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.

We propose an analytic model that accurately predicts the porosity and deposition rate of nanoporous films grown by oblique-angle deposition. The model employs a single fitting parameter and takes into account geometrical factors as well as surface diffusion. We have determined the porosity and deposition rate from the measured refractive index and thickness of SiO2 and indium tin oxide nanoporous films deposited at various incident angles. Comparison of experimental data with the model reveals excellent agreement. The theoretical model allows for the predictive control of refractive index, porosity, and deposition rate for a wide range of deposition angles and materials.