Abstract
We demonstrate that formation of p-n junction in gallium nitride (GaN) can be directly visualized on cleavage surfaces in a cross-sectional geometry, where the focused synchrotron radiation (soft x-ray) images the different doping layers on the nonpolar a -plane surface perpendicular to the polar growth direction. In contrast to the as-grown GaN polar surface, the in situ cleaved GaN a -plane surface is shown by using photoelectron spectroscopy to be under the flatband conditions. This unique surface property opens up the way to image and identify p-n junctions in III-nitride semiconductors. © 2009 American Institute of Physics.