Growth of high quality n-Al 0.5 Ga 0.5 N thick films by MOCVD

The control of stress, growth mode, and morphology in n-Al0.5Ga0.5N grown by metal-organic chemical vapor deposition (MOCVD) were systematically investigated. A 2-μm-thick completely relaxed n-Al0.5Ga0.5N was obtained by adjusting the structure of AlN/Al0.5Ga0.5N superlattices. N-Al0.5Ga0.5N showed an excellent 2D growth at a growth rate of 0.55 µm/h. An almost pit-free surface was realized by lowering the V/III ratio. Finally, the electron concentration and mobility of the optimized n-Al0.5Ga0.5N reached up to 4.2×1018 cm−3 and 48.2 cm2/(V s), respectively. The MQWs grown on the optimized n-Al0.5Ga0.5N demonstrated an outstanding internal quantum efficiency of 47% at 283 nm.