Patent ID: 8415708

Claim:
A nitride-based semiconductor light-emitting device, comprising: a first clad layer made of Al x1 In y1 Ga( 1-x1-y1 )N (where 0<x 1 <1, 0<y 1 <1, and 0<x 1+ y 1 <1); a multiple quantum well-structured active layer made of undoped In A Ga 1-A N (where 0≦A<1) formed on the first clad layer; and a second clad layer formed on the multiple quantum well-structured active layer, including a first layer made of In y2 Ga 1-y2 N (where 0<y 2 <1) formed on the active layer and a second layer made of Al x3 In y3 Ga( 1-x3-y3 )N (where 0<x 3 <1, 0<y 3 <1, and 0<x 3 +y 3 <1) formed on the first layer and a third layer made of In y4 Ga 1-y4 N (where 0≦y4<1) formed on the second layer, the first layer being configured to enhance hole injection efficiency in the active layer and the second layer being configured to block electron from overflowing into the active layer, wherein the thickness of the first layer is smaller than the thickness of the second layer, wherein the first layer is substantially Al-free, wherein the first layer is in contact with the multiple quantum well-structured active layer, and wherein the third layer consist of a low concentration p-type GaN semiconductor layer having a first doping concentration formed on the second layer, and a high concentration p-type GaN semiconductor layer having a concentration higher than the first doping concentration formed on the low concentration p-type GaN semiconductor layer.