Light-emitting element

A light-emitting element comprising:

• a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, and a fourth semiconductor layer in this order, wherein:
• the first semiconductor layer is Alx1Iny1Ga1-x1-y1N (0≤x1≤1, 0≤y1≤1, 0≤x1+y1≤1), the second semiconductor layer is Alx2Iny2Ga1-x2-y2N (0≤x2≤1, 0≤y2≤1, 0 x2+y2≤1), the third semiconductor layer is Alx3Iny3Ga1-x3-y3N (0≤x3≤1, 0≤y3≤1, 0≤x3+y3≤1), and the fourth semiconductor layer is Alx4Iny4Ga1-x4-y4N (0≤x4≤1, 0≤y4≤1, 0≤x4+y4≤1),
• the second semiconductor layer and the third semiconductor layer contain a p-type impurity,
• a thickness of the second semiconductor layer is less than a thickness of the third semiconductor layer,
• an Al composition ratio x2 of the second semiconductor layer is greater than any of an Al composition ratio x1 of the first semiconductor layer, an Al composition ratio x3 of the third semiconductor layer, and an Al composition ratio x4 of the fourth semiconductor layer, and
• the Al composition ratio x3 of the third semiconductor layer is greater than the Al composition ratio x1 of the first semiconductor layer and the Al composition ratio x4 of the fourth semiconductor layer.