InGaN/GaN resonant-cavity LED including an AlInN/GaN bragg mirror
We report on the growth by metalorganic vapor phase epitaxy of a InGaN/GaN resonant-cavity light emitting diode (RCLED) emitting at 454 nm and incorporating a 12-pair Al0.82In0.18N/GaN distributed Bragg reflector as bottom mirror. A(1-x)In(x)N layers with an Al content around x similar to 0.17 are lattice matched to GaN, thus avoiding strain-related issues in the subsequent active layers while keeping a high refractive index contrast of 7%, comparable to that achievable in the Al0.5Ga0.5N/GaN system. Devices exhibit clear resonant-cavity effects, improved directionality in the radiation pattern and achieve an optical output of 1.7 mW and 2.6% external quantum efficiency at 20 mA. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.