基于单体石墨纤维的场发射特性研究

Field Emission Characteristics Based on Monomer Graphite Fiber

利用化学气相沉积(CVD)法,以甲烷为碳源在管式炉中合成了单体石墨纤维(MGF)。选取长度为3.426 mm,顶端球面半径为11.26μm的单体石墨纤维直立于圆铜片上作为阴极,以导电ITO玻璃作为阳极,采用二极管结构在真空室中进行直流场发射测试,证实MGF的开启场强为0.4775 V/μm。基于有限元仿真软件ANSYS进行电磁场分析,计算了MGF在不同电压下的有效发射面积。结果表明,当电压为5.36 kV时,MGF达到最大发射面积为796.226μm^(2),在实验测量电压范围内,平均发射电流密度可以达到46.069 A/cm^(2),单体石墨纤维具有良好的场发射特性。

Field emission cold cathode electron source has a wide range of application prospects in many vacuum electronic devices.Carbon materials suitable for cold cathode materials include carbon nanotubes,carbon microtubes and carbon fibers.Field emission characteristics based on single graphite fiber were studied.Single graphite fiber(MGF)was synthesized by chemical vapor deposition(CVD)in a tubular furnace with methane as carbon source.The DC field emission test was carried out in a vacuum chamber by building a diode structure.A single graphite fiber with a length of 3.426 mm and a spherical radius of 11.26μm was selected and fixed on the copper plate as the cathode,and a conductive ITO glass was used as the anode.The opening field strength of MGF is confirmed to be 0.4775 V/μm.Furthermore,the electromagnetic field was analyzed based on the simulation software of ANSYS.The effective emission area of MGF under different voltages was calculated.The results show that when the voltage is 5.36 kV,the maximum emission area of MGF is 796.226μm^(2) and the average emission current density can reach 46.069 A/cm^(2) in the experimental voltage range.The monomer graphite fiber has good field emission characteristics.