Presentation Information
[23p-A307-2]Bias voltage induced - electrical conductivity at electrode interfaces of a rutile TiO2 single crystal: two different mechanisms depending on temperature
〇Taku Suzuki1, Yoshiyuki Yamashita1, Isao Sakaguchi1 (1.NIMS)
Keywords:
resistive switching
The electric field-induced conductivity of TiO2 is important in various emerging practical applications using resistive switching and related phenomena. In the present study, the bias voltage-induced electrical characteristics were investigated in between 295 K (ambient temperature) and 600 K for a semi-insulated rutile TiO2 single crystal. The appearance of conductivity by elevating the temperature was shown to be due to the electromigration of mobile dopants including defects. It was found that there are two different mechanisms causing the conductivity depending on the temperature. At low temperature, close to room temperature, hydrogen migrating primarily along the open [001] channel triggers the conductivity. On the other hand at high temperature above 450 K, the migration of oxygen vacancy (Vo) perpendicular to [001] induces the conductivity. It was observed that the Vo injection is not accompanied by the formation of the Magneli phase. The proposed mechanism was examined by spectroscopic techniques such as time-of-flight secondary ion mass spectrometry and hard X-ray photoemission spectroscopy.