氮气介质阻挡微放电中活性物种的诊断研究

Study on Diagnosis of Active Species in Nitrogen Dielectric Barrier Microdischarges by Molecular Beam Mass Spectrometry

利用三极差分抽气分子束质谱装置在亚大气压介质阻挡放电产生的氮等离子体中观测到,粒子流中的主要离子成分是N+,N2+,并且分别研究了放电气压、放电电压、放电重复频率对氮等离子体中N+与N2+活性物种离子流强度的影响。结果显示,N+的离子流强明显高于N2+,主要是由于产生的N+和N2+在电场作用下向阴极板运动时,N2+会与中性粒子及电子碰撞发生反应而进一步生成了N+,并且N+与N2+流强随放电电压、放电频率的增大而增大,N+,N2+的相对浓度几乎不变,而随N2压力变化N+与N2+流强会出现一个极值。进而对该现象的产生、检测和形成机制进行了研究。

With the three - stage differentially pumped molecular beam mass spectrometer, it was observed in the nitrogen plasma generated by dielectric harrier discharge （DBD） at sub - atmospheric pressure that the main ions in the particle flow were N2^＋ and N^＋. And the effects of the discharge air pressure/voltage/frequency on the fluxes of active species, that is, N2^＋ and N^＋ , in the nitrogen plasma were studied. The result showed that the flux of N^＋ was significantly higher than that of N2^＋ It is primarily because when N ^＋ and N2^＋ move toward the cathode plate under the action of the electric field, N2^＋＋ collide with neutral particles and electrons and hence react to generate N^ ＋. In addition, the fluxes of both N^＋ and N2^＋ were proportional to the discharge voltage and frequency, while the relative concentration, I（N^＋）/I）N2^＋）, almost kept changeless; both of the fluxes reached their respective extreme values as the N2 pressure changed. The generation and detection mechanisms for the phenomenon were also studied.