Authors: Ngoc Kim Pham Do Trung Nguyen Bang Tam Thi Dao Kieu Hanh Thi Ta Vinh Cao Tran Van Hieu Nguyen Sang Sub Kim Shinya Maenosono Thang Bach Phan
Publish Date: 2014/05/20
Volume: 43, Issue: 7, Pages: 2747-2753
Abstract
We have investigated the switching behavior of asdeposited CrO x and postannealed CrO y films by use of a variety of electrodes top electrode Ag Ti bottom electrode Pt fluorine tin oxide FTO Resistance switching is highly dependent on electrode material and postannealing treatment Among Pt devices I–V hysteresis was observed for the Ag/CrO x /Pt device only no resistance switching was observed for Ag/CrO y /Pt Ti/CrO x /Pt and Ti/CrO y /Pt devices Among FTO devices I–V hysteresis was observed for the Ag/CrO x /FTO device whereas I–V hysteresis with the opposite switching direction was observed for Ag/CrO y /FTO Ti/CrO x /FTO and Ti/CrO y /FTO devices The direction of switching depends not only on electrode material but also on postannealing treatment which affects the density of grain boundaries Thus the density of grain boundaries determines the type of charge carrier involved in the switching process For asdeposited CrO x films with a high density of grain boundaries Ag filament paths mediated by electrochemical redox reaction were observed irrespective of bottom electrode material Pt or FTO Postannealed CrO y films with a low density of grain boundaries suppressed electrochemical redox reaction in the Ag/CrO y /Pt device but promoted shortrange movement of O2− ions through the bottom interface resulting in resistance switching in the Ag/CrO y /FTO device Electrochemical redox reactioncontrolled resistance switching occurred solely in oxides with a high density of grain boundaries or dislocations
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