A nanometer size roughened structure is formed on a surface of a light-emitting element, and luminous efficiency is improved. The roughened structure on the surface of the light-emitting element of the invention is formed into the following shape such that the refractive index smoothly changes: (1) the...http://www.google.com/patents/US20050112886?utm_source=gb-gplus-sharePatent US20050112886 - Light-emitting device and method for manufacturing the same
