Control of Multilevel Resistance in Vanadium Dioxide by Electric Field Using Hybrid Dielectrics

We investigate the effect of electric field on VO2 back-gated field effect transistor (FET) devices. Using hybrid dielectric layers, we demonstrate the highest resistance modulation on the order of 102 in VO2 at a positive gate bias of 80 V (1.6 MV/cm). VO2 FET devices are prepared on SiO2 substrates of different thicknesses (100-300 nm) and hybrid dielectric layers of Al2O3/SiO2 (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 VO2 devices, decreasing the resistance and the transition temperature from 66.75 to 64 degrees C. The leakage analysis shows that the interface quality of VO2 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 VO2 in an electric field.