Fabrication and evaluation of nano probe pH sensor based on nanorobotic manipulation

This paper presets the assembly of a nanowire probe pH sensor and evaluation inside acid and alkali. An AFM cantilever was used for electrodes of the device and etched by FIB. Two carbon nanotubes (CNT) were assembled to the separated electrodes of AFM cantilever. A tungsten probe is etched by focused ion beam (FIB) into 300 nm in diameter and 25 in length. Then the probe is coated by parylene and cut the tip to open the tungsten. A tungsten nanowire is used for work electrode and a platinum nanowire is used for counter electrode. The nanowires were fabricated via field emission method by introducing hexacabonyl tungsten and trimethyl cyclopentadienyl platinum individually inside a field emission electron microscope. The nano probe pH sensor is tested inside acid and alkali buffer solution with different response.