Design,Preparation And Performance Research Of Reflective Field Emission Electron Source Based On One-dimensional Nanostructure

Field emission is a phenomenon in which the height of the material surface barrier is reduced and the width is narrowed by the action of an external electric field,and electrons pass through or over the surface barrier through the quantum mechanics tunnel effect and are shot into the vacuum.Vacuum electron emission sources composed of cold cathodes are widely used in the fields of electronic energy spectroscopy,material analysis,and light-emitting devices.In this paper,ZnO/Pt,ZnO/TiN and ZnO/ZrN core-shell structures are prepared on ZnO nanorod arrays by hydrothermal technology combined with sputtering process,field emission characteristics are studied,and a new type of T-ZnO/TiN reflective field emission is trial-produced Light source device,the main research work is as follows:(1)Using low-temperature hydrothermal combined with vacuum sputtering process,ZnO nanorod arrays(ZnO/Pt)modified with Pt nanoparticles of different thicknesses were prepared on thin zinc substrates.The field emission results show that when the Pt layer thickness is 15nanometers(ZnO/Pt15)nanorod array cathode has excellent field emission performance,the turn-on electric field is about 1.45 V/?m,the field enhancement factor is about 5405,and the maximum current density is 19.09 m A/cm².The excellent field emission performance of the ZnO/Pt array is mainly due to the synergistic effect of the morphology of the oriented growth of the emitter,the oxygen vacancy and the optimized emission point density.(2)Taking advantage of the large aspect ratio of ZnO nanoneedles,the low work function of TiN,and the advantages of high electrical and thermal conductivity,this paper uses hydrothermal method combined with low-energy magnetron sputtering process to prepare ZnO/TiN nanoneedle arrays on a flexible carbon cloth substrate.The microstructure characterization showed that the deposited TiN nanorods in the shell layer had a polycrystalline structure and were neatly epitaxial on the surface of the ZnO core layer.The threshold electric field of the ZnO/TiN nanoneedle array cathode is about 0.72 V/?m,the field enhancement factor is as high as 14752,and the maximum field emission current density is close to 20 times that of pure ZnO.The stability test results show that when the operating voltage is maintained at810 V and the launch time is 5000 s,no significant drop in current is seen.(3)The ZnO/ZrN core-shell nanoneedle array was synthesized.The effects of different N₂/Ar flow ratios on the microstructure and field emission performance of ZnO/ZrN core-shell cathodes were studied.The results show that when the N₂ flow rate is 1.6 SCCM,the surface composition of the ZrN shell is mainly composed of ZrN,ZrN_xO_yand Zr O₂.The field emission test shows that the ZnO/ZrN composite cathode exhibits the best emission characteristics.The threshold electric field is about 1.17 V/?m,the field enhancement factor is about 9578,and the maximum field emission current density is 25.45 m A/cm².This kind of ZnO/ZrN core-shell cathode,which is grown on a carbon cloth substrate and has excellent emission characteristics and is neatly arranged,has potential application prospects in future flexible light source devices.(4)Preparation and field emission performance research of a new type of reflective field T-ZnO/TiN field emission prototype device.This paper uses ANSYS finite element software to simulate the electric field distribution and electron trajectory of the reflective electron source,and optimize the device structure parameters.The semi-circular reflective anode was prepared by mechanical micro-machining technology;the T-ZnO/TiN composite cathode was prepared on the surface of the nickel wire with nano-silver as the binder,high-temperature oxidation and sputtering technology.The research results show that when the diameter of the reflective anode is 1500,2000 and 3000?m,the corresponding threshold electric field is 2.10,2.16 and 2.61V/?m,respectively.The current densities of the assembled light source devices are 132.73,51.73,and 47.89 m A/cm²,respectively,while the field emission current density of the traditional planar diode structure is only 28.56 m A/cm² under the same parameters.These results show that the new reflective field emission electron source proposed in this paper has excellent electron emission and luminescence properties.