Patent ID: 8148716

Claim:
A group III nitride semiconductor optical device comprising: a substrate comprising a group III nitride semiconductor; a first group-III nitride semiconductor region provided on a primary surface of the substrate; a second group-III nitride semiconductor region provided on the primary surface of the substrate; and an active layer provided between the first group-III nitride semiconductor region and the second group-III nitride semiconductor region; the primary surface of the substrate tilting with respect to a plane perpendicular to a reference axis at a tilt angle in a range of not less than 63 degrees and less than 80 degrees, the reference axis extending along the c-axis of the group III nitride semiconductor toward an m-axis of the group III nitride semiconductor; the first group-III nitride semiconductor region including a first conductive type semiconductor layer; the second group-III nitride semiconductor region including a second conductive type semiconductor layer; the first group-III nitride semiconductor region, the active layer, and the second group-III nitride semiconductor region being arranged in a direction of an axis normal to the primary surface of the substrate; the active layer being provided to generate light having a wavelength in a range of 580 nm to 800 nm; the active layer including an epitaxial semiconductor layer, the epitaxial semiconductor layer comprising a gallium nitride based semiconductor, the gallium nitride based semiconductor containing indium as a group III element; the epitaxial semiconductor layer having an indium content ranging from 0.35 to 0.65; the c-axis of the gallium nitride based semiconductor tilting with respect to the normal axis; and the reference axis being oriented in a direction of one of [0001] axis and [000−1] axis of the group III nitride semiconductor.