wherein said {HEAD ~ semiconductor layer} has {TAIL ~ a diamond} or zinc blende crystal structure, and 
has
wherein said { HEAD ~ semiconductor layer } has { TAIL ~ a diamond } or zinc blende crystal structure , and
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH