Buffer-less Cu(In,Ga)Se sub(2) solar cells with Zn(O,S):Al transparent conductive oxide film

Transparent conductive oxide Zn(O,S):Al (AZOS) films with S/(S+O) 0.00 to 0.25 were fabricated by co-sputtering of ZnO:Al and ZnS targets. All films showed high transparency of over 80% with edge shift at short wavelength which showed band gap changed as S/(S+O) increased. However, sheet resistance increased with increased S/(S+O), with over 10 super(4) Omega /sq at S/(S+O) of 0.25. These films were used in the fabrication of buffer-less Cu(In,Ga)Se sub(2) solar cells with cell structure of Al/NiCr/AZOS/CIGS/Mo/SLG. The cell performance increased with S/(S+O), with highest efficiency of 9.05% at S/(S+O) 0.09. However, at higher S/(S+O) cell performance dropped and at 0.25 no cell performance was recorded which was due to the high sheet resistance. ([copy 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)