Emergent elemental two-dimensional materials: an interview with leading scientist Guy Le Lay

By Tom Miller on January 25, 2017

Professor Guy Le Lay © Guy Le Lay

Journal of Physics D: Applied Physics recently published a fascinating Topical Review by leading 2D materials scientist, Guy Le Lay (Aix-Marseille Université). Guy and his co-authors focus on new elemental 2D materials such as silicene, phosphorene, germanene and stanene, discussing their properties and potential applications to electronic devices. Here, we talk to Guy Le Lay about his research, his views on where 2D materials research is heading and his former research life working for ESA and NASA. Read his Topical Review in JPhysD here. This review was published as part of the latest JPhysD special issue on 2D materials and electronic devices.

What research projects are you and your group currently working on?

We are currently working on the growth (on different crystalline substrates) and characterization (with diverse advanced complimentary experimental techniques and theoretical methods) of novel synthetic elemental column IV low-dimensional materials, which have no parent crystal in nature, at variance with graphene, which derives from graphite. These new emerging silicon, germanium and tin allotropes are created in the forms of epitaxial 0D hexasilabenzene-like Si nano-dots, massively parallel pentasilicene-like 1D crystalline Si nano-ribbons (SiNRs) with a definite width of just 8 or 16 Å, solely composed of pentagonal Si tiles, or 2D single- and multi-layer silicene and germanene sheets, as well as, presently, single-layer stanene sheets.

What motivated you to pursue this field of research?

The study started a few years before the advent of graphene, but, indeed, its isolation (by peeling graphite with scotch tape) by A. Geim and K. Novoselov, gave a strong further motivation to our research. We pursued the research because of the beauty of the STM images of the nano-objects we created, their exotic electronic, physical and chemical properties, and to unravel their hidden atomic structures (typically, inspired by the so-called UFO’s, or Unidentified Flying Objects, I originally named the aligned beautiful SiNRs lying on a silver template, ULO’s, or Unidentified Lying Objects!).

Where do you think the field is heading?

According to a recent citation-based study of the ten “hottest research fronts” in Physics of 2014 (see Charles Day, Physics Today, Sept. 25, 2015), “The growth and properties of silicene” is ranked fourth (after “Observation of Higgs boson”, Global neutrino data analysis”, and “Nonlinear massive gravity”), but first in Condensed Matter Physics, beating “MoS2 and transistors”. Despite its outstanding properties, because of the difficulty of opening a sizeable band gap, and because of the incompatibility of carbon-based materials with the current silicon-based technology, graphene is not suitable for use in digital electronics. To pursue Moore’s law beyond the 5 nm node, the use of such ultra-thin novel materials as silicene or germanene in functional devices will surely be necessary. An additional major advantage of silicene, germanene and stanene is the strong spin-orbit coupling, which makes these exotic 2D materials robust quantum spin Hall insulators with potential applications in spintronics and quantum computing.

What current problem facing humanity would you like science to provide a solution to?

I think that the key issue for a sustainable world is to solve the energy problem. Science will surely solve it at some point, e.g., either with the realization of more efficient solar cells and batteries and/or the development and implementation of fusion reactors.

What interests you outside of science?

Many aspects of cultural, social and political life, especially literature, visual arts, fashion design etc.

If you weren’t a scientist, what would you be?

I guess, I would be an artist, because my main motivation as a scientist is creativity.

And finally, tell us an interesting fact about yourself.

One of the most passionate times in my scientific life was when I was working with the ESA and the NASA as co- Principal Investigator of the Mercuric Iodide Crystal Growth experiment that flew onboard the Space Shuttle Discovery (Mission STS-42), in January 1992. The long preparation of the experiment, the close relationship with the astronauts and crew members, culminated with the launch at Kennedy Space Center, which I could attend, and the so exciting team work during the whole flight with the astronauts inside Discovery, as well as, at the Payload Operations Control Center of the Marshall Space Flight Center in Huntsville, Alabama, with the other three members of our MICG team, and all other participants of the International Microgravity Laboratory (IML-1).

On behalf of the Journal of Physics D: Applied Physics, I would like to thank Professor Le Lay for his time, and his contribution to the journal.

This work is licensed under a Creative Commons Attribution 3.0 Unported License. Front image and author image: copyright Guy Le Lay; used with permission. Not covered by CC-BY 3.0.