Controlling the function of carbon nanotube devices with re-writable charge patterns

We use atomic force microscopy lithography to write charge patterns in close proximity to carbon nanotube field-effect transistor devices. The silicon dioxide substrate retains the charge for days, allowing various charge configurations to be tested. We show that the written charge can move the Fermi level in the nanotube by 1 eV and we use this charge lithography to reconfigure a field-effect transistor into a pn junction. The substrate charge can be erased and rewritten, offering a new tool for prototyping nanodevices and optimizing electrostatic doping profiles. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3622138]