Our paper was published in Journal of Physics D
T. Yatsui, K. Kuribara, T. Sekitani, T. Someya, M. Yoshimoto, “Temperature-modulated annealing of c-plane sapphire for long-range-ordered atomic steps,” Journal Physics D, Volume 49, Number 11, 23 March 2016, 115302
[Significance of this article]
Temperature control has been widely used in chocolate cooking to obtain single-crystalline cacao, which has good taste. The process of tempering, in which cacao butter is heated slightly before it is cooled down, helps avoid the formation of mixed phases. In this study, inspired from chocolate cooking, we introduced a tempering process during sapphire annealing. The resulting surface was analysed using an atomic force microscope (AFM) to evaluate the atomic scale morphology and using XRD to evaluate the large-area uniformity. We successfully obtained a sapphire atomic step with nanometre-scale uniformity in the terrace width and atomic-step height. In addition, the atomic-step structure was formed uniformly on a millimetre-order scale. High-quality sapphire substrates prepared with this technique will find applications in the preparation of various semiconductors and devices.