Fabrication of carbon nanotube field effect transistors and their detection of biotin-avidin attachment

Carbon nanotubes (CNTs) are biocompatible 1D nanomaterials that have generated much interest in the area of biosensing. Carbon nanotube based field effect transistors (CNT-FETs) have high on/off ratios, transconductance and sensitivity, as well as size compatibility for biosensing applications. The work covered in this report can be split into two areas, the fabrication of CNT networks and FETs through solution deposition, and the detection of biotin-avidin attachment using the CNT-FET devices through liquid front gate measurements. Three methods of solution deposition were tested, namely film transfer, dropcasting and dipcasting. Dropcasting gave the cleanest and most uniform networks, and also has higher on/off ratios and lower leak current. The fabrication of CNT-FET devices with high resistances was also carried out in an attempt to obtain higher sensitivity. However, such devices could not be fabricated with high consistency due to the nature of solution deposition. Biotin was conjugated to the CNT networks through a PEI/PEG polymer coating. The effect of the polymer coating on the electrical characteristics of the CNT network is different from what has been reported in other papers. The detection of the attachment of avidin to biotin also could not be detected with good consistency, and the possible reasons are given at the end of the report.Bachelor of Engineering (Chemical and Biomolecular Engineering