CSS deposition of CdTe solar cells: Latest results from Roth&Rau's pilot line

Roth&Rau AG is offering Close Spaced Sublimation (CSS) deposition tools for CdTe solar modules. The advantages of this technique are high deposition rates of some ?m per minute and an excellent utilisation of the raw material, leading to low production costs and competitive module prices. Recently Roth & Rau established in close cooperation with the Fraunhofer Institute for Electron Beam and Plasma Technique (FEP) in Dresden a laboratory with a pilot line which is dedicated to research on CdTe solar cells. The pilot line covers all relevant process steps such as TCO deposition, CSS deposition of semiconductor layers, wet chemical surface treatment and cleaning, back contact formation by thermal evaporation and/or sputtering. Analytical investigations are done in the well equipped lab cover the development of single processes and the improvement of solar cell devices. Subsequent improvement of the process flow leads to efficiencies of 10% and above. Another gain up to 12% and above can be expected by further improvement of the TCO/CdS/CdTe interfaces.