碳纳米管阴极的短脉冲爆炸场发射与等离子体膨胀

采用碳纳米管制备了一种强流电子束发射阴极，并对碳纳米管阴极在双脉冲条件下的强流发射性能进行了研究.在双脉冲条件下获得了245 A/cm²的强发射电流密度，阴极的开启时间约为40 ns.采用高速分幅相机和CCD相机对强流电子束在空间和时间的分布进行了研究.研究表明连续脉冲实验时，离子体及其膨胀对发射电子束的强度和分布影响很大，双脉冲时脉冲间隔时间内等离子体的膨胀速率约为8.17 cm/μs.等离子体形成时没有优先位置，电子束发射的局部增强位置是随机的.结果表明碳纳米管阴极可以作为强流阴关键词：碳纳米管爆炸场发射等离子体膨胀强流电子束

Short-pulsed explosive field emission and plasma expansion of carbon nanotube cathodes

A large area cold cathode based on carbon nanotube films has been successfully fabricated. Investigation of the explosive field emission properties of the carbon nanotube cathode in a double-pulse mode was carried out and a high emission current density of 245 A/cm² was obtained. The turn-on time of the CNT cathode is about 40 ns. The time- and space-resolution of the electron beam emitted from the cathode was investigated. The formation of the cathode plasma layer was proved and the plasma expanded at a velocity of ～8.17 cm/μs toward the anode. The plasma has big influences on the intensity and distribution of electron beams. The formation of cathode plasma had no preferential position and the local enhancement of electron beams was random. This carbon nanotube cathode appears to be suitable for high-power microwave device applications.