Oct 26, 2007
Carbon nanotubes’ non-volatile memory elements
The term nanoelectronics is defined as a type of electronics integrated in a lateral scale associated with a minimum feature size that is significantly smaller than tens of nanometers. Under this definition, a number of phenomena stemming from quantum confinement dominate the processes governing the electron flow. For practical applications, the role of fundamental research is to investigate how a new material can be employed in useful devices. This is particularly important for nanoelectronics since any new technology must display significant benefits and advantages over conventional approaches. In this respect, carbon nanotubes are among the most versatile candidate materials for nanoelectronics, a dominant position that originates from their intrinsic structural and electronic properties.
From extensive theoretical studies, I recently proposed, in collaborative work with Bobby Sumpter at the Center for Nanophase Materials Sciences at the Oak Ridge National Laboratory, a new type of electronic switching device whose state depends on the relative position of a guest molecule inside a carbon nanotube. The mechanism is governed by the local molecular gating that modifies the electronic properties of the nanotube host. One stable position of the molecule yields a high current across the device (“ON” state) while a change in orientation is associated with an important, measurable decrease of the transmission property (“OFF” state).
The information is therefore stored in the form of the orientation of the molecule, which retains its position even when the external source of energy is switched off (non-volatility). Due to the intrinsic mechanical properties of the nanotube, the molecule’s orientation can be switched mechanically. We predicted that the information storage mechanism could be applied to any molecule-metallic nanotube combination as long as it displays the desired properties of significant charge transfer and the presence of at least two metastable molecule positions with respect to the nanotube core.
If realized in the laboratory, the nano-device studied here theoretically, is expected to be of great use in a large range of applications that require extreme miniaturization and low energy consumption.
About the author
|Vincent Meunier is an R&D staff scientist at Oak Ridge National Laboratory where he conducts theoretical and computational work in a range of areas related to nanoscience.|