A detailed study on electrical and optical inhomogeneity in N-face GaN grown by hydride vapor phase epitaxy is presented. There are two distinctive regions with non-homogeneous electrical and optical properties in N-face of GaN revealed by wet etching, Raman and cathodoluminescence. One region exclusively exhibited stronger donor-acceptor pair emission and higher carrier concentration due to impurity incorporation. A strong red-shift of near band edge emission of similar to 24 meV was also observed owing to additional carrier concentration. Furthermore, the activation energy difference of the etching process between the two regions is similar to 0.12 eV. The distinctive etching topography was probably due to the difference of surface potentials related to the level of carrier concentration in GaN. (C) 2013 Elsevier B.V. All rights reserved.