Thickness dependence of microcrystalline silicon solar cell properties

This paper addresses the performance of pin and nip solar cells with microcrystalline silicon (μc-Si:H) absorber layers of different thickness. Despite the reverse deposition sequence, the behavior of both types of solar cells is found to be similar. Thicker absorber layers yield higher short-circuit currents, which can be fully attributed to an enhanced optical absorption. Open-circuit voltage VOC and fill factor FF decrease with increasing thickness, showing limitations of the bulk material. As a result of these two contrary effects the efficiency η varies only weakly for absorber layers of ∼1 to ∼4 μm thickness, yielding maximum values up to 8.1 %. For a-Si:H/μc-Si:H stacked solar cells an initial efficiency of 12% has been obtained.