Areal inhomogeneities in MIS solar cells

The effects of the areal inhomogeneities, particularily oxide thickness variations, on minMIS solar cell performance are examined using an equivalent circuit approach. The presence of thinner regions in an oxide of optimum thickness leads to a reduction in the open-circuit voltage and efficiency and an increase in the dark current. Cells with an excessively thick oxide inhibit tunneling, but with sufficient thin oxide portions can exhibit acceptable performance though control of the thin oxide area is likely to be difficult. For such cells too small a fraction of the cell area of the thin oxide results in reduction in Jsc, FF, and η; too large a thin oxide area can result in VOCreduction if the regions are Schottky-like. The results clarify observed degradations in actual MIS solar cells.