Fabrication And Characterization Of Thin Film Transistors Based On Inorganic Nanostructure Composites

TFTs are undergoing tremendous growth with the ever increasing demand for a wide variety of electronic information display, and are also expanding to other emerging areas of transparent electronic devices, such as flexible electronics, wearable display, disposable electronics, electronic-paper, and artificial skin. The implementation of high performance macroelectronics including solar cells, photodetectors, digital X-ray imagers, radio-frequency identification tags. Due to the unique requirement of high electronic performance, high mechanical flexibility, large area deposition at low temperature, and low cost, the traditional materials are often difficult to simultaneously satisfy these multiple competing requirements. In the past decade, diverse nanostructured materials have tremendous progress in the TFTs technologies, such as quantum dots, nanowires, nanotubes, two-dimensional materials, or the various types of composites of such nanostructures. These above rapid growth of the novel nanostructures or composite thin films will play an increasingly important role in future thin film electronics, not only to address the critical challenges we are facing today in large area electronics, but also to enable in electronics-moving electronics on plastic substrates. Together, it will impact a broad range of areas of existing applications and enable a whole new range of electronic systems for computing, communication, storage, and display. It can also open up brand new opportunities beyond traditional electronics.Based on the above research background and significance, this paper focus on thin film electronics based on inorganic nanostructures and composites of amorphous metal oxide semiconductor and two-dimensional graphene as the research object, mainly to develop the composited nanostructures of high-performance TFTs, the main research work as follows:1. The preparation technology was study for each layer structure of TFTs. The conductive layer was prepared by a sol-gel process. The contact electrodes were obtained by the process of lithography and thermal evaporation. These experimental parameters provide a reliable guarantee for the thin film devices.2. The high performance TFTs with an amorphous IZO films were deposited by embedding In2O3 NCs into IZO films based on a sol-gel process. Excellent electrical properties have been demonstrated, including a field-effect mobility of 32.6 cm2V-1s-1, an on-off ratio of 107, which were obtained at 1 mol% In2O3 NCs in the amorphous IZO film. As the thickness of the dielectric insulator decreased, the operation voltage and the sub-threshold swing significantly decreased when the approximate mobilities of TFTs was obtained. The high performance n-IZO/p-GaN heterostructure can be prepared. Our findings demonstrate the feasibility of low temperature sol-gel-based oxide semiconductor transistors, which is more cost effective compared to conventional high-temperature vapor-phase fabrication techniques but with comparable performance, and provides a new pathway to high performance flexible electronics.3. High performance TFTs with amorphous IGZO and IZO films were deposited by doping alkali metal into IZO films, and earth metal into IGZO films, which were based on a sol-gel process. With 0.1 mol% Mg, the field-effect mobility of 16.7 cm2V-1s-1 and the sub-threshold swing of 0.16 V/dec were obtained. With appropriate concentration of alkali metal, both the field effect mobility of 22.7 cm2V-1s-1 and operational reliability were improved. These experiments show that earth metal and alkali metal by a sol-gel method under low temperature and atmospheric environment can also obtain good electrical properties of the IGZO and IZO TFTs, and can offering the low temperature processibility for the amorphous IGZO and IZO film electronics.4. The high-k BiFeO3 film can be used as the gate dielectric layer of the field-effect transistor. La3+ was doped in the BiFeO3 film by the sol-gel and hydrothermal process. La3+ was provided the good ferroelectricity. Salicylic acid as complexing agent was locked Bi3+ and Fe3+ on the hydroxyl of two similar functional groups. High energy urea was promoted Bi3+ and Fe3+ fast forming BiFeO3 at low temperature. BiFeO3 film has the certain ferroelectricity and ferromagneticity at room temperature.5.1 nm thickness of the metal particles deposited in graphene transistors modulated Dirac point, such as Au, Ag, Fe, Y, and Zn, respectively. Dirac point is shifted to the negative by Au and Ag particles. Dirac point is shifted to the positive by Fe and Y particles. Dirac point has a shifted tendency by Zn particles. In the entire process, the electrical properties of the graphene transistors were decreased by the metal particles. Top-gate transistor with Fe particles modified Dirac point to the zero point. These results demonstrate the different metal have effect on the properties of graphene transistors.