The forming-free bipolar resistive switching characteristics of Ag₂Se thin film

The resistive switching (RS) characteristics of silver selenide (Ag₂Se) thin film prepared by thermal evaporation are studied. The capacitor structures of 10 × 10 μm² are prepared using Au and Ag pads as top electrodes on the Ag₂Se thin film. The current-voltage (I-V) curves of the Au pad/Ag₂Se/Au structure and Ag pad/Ag₂Se/Au structure are observed. The Ag₂Se thin film shows the RS behavior by the formation and rupture of Ag filaments without the forming process in both Au and Ag pads. The high resistance state (HRS) current measured with the Ag pad is lower than that with the Au pad owing to the atomic rearrangement at the Ag pad/Ag₂Se interface region, showing a better low resistance state (LRS) current to HRS current ratio. In order to further understand the conduction mechanism in Ag₂Se, the temperature dependent characteristics are measured in the temperature range of 300-410 K. It can be seen that the HRS current level increases with temperature in both Au and Ag pads, indicating that the conductivity increases with temperature. From capacitance-voltage (C-V) measurements and transmission electron microscopy (TEM) image, the creation and annihilation of Ag filaments is confirmed.