GaN light-emitting diode with monolithically integrated photonic crystals and angled sidewall deflectors for efficient surface emission

In order to obtain efficient surface emission, we propose and demonstrate a GaN light-emitting diode (LED) structure. A two-dimensional photonic crystal (PC) pattern is integrated to the sapphire substrate before the epigrowth by employing laser holography. In addition, angled sidewall deflectors (ASDs) are formed on the mesa sidewalls. Both the PC and ASDs redirect guided photons into the surface-normal direction. When compared to a conventional LED structure, we could obtain a twofold increase in the total surface emission and the surface-normal emission intensity enhanced by a factor of 2.5.