Steve Purcell

Living on "N&Ns"

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© S. Godefroy/CNRS Photothèque

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This Canadian native from Halifax, Nova Scotia, first came to Lyon in 1992, intending to start production of nanometric electron sources. “I thought it would be a great way to enter the brand new field of nanoscience. I stayed because this city suits me in terms of quality of life. France is a country where life is good: its culture, its history, its monuments, walking through the small streets... even the language and the weather are attractive. Furthermore, CNRS research scientists have a very enviable position.” In fact, in 1982 Purcell chose Vancouver, British Columbia, to complete his Masters in solid-state physics. At Simon Fraser University (also in BC), he prepared his thesis on the “structure and magnetic properties of ultrathin layers of nickel on iron.” Those magnetic layers led him to the Netherlands for post-doctoral work at the Philips corporation, fulfilling his desire to live in Europe.

It was then that he turned to nanoscience. And on the fifth floor of his laboratory, he indulges in his favorite type of music. By applying an electrical voltage to nanotubes, Purcell modifies their resonance frequency in the same way that a musician produces different notes by adjusting string tension on a guitar. “It's as if I were tuning a nano-guitar,” he adds. But he can also make carbon nanotubes resonate in unison,² quite a feat considering that no two nanotubes are alike. This offers great hope for creating electromechanical systems on a scale of one billionth of a meter. The “Physics of nanostructures and field emissions” team he leads makes its own nanotubes,³ allowing researchers to manipulate all types of matter to the nearest atom.

Research scientists normally use nanotubes to induce the emission of an electrical field: By applying DC voltage, electrons are extracted from the ends of the nanotubes, making them a source of electrons for numerous applications (flat screens, radio frequency amplifiers, portable X-ray devices, etc.). But Purcell's team prefers to use this field emission to identify the properties of a nanotube or nanowire. The researchers thus manage to determine four nanotube properties: electrical conductivity, heat conductivity, absorption or emission of light, and mechanical rigidity. This has given them effective partnerships with companies like Thales but also with various laboratories including the Electronics and Information Technology Laboratory(Léti)⁴ at CEA (the Atomic Energy Commission).

This team has made Purcell a happy man: “Just twelve months ago, we were only two permanent employees–now there are five of us. And we're having a blast.” Their game is “N&Ns,” and their challenge is to help microelectronics reach nanometric scale... with a note of originality.

Magali Sarazin

© S. Godefroy/CNRS Photothèque