Low-voltage transparent SnO2nanowire transistors gated by microporous SiO2 solid-electrolyte with improved polarization response

Abstract

Low-voltage transparent SnO₂ nanowire transistors gated by microporous SiO₂ solid-electrolyte are fabricated using a nickel grid as a shadow mask. The operating voltage is found to be as low as 1.5 V due to the large gate capacitance (∼2 μF cm⁻²) related to the mobile ions-induced electric-double layer (EDL) effect. The polarization mechanism of microporous SiO₂ solid electrolytes is studied and three polarizations (EDL formation, ionic migration, and dipole relaxation) at different frequencies are identified. The polarization response is optimized and the improved specific capacitance is 1 μF cm⁻² at 1 kHz. The field-effect mobility, current on/off ratio and subthreshold swing are estimated to be 175 cm² V⁻¹ s⁻¹, 10⁵, and 116 mV/decade, respectively. The static and dynamic bias stress measurements indicate that transparent SnO₂ nanowire FETs can operate at low-voltage with highly reproducibility. Such high-performance, low-voltage SnO₂ nanowire transistors hold promise for novel device applications, such as portable ion-sensitive sensors.