Abstract
High-quality GaN films were grown on AlN/sapphire templates by metal organic vapor phase epitaxy (MOVPE). Various characterizations were performed using Hall effect measurement, X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) and photoluminescence (PL). Hall mobilities of GaN were 790 and 1454 cm(2)/Vs with electron carrier concentrations of 7.6x10(16) and 1.8x10(16) cm(-3) at 300 and 77 K, respectively. The XRD full width at half maximum (FWHMs) were 61 and 232 arcsec for the (0004) and (20 (2) over bar4) reflections, respectively. AFM images showed smooth surface morphology and clear step formation. Additionally, pit terminations could be hardly found. Cross-sectional TEM observation indicates that the AlN films contribute greatly to the growth of high-quality GaN films on AlN/sapphire templates. High PL intensity near the band edge was observed.