High‐efficiency AlGaN based UV emitters grown on high‐crystalline‐quality AlGaN using grooved AlN layer on sapphire substrate

Crack-free and low-dislocation-density AlGaN was successfully grown on grooved AlN layer. UV light-emitting diodes (LEDs) with a peak wavelength of 330 nm on these AlGaN films were fabricated. The efficiency of the UV LEDs is found to be strongly affected by the crystalline quality of the underlying AlN.