First-principles insights into Cs/NF3 co-activation effects on near-infrared In0.53Ga0.47As (0 0 1) surface

For InxGa1-xAs photocathodes, the negative electron affinity characteristics can often be obtained by adsorbing Cs/O or Cs/NF3. Moreover, the physical mechanism of the Cs/O adsorbing system has been extensively investigated, but for the Cs/NF3 adsorbing system, it is currently unclear yet. In this disquisition, the effect of Cs/NF3 co-adsorption on the In0.53Ga0.47As (001) β2 (2 × 4) surface was studied based on the density functional theory (DFT) calculation. The upshots manifest that NF3 molecule is beneficial to enhance the stability of the Cs covered In0.53Ga0.47As (001) β2 (2 × 4) surface. Besides, the newly generated dipole named [Cs–NF3] is beneficial to resist the depolarization phenomenon induced by excessive Cs adatoms. Therefore, it is conducive to the monotonically decreasing of surface work function, which is of great significance to enhance the performance of optoelectronic equipment. Also, the co-adsorption of Cs/NF3 changes the reflectivity and absorption coefficient of In0.53Ga0.47As (001) β2 (2 × 4) surface, which affects the photoelectric conversion efficiency of the photoemitter.