In a preferred embodiment, the LED has {TAIL ~ double heterojunction structure} having a semiconductor active layer between {HEAD ~ two confinement layers} 
In a preferred embodiment , the LED has { TAIL ~ double heterojunction structure } having a semiconductor active layer between { HEAD ~ two confinement layers }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD