Lowering of Ignition Voltage of Gas Discharge by Using Carbon Nanotube Electrodes and Its Application to Fluorescence Tubes

利用碳纳米管（CNT）阴极进行了气体放电实验，得到了以下结果：当电极间隙(d)为0.1mm时，与不锈钢（SUS）阴极相比，碳纳米管阴极以较低的电压点燃气体放电，而不考虑氩气压力(100Pa ？1700Pa)。而当间隙越宽（即d=1mm和10mm）时，点火电压差变小，气体压力越高，碳纳米管阴极的电压越高。点燃电压取决于阴极金属上碳纳米管薄膜的结构和纹理。电弧放电法制备的喷雾沉积的单壁和多壁CNTs有一定的降低着火电压的效果，而等离子体cvd法制备的高密度垂直排列的CNTs在阴极金属上几乎没有降低着火电压的效果，但在某些条件下会提高着火电压。当在阳极上使用碳纳米管薄膜时，点火电压升高。在维持放电电压方面，当间隙较窄（d=0.1 mm和1 mm）时，CNT阴极在氩气低压（100Pa ~ 1200pa）下的维持放电电压比SUS阴极低。相反，对于宽间隙（d=10 mm），碳纳米管阴极需要更高的电压来维持整个压力范围内的放电。放电电压随杂质气体分压的变化而变化，提示潘宁效应。在放电实验后，碳纳米管薄膜经常从阴极上脱落。综上所述，使用碳纳米管阴极可以在一定程度上降低气体放电电压，但电压降低幅度仅为10%。碳纳米管阴极在气体放电电压下的工业应用，需要对碳纳米管薄膜进行防剥离保护。

Gas discharge experiment was performed using carbon nanotube (CNT) cathodes, and the following results were obtained.1. When the gap between electrodes (d) was 0.1mm, the CNT cathode ignited gas discharge at a lower voltage compared with a stainless steel (SUS) cathode, irrespective of argon (Ar) gas pressures (100Pa ? 1700Pa) employed in the present experiment. For the wider gap (i.e., d=1mm and 10mm), however, the difference in the ignition voltage became small, and the CNT cathode showed higher voltages at higher gas pressure.2. The ignition voltage was dependent on the structure and texture of CNT films on the cathode metal. Spray deposited single-wall and multi-wall CNTs that were produced by arc-discharge method exhibited some effects on lowering the ignition voltage, while vertically-aligned CNTs with high density formed on the cathode metal by plasma-CVD method, rarely showed the lowering effect but raised the ignition voltage in some conditions.3. When CNT films were used on the anode, the ignition voltage was raised.4. Concerning the voltage for sustaining discharge, CNT cathodes could sustain discharge with lower voltage than the SUS cathode at low pressure of Ar gas (100Pa〜1200pa) when the gap was narrow (d=0.1 mm and 1 mm). For the wide gap (d=10 mm), on the contrary, CNT cathodes needed higher voltage to sustain discharge over the whole range of pressure.5. The discharge voltage changed by the partial pressure of impurity gases, suggesting the Penning effect.6. CNT films often peeled off the cathode after the discharge experiment.In summary, lowering of gas discharge voltages was observed to some extent by using CNT cathode, but the reduction in the voltage was only 10%. For the industrial application of CNT cathodes to gas discharge voltage but also protection of CNT films against peeling-off are necessary.