Preparation And Field-emission Study Of Carbon Nanomaterials And Their Composite Thin Films

Field emission display?FED?is a most promising flat panel displays to present excellent image and overall quality.Attention has always been paid on the cathodes during the research of the field emission devices?FEDs?.Carbon nanomaterials and their composite thin films have also been regarded as potential materials for the cathodes of FEDs.This work mainly focuses on the preparation and field-emission study of carbon nanomaterials and their composite thin films from the following two aspects:?1?Field-emission study of carbon nanowalls?CNWs?CNWs with field emission properties have been prepared by hot filament chemical vapor deposition?HFCVD?.Samples were prepared on the Mo substrate under various gas flows of methane and hydrogen.Field emission tests were also applied on the samples.Combined with the characterization results,the different field emission properties of the samples were given,making a reference for the future study of CNWs.?2?Outstanding field emission properties of TiO₂/CNTs on 3D nickel foamOutstanding field emission properties are achieved for titanium dioxide?TiO₂?coated screen-printed carbon nanotubes?CNTs?on a three-dimension?3D?nickel foam?Ni-F?substrate,namely TiO₂/CNTs@Ni-F cathode.Based on a comparison study and a proposed model,reasons for the significantly enhanced field emission properties are disclosed.The enhanced edge effect,simultaneously with the reduced field screening effect,arisen by TiO₂/CNTs micro films and multistage structure of the 3D Ni-F substrate mainly contributes to the lowered operation fields.In addition,the 3D metal substrate provides good adhesion for the TiO₂/CNTs cathode together with the excellent chemical stability of the TiO₂ modifier contributing to the remarkable electrical stability.The high-performance of the TiO₂/CNTs@Ni-F cathode demonstrates potential applications in vacuum electronic devices.