We use a variety of micro and nanofabrication techniques to study individual nanotube circuits. We focus not only on electron but also phonon transport through nanotube devices. Our lab contains several measurement setups in which low noise spectroscopic data can be collected as a function of temperature (down to 30mK) and magnetic field (up to 12T). In collaboration with Prof. Fischer's Group in the Materials Science Department here at Penn, we also study an effect of alkali doping on individual nanotube circuits.
    One subset of our work involved nanotube devices. We have succesfully fabricated a nanotube based diode out of a semiconducting nanotube and a nanoscopic impurity (see R. D. Antonov and A. T. Johnson in the publication page.) We have also used scanning probe manipulation to create multi-tube devices. This work involves using an AFM tip to translate and rotate individual nanotubes into precribed positions. In one such experiment we used one nanotube in a crossed nanotube-nanotube junction to electrostatically dope the other. We showed that the transport through a nanotube is significantly altered by local doping. (see J. Lefebvre, et al. in the publication page.)
    Another project involves attaching 4 nanoscopic probes to large nanotube bundles (~1000 tubes each) and measuring transport as a function of temperature and electrostatic doping. This work reveals interesting information regarding the tube-tube interaction within a bundle. (in the process of being written up) Also, in collaborative effort with Prof. Fischer's Group, we have used these samples to study the effect of potassium doping on such a system.
    We have also explored a possibility of using nanotubes in nanofabrication. Nanotubes can make great lithographic masks due to their nanometer scale diameter and mechanical stiffness. We have successfully used nanotubes to create pairs of wide(up to 500nm) electrodes separated by nanometer spacings which are beyond the limit of conventional e-beam lithography. We have used such spacings to study small quantum wires made of metallic nanotubes, and short nanotube based field effect transistors. (submitted for publication.)