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