Optimization studies of chemical bath deposition of Zn(S,O,OH) Buffer Layers for Large Area Co-evaporated Cu(In,Ga)Se_2 (CIGS) and Electrodeposited CuIn(S,Se)_2 (CIS) Solar Cells

摘要

This paper is focused on the basic study and optimization of Chemical Bath Deposition (CBD) of Zn(S,O,OH)buffer layers in CIGS and CIS solar cells. First the influence of deposition parameters is studied from theoretical solutionchemistry considerations by constructing solubility diagrams of ZnS, ZnO, and Zn(OH)_2. Experimental growth depositionstudies are then carried out by the in situ quartz crystal microgravimetry (QCM) technique. A global equation for the growthrate is derived from these experiments. The structural and optical properties of Zn(S,O,OH) films are then determined usingSEM and transmittance techniques. Electrodeposited-CIS/Zn(S,O,OH)/ZnO and co-evaporated-CIGS/Zn(S,O,OH)/ZnO cellswere prepared with efficiencies similar or better (≥13.6 % for CIGS and 8.1 % for CIS) than with reference CdS CBD bufferlayers. These results are obtained with an optimized process allowing short deposition time for the ZnS based buffer layer (<10 min).