Electrical properties of carbon nanotube FETs

The electrical properties of carbon nanotube FETs (CNTFETs) have been studied in detail. The conduction type of the CNTFETs was dependent on the work function of the contact metal, which suggests that Fermi level pinning at the metal/nanotube interface is not strong. Chemical doping using F⁴TCNQ was found to be effective in reducing not only the channel resistance but also the contact resistance. In the CNTFETs fabricated using PECVD-grown nanotubes, the drain current of the most of the devices could be modulated by the gate voltage with small OFF current suggesting the preferential growth of the nanotubes with semiconducting behavior. Multichannel top-gate CNTFETs with horizontally-aligned nanotubes have been successfully fabricated using CNT growth on the ST-cut quartz substrate. CNTFETs with nanotube network have also been fabricated by using grid-inserted PECVD and catalysts formed on the channel area of the FETs. The uniformity of the electrical properties of the network channel CNTFETs was very good.