Light emitting device and lighting system having the same

摘要

Disclosed are a light emitting device and a lighting system having the same. The light emitting device includes a first conductivity-type semiconductor layer, an interfacial layer including at least two superlattice structures adjacent to the first conductivity-type semiconductor layer, an active layer adjacent to the interfacial layer, and a second conductivity-type semiconductor layer adjacent to the active layer. The first conductivity-type semiconductor layer, interfacial layer, active layer, and second conductivity-type semiconductor layer are stacked in a same direction, the first and second semiconductor layer are of different conductivity types, an energy band gap of the superlattice structure adjacent to the active layer is smaller than an energy band gap of the superlattice structure adjacent to the first conductivity-type semiconductor layer.

主权项

1. A light emitting device comprising:
a first conductivity-type semiconductor layer; an interfacial layer including at least two superlattice structures adjacent to the first conductivity-type semiconductor layer; an active layer adjacent to the interfacial layer; and a second conductivity-type semiconductor layer adjacent to the active layer, wherein: the first conductivity-type semiconductor layer, the interfacial layer, the active layer, and the second conductivity-type semiconductor layer are stacked in a same direction, the first and second semiconductor layer are of different conductivity types, wherein each superlattice structure has at least a first layer, a second layer and a third layer disposed between the first layer and the second layer, the first layer and the second layer are repeated at least twice, wherein an energy band gap of the superlattice structure adjacent to the active layer is smaller than an energy band gap of the superlattice structure adjacent to the first conductivity-type semiconductor layer, and wherein a quantum wall forms a boundary between a first superlattice structure and a second superlattice structure, an energy band gap of the first layer in the first superlattice structure is same as an energy band gap of the second layer in the first superlattice structure, an energy band gap of the first layer in the second superlattice structure is same as an energy band gap of the second layer in the second superlattice structure, and the energy band gap of the first layer in the first superlattice structure is higher than the energy band gap of the first layer in the second superlattice structure, and wherein the first superlattice structure and the second superlattice structure are disposed between the first conductivity-type semiconductor layer and the active layer, wherein an energy band gap of the third layer is higher than the energy band gap of the first layer and the energy band gap of the second layer in each superlattice structure, and wherein an energy band gap of the third layer is smaller than an energy band gap of adjacent quantum walls.