Chemical Solution Deposition of <100>-oriented SrTiO3 Buffer Layers on Ni Substrates

Abstract

Biaxially textured <100>-oriented SrTiO3 films were solution deposited on <100> LaAlO3 single crystals and <100>-oriented polycrystalline Ni tapes. Solution variables including varying titanium alkoxide chain length, inclusion of chelating agents, and inclusion of donor dopant, were investigated for their effect on film orientation, morphology, and oxygen diffusivity. The best <100> SrTiO3 orientation on high lattice mismatch (11%) Ni substrates was achieved through use of a discontinuous nucleation seed layer, which provided nucleation sites for subsequent continuous SrTiO3 films. Increased titanium alkoxide chain lengths appeared to suppress titanium hydrolysis reactions and improve film orientation. 13C nuclear magnetic resonance showed that significant quantities of water were generated due to esterification reactions, which appeared to cause hydrolysis and subsequent orientation degradation in the absence of chelating agents such as acetylacetone.