Atomic Steps on Thermally Annealed Oxide Substrates

Atomically smooth perovskite oxide substrates are necessary for high quality thin-film growth. We have optimized the annealing conditions for the substrates, LaAlO$_{3}$, SrTiO$_{3}$ and NdGaO$_{3}$, which are commonly used substrates for growing thin-film perovskite oxides. The optimal annealing temperatures were between 950 $^{o}$C$^{ }$and 1050 $^{o}$C and the annealing time for each sample was varied by approximately 20{\%}. Atomic force microscopy was used to compare the surfaces of the annealed substrates with the unannealed ones. These images capture the terrace steps that occur due to the annealing process, and we have confirmed that the heights of the steps are approximately one unit cell (0.4 nm). Currently, we are investigating methods for determining the site termination of the substrates and their effects on thin-film growth.