Patent ID: 8829545

Claim:
A group III nitride semiconductor light-emitting device comprising: an n-type gallium nitride-based semiconductor layer; a first p-type Al X Ga 1-X N (0≦x<1) layer; an active layer including an InGaN layer, the active layer being provided between the n-type gallium nitride-based semiconductor layer and the first p-type Al X Ga 1-X N layer, the active layer being in physical contact with the first p-type Al X Ga 1-X N layer; a second p-type Al Y Ga 1-Y N (0≦Y≦x<1) layer provided on the first p-type Al X Ga 1-X N layer, a p-type dopant concentration of the second p-type Al Y Ga 1-Y N layer being greater than a p-type dopant concentration of the first p-type Al X Ga 1-X N layer, the second p-type Al Y Ga 1-Y N layer being in physical contact with the first p-type Al X Ga 1-X N layer, the p-type dopant concentration of the first p-type Al X Ga 1-X N layer continuously decreasing from the second p-type Al Y Ga 1-Y N layer to the active layer, a minimal p-type dopant concentration of the first p-type Al X Ga 1-X N layer being at the interface between the first p-type Al X Ga 1-X N layer and the active layer; a third p-type Al Z Ga 1-Z N layer (0≦z≦Y≦x<1) provided on the second p-type Al Y Ga 1-Y N layer, the p-type dopant concentration of the second p-type Al Y Ga 1-Y N layer being greater than a p-type dopant concentration of the third p-type Al Z Ga 1-Z N layer; and a p-electrode in physical contact with the third p-type Al Z Ga 1-Z N layer.