Epitaxial Lift-Off of Ultra-Thin GaAs Solar Cells with Textured Back Contact Layer and Diffuse Silver Mirror

Ultra-thin GaAs solar cells have the benefits of cost reduction and increased radiation tolerance for space applications, but this comes at the cost of reduced photon absorption. In this work, invertedly grown ultra-thin GaAs solar cells with a light-confining diffuse silver back mirror are obtained with epitaxial lift-off. This is achieved by wet chemical etching of the rear contact layer in a grid pattern to ensure compatibility with the epitaxial lift-off process. The textured cells demonstrate strong light-trapping effects and a relative increase of 18.8% in short-circuit current density is achieved with respect to equivalent planar cells.