Near-UV LEDs on sapphire using single crystal AlN-buffer

UV-LEDs were fabricated on GaN formed on sapphire using high-temperature-grown AlN buffer. For flip-chip devices, peak wavelength, output power, operation voltage and external quantum efficiency at 20 mA were 383 nm, 23 mW, 3.5 V and 36%, respectively. The internal quantum efficiency was estimated to be as high as 72%. These values were comparable to those for visible LEDs.