The contact is made by etching {HEAD ~ the film} with {TAIL ~ an acidic solution} and thereafter treating the etched surface with an alkaline solution 
The contact is made by etching { HEAD ~ the film } with { TAIL ~ an acidic solution } and thereafter treating the etched surface with an alkaline solution
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH