Bipolar resistive switching behaviors in Cr-doped ZnO films

•The controllable switching properties of Zn1−xCrxO-based devices are observed.•Devices exhibit uniform RS performances and good retention characteristics.•Bipolar switching behavior is demonstrated by conductive atomic force microscopy.

Highly c-axis oriented sol–gel Zn1−xCrxO (x = 1%, 2%, 3%, and 5%) thin films were deposited on Pt/Ti/SiO2/Si substrates. The effect of Cr content on resistive switching behavior was investigated. It was found that the ratio of the high-resistance state (HRS) to the low-resistance state (LRS) was improved from ∼17 to ∼7 × 103 with increasing Cr content from 1% to 5%. In addition, resistive switching (RS) memory devices with Pt/Zn1−xCrxO/Pt structures exhibit uniform RS performances, good retention characteristics (>10 h at room temperature (RT)), stable and reversible bipolar resistive switching phenomena without forming process. Conductive atomic force microscopy (C-AFM) results suggest that bipolar resistive switching behavior is observed in the polycrystalline Cr-doped ZnO thin films.

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