Structural and chemical characterization of free-standing GaN films separated from sapphire substrates by laser lift-off

Laser lift-off of GaN heteroepitaxial layers from sapphire substrates is a promising method for electronic device integration and GaN substrate creation. Of critical importance is the structural and chemical quality of the GaN layers following laser processing. In this letter, transmission electron microscopy techniques are used to characterize the modifications that occur at the resulting GaN surfaces. Structural alteration and chemical intermixing following lift-off are confined to approximately the first 50 nm. These results indicate that laser lift-off is a viable route for GaN substrate creation, as well as for electronic device integration.