Nitride semiconductor light emitting device, ultraviolet light emitting module

A nitride semiconductor light emitting device comprising:

• a substrate;
• a nitride semiconductor laminate containing a first nitride semiconductor layer having a first conductivity type formed on the substrate, a nitride semiconductor light emitting layer formed on the first nitride semiconductor layer, and a second conductivity type second nitride semiconductor layer formed on the nitride semiconductor light emitting layer, the nitride semiconductor light emitting layer and the second nitride semiconductor layer being formed in one part on the first nitride semiconductor layer to configure a mesa portion, wherein a side surface of the mesa portion is defined by the second nitride semiconductor layer, the nitride semiconductor light emitting layer, and a portion of the first nitride semiconductor layer;
• a first electrode layer formed on the first nitride semiconductor layer except the one part;
• and
• a second electrode layer formed on the second nitride semiconductor layer, wherein
• a planar shape of the mesa portion is a shape containing a convex-shaped tip portion formed by a curved line or a plurality of straight lines and a base portion continuous to the convex-shaped tip portion, the convex-shaped tip portion formed by the plurality of straight lines having an obtuse angle formed by adjacent two straight lines, and
• an angle θ (≤90°) defined by a cross angle between the side surface of the mesa portion facing the first electrode layer and a surface parallel to a surface of the substrate on which the first nitride semiconductor layer is formed is smaller in the convex-shaped tip portion than in the base portion.