阴极氧化对逸出功的影响

Influence of Aluminum Cathode Oxidation on Work Function

为了探索阴极的氧化程度对环形He-Ne激光器引燃特性的影响,利用光电减速场法研究阴极材料的逸出功随阴极氧化的变化情况.在高真空条件下,用自制的卢基尔斯基球形光电测试平台和平行电极光电-放电器件,通过实验测出了铝作为放电器件的冷阴极在氧化工艺处理前后的逸出功及逸出功的值随氧化程度的变化情况.实验测得铝阴极在自然氧化后的逸出功为2.60±0.2eV,此时被测铝阴极表面氧的质量百分比为3.2%.经不同时间氧化工艺处理的铝阴极,其逸出功随氧化时间的增长而降低.解释了铝阴极逸出功测量值可能处于2.5～4.3eV之间的原因.由实验结果得到在一定范围内,氧化时间越长,材料的逸出功越小,越有利于环形He-Ne激光器的点燃.但阴极氧化也会影响气体放电过程的着火点压和阴极位降,因此对最佳氧化时间的选择要综合考虑这两方面的因素.

To explore how the degree of cathode oxidation influences the ignites characteristics of ring He-Ne laser,photoelectric retarding potential method is used to investigate the variation of the work function with the cathode oxidation.As the cold cathode of discharge device,aluminum′s work function and the work function variation before and after oxidation are measured under the high vacuum conditions by Лукирский spherical photo electronic measure equipment and parallel electrodes optic-electronic & discharge device.The experimental results show that work function of aluminum cathode in the natural oxidation is 2.60±0.2 eV.The mass percent of oxygen on aluminum cathode surface is 3.2%.At different times of oxidation process,the work function of aluminum cathode decreases with the growth of the oxidation time.The reasons that work function measurements of aluminum cathode may be in 2.5～4.3 eV are explained.The conclusion from the experimental results is the oxidation time is longer,the smaller the work function of the material,the more conducive to the ignition of the ring He-Ne laser within a certain range.Cathode oxidation also affect the ignition voltage and the cathode potential drop of gas discharge process.So the choice of the optimal oxidation time ought to consider these two factors.