Nanocarbon based field effect transistors for biosensing applications

Nanocarbon materials, including Single Walled Carbon Nanotubes (SWNTs) and graphene, with their unique combination of electrical, physiochemical, and structural properties, has recently emerged as a novel nanoelectronic biosensor for chemical and biomolecular detection. Their major advantages; including the simple detection scheme, high sensitivity and selectivity, and capability to show real time monitoring; make those materials to receive increasing attention in the last few years. In the synthesis process of carbon nanotubes (CNTs), the product obtained is always mixture of metallic and semiconducting; an electrical property which is determined by their chiralities. Effective separation technique, which mainly aims for high purity semiconducting tubes, should be achieved to develop high-quality sensor. Among various techniques for chirality characterization, our results demonstrate that the electrical transport measurement (through Ion/Ioff ratio) of thin film Field Effect Transistors (FETs) is the most sensitive technique; compare to photoluminescence excitation spectroscopy, optical absorption spectroscopy, or Raman spectroscopy; in order to evaluate the purity of semiconducting CNTs.DOCTOR OF PHILOSOPHY (SCBE