Investigation of Size Dependence on Sensitivity for Nanowire FET Biosensors

Abstract

Label-free electrical detection of biomolecules is demonstrated with a double-gate (DG) nanowire (NW) field-effect transistor (FET). Experimental results confirm that detection sensitivity is favorably improved by the increment of NW size in the DG-NWFET, whereas it is enhanced by the decrement of NW size in a conventional single-gate (SG) NWFET. Sensitivity improvement by the augmentation of the NW size in the DG-FET paves the way to overcome technical challenges we face in achieving ultimate miniaturization of the NW size in the SG-FET. This result is comprehensively understood by simple capacitive modeling. The proposed model explains the observed experimental data and provides a design guideline for highly sensitive NW biosensors.