Published: 04.08.11
Science

«Amazing opportunities»

Vanessa Wood is one of those scientists who can easily be described as a high-flyer. She graduated from Yale at 22, finished her doctorate at 26 and became a professor at 27. In this interview, the friendly nanoresearcher tells us what enticed her away from the Massachusetts Institute of Technology (MIT) to join ETH Zurich – where she is now working in areas such as the new «Binnig and Rohrer Nanotechnology Center».

Christine Heidemann
Vanessa Wood in her laboratory at ETH Zurich. The equipment in the background allows researchers to fabricate thin film LEDs, solar cells, and batteries. (Image: Tom Kawara)
Vanessa Wood in her laboratory at ETH Zurich. The equipment in the background allows researchers to fabricate thin film LEDs, solar cells, and batteries. (Image: Tom Kawara) (large view)

Ms. Wood, how did you hear that ETH Zurich was looking for a professor for nanophotonics and nanoelectronics?
I got a call from ETH in early February 2010. ETH was looking for someone in my field and had heard that I was applying to become a professor. So they invited me to apply here - and I did.

What made you decide to come to Zurich?
I was very impressed by the resources that were available and the other scientists I met when visiting here. It was clear there was a strong spirit of collaboration and enthusiasm for research.

When you say resources, you are speaking in particular about the new nanoresearch center in Rüschlikon, which ETH Zurich runs together with IBM.
My team and I are fortunate to have two research locations: an optoelectronics Laboratory on the «Zentrum» campus and an energy storage laboratory at

the «Binnig and Rohrer Nanotechnology Center». This Center also houses a clean room that is a shared space between ETH and IBM. The clean room is specifically designed to enable the introduction of new materials and processes to standard fabrication. This sort of facility is crucial for realizing the scientific and industrial potential of nanotechnology. It is not possible to bring exploratory nanomaterials into most clean rooms so the «Binnig und Rohrer Nanotechnology Center» addresses a major need and sets a new standard in doing so.

What exactly do you work on in the two laboratories?
We study charge transport in nanoscale systems and apply these findings to the design of devices such as solar cells, batteries, and light emitting devices. For example we focus on new techniques for characterizing battery materials and designing novel battery architectures. As you make battery active materials smaller, you have higher surface area to volume ratios. This means you can have features such as higher charge and discharge rates that could be of interest for electric vehicle applications.

What kind of sizes are we talking about for the nanomaterials that you use?
We are talking about sizes that are 80,000 times smaller than the diameter of a human hair. In our laboratory, we are interested in materials that have dimensions below 50 nanometers. Below this size scale, a material starts behaving very differently from the way larger particles of the same material behave.

Can you give us an example?
For example, if you take a bunch of large chunks of a given optically-active, semiconducting material, each chunk will absorb the same color light. However, if you take this same semiconductor material and make particles that range in size from 2 nanometers to 10 nanometers in diameter, you can get different color light absorbed from each sized particle because you have changed the electronic structure of the material. These nanoparticles, which we refer to as quantum dots, are extremely interesting for solar cell and lighting applications. But while quantum dots have outstanding optical properties, their small size also makes it difficult to transport charge. One of our research projects at the Laboratory for Nanoelectronics focuses on finding ways to benefit from the good optical properties of these materials without being limited by their poor electronic transport.

How important is the collaboration with the researchers from IBM in this respect?
Students from ETH who work in the clean room at the «Binnig and Rohrer Nanotechnology Center» will have the extraordinary opportunity to share space, equipment, and knowledge with IBM researchers, who are leaders in nanotechnology research and development. The spatial and intellectual proximity enabled by the Center will greatly facilitate our interactions with IBM researchers, and we look forward to building even more extensive collaborations with our IBM colleagues.

A lot of people are afraid that nanoparticles could enter the environment in an uncontrolled manner. What would you say to those people?
The first thing to remember is that nanotechnology can mean a lot of different things. Some research groups are interested in using nanoparticles for applications in health. In our laboratory, we do not work on any biological applications. Our nanoparticles are encapsulated in devices so they are not in contact with the human body or the environment. Nonetheless, all our labs have special air handling systems and chemical disposal procedures that are designed to isolate nanoparticles. We think it is better to take every precaution to keep researchers safe and ensure zero environmental impact.

What about the responsibility of the scientists themselves?
In general, I believe it is our ethical obligation as scientists and engineers to keep in mind the impact of the manufacturing and the disposal of the materials and products we develop. This is true for any technology, not only those involving nanomaterials. A first step is performing research to understand what the risks are. In Switzerland, we are fortunate to have a good dialogue about and investment in safety through the national research program «Chancen und Risiken von Nanomaterialien».

When will the first nanosolar cells appear on the market?
There is a lot of interest from companies right now in this area so I expect we will see products in the next few years. However, I do not think solar cells using nanomaterials will be a mature field for many years. Nanomaterials do not instantly make a better technology; we need to understand how and when to use them most effectively. But the open questions about nanomaterials and how best to use their novel properties is what makes this field so exciting to be a part of.

Vanessa Wood

joined the Department of Information Technology and Electrical Engineering at ETH Zurich in January 2011, where she leads the Laboratory for Nanoelectronics. Previously, she was a postdoctoral researcher with Professors Yet-Ming Chiang and Craig Carter in the Dept. of Materials Science and Engineering at MIT, where she studied nanostructured colloidal suspensions for energy storage applications. She also holds MS and PhD degrees from the Department of Electrical Engineering and Computer Science at MIT, during which she investigated colloidal nanocrystals for use in optoelectronic devices such as LEDs and solar cells.See also ETH Life from 18 May 2011 and 19 May 2011.

 
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