Self-assembled dual in-plane gate thin-film transistors gated by nanogranular SiO2proton conductors for logic applications

Abstract

Phosphorus (P)-doped nanogranular SiO₂ films are deposited by plasma-enhanced chemical vapor deposition at room temperature, and a high proton conductivity of ∼5.6 × 10⁻⁴ S cm⁻¹ is measured at room temperature with a relative humidity of 70%. The accumulation of protons at the SiO₂/indium-zinc-oxide (IZO) interface induces a large electric-double-layer (EDL) capacitance. Thin-film transistors (TFTs) with two in-plane gates are self-assembled on transparent conducting glass substrates. The large EDL capacitance can effectively modulate the IZO channel with a current ON/OFF ratio of >10⁷. Such TFTs calculate dual input signals at the gate level coupled with a floating gate, analogous to that of neuron MOS (vMOS). AND logic is demonstrated on the neuron TFTs. Such neuron TFTs gated by P-doped nanogranular SiO₂ shows an effective electrostatic modulation on conductivities of oxide semiconductors, which is meaningful for portable chemical-biological sensing applications.