A red light emitting device comprising: a first conductivity type first semiconductor layer; an active layer on the first conductivity type first semiconductor layer and the active layer including a quantum well and a quantum barrier; a second conductivity type second semiconductor layer on the active layer; a second conductivity type third semiconductor layer on the second conductivity type second semiconductor layer; a second conductivity type fifth semiconductor layer on the second conductivity type third semiconductor layer, wherein the second conductivity type third semiconductor layer includes an AlGaInP-based semiconductor layer, wherein Al composition of the second conductivity type third semiconductor layer is graded, wherein the quantum barrier comprises a last quantum barrier closest to the second conductivity type second semiconductor layer and characterized in that the last quantum barrier comprises: a first last quantum barrier (114B1) having Al composition of a first concentration; and a second last quantum barrier (114B2) having Al composition of a second concentration higher than the first concentration, and wherein the second last quantum barrier (114B2) is provided closer to the second conductivity type second semiconductor layer than the first last quantum barrier (114B1), wherein the second conductivity type fifth semiconductor layer includes a superlattice structure of a GaP layer /In x Ga 1-x P (0≤x≤1) and comprises a third GaP layer directly under and directly above the superlattice structure of the GaP layer /In x Ga 1-x P (0≤x≤1), wherein the second conductivity type fifth semiconductor layer is doped with a second conductivity type dopant having a first dopant concentration, and the GaP layer is doped with the second conductivity type dopant having a second dopant concentration lower than the first dopant concentration, and the In x Ga 1-x P (0≤x≤1) layer is not doped with the second conductivity type dopants. a first conductivity type first semiconductor layer; an active layer on the first conductivity type first semiconductor layer and the active layer including a quantum well and a quantum barrier; a second conductivity type second semiconductor layer on the active layer; a second conductivity type third semiconductor layer on the second conductivity type second semiconductor layer; a second conductivity type fifth semiconductor layer on the second conductivity type third semiconductor layer, wherein the second conductivity type third semiconductor layer includes an AlGaInP-based semiconductor layer, wherein Al composition of the second conductivity type third semiconductor layer is graded, wherein the quantum barrier comprises a last quantum barrier closest to the second conductivity type second semiconductor layer and characterized in that the last quantum barrier comprises: a first last quantum barrier (114B1) having Al composition of a first concentration; and a second last quantum barrier (114B2) having Al composition of a second concentration higher than the first concentration, and wherein the second last quantum barrier (114B2) is provided closer to the second conductivity type second semiconductor layer than the first last quantum barrier (114B1), wherein the second conductivity type fifth semiconductor layer includes a superlattice structure of a GaP layer /In x Ga 1-x P (0≤x≤1) and comprises a third GaP layer directly under and directly above the superlattice structure of the GaP layer /In x Ga 1-x P (0≤x≤1), wherein the second conductivity type fifth semiconductor layer is doped with a second conductivity type dopant having a first dopant concentration, and the GaP layer is doped with the second conductivity type dopant having a second dopant concentration lower than the first dopant concentration, and the In x Ga 1-x P (0≤x≤1) layer is not doped with the second conductivity type dopants. a first last quantum barrier (114B1) having Al composition of a first concentration; and a second last quantum barrier (114B2) having Al composition of a second concentration higher than the first concentration, and wherein the second last quantum barrier (114B2) is provided closer to the second conductivity type second semiconductor layer than the first last quantum barrier (114B1), wherein the second conductivity type fifth semiconductor layer includes a superlattice structure of a GaP layer /In x Ga 1-x P (0≤x≤1) and comprises a third GaP layer directly under and directly above the superlattice structure of the GaP layer /In x Ga 1-x P (0≤x≤1), wherein the second conductivity type fifth semiconductor layer is doped with a second conductivity type dopant having a first dopant concentration, and the GaP layer is doped with the second conductivity type dopant having a second dopant concentration lower than the first dopant concentration, and the In x Ga 1-x P (0≤x≤1) layer is not doped with the second conductivity type dopants.