Patent ID: 8294164

Claim:
A light-emitting device comprising: an n-type semiconductor layer; a p-type semiconductor layer; an active layer interposed between the n-type semiconductor layer and the p-type semiconductor layer and emitting light by electrons supplied from the n-type semiconductor layer and holes supplied from the p-type semiconductor layer; and a clad layer having one or more units, the clad layer being provided between the p-type semiconductor layer and the active layer, wherein each unit has a structure in which a first to n th unit layers (n is a natural number equal to or greater than three) with different energy bandgaps are sequentially stacked and has an asymmetric energy band diagram, wherein the energy bandgap sizes of the first to n th unit layers which constitute the unit of the clad layer provided on the upper portion of the active layer increase in the order of the first to n th unit layers, and wherein the energy level of the valence band of the first unit layer nearest to the active layer is higher than that of the p-type semiconductor layer in a state where the electric field is applied in the direction from the n-type semiconductor layer to the p-type semiconductor layer while the energy level of the conduction band of the first unit layer nearest to the active layer is higher than that of the active layer in the state.