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