From randomly self-textured substrates to highly efficient thin film solar cells: Influence of geometric interface engineering on light trapping, plasmonic losses and charge extraction

- Interface engineering is powerful tool to improve solar cell performances.
- Charge extraction in µc-Si solar cells is limited by the crack formation.
- Methods that enable complete virtual fabrication of solar cells are developed.
- Influence of interface engineering on optics and crack formation is investigated.
- Analytical model to predict crack formation is presented.

An approach that models the fabrication and enables the characterization of randomly self-textured silicon thin film solar cells is developed and are compared to experimental results. The optical and electrical properties of the solar cells depend on the morphology of the randomly self-textured substrate and the formation of the individual layers of the solar cell. The influence of the interface morphology on the optical and electrical properties is investigated by 3D morphological algorithms. The calculated interface morphologies are compared to measured surfaces, and used as input parameters to simulate the optical wave propagation and to determine the formation of regions with reduced order (cracks) in the solar cells. The calculations are compared to experimentally realized 1.1 µm thick microcrystalline silicon solar cells prepared on randomly self-textured substrates with high energy conversion efficiency of up to 9.4%. Guidelines for the optical and electronic optimization are provided.