The difference in the contact potential measured before and after heating provides an indication of {HEAD ~ the mobile ion concentration} in {TAIL ~ the oxide layer} 
in
The difference in the contact potential measured before and after heating provides an indication of { HEAD ~ the mobile ion concentration } in { TAIL ~ the oxide layer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL