Monocrystalline GaN(0001) thin films, void of oriented domain structures and associated low-angle grain boundaries, have been grown via organometallic vapor phase epitaxy (OMVPE) on high-temperature monocrystalline AlN(0001) buffer layers predeposited on vicinal α(6H)–SiC(0001) wafers using TEG, TEA, and ammonia in a cold wall, vertical, pancake-style reactor. The surface morphology was smooth, and the PL spectrum showed strong near-band-edge emission with a full width at half-maximum (FWHM) value of 4 meV. The dislocation density within the first 0.5 μm was ≊1×109 cm−2; it decreased substantially with increasing film thickness. Controlled n-type Si doping of GaN has been achieved for net carrier concentrations ranging from ∼1×1017 to 1×1020 cm−3. Double-crystal XRC measurements indicated a FWHM value of 66 arcsec for the GaN(0004) reflection.