铁电冷阴极材料电子发射实验研究

铁电冷阴极材料是一种在脉冲电压激励下从铁电表面获得很强的脉冲电子发射的新型功能材料。如何提高该材料的发射电流密度、束发射度和束亮度,是其研究的一个热点。本实验采用硅橡胶,清漆作为底电极表面及栅电极边缘的绝缘保护层,避免了表面放电现象,使得激励场强增大,从而极大地提高了铁电冷阴极材料的发射电流密度,最高达187 A/cm2,从归一化均方根发射度εn(m·rad)和归一化峰值亮度βn(A/m2·rad2)理论计算值来看,也大大改善了材料的束发射度和束亮度。

Study on the Electron Emission of Ferroelectric Cathode Materials

Ferroelectric cold cathode is a new source of electron emission. With it, electrons emission can be caused by polarization switching when pulse voltage applied on it at room temperature. The electron emission density of the ferroelectric cathode is greatly dependent on the applied electric field. Usually, the increase of the electric field is seriously inhibited by surface discharge between the electrodes of the cathode. In this experiment, two kinds of insulation coating materials, silastic and varnish were used as insulation layer to avoid surface discharge, which effectively increased the applied field and the electron emission density reached the level up to 187 A/cm2. By theoretical estimation, the normalized RMS emittance and the peak brightness of the emitting beam have been obviously improved by this method.