Quantification and control of the sulfur c(2 × 2) superstructure on (100)<100> Ni for optimization of YSZ, CeO₂, and SrTiO₃ seed layer texture

We investigated the influence of a chemisorbed S template with c(2 × 2) structure on the epitaxial growth of different oxide buffer layers on (100)<100> Ni. The sulfur superstructure spontaneously forms on the Ni surface during the texturing anneal as a consequence of segregation. However, depending on the initial S bulk concentration and/or specific annealing conditions, the S layer can cover less than the entire substrate's surface. We show that an incomplete c(2 × 2) coverage causes degradation of the seed buffer layer texture as compared to the substrate texture. A simple step consisting of an H₂S predeposition anneal can be used to control the superstructure coverage and optimize the seed layer texture.