Dependence of catalytic properties of indium implanted SiO_2 thin films on the film-substrate temperature during indium ion implantation

摘要

Chemical substances that contain indium (In) and silicon (Si) in close proximity are known to catalyze certain organic chemical reactions. An earlier paper [Yoshimura, Hine, Kiuchi, Nishimoto, Yasuda, Baba, Hamaguchi, Appl. Surf. Sci. 257 (2010) 192] has demonstrated that In implanted silicon dioxide (SiO_2) films formed at room temperature catalyze a reaction of benzhydrol with acetylacetone. This study, thus, examined effects of substrate temperature during In ion implantation, revealing that, if In ions were implanted into a SiO_2 film at the substrate holder temperature of 200 ℃ or higher, the film exhibited no catalytic ability. Surface analyses by the X-ray diffraction, the X-ray photoelectron spectroscopy, and the atomic force microscopy indicated that, at such high temperature, implanted In atoms either formed separate phases of metallic In on the SiO_2 film surface or were simply nonexistent due to vaporization.