Structure and electrical properties of Mo back contact for Cu(In, Ga)Se2 solar cells

Mo layers were deposited on soda lime glass via DC magnetron sputtering of a Mo target in a pure Ar atmosphere. The structure and electrical resistivity of Mo thin films, which may be varied by controlling the sputtering pressure, were investigated. The films showed (110) preferred orientation regardless of the working pressure. Films sputtered at low working pressure had low resistivity but adhered poorly to glass. A study of the deposition of a Mo bilayer was conducted. Optimum properties of the Mo bilayer were obtained when the bottom layer was deposited at 10 mtorr and the top layer was deposited at 2.5 mtorr. The extremely low resistivity of 6.57 μΩ-cm was obtained, which is better than other literatures. A Cu(In, Ga)Se₂ cell fabricated on a Mo film sputtered under optimized conditions showed 10.40% efficiency.