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26th European Photovoltaic Solar Energy Conference and Exhibition; 2704-2708, Transparent conductive oxides (TCO) are often used as transparent front electrodes for thin film solar cells. Besides their conductivity and transparency in the absorption range of the solar cell also the light scattering ability is important for light management. The TCOs are textured, e.g. as grown LPCVD ZnO:B or texture-etched ZnO:Al, and depending on their morphology they are differently adequate for their application as front electrode in solar cells. An evaluation method based on angular resolved light scattering (ARS) is presented in this paper. Measurement results and evaluation of different types of textured doped TCOs like reactively MF sputtered ZnO:Al (Zn:Al target), RF sputtered ZnO:Al (ZnO:Al2O3 target) and LPCVD ZnO:B are shown. A correlation between ARS and short-circuit density of a-Si:H/μc-Si:H p-i-n solar cells was found for LPCVD ZnO:B and reactively or RF sputtered and etched ZnO:Al until a saturation current was reached.

25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 3174-3176, We report on Sunfilm’s recent development of ZnO:Al layers for front contact TCO in a-Si/μc-Si tandem modules. Our new process allows to produce ZnO:Al layers of excellent optical and electrical properties on 1.78 m2 float glass substrates in an industrial DC sputter line. After etching in diluted hydrochloride acid, the TCO exhibits haze values > 60 % at 700 nm and a surface texture tailored for a-Si/μc-Si tandem modules. TCO with such properties is usually obtained using lab scale RF sputter processes only, which, however, have too low deposition rates and are difficult to scale to large areas for industrial application. On the new TCO substrates a-Si/μc-Si tandem modules with a stabilized total area efficiency of 8.3 % have been produced at Sunfilm. This is comparable to our typical module performance on commercial SnO2:F based TCO substrates.