Chinese Optics Letters, 2015, 13 (10): 100401, Published Online: Sep. 13, 2018
Quantum efficiency decay mechanism of NEA GaN photocathode: A first-principles research Download: 870次
Abstract
Using the first-principles method based on the density functional theory (DFT), the work function of seven different GaN (0001) ( 1 × 1 ) surface models is calculated. The calculation results show that the optimal ratio of Cs to O for activation is between 3 ∶ 1 and 4 ∶ 1 . Then, Cs/O activation and stability testing experiments on reflection-mode negative electron affinity GaN photocathodes are performed. The surface model [GaN (Mg): Cs] Cs-O after being activated with cesium and oxygen is used. The experiment results illustrate that the adsorption of O contained in the residual gas increases the surface potential barrier and the reduction of the effective dipole quantity is the basic cause of the quantum efficiency decay.
Yang Shen, Liang Chen, Shuqin Zhang, Yunsheng Qian. Quantum efficiency decay mechanism of NEA GaN photocathode: A first-principles research[J]. Chinese Optics Letters, 2015, 13(10): 100401.