Technique may speed development of molecular electronics

To produce materials for modern electronics, small amounts of impurities are introduced into silicon - a process called doping. It is these impurities that enable electricity to flow through the semiconductor and allow designers to control the electronic properties of the material.

Scientists at the Weizmann Institute of Science, together with colleagues from the US, claim to be the first to implement doping in the field of molecular electronics - the development of electronic components made of single layers of organic molecules.

Such components might be inexpensive, biodegradable, versatile and easy to manipulate. The main problem with molecular electronics, however, is that the organic materials must first be made sufficiently pure and then ways must be found to successfully dope these somewhat delicate systems.

This is what Prof David Cahen and postdoctoral fellow Dr Oliver Seitz of the Weizmann Institute's Material and Interfaces Department, together with Dr Ayelet Vilan and Dr Hagai Cohen from the Chemical Research Support Unit and Prof. Antoine Kahn from Princeton University, did.

They showed that such contamination is possible, after they succeeded in purifying the molecular layer to such an extent that the remaining impurities did not affect the system's electrical behaviour.

The scientists doped the 'clean' monolayers by irradiating the surface with ultraviolet light or weak electron beams, changing chemical bonds between the carbon atoms that make up the molecular layer. These bonds ultimately influenced electronic transport through the molecules.

The researchers claim that this method may enable scientists and electronics engineers to substantially broaden the use of these organic monolayers in the field of nanoelectronics.