Scientists have long foreseen that the spectacular technological evolution in integrated circuits—which has led to the famous Moore’s law stating that the number of components per circuit doubles every 18 months—will soon attain insurmountable physical limitations requiring a complete reevaluation of the present-day technological industry. The development of CMOS technologies will enable these limits to be pushed back in the short term, but for the long term it will become necessary to invent new devices, and several possibilities are being explored simultaneously in laboratories. Molecular electronics have been the subject of increased focus over the last few years: molecules—typically organic ones—are used to carry out operations equivalent to those of transistors, diodes, switches and other components used in microelectronics on silicon. By extension, we can still talk of molecular electronics when we are no longer referring to single organic molecules but to organized mono-molecular layers and more generally when using the electronic properties of nano-objects or nano- structures where at least one of the dimensions is in the scale of molecular dimensions.
Molecular electronics clearly offer a number of advantages over conventional silicon electronics, first of all when the miniaturization of the components is concerned, which can theoretically be reduced to the ultimate size of atoms and molecules, not to mention the associated energy gains. Another great advantage will be offered some day by lower production costs, thanks to fabrication methods that will be simpler than lithography, implemented through a "bottom-up" approach.
In this report we will try to provide an overview of the various approaches that are being elaborated at present in American laboratories in order to develop new electronic devices on a molecular scale. In the first part we will deal with efforts relating to organic molecules, and in the two following sections we will describe the investigations which aim to exploit the exceptional electronic properties of carbon materials such as graphene and carbon nanotubes.
Contents:
1. Organic Molecules
1.1 Interest and difficulties
1.2 Tools for determining electrical characteristics of molecules
1.3 Fabrication of molecular junctions
1.4 Early break-junction devices
1.5 Early organic electronic devices
1.6 Modeling and multi-scale simulation
2 Graphene
2.1 Electronic properties
2.2 Obtaining graphene samples
2.3 Characterizing the physical properties of graphene
2.4 Graphene and molecular electronics
2. Carbon nanotubes
2.1 Interest and difficulties
2.2 Carbon nanotube devices
2.3 Other electronic applications for carbon nanotubes
Conclusion
Authors: ALLEGRE Raphaël – FAYOL Romaric – HERINO Roland – OCHOA Daniel
Publication date: 07/1/2007 – 23 pages – pdf 1,1 Mo
