Nano-diamond Composite Coatings Field Emission Critical Study

Field emission display (FED), bearing almost both advantages of cathode ray tube (CRT) display and flat-panel display (FPD) on the current market, is widely regarded one of the most promising display technology and is expected to become the mainstream of the next generation display device. Nano-diamond film material has excellent physical and chemical properties, so the application of it in FED is an exploitation direction of field emission cathode. Nano-diamond composite film material has more superior field emission characteristic compared with nano-diamond film material, so it becomes a focus of present field emission studies.The technology of after-treatment and driving circuit of Nano-diamond composite coating material field emission cathode were studied. The after-treatment technologies include the technology of substrate pretreatment, diamond powder dispersion, electrophoretic deposition, heat treatment, hydrogen plasma treatment and so on. A set of intact preparation technology, with uniform and stable coating, suiting for large area deposition, was obtained.In the preparation process of nano-diamond composite coating field emission cathode, the influence of technological parameter on field emission turn-on field and current density of cathode sample was studied by orthogonal experiment. Combining with the micro-analysis of surface appearance of composite coating cathode sample and the luminescence effect of the cathode in analog display, the optimal technological parameter of cathode preparation was screened out.Respectively, the nano-diamond was doped with nano-Ti powder, nano-Hf powder, nano-ZnO, carbon nano-tube etc, and field emission characteristic of nano-diamond composite material was studied.The influence of after-treatment technology (such as hydrogen plasma treatment, gummed tape treatment, and metallographic abrasive paper, etc) on cathode field emission characteristic was studied. The technological parameter of hydrogen-treating was optimized.With the help of X-Ray Diffraction (XRD), Raman, metalloscope, scanning electron microscope (SEM), atomic force microscope (AFM), etc, the constituents, structure, and surface appearance of the nano-diamond composite material cathode sample were analyzed and characterized. Combining with the field emission characteristic curve of the sample, the internal reasons between the preparation process conditions and the field emission characteristic were analyzed, which provides the theoretical and experimental basis for the improvement of field emission characteristic of nano-diamond composite coating.The influence of vacuum on the field emission characteristic of nano-diamond cathode and temperature dependence of field emission of nano-diamonds were studied, and the mechanism of nano-diamond field emission in high temperature was discussed, which offered the experimental foundation for the industrialization of nano-diamond composite material FED.Working principle and addressing mode of driving system of nano-diamond composite coating FED were analyzed, and the 16×16 lattice driving circuit of the nano-diamond FED was designed. Logic controlling function of the designed driving circuit was tested and verified by LED screen.