Novel Epitaxial Lift-Off for Flexible, Inexpensive GaAs Solar Cells

Epitaxial lift-off (ELO) is an efficient method to greatly reduce the cost of GaAs photovoltaics without sacrificing their performance. However, the use of strong acids to remove the sacrificial layer in the conventional ELO method restricts the reusability of the substrate and adds extra substrate polishing costs. Here, we report a novel method of using a water-dissolvable `NaCl' sacrificial layer which provides the advantage of repeated reusability of GaAs wafers without any substrate polishing costs. Good-quality epitaxial GaAs has been grown on NaCl sacrificial layer. Atomic Force Microscopy results show very smooth GaAs wafer after epitaxial liftoff.