Origin of p-type conduction in Cu-doped ZnO nano-films synthesized by hydrothermal method combined with post-annealing

Abstract Cu-doped ZnO nano-films were synthesized by a hydrothermal method combined with post-annealing process. The mechanism for the formation of the nano-films can be explained by a Cu-adsorbed face-selective crystal growth inhibition mechanism. The 2 at.% Cu-doped sample behaved p-type conductivity, which can be verified by a p–n homojunction with well-defined rectifying characteristic. The origin of p-type conduction of the Cu-doped sample was studied by XPS and PL analyses. The Cu Zn +1 acceptor with the ionization energy of 326 meV should be the main reason for the p-type conductivity.