Gordon Moore, co-founder of the chip-manufacturer Intel, determined already in 1965 that the integration density of transistors on silicon chips would close to double every year. "Moore’s Law" is still applied today to forecast the performance increases of computers and the technological demands associated with these increases. According to Moore’s prognosis, the physically smallest possible transistor, built from only a few atoms or molecules, will be realized in about 20 years time.

In order to build the ultimate switch, however, new technologies are required because currently available methods are not up to the task. Here, new horizons are being opened by nanotechnology. Already today, materials can be manipulated in a controlled fashion on an atomic scale. Nobel Prize winner Richard Fenyman introduced this vision back in 1959 when he said, «The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom.»

The search for the construction set

Fact: Nanotechnologists at Empa are currently also trying to realize basic electronic elements through the assembly of suitable molecules: They are searching for the future construction set of circuit nano-elements. In the future, up to 109 transistors should fit onto an area of 1 square centimeter, more than a 1000 times the number on today’s Pentium 4 processor. In order to achieve this enormous density, the approach of molecular self-organization is being applied. This means that electronic circuits form themselves spontaneously from a myriad of molecules under suitable processing conditions.

From carbon atoms to circuits

The concept is copied from nature, which, with the help of a few molecular buildingblocks, the amino acids, has given rise to an unbelievable variety of life-forms. Currently, the suitable building-blocks for molecular electronics are being searched for at Empa. The department nanotech@surfaces in Thun, for example, is researching the electronic switch of the future. The central component of this transistor is a 42-carbon plate-like molecule, so-called hexabenzocoronene (HBC), which may be switched into an "on" or "off" state under the influence of a single electron. The research includes the topic of whether suitable chemical functionalization of this molecule will permit it to form self-organizing and complex supermolecular structures in combination with other molecules. In a few cases, researchers have been able to show that such technologies are basically feasible. They are, however, still far away from fundamentally understanding the associated phenomena and processes.

Ansprechperson

Dr. Pierangelo Gröning, Abt. nanotech@surfaces, Tel. +41 33 228 52 15, E-mail: pierangelo.groening@empa.ch

P. Ruffieux, P. Gröning, et al.: Supramolecular columns of hexabenzocoronenes on the copper and gold (111) surface. Phys. Rev. B 66, 073409 (2002)