Spatial variation of electrical properties in lateral epitaxially overgrown GaN

Using confocal Raman and scanning probe microscopies, we show that the elec trical properties of lateral epitaxial overgrown GaN films vary at the subm icron scale. Wing regions, which are located directly above the SiOx stripe s, contain carrier densities similar to 10(20) cm(-3), but possess a Fermi level deep in the band gap. This cannot be explained by having a high densi ty of free electrons in the conduction band, but is consistent with high le vels of compensation and impurity band transport. In the coalescence region , stripes of different electrical properties are evident, indicating the in corporation of impurities and defects being dictated by the growth dynamics . (C) 2001 American Institute of Physics.