The TFT 6, wherein when {TAIL ~ the first impurity} is {HEAD ~ a group V recipient} the second impurity is a group III donor 
The TFT 6 , wherein when { TAIL ~ the first impurity } is { HEAD ~ a group V recipient } the second impurity is a group III donor
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH