Patent ID: 8212273
Filing Date: 2012-07-03
Classification: H01L

Abstract:
1. A light emitting device comprising: a first semiconductor layer having doping of a first type; a second semiconductor layer having doping of a second type; a light emitting region interposed between the first and second semiconductor layers, wherein light generated in the light emitting region is extracted from the device through a surface of the second semiconductor layer; a first multilayer reflector stack disposed proximal to the first semiconductor layer and distal to the second semiconductor layer, the first multilayer reflector stack at least partially covering the first semiconductor layer, wherein, in use, at least 60% of light that is generated in the light emitting region and that is incident on the first multilayer reflector stack is reflected by the first multilayer reflector stack; a first electrode disposed on the first multilayer reflector stack and at least partially covering the first multilayer reflector stack; and, a first network of electrically conductive elements disposed in the first multilayer reflector stack, wherein: the first reflector stack comprises at least three layers, including two layers of different materials having different refractive indexes, and a layer of a metal, the two layers disposed distal to the first electrode and the layer of metal disposed proximal to the first electrode, the conductive elements of the first network extending through said two layers to the layer of metal whereby to provide an electrically conductive path between the first semiconductor layer and the first electrode, at least one of the first semiconductor layer, the second semiconductor layer and the light emitting region has a refractive index with a magnitude greater than that of the lowest refractive index of material residing in the first multilayer reflector stack by a factor of at least 1.25; and, location, shape and transverse dimensions of the electrically conductive elements in the first network are predetermined such that, in use, light generated in the light emitting region that is incident on the first network of conductive elements is reflected and is forbidden to couple into localized or propagating surface plasmon modes associated with the first network of electrically conductive elements.