Logic circuits based on individual semiconducting and metallic carbon-nanotubedevices

Abstract

Nanoscale transistors employing an individual semiconducting carbon nanotube as thechannel hold great potential for logic circuits with large integration densities that can bemanufactured on glass or plastic substrates. Carbon nanotubes are usually produced as amixture of semiconducting and metallic nanotubes. Since only semiconductingnanotubes yield transistors, the metallic nanotubes are typically not utilized.However, integrated circuits often require not only transistors, but also resistiveload devices. Here we show that many of the metallic carbon nanotubes thatare deposited on the substrate along with the semiconducting nanotubes can beconveniently utilized as load resistors with favorable characteristics for the design ofintegrated circuits. We also demonstrate the fabrication of arrays of transistorsand resistors, each based on an individual semiconducting or metallic carbonnanotube, and their integration on glass substrates into logic circuits with switchingfrequencies of up to 500 kHz using a custom-designed metal interconnect layer.