InGaN‐based LEDs grown by plasma‐assisted MBE on (0001) sapphire with GaN QDs in the nucleation layer

Blue‐violet LEDs based on InGaN MQWs were grown by RF‐plasma MBE on (0001) sapphire with GaN QDs incorporated in the nucleation layer as a mechanism of dislocation filtering. Devices with dimensions 800 μm x 800 μm were fabricated and evaluated at a bare die configuration by measuring their EL spectra and power output. At low injection current, the EL spectra peak at 440 nm. At high injection current a second peak at 385 nm becomes the dominant one and it is attributed to tunneling of injected electrons through the electron blocking layer. The dependence of the power output as a function of the injection current was studied systematically in order to evaluate the effects of heating. Power outputs up to 9 mW were measured at injection current of 1 A. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)