The effects of sapphire annealing on high-quality AlN growth by molecular beam epitaxy have been studied. AlN thin films grown on annealed sapphire (1200 °C, 12 h) were hole-free. The full width at half maximum of the (0 0 0 2) and (1 0 over(1, -) 5) ω-rocking curves for 260 nm-thick AlN thin films grown on annealed sapphires were 200 and 900 arcsec, respectively. The substantial improvement of AlN quality is ascribed to reduction of dislocation density by sapph...
