POST DEPOSITION TREATMENTS OF ELECTRODEPOSITED CUINSE2-BASED THIN FILMS

摘要

Single bath electrodeposition of polycrystalline Cu(In,Ga)Se₂ thin films for photovoltaic applications is disclosed. Specifically, Cu(In,Ga)Se₂ was deposited onto Mo electrodes from low concentration buffered (pH 2.5) aqueous baths containing CuCl₂, InCl₃, GaCl₃ and H₂SeO₃. Moreover, buffered aqueous baths are disclosed wherein Se⁴⁺/Cu²⁺ concentration ratios were controlled to optimize Se and Cu levels, while In³⁺ concentration was adjusted to control deposited In and Ga. Further disclosed are pre- and post-deposition processing methods resulting in smooth, compact, crack-free films of near stoichiometric values. Post deposition heat treatments on electrodeposited CuInSe₂-based films in selenium and sulfur containing atmosphere are described. CuInSe₂-based films from a single bath deposited onto Mo electrodes from low concentration aqueous baths. Heat treatment of electrodeposited Cu(In,Ga)Se₂ in H₂Se producing an O-free crystalline film and annealing in Se-vapor producing crystalline CuInSe₂ without loss of Ga or O).