High-resolution x-ray diffraction (XRD) and atomic force microscopy (AFM) of pendeo-epitaxial (PE) GaN films confirmed transmission electron microscopy (TEM) results regarding the reduction in dislocations in the wings. Wing tilt less than or equal to0.15degrees was due to tensile stresses in the stripes induced by thermal expansion mismatch between the GaN and the SiC substrate. A strong DdegreesX peak at approximate to 3.466 eV (full-width half-maximum (FWHM) less than or equal to 300 mueV) was measured in the wing material. Films grown at 1020degreesC exhibited similar vertical  and lateral [11 (2) over bar0] growth rates. Increasing the temperature increased the latter due to the higher thermal stability of the GaN(1120). The (11 (2) over bar0) surface was atomically smooth under all growth conditions with a root mean square (RMS) = 0.17 nm.
Maskless pendeo-epitaxial growth of GaN films
Roskowski, AM., Preble, EA., Einfeldt, S., Miraglia, PM., & Davis, RF. (2002). Maskless pendeo-epitaxial growth of GaN films. Journal of Electronic Materials, 31(5), 421-428.