removing {HEAD ~ at least one portion} of the plurality of carbon nanotubes to expose {TAIL ~ at least one portion} of the semiconductor substrate within the plurality of carbon nanotubes 
to expose
removing { HEAD ~ at least one portion } of the plurality of carbon nanotubes to expose { TAIL ~ at least one portion } of the semiconductor substrate within the plurality of carbon nanotubes
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH