| abstract |
A nitride crystal or wafer with a removable surface layer comprises a high quality nitride base crystal, a release layer, and a high quality epitaxial layer. The release layer has a large optical absorption coefficient at wavelengths where the base crystal is substantially transparent and may be etched under conditions where the nitride base crystal and the high quality epitaxial layer are not. The high quality epitaxial layer may be removed from the nitride base crystal by laser liftoff or by chemical etching after deposition of at least one epitaxial device layer. The nitride crystal with a removable surface layer is useful as a substrate for a light emitting diode, a laser diode, a transistor, a photodetector, a solar cell, or for photoelectrochemical water splitting for hydrogen generation. |