负电子亲和势GaN光电阴极光谱响应特性研究

Study of spectral response characteristics of negative electron affinity GaN photocathode

针对负电子亲和势(NEA)GaN光电阴极成功激活后的量子效率问题,利用自行研制的紫外光谱响应测试仪器,测试了成功激活的NEAGaN光电阴极的光谱响应,给出了230—400nm波段内反射模式NEAGaN光电阴极的量子效率曲线.测试结果表明:反射模式下NEAGaN光电阴极在230nm具有高达37.4%的量子效率,在GaN光电阴极阈值365nm处仍有3.75%的量子效率,230nm和400nm之间的抑制比率超过2个数量级.文中还结合国外的研究结果,综合分析了影响量子效率的因素.

Aiming at determining the quantum efficiency of fully activated negative electron affinity（NEA） GaN photocathodes,we have investigated the spectral response of NEA GaN photocathodes by using a dedicated ultraviolet spectral response measurement instrument. The quantum efficiency curve of reflection-mode NEA GaN photocathode has been obtained in the band region from 230nm to 400nm. The experimental results show that the quantum efficiency of reflection-mode NEA GaN photocathode reaches up to 37. 4% at 230 nm,and at 365 nm,which is the threshold of GaN photocathode,the quantum efficiency remains 3. 75%. A sharp cutoff characteristic with over two orders of magnitude degradation from 230 nm to 400 nm has been observed. Based on the former research results,the factors influencing quantum efficiency were also comprehensively analyzed in the paper.