A bulk GaN layer is grown on {HEAD ~ the transitional layer} by {TAIL ~ HVPE} under the substantially 2D growth mode 
by
A bulk GaN layer is grown on { HEAD ~ the transitional layer } by { TAIL ~ HVPE } under the substantially 2D growth mode
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH