The fabrication of large-area, free-standing GaN by a novel nanoetching process

\ A simple yet versatile nanoetching process in porosifying and 'machining' GaN is reported in this work. By combining different porosifying conditions through potentiostatic modulation or embedding doping design, we are able to separate and lift off GaN layers over a macroscopic area (>= cm(2)). Strain relaxation and single crystallinity are confirmed by Raman and transmission electron microscopy, respectively. This method is expected to open up a new dimension in epitaxy, design and manufacture of GaN heterostructures and devices.