Patent ID: 7692209

Claim:
A semiconductor structure for light emitting devices that can emit in the red to ultraviolet portion of the electromagnetic spectrum, said structure comprising: a first n-type layer of Al x In y Ga 1−x−y N, where 0≦x≦1 and 0≦y<1 and 0<(x+y)≦1; a second n-type layer of Al x In y Ga 1−x−y N, where 0≦x≦1 and 0≦y<1 and 0(x+y)≦1, wherein said second n-type layer is undoped; an active layer of Al x In y Ga 1−x−y N, where 0≦x<1 and 0≦y≦1 and (x+y)≦1, wherein said active layer is n-type and is positioned between said first n-type layer and said second n-type layer; and a p-type layer of a Group III nitride on said second n-type layer, wherein said second n-type layer forms a p-n junction with said p-type layer; and wherein said n-type layers have a higher fraction of gallium than said active layer, such that said first and second n-type layers have respective bandgaps that are each larger than the bandgap of said active layer.