Microstructural, ferroelectric and photoluminescence properties of Er3+-doped Ba0.85Ca0.15Ti0.9Zr0.1O3 thin films

Highlights: • Er³⁺-doped BCTZ thin films fabricated by the chemical solution deposition. • Fine, uniform and well-crystallized films with perovskite structure were obtained. • The 0.01Er-BCTZ thin film exhibits high P_r and enhanced up-conversion PL. • Oxygen vacancies of the films affect both ferroelectricity and PL intensity. • The work can provide guidance for other ferroelectric-luminescent thin films. Er³⁺-doped Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃ (xEr-BCTZ, x = 0, 0.005, 0.01) ferroelectric-luminescent thin films were prepared by the chemical solution deposition method. The effects of annealing temperature on microstructures of the samples were examined. Fine, uniform and well-crystallized thin films with pure perovskite structure were obtained through annealing at 750 °C. And the number of pores reduce with denser microstructure by increasing the Er³⁺ content. Additionally, ferroelectric and photoluminescence (PL) properties of xEr-BCTZ thin films were studied. Owing to dense microstructure and few defects, high remanent polarization and strongest up-conversion PL intensity were obtained at x = 0.01. The result of X-ray photoelectron spectroscopy confirms the existence of oxygen-related defects in the films, which can partly deteriorate the ferroelectricity and PL intensity. This work can guide other multifunctional lead-free ferroelectric-luminescent thin films for micro-optoelectronic applications.