Effects of the electroforming polarity on bipolar resistive switching characteristics of SrTiO3-δ films

Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
Applied Physics Letters (Impact Factor: 3.52). 10/2010; DOI: 10.1063/1.3488810
Source: IEEE Xplore

ABSTRACT The effects of the electroforming polarity on the bipolar resistive switching characteristics in SrTiO 3-δ thin films have been investigated. The conduction mechanisms of high resistance state and low resistance state are Poole–Frenkel emission and tunneling, respectively. The temperature dependences of the resistance at high and low resistance state are both semiconductorlike. The impact of the polarity of the electroforming voltage on the resistive switching mechanism and the distribution of defects was discussed. A simple model describing the combination of bulk and the interface effect was proposed to explain the resistive switching in this material.

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    ABSTRACT: Ag/0.7 wt% Nb-doped SrTiO3 (Nb:STO)/Ti structure was prepared by sputtering Ag and Ti electrodes on a Nb:STO single crystal substrate and the resistance switching (RS) properties were investigated. Reversible multilevel resistance switching behavior was obtained by applying different voltages. The resistance switching (RS) effect comes from the Schottky barrier existed between Ag and Nb:STO interface. The multilevel switching mechanism may be related to the different number of electrons trapped or detrapped by oxygen vacancies (Vo2+) at the Ag/Nb:STO interface, which can change the width of depletion layer. The temperature dependence on resistance of Ag/Nb:STO/Ti suggests that both high resistance state (HRS) and low resistance state (LRS) are of semiconductor behavior. Substrate annealing in vacuum degrades the RS properties of Ag/Nb:STO/Ti structure due to the increase of Vo2+ in Nb:STO.
    Applied Physics A 109(1). · 1.69 Impact Factor