A tradition of research –
then and now

Michel Côté

The pervasive presence of electronic components in our daily lives points up the importance of materials science. Michel Côté, an expert in the computation of material properties, is a professor in the Department of Physics. "The more we can manipulate different materials, the more we'll be able to manufacture devices that meet our expectations."

Michel Côté, working closely with engineers and experimental physicists, is attempting to predict laboratory results as accurately as possible. "Like auto makers who use computer-assisted design technology, I conduct virtual experiments before physicists embark on long, costly experiments. We are familiar enough with how electrons behave to evaluate various arrangements of atoms and single out the experiments mostly likely to produce results in real terms."

Light in optical fibres

Years of research and experimentation have improved understanding of the properties of silicon (Si). The vast majority of semiconductors (98%) used for transistors or diodes are now made from silicon, and the industry is constantly seeking to improve the manufacturing techniques.

Michel Côté's investigations are at the heart of a major effort in Quebec to make a semiconductor able to emit light in optical fibres. Gallium arsenide (GaAs) is a good possibility. "In theory, by adding atoms of nitrogen (N), we should obtain a material having the desired properties. This is not what happens in actual fact, however. We think the problem has to do with an excessive interaction between nitrogen atoms. Through modelling, we can vary selected parameters and suggest the best possible tests to the bench scientists."

Plastics as semiconductors

Researchers are becoming more and more excited about the semiconducting properties of some carbon-based organic materials, such as plastics. For one thing, semiconductor manufacturing costs could drop significantly if the devices were made from plastic. "Unlike materials such as silicon that require huge, costly manufacturing plants, organic materials are fairly simply to make," Michel Côté points out. "They can be made in a laboratory beaker through chemical reactions." They have some of the properties of plastics, especially flexibility. The first foldable screens are one example.

Michel Côté's vision goes even further. "What if we could make semiconductors that spread like paint! We just need to find the right polymers, meaning the right carbon chain. This supposes discovering how the atoms are organized and then modifying that arrangement."

For now, Michel Côté is trying to manufacture polymers for making semiconductors that emit blue light. This in itself is no simple matter. He is also looking into possibilities for boosting the performance of light-absorbing materials and transforming that light into energy, as with solar-powered calculator display screens, but over far larger surfaces. Here again, the right arrangement of atoms has to be found. Michel Côté's projects also include the fabrication of nanotubes, not with carbon as is now the case, but with gallium selenide (GaSe).