Light-extraction enhancement of GaInN light-emitting diodes by graded-refractive-index indium tin oxide anti-reflection contact

GaInN LEDs with a six-layer graded-refractive-index antireflection coating made entirely of indium tin oxide (ITO) are demonstrated to have 24.3 % higher light output than LEDs with dense ITO coating. The increased light-output of the LEDs with graded-refractive-index antireflection coating is attributed to the virtual elimination of Fresnel reflection and surface roughening of low-refractive index ITO.