Investigation On Growth And Characterization Techniques Of CNTs With Strong Adhension Ant Its Field Emission Application

Carbon nanotubes are considered to be very promising field emitters due to their high aspect ratio,mechanical strength,and chemical inertness.In this work,the carbon nanotubes were grown directly on the 304 stainless steel(SS)substrate,which was anodized in acid solution before carbon nanotube growth.The microstructure,adhesion,field emission properties of the carbon nanotubes were investigated systematically,and its application in ionization vacuum gauge was also studied in detailed.The morphology,adhesion and the field emission properties of MWNTs were investigated for four different synthesis processes.The MWNTs grown on the SS substrate directly after the acid treatment showed excellent adhesion and field emission stability performance than the one grown on the silicon substrate or SS substrate with catalyst particles.The MWNTs film grown on the metal directly could contribute to the longer working life and better working stability,especially in the vacuum electronic devices applications which need large field emission current generally.The vacuum measurement applications were investigated from the MWNTs grown directly on catalytic stainless steel substrates.The MWNTs-based ionization gauge was able to work down to the extreme-high vacuum(XHV)range with good linear measurement performance in wide range from 10-11 to 10-6 Torr.A modulating grid was attempted with improved gauge sensitivity.The extension of the lower pressure limit was attributed largely to low outgassing effect due to direct growth of MWNTs and justified design of the electron source.