The
miniaturization of electronic devices is currently reaching its physical limits
for several different dimensions. In this situation, one possible extension of the
previous technology is the use of molecules to replace functional parts of the
device with the prospect of having devices built to a large degree or even
completely from molecules. For these molecular electronic devices, the atomic
structure and the electronic transport as a function of the structure can be
predicted from simulation
Example: Carbon-Nanotube Schottky Devices*
The
conductivity of semiconducting carbon nanotubes can be changed by an electric field, which allows
to switch a current through the nanotube on and off,
i.e., to use it as a transistor. One of the important questions in this area is
the influence of the contact structure on the current that can be sent through
the nanotube at a given voltage. We are studying
contact formation for carbon nanotubes in contact
with several metals using accelerated ab-initio
molecular dynamics methods and Landauer-type electron
transport models. We find significant influence of the contact on the
conductivity of the nanodevice (Fig. 3).
*W.
Windl, K. Ravichandran and L. Fonseca (to be
published).