Study Of Indium Tungsten Oxide-based Low Voltage Electric-Double-Layer Thin-Film Transistors

As one of the basic components of integrated circuits,thin film transistors?TFTs?are widely used in flat-panel displays,smart sensors,inverters and other fields.Amorphous thin film transistors,especially a-IGZO TFTs,have attracted more attention due to their low voltage,high mobility,high on/off ratio,large area uniformity,low preparation temperature and low cost.However,a-IGZO contains acid-soluble Ga₂O₃ and ZnO,which are easily affected by wet etching.It leads to poor performance and stability when wet etching the electrodes.Therefore,it is necessary to find Ga/Zn-free amorphous semiconductor material.Indium Tungsten Oxide?IWO?is insoluble in common acids and has been used in solar cells,organic light-emitting devices,and TFTs.In addition,with the rapid development of portable electronic devices,TFTs devices and related circuits are generally required to have simple design and low power consumption.So some researchers have proposed an Electric-Double-Layer Transistors?EDLTs?,whose gate dielectric are electrolyte materials that can form electric-double-layer under external electric field.EDLTs have the advantages of high capacitance,low operating voltage,and high mobility.Current research about EDLTs are focus on materials,device structures,and device performance.There have few studies about the applications of EDLTs in circuits.This paper mainly studies the amorphous IWO-based Electric-Double-Layer TFTs and its application in the simple Schmitt triggers circuits.The main contents and results include:1.IWO-based electric double layer transistor based on nanogranular SiO₂ solid gate dielectric and flexible IWO-based TFTs based on chitosan gate dielectric are prepared by vacuum technique such as PECVD or RF-MS.2.The IWO-based EDL TFTs have bottom-gate structure and dual in-plane-gate structure.The bottom-gate IWO-based TFTs has good performance,the operating voltage is lower than 2V,the threshold voltage is about 0.17V,and the current on/off ratio,field-effect mobility,and subthreshold swing are 3.6*10⁷,5.9 cm²V^-1s^-1 and 107mV/decade respectively.The Schmitt triggers based on bottom-gate IWO-TFTs could operate at low voltages?<3V?and consume less power.The transient response curve of the simple Schmitt trigger to the triangular wave signal is given.Schmitt trigger with adjustable hysteresis window based on one in-plane gate IWO-based homo junction TFT was reported for the first time.3.The flexible IWO-TFTs based on chitosan gate dielectric have good performance and the threshold voltage is 0.30V.The current on/off ratio,field-effect mobility,and subthreshold swing of the IWO-TFTs are 1.92*10⁷,3.1 cm²V^-1s^-1 and 75.2mV/decade,respectively.Schmitt triggers based on flexible IWO-TFTs can also operate at low voltages with low power consumption.In summary,both IWO-EDL TFTs have good performance and can build simple Schmitt trigger circuit.This paper provides a new idea for the application of EDLTs.The simple Schmitt trigger circuits based on such devices have potential applications in noise filtering,smart sensors and neuromorphic computing.