One-Volt Oxide Thin-Film Transistors on Paper Substrates Gated by -Based Solid Electrolyte With Controllable Operation Modes

摘要

Microporous $hbox{SiO}_{2}$ can provide large electric-double-layer (EDL) capacitance and negligible leakage current, owing to lack of electron carrier and limited mobility of mobile ions. The impedance spectroscopy (ionic-conductivity–frequency and capacitance–voltage characteristics) and Fourier-transformed infrared spectroscopy of microporous $hbox{SiO}_{2}$ are characterized, which demonstrated that such dielectric is actually a solid-electrolyte dielectric. $hbox{InGaZnO}_{4}$ thin-film transistors (TFTs) on paper substrates gated by microporous- $hbox{SiO}_{2}$ solid electrolyte are fabricated at room temperature. The large EDL-specific capacitance (1.36 $muhbox{F}!/breakhbox{cm}^{2}$) results in the paper TFTs operate at a battery-drivable low voltage of 1.0 V. Both depletion-mode $(V_{rm th} = -hbox{0.45} hbox{V})$ and enhancement-mode $(V_{rm th} = hbox{0.25} hbox{V})$ operations are realized by rationally controlling the oxygen concentration in argon ambient during $hbox{InGaZnO}_{4}$ channel deposition. Electrical characteristics with an equivalent field-effect mobility of $sim!!hbox{21} hbox{cm}^{2}/hbox{V}cdothbox{s}$, a current on/off ratio of greater than $ hbox{10}^{5}$, and a subthreshold swing of $sim$ 80 mV/dec are demonstrated at low frequencies, which are promising for portable paper electronics.