Pulsed laser deposition of epitaxial MgO buffer layer for proton-conducting ceramic electrolytes

This work studies the deposition of epitaxial MgO thin films with thickness of 40nm deposited on bare Si (100) wafer using pulsed laser deposition (PLD), which can serve as a buffer layer for subsequent growth of textured Y-BaZrO3 with high proton-conductivity. The success of epitaxial deposition were achieved by careful preparation of Si substrate by pre-etching with HF solution, as well as by optimizing deposition parameters including oxygen partial pressure and substrate temperatures. Epitaxial (100) MgO film with cubic lattice structure and the lattice constant of 4.21Å were obtained, which showed highly lattice match with Y-BaZrO3 perovskite of 4.21Å. •Epitaxial MgO thin film was fabricated on Si wafer directly by PLD.•Effects of substrate temperature and chamber pressure are systematically studied.•Accurate epitaxial growth and clear film/substrate interface were revealed by XRD and TEM.