Electro-optical modelling of solar cells with photonic structures

In this paper we present a simulation method for the investigation of diffractive effects in solar cells. The method is based on a coupling of a rigorous wave optical simulation program and a semiconductor device simulation tool. By comparing characteristic values for a solar cell simulated with this coupled approach to results obtained with a standard procedure, we show that solar cells can be modelled with the presented approach consistently. Following that, we use this method to investigate the effects induced by a photonic structure into a crystalline silicon solar cell. As an exemplary system a diffractive backside linear grating was used. We show that with an optimized grating, the solar cell efficiency can be increased by more than 1% absolute. Finally, we investigate the absorption in the aluminium reflector for a solar cell with backside grating theoretically and experimentally. We find that structuring of the aluminium causes parasitic absorption and should be avoided.