Dielectric control of electrostatic barriers for molecular electronics

We describe an approach for controlling electrostatic barriers in molecular electronics devices which uses anisotropic dielectric material to modify t he analytic form of the effective electrostatic interactions within the dev ice. We study the one-dimensional geometry relevant to interfaces between c arbon nanotubes and find that the bound charge induced in a uniaxial dielec tric can replace the bare electrostatic interaction between charges with se paration z by an effective -log(z) interaction or a confining \z\ interacti on. We use these models to study the depletion region formed at heterojunct ions between segments of doped carbon nanotubes. (C) 2001 American Institut e of Physics.