Interaction of plasma-generated water cluster ions with chemically-modified Si surfaces investigated by infrared absorption spectroscopy
Ayumi Hirano-Iwata,
Ryosuke Matsumura,
Teng Ma,
Yasuo Kimura,
Michio Niwano,
Kazuo Nishikawa
Affiliations
Ayumi Hirano-Iwata
Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba, Sendai, Miyagi, 980-8579, Japan
Ryosuke Matsumura
Graduate School of Biomedical Engineering, Tohoku University, 6-6 Aoba, Aramaki, Aoba, Sendai, Miyagi, 980-8579, Japan
Teng Ma
Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
Yasuo Kimura
Faculty of Engineering, Tokyo University of Technology, Hachioji 192-0914, Tokyo, Japan
Michio Niwano
Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
Kazuo Nishikawa
Appliance Systems Product Development Laboratories, Sharp Corporation, 3 -1-72 Kitakamei-cho, Yao 581-8585, Japan
We have investigated the interaction of water cluster ions generated by discharge plasma, with chemically modified Si surfaces using infrared absorption spectroscopy in the multiple internal reflection geometry. We observe that water cluster ions readily adsorb on SiO2-covered Si surfaces to form water droplets. We demonstrate that positively- and negatively-charged cluster ions adsorb on the SiO2-covered Si surface in different manners, indicating ionic interaction of the water droplets with the negatively-charged SiO2 surface. Water droplets formed on the protein-coated surface rupture the amide bond of the proteins, suggesting the function of protein decomposition of water cluster ions.
