1. Field of the Invention
The present invention relates to a light emitting diode, and more particular, to a light emitting diode having a strain-enhanced well layer.
2. Discussion of the Background
Generally, a Group III-V nitride-based laser diode/light-emitting diode (LD/LED) includes an InxGa1-xN buffer layer, an n-GaN layer, an active layer having a quantum-well structure of InGaN/GaN, a p-AlGaN electron blocking layer, and a p-GaN layer, which are sequentially formed on a patterned sapphire substrate having a c-plane (0001).
In a general GaN/In0.15Ga0.75N quantum-well structure, an InGaN well layer has compressive strain of about 1.6%. In the related art, since strain applied to an active layer has been considered to deteriorate efficiency, a strain relieving technique has been developed.
On the other hand, a high brightness LED undergoes a droop phenomenon wherein optical output efficiency decreases with increasing drive current. Therefore, there is a need to relieve the droop phenomenon of a light emitting diode in order to obtain high optical efficiency at high drive current.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form any part of the prior art nor what the prior art may suggest to a person of ordinary skill in the art.