Fabrication And Properties Of Diamond/ Carbon Nanosheets Compound Field Emission Cathodes

Diamond thin films have a variety of excellent properties such as high thermal conductivity,high breakdown voltage,radiation resistance,low coefficient of thermal expansion,and chemical stability,which have been considered one of the important candidates in next-generation semiconductor devices.Diamond film has a negative electron affinity,in the diamond,the bottom of the conduction band electron energy level is higher than the vacuum level,has a stable physical and chemical properties,high electron mobility,is a kind of excellent field emission material.Carbon nanosheets is a kind of two-dimensional nano carbon materials with excellent electrical conductivity and thermal conductivity,good stability,large length to diameter ratio,high specific surface area,rich edge,so it has very good field emission performance.And combined with the carbon nanosheets with high mechanical strength,good toughness and outstanding mechanical properties,make it become the ideal add phase of composite materials,the compound together with diamond,not only can use diamond dielectric properties to enhance the stability of field emission device,but also can use that may exist between diamond and carbon nanosheets internal field emission effect to improve the performance of the composite film field emission devices,plus diamond has good thermal conductivity,also is advantageous to the heat dissipation of the device.So if we can combine the advantages of the diamond and carbon nanosheets will improve carbon nanosheets field emission performance,also can be prepared with more superior performance of composite materials.Research of this paper is mainly using microwave plasma chemical vapor deposition?MPCVD?method for the preparation of diamond,diamond carbon nanosheets,carbon nanosheets,through the optimization of process parameters,the implementation of carbon nanosheets field emission performance.Experiments,we use optical microscope?OM?,field emission scanning electron microscope?FE-SEM?,X-ray diffraction?XRD?,Raman spectroscopy?Raman?of the testing methods such as membrane layer of sample surface morphology and composition of the various kinds of test and analysis,the final our laboratory use of CS-380 high vacuum test bed under the high vacuum degree of 1 x 10^-4 Pa and the field emission properties were tested and analyzed.Finally found that the diamond/carbon entry field emission cathode,has higher field emission current density than single carbon nanosheets?double the biggest field emission cathode current density increased by more than 3 times?;Field emission cathode is better than single layer and double diamond has better field emission characteristics and lower open electric field,after adding the buffer layer and catalyst layer,the morphology of carbon nanosheets has become more prominent and field emission performance is improved.In this paper,the research results show that the diamond/carbon nanosheets composite thin film field emission cathode is a potential efficient field emission cathode.