ACS Applied Materials & Interfaces · 2017 · 37 citations · 39 references
We investigate the effect of electric field on VO<sub>2</sub> back-gated field effect transistor (FET) devices. Using hybrid dielectric layers, we demonstrate the highest resistance modulation on the order of 10<sup>2</sup> in VO<sub>2</sub> at a positive gate bias of 80 V (1.6 MV/cm). VO<sub>2</sub> FET devices are prepared on SiO<sub>2</sub> substrates of different thicknesses (100-300 nm) and hybrid dielectric layers of Al<sub>2</sub>O<sub>3</sub>/SiO<sub>2</sub> (500 nm). For thicknesses less than 300 nm, no electric-field effects are observed, whereas for a 300 nm thickness, a small decrease in resistance is observed under a 0.2 MV/cm electric field. Under the electrostatic effect, the carrier concentration increases in VO<sub>2</sub> devices, decreasing the resistance and the transition temperature from 66.75 to 64 °C. The leakage analysis shows that the interface quality of VO<sub>2</sub> films on hybrid dielectric layers can be further improved. These studies suggest a multilevel fast resistance switching with the electric field and give an insight into the gate-source leakage current, which limits the phase transition in VO<sub>2</sub> in an electric field.
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