Near-infrared photocathode In0.53Ga0.47As doped with zinc: A first principle study

In0.53Ga0.47As is an important material for the shortwave near-infrared negative electron affinity photocathodes. As we all known, doping is a necessary step for the formation of the negative electron affinity and zinc is a traditional substitutional element to generate the P-type semiconductor. The In0.53Ga0.44Zn0.03As and In0.50Ga0.47Zn0.03As were formed from In0.53Ga0.47As by a zinc atom substituting a gallium atom or an indium atom in the article. The atom structures, the band structures and the populations were studied by the first principle method for these two supercell models. Two problems, how the zinc-doping change the characters of intrinsic In0.53Ga0.47As and the differences between In0.53Ga0.44Zn0.03As and In0.50Ga0.47Zn0.03As, were solved by the research. Firstly, the atom structures were changed and the band gaps were narrowed after zinc doping. The ionicity was enhanced which is agreed with the character of P-type semiconductor. Secondly, there were small differences between the two supercells in electronic structures. Therefore, there is no need to consider which kind of atom to be substituted during the material growth for the near-infrared InGaAs photocathode.