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Thinnest Material

Thinnest Material Photo Credit: Ephemeronium [CC0], via Wikimedia Commons

The world's thinnest material has been created, and nothing can top it.


Transcript

Eliminating the third dimension. I'm Bob Hirshon and this is Science Update.

A few years ago, scientists created the thinnest material possible: a coating that's only one atom thick. It's called graphene, a form of graphite, the so-called “lead” in a pencil. Now, two teams of researchers have created free-standing sheets of graphene, which even recently was thought impossible. Physicist Andre Geim, of Manchester University in England, says that despite its thinness, graphene is remarkably strong and stable.

Geim:

To break bonds in graphene, it requires a stronger force than in the case of diamonds. So that's the toughest and, at the same time, lightest membrane.

That means sheets of graphene could be used in many high-tech applications, including platforms for single molecules, filters for very light gases, and transistors for computer chips. I'm Bob Hirshon, for AAAS, the science society.


Making Sense of the Research

You can't make anything thinner than graphene, one of several new two-dimensional materials in our three-dimensional world. It's only one atom thick, which is less than a nanometer (one billionth of a meter)—or, to put it in perspective, well over 100,000 times thinner than a typical sheet of copy paper. This research falls under the rapidly growing field of nanotechnology: the development of materials, devices, and electronic components on the nanometer scale: the scale of the smallest units of matter.

As the story mentions, Geim and his colleagues had already created a graphene film that coated another substance. However, making a free-standing sheet of graphene isn't the same as making a coating. With nothing to support it, scientists assumed that the graphene sheet would curl up into a ball or some other more stable molecular structure.

Now, Geim's team (along with a separate group based at Cornell University) has proven that assumption wrong. They mounted a silicon chip on a golden scaffold, coated the chip with a graphene film, and then dissolved only the chip in acid, which left behind a tiny, free-standing sheet of graphene hanging from the scaffold like a bedsheet on a laundry line.

Why didn't scientists expect this to work? It has to do with the shape of the graphene sheets. Scientists had assumed that the one-atom-thick graphene film was perfectly flat. The laws of physics suggest that a perfectly flat, thin crystal would be very delicate; any slight nudge by a particle floating by would knock some of the atoms out of place, and cause the sheet to collapse. However, Geim's team discovered that graphene sheets aren't flat after all. In fact, they have a wavy, crumpled-looking structure. That built-in irregularity actually stabilizes the sheet, making it more resilient when it's jostled around.

While you won't see graphene film lining the shelves at Wal-Mart anytime soon, it could have a big impact on many technologies, including the computers and electronics you use every day. Over the past several decades, engineers have crammed more and more transistors onto computer chips, which has made computers and electronics smaller and more powerful every year. However, there's a theoretical limit to how densely packed today's conventional transistors can be. Since graphene can act as a transistor, it has the potential to break through that limit and create a whole new generation of incredibly tiny computer chips. Within a couple decades, graphene may make today's gadgets look like the primitive video games of the '70s, the clunky home computers of the '80s, or the giant cell phones of the '90s.

Now try and answer these questions:

  1. What is graphene? What's so unusual about it?
  2. Why did scientists believe free-standing sheets of graphene couldn't exist?
  3. What are some potential applications for graphene?
  4. Why is miniaturization so important in technology?

You may want to check out the April 13, 2007, Science Update Podcast to hear further information about this Science Update and the other programs for that week. This podcast's topics include: how supernovas make heavy elements, why teenagers have angst, some fierce arachnids get cuddly, why tanning is addictive, and the thinnest material ever made.


For Educators

Several National Geographic News Articles discuss nanotechnology, the science of atomic-scale materials, including Nano-Switches and Nano-Brushes.

The interactive National Geographic feature, Nano's Big Future, gives an overview of the field of nanotechnology.


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