Reconfigurable Carbon Nanotube Network Devices

Semiconducting single-walled carbon nanotubes (SWNTs) are an attractive channel material for a wide range of applications, from flexible, low cost printed electronics to high performance field effect transistors. Though recent advances in developing high purity semiconducting SWNT solutions have yielded devices with excellent on/off ratios and improved ON currents, determining the true nature of conduction of a network with a mixture of metallic and semiconducting nanotubes remains a challenge. Here, we fabricated split-gate devices that can reconfigure as either a metal-oxide-semiconductor field effect transistor (MOSFET) or a p-n diode. The spacing between the split gates was varied from 10 μm down to 100 nm to allow a detailed comparison between properties of unipolar conduction (MOSFET) and that of ambipolar transport dominated by minority carriers (p-n Diode). In addition, we varied the metallic concentration of SWNTs in the network channel. We show that the conduction is determined not only by the metallic concentration, but also by the environment that acts as strong generation and recombination centers.