Optimisation of Periodic Surface Textures in Thin-film Silicon Solar Cells Using Rigorous Optical Modelling by Considering Realistic Layer Growth

Rigorous optical simulations based on finite element method (Comsol simulator) were carried out in order to analyse the effect of different periodic substrate textures on short-circuit current density of a tandem micromorph solar cell. In our modelling an important aspect of non-conformal growth of the layers comprising the solar cell was considered. Optimisation shows that introducing 2-D textures into the substrate surface results in higher photocurrents than in the case of 1-D textures. The shape of initial sinusoidal textures was additionally altered to enable growth of layers of greater quality, thus improving electrical properties of the cell. Such textures were found to further improve optical properties as well, peaking at 98% increase (ref. flat cell) of photocurrent of bottom cell, surpassing the photocurrent generated when introducing random textures.