Ag and Mn dopants were incorporated into Cu2ZnSnS4 thin film to reduce defects in thin film and improve thin film properties. Sol-gel and spin-coating techniques were employed to deposit Ag and Mn co-doped Cu2ZnSnS4 thin films. The structures, compositions, morphologies, and optical properties of the co-doped thin films were characterized. The experimental results indicate the formation of kesterite structure without Ag and Mn secondary phases. The amount of Ag in the thin films is close to that in the sols. The co-doped Cu2ZnSnS4 thin films have an absorption coefficient of larger than 1.3 × 104 cm-1, a direct optical band gap of 1.54-2.14 eV, and enhanced photoluminescence. The nonradiative recombination in Cu2ZnSnS4 thin film is reduced by Ag and Mn co-doping. The experimental results show that Ag and Mn incorporation can improve the properties of Cu2ZnSnS4 thin film.
Keywords: Ag and Mn co-doping; Cu2ZnSnS4; sol–gel preparation; thin films.