28th EU PVSEC, Paris, September 2013

Abstract

The Australian National University (ANU) recently fabricated a 24.6% ± 0.5% efficiency IBC solar cell on n-type Cz-Si. This paper discusses the optimisation of the diffusions and contact openings of that solar cell, which combined detailed characterisation with 3D device modelling. Given the many competing effects in an IBC cell structure, the optimal diffusion profiles and geometry are very dependent on the device fabrication technology, particularly on the surface passivations and metalisation techniques. The crucial device parameters are discussed and the method of experimentally measuring the surface passivation quality, emitter recombination, contact recombination and specific contact resistivity are presented. With these experimental values and 3D device modelling, efficiency contour plots are generated for a pertinent range of phosphorus sheet resistance and contact fraction.