The method 2 further including the step of maintaining {TAIL ~ a negative bias} with respect to {HEAD ~ the first electrode} and a positive bias with respect to the second electrode 
The method 2 further including the step of maintaining { TAIL ~ a negative bias } with respect to { HEAD ~ the first electrode } and a positive bias with respect to the second electrode
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH