Evaluation of correlation between fill factor and high mobility transparent conductive oxide film deposition temperature in the silicon heterojunction solar cells

Abstract We investigated the degradation factor of the conversion efficiency of the silicon heterojunction solar cells. In particular, we clarified the effect of the transparent conductive oxide film deposition conditions on the film quality and interface states, and the relationship between these factors and the conversion efficiency. Heat process causes a decrease in carrier mobility due to a decrease in the grain size of the TCO film, but has an effect of improving the TCO/a-Si:H(p) interface states. In particular, the silicon oxide layer between the TCO film and a-Si:H(p) increases the series resistance and moderates the band bending at the TCO/a-Si:H(p) interface, leading to FF degradation. Since In2O3:H film easily forms a silicon oxide layer at the TCO/a-Si:H(p) interface, the interface treatment is important factor in the cell manufacturing process.