Two categories of reconstructions were identified which occurred on wurtzite GaN surfaces. The first was associated with the N face, (00•¯1), and the second with the Ga face, Not only did these two types of reconstructions have completely different symmetries, but they also exhibited a differing temperature dependence. It was demonstrated that surface reconstructions could be used to identify lattice polarity. Confirmation of the polarity assignment was provided by polarity-selective wet chemical etching of the surfaces

Determination of Wurtzite GaN Lattice Polarity Based on Surface Reconstruction. A.R.Smith, R.M.Feenstra, D.W.Greve, M.S.Shin, M.Skowronski, J.Neugebauer, J.E.Northrup: Applied Physics Letters, 1998, 72[17], 2114