Influence of CbdDeposited CdS on the Carrier Collection in CigsBased Solar Cells.pdf

INFLUENCE OF CBD-DEPOSITED CdS ON THE CARRIER COLLECTION IN CIGS- BASED SOLAR CELLS Marika Edoff, Lina Malmberg, Ulf Malm and Lars Stolt Ångström Solar Center Ångström Laboratory, P.O. Box 534, SE-751 21, Uppsala, Sweden ABSTRACT itself. Apart from resulting in a CdS layer, the CBD bath acts as an etchant, removing oxides at the interface and it CdS films were deposited with Chemical Bath has also been suggested that the CBD process results in Deposition (CBD) onto Cu(In,Ga)Se /Mo/Soda-lime glass a Cd doping at the very outermost layer of the CIGS[3,9]. 2 structures. The basic ingredients for the CBD were This has motivated us to study also the CBD-CdS, by ammonia (NH OH), cadmium acetate (CdAc), and comparing our baseline buffer to CBD-CdS buffer layers 4 thiourea CS(NH ) . Two recipes with very low thiourea fabricated with modified process recipes. The main 2 2 concentration were compared to the baseline recipe. From variable has been the concentration of the sulphur donor, quantum efficiency measurements we observe an thiourea and the process time. increased carrier collection for longer wavelengths for the modified buffer recipes as compared to baseline. The EXPERIMENTAL h