Research On Organic-inorganic Composite Dielectric Films And InBO Nanofiber Thin Film Transistors

In recent years,the flat panel displays(FPDs)exhibit the trends towards the high resolution,wide viewing angle,fast response speed and flexible fabrication.Among the serious of FPDs,organic light emitting diode(OLED)is considered as one of the representative FPDs.In FPDs,the thin film transistors(TFT)act as either the switch or the driver unit in the OLED pixel circuit.In this consideration,the TFT performance is of great significance for the evolution of FPDs.Traditional silicon-based TFT has its own disadvantages(such as low mobility of amorphous silicon TFT,high preparation cost and poor uniformity of polycrystalline silicon TFT),which restrict its application in future flat panel display.Compared with the traditional silicon-based materials,metal oxide semiconductors show great advantages for their wide band gap,high carrier concentration,good chemical stability,low preparation temperature and large area preparation.These advantages are expected to be applicable for the next-generation FPDs technologies,and have been the research interest in past decades.In this thesis,high-performance metal oxide TFT was prepared by sol-gel method and electrospinning technology,and the TFT performance dependence on the experimental conditions were investigated.This research is mainly composed of following two parts:1.The organic-inorganic Al₂O₃-PVP composite dielectric film was prepared by sol-gel method.The composite film retains not only the mechanical flexibility of organic polymer,but also exhibits the high dielectric constant of the inorganic oxide.The dielectric properties of the composite film have been analyzed,and the solution-processed oxide TFT was integrated based on the optimal composite film.The electrical performance of the TFT was investigated,the experimental result indicates that the TFT device exhibits acceptable performance for the TFT based on Al₂O₃-PVP composite dielectric film.2.The electrical properties of In₂O₃ nanofibers were modulated accurately by introducing boron(B)as carrier inhibitor.The In BO nanofibers with different B doping concentrations were prepared by electrospinning.The morphology and crystallization properties of the nanofibers were analyzed.The fabricated In BO nanofibers were used to fabricate TFT as channel on the Si O₂ dielectric layer.The experimental results show that when the B doping concentration is 6%,the fabricated device exhibits the optimal electrical performance,the on/off current ratio of 3.1×10⁷,the threshold voltage of 11.6V,the saturation mobility of 2.11 cm² V^-1 s^-1.In order to further improve the device performance,the In BO TFT was fabricated with high-permittivity Zr O_x as gate dielectric layer to replace Si O₂.The performance of the device has been further improved,with the operating voltage of 4 V and the mobility of 3.75 cm²/V s.