Influence of the surface morphology of macroporous silicon on the performances of n-Si(100)/SnO2 photovoltaic cells

Impedance measurements on (100) n-Si/SiOx/SnO2 (spray deposited) structures reveal that the band edges of Si are systematically shifted positively und er illumination. This effect, which influences the photocurrent and fill fa ctor of cells with mirror-polished surfaces, is much less pronounced when t he surface is made macroporous by photoelectrochemical etching. A combined analysis of the open-circuit voltage and capacitance data is developed to c alculate the thickness of the SiOx layer grown during the spray deposition of SnO2. Compared to a mirror polished surface, the SiOx layer is found to be thicker with a macroporous surface resulting in lower open circuit volta ges.