Speaker: Prof. Hiromichi Ohta (Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Japan)

Time: September 26, 2017 15:00

Place: 物理系理科楼C302报告厅

摘要： Water is composed of two strong electrochemically active agents, H+ and OH− ions, but has not been used as an active electronic material in oxides. One of our research strategies is free manipulation of functional properties, i.e. optical, electrical, and magnetic, of oxide thin films by using the electrochemical activity of water. In order to handle water, we use a water-infiltrated mesoporous glass [1] −amorphous 12CaO·7Al2O3 (CAN)− as the gate insulator of thin film transistor structure with three-terminal electrodes geometry. Positive gate voltage, chemisorption (or physisorption) of H+ and/or proton intercalation results in electron accumulation in the active oxide, while negative gate voltage, chemisorption (or physisorption) of OH- and/or oxidation results in hole accumulation in the active oxide. By using this technique, we could modulate not only electrical conductivity but also optical [2, 4], magnetic [3], and thermoelectric properties [5] of active oxides. The electron activity of water as it infiltrates mesoporous glass may find many useful applications in electronics or in information storage.

报告人简介：Prof. Hiromichi Ohta received his PhD. at Tokyo Institute of Technology in 2001. In 2003, he moved to Nagoya University as an associate professor and worked on thermoelectric materials. In 2012, he moved to Hokkaido University as a full professor. Now his group is focusing on functional oxides thin films with atomically flat surface. The main interest of Prof. Ohta is to extract the intrinsic performance of functional oxides, aiming to develop novel devices, especially “Optic, electric, and magnetic memory devices”, “Thermoelectric materials”, “Spintronic devices” based on functional oxides. Further, they have also developed “Special epitaxial growth technique” to fabricate high-quality thin films of functional oxides.