Dual-gate low-voltage transparent electric-double-layer thin-film transistors with a top gate for threshold voltage modulation

Abstract

Dual gate (DG) low-voltage transparent electric-double-layer (EDL) thin-film transistors (TFTs) with microporous-SiO₂ for both top and bottom dielectrics have been fabricated, both dielectrics were deposited by plasma-enhanced chemical vapor deposition (PECVD) at room temperature. The threshold voltage of such devices can be modulated from −0.13 to 0.5 V by the top gate (TG), which switches the device from depletion-mode to enhancement-mode. High performance with a current on/off ratio (∼2.1 × 10⁶), subthreshold swing (76 mV per decade), operating voltage (1.0 V), and field-effect mobility (∼2.6 cm² V⁻¹ s⁻¹) are obtained. Such DG TFTs are promising for ion-sensitive field-effect transistors sensor applications with low-power consumptions.