Nitride-based semiconductor light-emitting element

A nitride-based semiconductor light-emitting element, comprising:na GaN substrate, formed of a hexagonal GaN semiconductor and having a principal surface which makes a finite angle with a reference plane perpendicular to a reference axis extending in a c axis direction of the GaN semiconductor;an n-type nitride-based semiconductor layer;a p-type nitride-based semiconductor layer;a light-emitting layer including a plurality of well layers and a plurality of barrier layers, which are layered in alternation; anda strain relaxation layer formed of InGaN,wherein the strain relaxation layer includes defects due to misfit dislocations at an interface on the GaN substrate side of the strain relaxation layer;wherein n-type nitride-based semiconductor layer is provided between the GaN substrate and the light-emitting layer,wherein the strain relaxation layer is provided between the n-type nitride-based semiconductor layer and the light-emitting layer,wherein the principal surface exhibits semipolarity,wherein the finite angle is in a range of greater than or equal to 40° to less than or equal to 50° or in a range of greater than 90° to less than or equal to 130°,wherein the light-emitting layer is provided between the n-type nitride-based semiconductor layer and the p-type nitride-based semiconductor layer,wherein each of the plurality of well layers is formed of InGaN,wherein each of the plurality of barrier layers is formed of a GaN-based semiconductor,wherein a difference between a band gap energy of each of the plurality of well layers and a band gap energy of a barrier layer, from among the plurality of barrier layers, which is adjacent to each of the well layers is 0.7 eV or greater, andwherein a direction of piezoelectric polarization of each of the plurality of well layers is a direction from the n-type nitride-based semiconductor layer toward the p-type nitride-based semiconductor layer.