Effects of humidity on performance of electric-double-layer oxide-based thin-film transistors gated by nanogranular SiO2 solid electrolyte

Electric-double-layer oxide-based thin-film transistors gated by nanogranular SiO2 solid electrolyte have been fabricated at room temperature. The effects of humidity on performances are investigated. At the relative humidity of 65 %, the measured capacitance is 10 μF/cm2, and the device shows Ion/off ratio of 8.93 × 107, field-effect mobility of 5.9 cm2/Vs. As relative humidity declines, the measured capacitance decreases, which gives rise to the degradation in performance. Especially, at the relative humidity of 0 %, the capacitance of 0.01 μF/cm2 is measured, so the device cannot be turned off. The reason may be that humidity can promote H2O molecules to permeate into solid electrolyte, which can cause charges accumulation.