Dual in-plane-gate coupled IZO thin film transistor based on capacitive coupling effect in KH550-GO solid electrolyte

Abstract

Low-voltage electric-double-layer oxide-based thin-film transistors are of great prospect and investigative value in the fields of micro multi-state memory devices, detectors, electrochemical sensors, and biological synapses simulation, and so on. In addition, low-voltage electric-double-layer oxide-based thin-film transistors have increasingly attracted attention among researchers due to the characteristics of high mobility, high visible light transmittance and low temperature preparation. Currently, the researches about low-voltage electric-double-layer oxide-based thin-film transistors are broadly divided into two aspects. On the one hand, the researches focus on ZnO as a channel layer, source and drain electrode materials, then gradually develop into In, Sn and Ga oxides as well as complex oxides containing these elements, which has made tremendous progress. On the other hand, the development and research of the gate dielectric materials have received more attention. It is found that by adopting an organic/inorganic proton conductor film as the gate dielectric of low-voltage electric-double-layer oxide-based thin-film transistors, the protons in the gate dielectric will move in the direction away from gate, and finally accumulate on the surface of gate dielectric layer close to the channel layer, with the positive bias applied to the gate. In conclusion, though the researches about low-voltage electricdouble- layer oxide-based thin-film transistors have already made great progress, further explorations and investigations are necessary from its wide applications. Consequently, the development of new material architecture of low-voltage electric-double-layer oxide-based thin-film transistor is one way to achieve this goal. Silane coupling agents (3-triethoxysilylpropyla-mine)-graphene oxide (KH550-GO) solid electrolyte is prepared on plastic substrate by spin coating process. The electrical performances of dual in-plane-gate coupled protonic/electronic hybrid IZO thin film transistor gated by KH550-GO solid electrolyte are further studied. The results indicate that the electric-double-layer capacitance and proton conductivity of KH550-GO solid electrolyte respectively achieve 2.03 F/cm2 and 6.9910-3 S/cm, respectively. Due to high electric-double-layer capacitance and proton conductivity, protonic/electronic hybrid IZO thin film transistor gated by KH550-GO solid electrolyte has lower power consumption (its operation voltage ~2 V). Current on/off ratio of 1.23107 and field-effect mobility of 24.72 cm2/(Vs) are shown in the device. Due to the capacitive coupling effect of KH550-GO solid electrolyte, the device with the stimulus of dual in-plane-gate voltage, can effectively modulate the threshold voltage, the subthreshold swing and the field-effect mobility, and demonstrate AND logic operation successfully. Dual in-plane-gate coupled protonic/electronic hybrid IZO thin film transistors prepared in this paper have potential applications in the field of biosensors and artificial synapses.