Nitride semiconductor light-emitting element

1. A nitride semiconductor light-emitting element comprising a light-emitting element structure portion having a plurality of nitride semiconductor layers including at least an n-type layer, an active layer and a p-type layer, wherein

the active layer disposed between the n-type layer and the p-type layer has a quantum well structure comprising at least one well layer composed of a GaN-based semiconductor,

in the well layer, a shortest distance between a first surface on the n-type layer side and a second surface on the p-type layer side varies in an orthogonal plane to the layering direction of the nitride semiconductor layers,

a peak emission wavelength of light emitted from the light-emitting element structure portion is shorter than 354 nm, and

an emission spectrum of light emitted from the light-emitting element structure portion has a composite peak formed by integrating at least two of a first peak of 339 nm or more and less than 343 nm, a second peak of 343 nm or more and less than 349 nm, and a third peak of 349 nm or more and less than 353 nm; and further including

an underlying portion including a sapphire substrate, wherein

the sapphire substrate has a main surface inclined by a predetermined angle with respect to a (0001) plane,

the light-emitting element structure portion is formed above the main surface, and

at least each layer from the main surface of the sapphire substrate to the surface of the active layer is an epitaxially grown layer having a surface on which multi-step terraces are formed.

2. The nitride semiconductor light-emitting element according to claim 1 , wherein a full width at half maximum of the composite peak is 10 nm or less.

3. The nitride semiconductor light-emitting element according to 1, wherein the emission spectrum has a composite peak formed by integrating the first peak and the second peak, and the peak emission wavelength is greater than or equal to 343 nm and less than 349 nm.