Patent ID: 8304793

Claim:
A III-nitride semiconductor optical device comprising: a support base comprised of a III-nitride semiconductor and having a primary surface at an angle with respect to a reference plane perpendicular to a reference axis, the reference axis extending in a c-axis direction of the III-nitride semiconductor; an n-type gallium nitride based semiconductor layer provided on the primary surface of the support base; a p-type gallium nitride based semiconductor layer provided on the primary surface of the support base and doped with magnesium; and an active layer provided between the n-type gallium nitride based semiconductor layer and the p-type gallium nitride based semiconductor layer on the primary surface of the support base, the angle being in the range of not less than 40 degree and not more than 140 degree, the primary surface having either one of semipolar nature and nonpolar nature, the p-type gallium nitride based semiconductor layer containing carbon as a p-type dopant, a carbon concentration of the p-type gallium nitride based semiconductor layer being not less than 2×10 16 cm −3 , and the carbon concentration of the p-type gallium nitride based semiconductor layer being not more than 1×10 19 cm −3 .