The research group led by Dr. Tetsuya Hasegawa grew compressively strained epitaxial thin films of perovskite oxynitride SrTaO2N and found that the films included small domains exhibiting ferroelectric behavior. This is the first observation of ferroelectric behavior in oxynitrides. First-principles calculations suggested that the ferroelectric behavior originated from trans-type anion arrangement in the films stabilized by compressive stress from the substrates. Possible coexistence of ferroelectricity and visible light absorption in perovskite oxynitrides may lead to higher efficiency of optoelectronic devices using photovoltaic effect of ferroelectric materials such as photosensors and solar cells.
Research Area: “Creation of Innovative Functions of Intelligent Materials on the Basis of Element Strategy”
Research Theme: “Development of Novel Electronic Materials Utilizing Light Elements”
Daichi Oka, Yasushi Hirose, Hideyuki Kamisaka, Tomoteru Fukumura, Kimikazu Sasa, Satoshi Ishii, Hiroyuki Matsuzaki, Yukio Sato, Yuichi Ikuhara, and Tetsuya Hasegawa
“Possible ferroelectricity in perovskite oxynitride SrTaO2N epitaxial thin films”
Scientific Reports, Published online May 16, 2014
Tetsuya Hasegawa, Ph.D.
Professor, Department of Chemistry, School of Science, The University of Tokyo
Green Innovation Group, Department of Innovation Research, JST