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