Epitaxial growth of cerium oxide thin films by pulsed laser deposition

The epitaxial cerium oxide (CeO₂) thin films were deposited on yttria stabilized zirconia (YSZ) (100) substrates at various substrate temperatures (673–973 K), energy densities (1–5 J/cm²) and repetition rates (5–30 Hz) with an optimized oxygen partial pressure of 3 Pa, by pulsed laser deposition technique. The films were characterized by X-ray diffraction and atomic force microscopy to study the influence of substrate temperature, laser fluence and repetition rate on epitaxy, growth mode and surface morphology. The X-ray diffraction studies revealed the epitaxial nature of CeO₂ (200) films on yttria stabilized zirconia (100) substrate (CeO₂ (200) ‖ YSZ (100)) deposited in the temperature range 673–973 K. The films prepared at low energy densities (1–3 J/cm²) and low repetition rates (1–25 Hz) also indicated the fully epitaxial nature, whereas the films prepared at higher energy density (≥ 4 J/cm²) and repetition rate (30 Hz) indicated deviation from epitaxy. The atomic force microscopy studies showed the formation of dense and uniform nanocrystallites with smooth morphology. The root mean square surface roughness of the films increased with the increase of substrate temperature, increase of energy density and repetition rate.