Optimization of the ZnO back contact layer in terms of module power increase and cost reduction in 60MW micromorph TM production line

E. Koutsioumpi, K. Raftopoulou, E. Katsia, C. Sarigiannidis, T. Carlo, C.M. Schmidt, D. Zimin, B. Bondu, F. Farmakis, D. Girginoudi and N. Georgoulas
2011. Proc. 26th EU PVSEC,Hamburg, Germany, September 5-9, 2011, 2684-2687, doi: 10.4229/26thEUPVSEC2011-3AV.2.31

Abstract: Heliosphera SA produces 1.43 m2 micromorph® modules with Boron- Doped LPCVD ZnO (ZnO:B) layers as front and back contacts, manufactured on equipment provided by Oerlikon Solar. Heliosphera SA is searching for solutions on the large production scale that would allow module performance increase without production cost raise. This paper is focused on the module power improvement, taking into account the cost reduction which is a major factor leading to a sustainable production line. The influence of deposition temperature, deposition time and doping ratio, of the back contact (BC) transparent conductive oxide (TCO) layer, on the optical and electrical properties of the modules is studied. It is shown that LPCVD ZnO applied as back contact in p-i-n configured thin film silicon solar cells, has great potential in improving the module properties. Low cost, high quality TCO BC layers can therefore play an important role in thin film silicon cells in order to improve the module power and further reduce the production costs.