Epitaxy of m-plane GaN on nanoscale patterned c-plane sapphire substrates

Nonpolar (101¯0) m-plane GaN epilayer was grown on nanoscale patterned c-plane sapphire substrates by MOCVD. The nanoscale patterned sapphire substrates were fabricated by natural lithography and dry etching methods. The nanopatterns are defined particularly with no c-plane surfaces exposed. The (101¯0) m-plane GaN epilayer was characterized by X-ray diffraction and atomic force microscope, which indicated the FWHM of the rocking curve is 316 arcsec and the rms surface roughness is 0.3 nm, respectively. The SEM and TEM studies reveal that the m-plane GaN grains nucleate on the exposed n-plane facets of the etched c-plane sapphire substrates.