Abstract: A light emitting device based on a AlInGaN materials system wherein a coating is used to improve the extraction of light from a device. A coating has a very low optical loss and an index of refraction greater than 2. In a preferred embodiment the coating is made from Ta2O5, Nb2O5, TiO2, or SiC and has a thickness between about 0.01 and 10 microns. A surface of a coating material may be textured or shaped to increase its surface area and improve light extraction. A surface of the coating material can also be shaped to engineer the directionality of light escaping the layer. A coating can be applied directly to a surface or multiple surfaces of a light emitting device or can be applied onto a contact material. A coating may also serve as a passivation or protection layer for a device.

Abstract: A light-emitting device with an array of window openings to enhance the light extraction efficiency from this device is provided. This array of window openings is employed to create a much larger sidewall area to enhance the light extraction from the sidewalls of these openings. With this array of window openings, photons trapped due to the total internal reflection can propagate within the device and be extracted from the sidewalls of these openings. A variation of designs can be applied to the array of window openings. Even the shape of these openings can be designed such that the area of the sidewalls is increased. Large-sized light-emitting diodes can improve the light extraction efficiency by employing the array of window openings.

Abstract: The present invention utilizes high-indium-content InxGa1-xN islands (0<x?1) formed on a top of a p-type GaN based layer to reduce contact resistance between an electrode and the p-type GaN based layer. These InxGa1-xN islands serve as channels for electrical current to flow through and dramatically reduce the contact resistance between the electrode and the p-type GaN based layer so as to improve device performance. This structure of InxGa1-xN islands can be applied to all III-nitride based electronic and optoelectronic devices requiring good p-type ohmic contacts to improve device performance.