Influence of electrode position in the electrolytic cell configuration for the electrodeposition of Cu(In,Ga)Se2 thin films

Abstract

Cu(In,Ga)Se2 (CIGS) is a semiconductor that has an absorption coefficient (more than 105) suitable for building high efficiency thin film solar cells. There are a lot of reports that mention different techniques to CIGS synthesis. These techniques can involve physical or chemical processes with technical and economical advantages and disadvantages. Probably, one of the major obstacles to CIGS solar cell commercialization is that there are various synthesis techniques for this type of solar cell and the most economical and feasible techniques do not produce an adequate absorber formation. Among these processes, electrodeposition is a versatile technique due to the possibility of making CIGS films in a large area. However, one of the major problems during the CIGS growth by electrodeposition is the microcracks formation stemming from some experimental conditions such as bath composition, type of substrate, electrode distance, etc. In this paper, the electrolytic cell for CIGS co-electrodeposition was analyzed in order to know the film composition and morphology as a function of electrode position in the electrolytic cell. We found that the CIGS film composition was not homogeneous and the morphology was not uniform in an electrolytic cell with electrodes placed vertically. As a result of the previous experimentation, we have designed an electrolytic cell with horizontal electrodes where the composition was more homogeneous and the morphology was more uniform.