Patent ID: 6958497

Claim:
A Group III nitride based light emitting diode, comprising: a Group III nitride based superlattice comprising a gallium nitride based superlattice having at least two periods of alternating layers of In X Ga 1−X N and In Y Ga 1−Y N, where 0≦X<1 and 0≦Y<1 and X is not equal to Y; and a Group III nitride based active region on the superlattice comprising at least one quantum well structure comprising: a first Group III nitride based barrier layer comprising a first well support layer comprising a Group III nitride; a first Group III nitride based quantum well layer on the first barrier layer; and a second Group III nitride based barrier layer on the first Group III nitride based quantum well layer comprising a first cap layer comprising a Group III nitride on the first quantum well layer; a second well support layer comprising a Group III nitride on the cap layer; a second quantum well layer comprising a Group III nitride on the second well support layer; and a second cap layer comprising a Group III nitride on the second quantum well layer; and wherein the cap layers have a lower crystal quality than the well support layers.