Correlation between Ni Valence and Resistance Modulation on a SmNiO₃ Chemical Transistor

The resistance modulation under various gate voltage (Vg) application conditions was systematically studied for a chemical field effect transistor (FET) composed of a SmNiO3 (SNO) film channel and an ionic liquid gate insulator. The channel resistance of the SNO chemical FET changed nonlinearly over a wide range for different temperatures, Vg magnitudes, and Vg application durations. The correlation between the modulated resistance and the Ni valence state was quantitatively revealed using X-ray photoelectron spectroscopy. A model describing the resistance change with the Vg application conditions was proposed by considering the kinetics of the reduction reaction on the SNO channel. This model enables the resistance to be predicted for given Vg application conditions and selective resistance modulation over a wide range of resistances has been demonstrated.