Nitride based semiconductor optical device, epitaxial wafer for nitride based semiconductor optical device, and method of fabricating semiconductor light-emitting device

Abstract

In the nitride based semiconductor optical device, the strained well layers extend along a reference plane tilting at a tilt angle α from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. A gallium nitride based semiconductor layer is adjacent to a light-emitting layer with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer and the gallium nitride based semiconductor layer.

1 . 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.   
     
     
         2 - 20 . (canceled)