Laser liftoff of gallium arsenide thin films

The high cost of single-crystal III-V substrates limits the use of gallium arsenide (GaAs) and related sphalerite III-V materials in many applications, especially photovoltaics. However, by making devices from epitaxially grown III-V layers that are separated from a growth substrate, one can recycle the growth substrate to reduce costs. Here, we show damage-free removal of an epitaxial single-crystal GaAs film from its GaAs growth substrate using a laser that is absorbed by a smaller band gap, pseudomorphic indium gallium arsenide nitride layer grown between the substrate and the GaAs film. The liftoff process transfers the GaAs film to a flexible polymer substrate, and the transferred GaAs layer is indistinguishable in structural quality from its growth substrate.