Effect of step edges on the growth of Pt thin films on oxide single-crystal substrates

Abstract

To study the effect of step edges on the growth of Pt thin films on oxide substrates, Pt films were grown on SrTiO₃(100), rutile TiO₂(100), and Al₂O₃(11–20) stepped surfaces at 673 and 973 K by pulsed laser deposition. No clear effect due to the step edges on the film growth was found on the SrTiO₃ at 673 K. However, the Pt grains were larger in size at the step edges than on the terraces at 973 K. The estimated length of the Pt surface diffusion was longer than the average terrace width at 973 K and shorter at 673 K. Similar growth behavior was also observed on the TiO₂ at 973 K, while there was no clear effect caused by the step edges in the case of the Al₂O₃. The Pt diffusion length was estimated to be longer than the terrace width on the TiO₂ and shorter on the Al₂O₃. The effect of the step edges can therefore be understood by considering the Pt surface diffusion.