8

Chemical Papers 80 (3) 3113–3119 (2026)