Symmetrical negative differential resistance behavior of a resistive switching device.

Du, Yuanmin; Pan, Hui; Wang, Shijie; Wu, Tom; Feng, Yuan Ping; Pan, Jisheng; Wee, Andrew Thye Shen · ACS Nano · 2012

basic_science · Level V

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Abstract

With a thin insulator sandwiched between two electrodes, the negative differential resistance (NDR) behavior has been frequently reported for its potential device applications. Here we report the experimental observation of a symmetric NDR characteristic in a resistive switching device based on TiO(2). We propose a charge storage mechanism for the NDR effect, with oxygen molecular ions working as the active source, in a thin insulating layer. Current-voltage measurements demonstrated a highly reproducible state at about 0.65 eV, and the photoelectron spectroscopy measurements showed that it complies well with the Ti3d band gap state. Our first-principle calculations confirm that charge storage and release arise from trapping and detrapping of oxygen molecular ions at the defect sites. The results and mechanism demonstrated here in a thin layer could be extended to other systems approaching molecular dimensions for device applications.