Because of the energy difference 410 that exists between {HEAD ~ the lowest empty electron energy state} 411 1 and the Fermi level Ef, {TAIL ~ electrons} cannot tunnel from the control gate 408 into the quantum dot 405 
Because of the energy difference 410 that exists between { HEAD ~ the lowest empty electron energy state } 411 1 and the Fermi level Ef , { TAIL ~ electrons } can not tunnel from the control gate 408 into the quantum dot 405
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH