Engineering Gaussian disorder at rough interfaces for light trapping in thin-film solar cells

A theoretical study of randomly rough interfaces to obtain light trapping in thin-film silicon solar cells is presented. Roughness is modeled as a surface with Gaussian disorder, described using the root mean square of height and the lateral correlation length as statistical parameters. The model is shown to describe commonly used rough substrates. Rigorous calculations, with short-circuit current density as a figure of merit, lead to an optimization of disorder parameters and to a significant absorption enhancement. The understanding and optimization of disorder is believed to be of general interest for various realizations of thin-film solar cells.