Patent ID: RE45059

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 (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 (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 is positioned between said p-type layer and said active layer ; and a third n-type 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 third n-type layer is positioned between said second n-type layer and said p-type layer, 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 , and wherein at least one of said first and second n-type layers comprises aluminum .