The Study Of Doped Zinc Oxide Thin Films And Its Application In Novel Display

With the rapid development of novel display technologies such as high-resolution liquid crystals(LCD),organic light emitting diodes(OLED),quantum dots light emitting diodes(QLED)and electronic paper(E-paper),the technical requirements of these display products for driving backplanes are also higher and higher.Thin film transistors(TFT)are the core components that drive various kinds of display devices and their performance determine the quality of display devices.At present,amorphous silicon TFTs are widely used,but conventional amorphous silicon TFT are difficult to apply to high resolution display and OLED display because of their low mobility and high threshold voltage drift.Although polysilicon TFTs have good mobility and stability,due to the presence of grain boundaries,the uniformity is poor,which limits the application of polysilicon TFTs in high-resolution and large-size displays.The amorphous oxide TFT has good uniformity and mobility at the same time,and high transparency and good stability,which can realize a low-temperature process,and is widely used in novel display products.In addition,in order to develop flexible displays and transparent displays with better performance,flexible transparent conductive electrode that can replace ITO is a key component.This paper studies the oxide TFT with back-channel etching(BCE)structure,firstly.The BCE structure is a low-cost process for mass production oxide TFT because the BCE process is not only simple in structure,but also can realize miniaturized devices.However,since the active layer of oxide TFT is sensitive to the etching solution and the plasma process.When the source/drain(S/D)electrode is prepared,the oxide active layer is easily etched and damaged,resulting in difficulty in preparing high performance.Among many oxide semiconductor materials,tin oxide films have good chemical stability and photoelectric properties.Therefore,this dissertation mainly focuses on the related technology of using tin-doped zinc oxide(ZTO)as a protective layer in the back channel etching process.At the same time,the ZTO material can also be used as the second active layer of the BCE structure TFT to form a dual active layer.In this dissertation,ZTO thin films were prepared by solution method,which can reduce the use of vacuum equipment and the process is simple.It can realize large-scale and low-cost TFT devices.In this paper,the performance of TFT fabricated with solution process ZTO thin films as protective layer can be comparable to vacuum sputtering TFTs with the same structure.Secondly,in order to solve the current problems of high-cost ITO transparent conductive films in the novel display,silver nanowire conductive film was studied.Silver nanowires have good electrical conductivity,high transmittance and good bending performance,but silver nanowires still have many problems,such as poor temperature resistance and easy oxidation,so we use doped Zinc oxide to protect silver nanowires.The doped Zinc oxide protects the silver nanowires,thereby obtaining a transparent conductive film with good performance.A magnesium-doped zinc oxide thin film is prepared by an atomic layer deposition(ALD)method as a protective layer of the silver nanowire,so that the silver nanowire thin film can achieve good temperature resistance and better oxidation resistance,while maintaining good electrical conductivity.