{TAIL ~ The carbon nanotubes} may extend across {HEAD ~ the entire channel region} or a portion of the channel region 
{ TAIL ~ The carbon nanotubes } may extend across { HEAD ~ the entire channel region } or a portion of the channel region
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH