Patent ID: 7973322

Claim:
A nitride semiconductor light emitting device comprising: a first conduction type gallium nitride-based semiconductor region; a second conduction type gallium nitride-based semiconductor region; and an active layer which is provided between the first conduction type gallium nitride-based semiconductor region and the second conduction type gallium nitride-based semiconductor region so as to emit light having a wavelength in the range of 440 to 550 nm, wherein the active layer includes a well layer composed of hexagonal In x Ga 1-x N (0.16≦X≦0.35, the indium composition X: strained composition), a thickness D of the well layer is more than 2.5 nm, the thickness D of the well layer is 10 nm or less, the indium composition X and the thickness D satisfy X≧−0.1×D+0.6, the first conduction type gallium nitride-based semiconductor region, the active layer, and the second conduction type gallium nitride-based semiconductor region are disposed in a predetermined axis direction, the a-plane of the hexagonal In x Ga 1-x N is aligned in the predetermined axis direction, further comprising an n-type freestanding substrate composed of a hexagonal Al z Ga 1-z N semiconductor (0≦Z≦1), wherein the first conduction type gallium nitride-based semiconductor region, the active layer, and the second conduction type gallium nitride-based semiconductor region are mounted on a primary surface of the substrate, and an n-electrode located on the back surface of the substrate.