热退火对GaN阴极光电发射性能的影响

Effects of Thermal Annealing on the Photoemission Performance of GaN Photocathode

热退火不但可以减少GaN阴极样品中的各种缺陷和寄生电容,改善材料的结晶属性,而且可以改善样品的表面质量,对提高样品的光谱响应是一种有力的手段。对GaN阴极样品进行了不同温度、不同时间的退火处理,使样品的性能得到了改善,最优条件下样品的暗电流为200 pA,电阻率为1.6Ω·cm,最大光谱响应为0.19 A/W。依据光谱响应作为评估标准,可以得出,采用700℃热退火10 min制备出的阴极具有更高的光电发射性能,从而实现了GaN光电阴极的优化制备工艺。

Thermal annealing can greatly reduce the defects and parasitic capacitance in GaN photocathode,and can improve the crystalline properties and the morphologies of the sample.It is a powerful means to improve the responsiveness of the sample.The GaN photocathode sample was annealed at different temperatures and at different time periods in order to improve the performance of the sample.The ideal experimental data for the sample are as follows:the minimum dark current is 200 pA,the minimum resistivity is 1.6Ω·cm,and the maximum responsivity is 0.19 A/W.It can be concluded that the GaN photocathode sample annealed by 700℃for 10 min has higher photoemission performance.