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以金属有机化学气相沉积(MOCVD)外延的p型GaN为阴极发射层材料,通过对激活过程中阴极光电流的在线监测,考察了Cs激活,Cs/O交替激活以及高低温两步激活对GaN阴极光电发射性能的影响。实验结果表明,单用Cs激活就可制备出量子效率约为20%的GaN光电阴极,Cs激活后再进行2～3个Cs/O循环激活可小幅度提高量子效率,高低温两步激活不能进一步提高量子效率。利用偶极层表面模型对实验现象进行了解释。
By means of MOCVD, the p-type GaN is used as the cathode emitter layer material. Through on-line monitoring of photocathode current, the effects of Cs activation, Cs / O activation and high and low temperature activation on GaN Effect of cathode photoemission performance. The experimental results show that GaN photocathodes with quantum efficiency of about 20% can be prepared by Cs activation alone. Cs activation followed by 2 ~ 3 cycles of Cs / O activation can increase the quantum efficiency by a small margin. Further improve the quantum efficiency. The dipole layer surface model is used to explain the experimental phenomena.