Quantitative assessment of diffusivity and specularity of surface-textured reflectors for light extraction in light-emitting diodes

Surface-textured reflectors fabricated by natural lithography and ion beam etching have a specular and a diffusive component of the reflectivity. The diffusely and specularly reflected powers of surface-textured reflectors are measured and analyzed quantitatively in terms of a theoretical model. The diffusive-power-to-total-power ratio is determined and shown to strongly depend on the surface texture. The light extraction efficiency from a waveguide clad by a partially diffuse reflector is analyzed and shown to be enhanced.