Trap-controlled Space-charge-limited current conduction in the cr-doped SrTiO3 thin films deposited by using pulsed laser deposition

Current-voltage (I-V) characteristics of 0.2 % Cr-doped SrTiO3 (Cr-STO) thin film in a metal-insulator-metal (MIM), i.e., Pt/Cr-STO/La0.5Sr0.5CoO3, structure were measured, and the electrical conduction was investigated. The I-V characteristics exhibited hysteretic and asymmetric behaviors. The hysteretic behavior is attributed to bistable resistive switching between a high-resistance state (HRS) and a low-resistance state (LRS) with voltage polarity. The voltages that induced the resistance switching were above +/-3 V. The resistance ratio between the two conduction states was about two orders of magnitude. An analysis of the I-V characteristics revealed that the electrical conduction behavior followed a trap-controlled space-charge-limited current. The trap-filled limit voltage, V-TFL, was -1.6 V.