Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7223434 | Optik - International Journal for Light and Electron Optics | 2018 | 4 Pages |
Abstract
Mg δ-doping GaN material is grown by MOCVD and activated by Cs/O in UHV subsequently, then NEA GaN photocathode can be obtained. Compared with the p-type uniform doping, the δ-doping NEA GaN photocathode shows better photoemission performance, and the photocurrent is twice as the uniform. The QE of δ-doping and uniform doping are 24% and 10% at 5.16â¯eV, respectively. The hole concentration of δ-doping and uniform doping are 8.7â¯Ãâ¯1017â¯cmâ3 and 3.3â¯Ãâ¯1017â¯cmâ3, while better crystal quality for δ-doping is proved by the XRD results simultaneously. Profited from the higher hole concentration and better crystal quality, the P and L of δ-doping NEA GaN photocathodes are raised to 0.51 and 258â¯nm, respectively. After introduction of O during the activation, the photocurrent of uniform doping GaN photocathode has obvious improvement, however, it is even worse than before for the δ-doping. On the basis of [GaN(Mg)- Cs]:[O-Cs] model, it is found that the surface roughness is beneficial for improving photocurrent during the Cs/O alternating activation stage.
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Authors
Xiaohui Wang, Yijun Zhang,