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