As the scaling of silicon-based devices is approaching its limits, intense efforts are made to find ways to supplement or replace silicon electronics. One of the most promising systems for this purpose is carbon nanotubes (CNTs). CNTs are one-dimensional nanostructures with unique properties that make them ideal for applications in nanoelectronics and optoelectronics. Although a variety of different electronic devices based on CNTs have been demonstrated, most of the emphasis has been placed on CNT field-effect transistors (CNTFETs). In these devices a single semiconducting nanotube molecule replaces silicon as the transistor “channel.” The resulting devices have in many respects superior characteristics than conventional silicon devices. However, they also pose a set of new challenges. These include understanding the new physics of transport in one-dimension, deciphering the different device scaling laws, understanding charge-transfer and the formation of barriers at metal-nanotube interfaces, doping them, etc. In my talk I will discuss these issues and demonstrate solutions that allow the fabrication of not only individual devices with superior characteristics, but also more complex integrated circuits based on a single CNT molecule.
Unlike silicon, semiconducting CNTs allow the direct absorption and emission of light. We have used the radiative recombination of electrons and holes in CNTFETs to produce electrically-excited, single nanotube molecule light sources. We have also found that localized emission can be generated under unipolar transport conditions. The mechanism of this new type of electroluminescence will be discussed The reverse process of current generation by light illumination of a CNTFET has led to a single molecule photodetector.