Homojunction diodes were fabricated by doping of phosphorus to n-type Cu-In-Se thin films. The junction prepared by P implantation at the energy of 50 keV with the dose of 1 x 10(15) ions/cm 2 showed a rectification ratio of more than 100. Conduction in Cu-In-Se thin films, whose crystal structure is of the chalcopyrite type, changes from n- to p-type in such a way that group V elements (N, P, Sb, or Bi) substitute for Se in the film
