Patent ID: 8067257

Claim:
A nitride based semiconductor optical device comprising: a first gallium nitride based semiconductor region; a light-emitting layer including a well layer and a barrier layer, the well layer being composed of a strained hexagonal gallium nitride based semiconductor, and the barrier layer being composed of gallium nitride based semiconductor; and a second gallium nitride based semiconductor region, the light-emitting layer being provided between the first gallium nitride based semiconductor region and the second gallium nitride based semiconductor region; the first gallium nitride based semiconductor region including one or more n-type gallium nitride semiconductor layers; the second gallium nitride based semiconductor region including a gallium nitride based semiconductor layer and one or more p-type gallium nitride semiconductor layers, the gallium nitride based semiconductor layer having a band gap larger than that of the barrier layer; each of the well layer and the barrier layer extending along a reference plane, the reference plane tilting at a tilt angle in the range of 59 degrees to less than 80 degrees and greater than 150 degrees to less than 180 degrees from a plane orthogonal to a reference axis, the reference axis extending in the direction of a c-axis; a piezoelectric field in the light-emitting layer including a component of a direction opposite to a direction from the second gallium nitride based semiconductor region toward the first gallium nitride based semiconductor region; the gallium nitride based semiconductor layer of the second gallium nitride based semiconductor region being adjacent to the light-emitting layer; and the gallium nitride based semiconductor layer of the second gallium nitride based semiconductor region including one of an electron blocking layer and a cladding layer.