中文摘要：

研究了铌镁酸铅-钛酸铅铁电材料的铁电、介电性能对阴极发射阈值电压的影响,以及铁电阴极发射电流与激励脉冲电压和抽取电压之间的关系,并分析了其发射机理.结果表明,室温介电常数高、极化强度变化量大的弛豫铁电体0.9Pb（Mg1/3Nb2/3）O3-0.1PbTiO3具有较小的发射阈值电压;铁电阴极电子发射与快极化反转和等离子体的形成有关;由极化反转所致电子发射的自发射电流随激励脉冲电压的增大呈幂律增长关系,其发射电流开始于激励脉冲电压的下降沿;在抽取电压较大时,发射电流随抽取电压的增大呈线性增长关系,说明大电流主要取决于抽取电压;其发射电流开始于激励脉冲电压的上升沿,与＂三介点＂处的场增强效应和等离子体的形成有关;当抽取电压为2500 V时,得到的发射电流幅值为210 A,相应的电流密度为447 A/cm^2.

英文摘要：

1- xPb（Mg1/3Nb2/3）O3- x Pb TiO3 materials near the morphotropic phase boundary are selected for tentative electron emission experiments due to their excellent piezoelectric and ferroelectric properties and relatively high dielectric constants. The influences of ferroelectric and dielectric properties of ferroelectric cathode material on its threshold voltage are studied. The relationship between emission current and triggering voltage is investigated, and the relationship between emission current and extracting voltage is studied as well. The electron emission mechanism is also analyzed. The results show that emission threshold voltage of the relaxation ferroelectric 0.9Pb（Mg1/3Nb2/3）O3-0.1Pb TiO3 is smaller due to its high dielectric constant at room temperature and large polarization variation. Low threshold voltage means low power consumption. This is an important factor to be considered in actual application for ferroelectric cathode and it has an important reference value. Electron emission is associated with fast polarization reversal and the formation of the plasma. The self-emission current starts on the falling edge of the triggering voltage pulse, which means that it is caused by polarization reversal. The amplitude of the self-emission current grows exponentially with the increase of triggering voltage. The amplitude of emission current shows a linear growth with the increase of extracting voltage when it is larger. It indicates that large current is determined mainly by extracting voltage. Larger current needs larger extracting voltage. The emission current starts on the rising edge of the triggering voltage pulse. It is associated with the field enhancement effect near ＂three interface points＂ and the formation of the plasma. An emission current of 210 A is obtained from the ferroelectric cathode under an extracting voltage of 2500 V, and the corresponding current density is 447 A/cm^2.