Preparation And Performance Study Of Indium Oxide Nanofiber Thin Film Transistor

At present,with the rapid development of the flat panel display industry,the demand for display performance is increasing.In order to realize technologies such as ultra large screen,ultra-high definition,transparency and flexible display,the inherent defects of traditional silicon-based thin film transistors（TFTs）based on field effect transistors（FETs）have become shackles that hinder the development of the industry.As the core device of flat panel display,TFTs need to develop towards high performance,full transparency and full flexibility.In this study,through systematic research on indium oxide（In₂O₃）nanofibers and hafnium oxide（HfO₂）high-k film materials,HfO₂/In₂O₃ nanofibers TFTs suitable for high-end flat panel displays were prepared and integrated.The main research contents include:Firstly,In₂O₃ thin films were prepared by sol gel technique,and then In₂O₃ nanofibers were prepared by self-assembly electrospinning technique.The TFTs with double In₂O₃channels were prepared and annealed at different temperatures.The results showed that the TFT annealed at 250℃exhibits high performance by using the technology of sol gel and the welding process.Includes:ON/OFF current ratio of 2.0×10⁸,subthreshold swing of 0.43 V/dec,and carrier mobility of 0.18 cm²/Vs.Secondly,In₂O₃ nanofibers with different morphologies（solid and hollow）were prepared by electrospinning and Kirkendall effect with different heating rates during annealing,and In₂O₃ nanofiber TFTs were further integrated.The results show that In₂O₃ nanofibers show hollow structure at heating rate less than 2 ℃/min;When the heating rate is greater than 2℃/min,In₂O₃ nanofibers exhibit the most common solid nanofiber structure.By analyzing the electrical performance of In₂O₃ nanofiber TFTs,it is found that the hollow In₂O₃ nanofibers TFT annealed with the heating rate of 2 ℃/min exhibits the best comprehensive performance,including the best switching characteristics,field-effect mobility and good stability.Finally,HfO₂ high-k dielectric films with small leakage current and large areal capacitance were prepared by polymer assisted deposition technology.The effects of annealing temperature on the properties of HfO₂ thin films were studied by the investigations of X-ray diffraction,thermogravimetric analysis,optical transmittance,C-F,I-V and other measurement techniques.The TFTs based on HfO₂/In₂O₃ nanofibers were prepared by using HfO₂ film annealed at 500 ℃ as the dielectric layer and In₂O₃ nanofibers annealed at 280 ℃ as the channel layer.The results show that the TFT device shows excellent electrical performance,including saturation field-effect mobility of 18.3 cm²/Vs,subthreshold swing of78 mV/dec,on voltage of 0.51 V,and ON/OFF current switching ratio of 3.4×10⁷.The device can be used as a switch or drive for OLED,which provides a research direction and experimental basis for the preparation of high-performance TFTs devices.