Effect of phosphate buffered saline solutions on top-down fabricated ZnO nanowire field effect transistor

Abstract

ZnO based nanowire FETs have been fabricated by implementing a top-down approach, which uses optical photolithography, atomic layer deposition (ALD) of ZnO thin film, and anisotropic plasma etching. The effects of Phosphate Buffered Saline (PBS) solution on the surface of ZnO nanowire were investigated by measuring the FET characteristics at different PBS dilutions. The drain current, ION, exhibited an increase of 39 times in the highest PBS solution concentration compared to measurement in air. From the measured transfer characteristics and output characteristics in various PBS dilutions, the device was found to maintain n-type behaviour. These results indicate that the device can be effectively used for biomolecules sensing.