Abstract: Provided is a light emitting device, which includes a second conductive type semiconductor layer, an active layer, a first conductive type semiconductor layer, and a intermediate refraction layer. The active layer is disposed on the second conductive type semiconductor layer. The first conductive type semiconductor layer is disposed on the active layer. The intermediate refraction layer is disposed on the first conductive type semiconductor layer. The intermediate refraction layer has a refractivity that is smaller than that of the first conductive type semiconductor layer and is greater than that of air.

Abstract: Provided is a light emitting device, which includes a second conductive type semiconductor layer, an active layer, a first conductive type semiconductor layer, and a intermediate refraction layer. The active layer is disposed on the second conductive type semiconductor layer. The first conductive type semiconductor layer is disposed on the active layer. The intermediate refraction layer is disposed on the first conductive type semiconductor layer. The intermediate refraction layer has a refractivity that is smaller than that of the first conductive type semiconductor layer and is greater than that of air.

Abstract: Provided are a semiconductor light emitting device. The semiconductor light emitting device comprises a first semiconductor layer; a second semiconductor layer disposed on the first semiconductor layer; an active layer disposed between the first semiconductor layer and the second semiconductor layer; a third semiconductor layer disposed on the second semiconductor layer; and a fourth semiconductor layer disposed on the third semiconductor layer. The second semiconductor layer is formed of an InAlGaN semiconductor layer, the third semiconductor layer is formed of an AlGaN semiconductor layer, and the fourth semiconductor layer is formed of a GaN semiconductor layer.

Abstract: Provided is a light emitting device, which includes a second conductive type semiconductor layer, an active layer, a first conductive type semiconductor layer, and a intermediate refraction layer. The active layer is disposed on the second conductive type semiconductor layer. The first conductive type semiconductor layer is disposed on the active layer. The intermediate refraction layer is disposed on the first conductive type semiconductor layer. The intermediate refraction layer has a refractivity that is smaller than that of the first conductive type semiconductor layer and is greater than that of air.

Abstract: A semiconductor light emitting device includes a first nitride semiconductor layer, a dopant doped semiconductor layer on the first nitride semiconductor layer, an active layer on the dopant doped semiconductor layer, a delta doped layer on the active layer, a superlattice structure on the delta doped layer, an undoped layer on the superlattice layer, a second nitride semiconductor layer including a first n-type dopant, a third nitride semiconductor layer including a second n-type dopant, and a fourth nitride semiconductor layer including a third n-type dopant.

Abstract: Provided are a semiconductor light emitting device. The semiconductor light emitting device comprises a first semiconductor layer; a second semiconductor layer disposed on the first semiconductor layer; an active layer disposed between the first semiconductor layer and the second semiconductor layer; third semiconductor layer disposed on the second semiconductor layer; and a fourth semiconductor layer disposed on the third semiconductor layer. The second semiconductor layer is formed of an InAlGaN semiconductor layer, the third semiconductor layer is formed of an AlGaN semiconductor layer, and the fourth semiconductor layer is formed of a GaN semiconductor layer.

Abstract: A light emitting device, a method of manufacturing the same, a light emitting device package, and a lighting system are disclosed. The light emitting device may include a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer interposed between the first and second conductive semiconductor layers. The first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer may include Al. The second conductive semiconductor layer may have Al content higher than Al content of the first conductive semiconductor layer. The first conductive semiconductor layer may have Al content higher than Al content of the active layer.

Abstract: Provided is a light emitting device, which includes a second conductive type semiconductor layer, an active layer, a first conductive type semiconductor layer, and a intermediate refraction layer. The active layer is disposed on the second conductive type semiconductor layer. The first conductive type semiconductor layer is disposed on the active layer. The intermediate refraction layer is disposed on the first conductive type semiconductor layer. The intermediate refraction layer has a refractivity that is smaller than that of the first conductive type semiconductor layer and is greater than that of air.

Abstract: Provided are a semiconductor light emitting device and a method of manufacturing the same. The semiconductor light emitting device comprises a first conductive type semiconductor layer, an active layer, a first thin insulating layer, and a second conductive type semiconductor layer. The active layer is formed on the first conductive type semiconductor layer. The first thin insulating layer is formed on the active layer. The second conductive type semiconductor layer is formed on the thin insulating layer.

Abstract: A light emitting device, a method of manufacturing the same, a light emitting device package, and a lighting system are disclosed. The light emitting device may include a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer interposed between the first and second conductive semiconductor layers. The first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer may include Al. The second conductive semiconductor layer may have Al content higher than Al content of the first conductive semiconductor layer. The first conductive semiconductor layer may have Al content higher than Al content of the active layer.

Abstract: A semiconductor light emitting device includes a first nitride semiconductor layer, a dopant doped semiconductor layer on the first nitride semiconductor layer, an active layer on the dopant doped semiconductor layer, a delta doped layer on the active layer, a superlattice structure on the delta doped layer, an undoped layer on the superlattice layer, a second nitride semiconductor layer including a first n-type dopant, a third nitride semiconductor layer including a second n-type dopant, and a fourth nitride semiconductor layer including a third n-type dopant.

Abstract: A semiconductor light emitting device includes a first nitride semiconductor layer, a dopant doped semiconductor layer on the first nitride semiconductor layer, an active layer on the dopant doped semiconductor layer, a delta doped layer on the active layer, a superlattice structure on the delta doped layer, an undoped layer on the superlattice layer, a second nitride semiconductor layer including a first n-type dopant, a third nitride semiconductor layer including a second n-type dopant, and a fourth nitride semiconductor layer including a third n-type dopant.

Abstract: A light emitting device, a method of manufacturing the same, a light emitting device package, and a lighting system are disclosed. The light emitting device may include a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer interposed between the first and second conductive semiconductor layers. The first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer may include Al. The second conductive semiconductor layer may have Al content higher than Al content of the first conductive semiconductor layer. The first conductive semiconductor layer may have Al content higher than Al content of the active layer.

Abstract: Provided are a semiconductor light emitting device and a method of manufacturing the same. The semiconductor light emitting device comprises a first conductive type semiconductor layer, an active layer, a first thin insulating layer, and a second conductive type semiconductor layer. The active layer is formed on the first conductive type semiconductor layer. The first thin insulating layer is formed on the active layer. The second conductive type semiconductor layer is formed on the thin insulating layer.

Abstract: A wafer recycling method comprises varying a temperature and pressure conditions to remove a first semiconductor layer deposited on a wafer, removing a remaining semiconductor layer on the wafer through a chemical or physical process, and washing the wafer.

Abstract: A light emitting device includes a second metal layer, a second semiconductor layer on the second metal layer, an active layer on the second semiconductor layer, a first semiconductor layer on the active layer, a first metal layer on the first semiconductor layer, an insulating layer between the second metal layer and the second semiconductor layer at a peripheral portion of an upper surface of the second metal layer, and a passivation layer surrounding lateral surfaces of the insulating layer, the second semiconductor layer, the active layer, and the first semiconductor layer, the passivation layer being on the second metal layer, wherein a lateral surface of the insulating layer is adjacent to a lateral surface of the second metal layer, and wherein a lowermost surface of the passivation layer is disposed lower than a lowermost surface of the insulating layer.

Abstract: Provided is a light emitting device, which includes a first conductive type semiconductor layer, an active layer, a roughness pattern, and a second conductive type semiconductor layer. The active layer is disposed on the first conductive type semiconductor layer. The roughness pattern is disposed on the active layer. The second conductive type semiconductor layer is disposed on the roughness pattern and the active layer, and includes a metal oxide.

Abstract: Provided are a semiconductor light emitting device and a method of manufacturing the same. The semiconductor light emitting device comprises a first conductive type semiconductor layer, an active layer, a first thin insulating layer, and a second conductive type semiconductor layer. The active layer is formed on the first conductive type semiconductor layer. The first thin insulating layer is formed on the active layer. The second conductive type semiconductor layer is formed on the thin insulating layer.

Abstract: Provided is a light emitting device, which includes a second conductive type semiconductor layer, an active layer, a first conductive type semiconductor layer, and a intermediate refraction layer. The active layer is disposed on the second conductive type semiconductor layer. The first conductive type semiconductor layer is disposed on the active layer. The intermediate refraction layer is disposed on the first conductive type semiconductor layer. The intermediate refraction layer has a refractivity that is smaller than that of the first conductive type semiconductor layer and is greater than that of air.

Abstract: A light emitting device may include a first conductive semiconductor layer, an active layer adjacent to the first conductive semiconductor layer and a second conductive semiconductor layer adjacent to the active layer. The active layer may include a first quantum well layer, a second quantum well layer and a barrier layer between the first quantum well layer and the second quantum well layer. The first quantum well layer may include a first plurality of sub-barrier layers and a first plurality of sub-quantum well layers, and the second quantum well layer may include a second plurality of sub-barrier layers and a second plurality of sub-quantum well layers. A bandgap of the first quantum well layer may be different than a bandgap of the second quantum well layer.