New conditions for one-step epitaxial lateral overgrowth were implemented to grow coalesced (11▪0) non-polar and (11▪2) semi-polar GaN layers starting, respectively, from R- and M-plane sapphire. A large portion of the stacking faults and dislocations were filtrated resulting in GaN material with better structural and optical properties. In the ELO-like (11▪0) and (11▪2) films, the near-bandedge emission dominated photoluminescence spectra and was in the range of 3.45 to 3.48eV; depending upon lattice deformation. The strongest emission was found for the semi-polar (11▪2) ELO. When mask stripes were not normal to the c-axis, a singular epitaxial lateral overgrowth developed with inclined coalescence facets. In this case, stacking faults overgrew the mask and so led to poor optical properties, dominated by stacking fault- and dislocation-related peaks. In each case, the internal electric field reduction in (Al,Ga)N/GaN non- or semi-polar quantum-wells stacks was better viewed when the heterostructures were grown onto epitaxial lateral overgrowth with stripes normal to the c-axis.

Reduction of Stacking Faults in (11▪0) and (11▪2) GaN Films by ELO Techniques and Benefit on GaN Wells Emission. Z.Bougrioua, M.Laügt, P.Vennéguès, I.Cestier, T.Gühne, E.Frayssinet, P.Gibart, M.Leroux: Physica Status Solidi A, 2007, 204[1], 282-9