Analysis of Ti valence states in resistive switching regions of a rutile TiO2−x four-terminal memristive device. (20th April 2018)

• Record Type: Journal Article
• Authors: Yamaguchi, Kengo; Takeuchi, Shotaro; Tohei, Tetsuya; Ikarashi, Nobuyuki; Sakai, Akira
• Is Part Of: Japanese journal of applied physics. Volume 57:Number 6(2018)Supplement 3
• Publication Date: 2018-04-20
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.57.06KB02
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: We have performed Ti valence state analysis of our four-terminal rutile TiO2− x single-crystal memristors using scanning transmission electron microscopy–electron energy loss spectroscopy (STEM–EELS). Analysis of Ti-L2, 3 edge EELS spectra revealed that the electrocolored region formed by the application of voltage includes a valence state reflecting highly reduced TiO2− x due to the accumulation of oxygen vacancies. Such a valence state mainly exists within ∼50 nm from the crystal surface and extends along specific crystal directions. These electrically reduced surface layers are considered to directly contribute to the resistive switching (RS) in the four-terminal device. The present results add new insights into the microscopic mechanisms of the RS phenomena and should contribute to further development and improvements of TiO2− x based memristive devices.