On this page
Every time you write with a pencil you leave thin flakes of graphite on the paper. In 2004 two physicists in Manchester showed how to get a flake just one atom thick, and that it was stable and conducted electricity. This post covers who they are, how a side project turned into a Nobel Prize, worked numbers on graphene's size, and what you can learn from their way of working.
Who are Andre Geim and Konstantin Novoselov?
Geim was born on 21 October 1958 in Sochi, Russia, according to his Nobel facts page. Novoselov was born on 23 August 1974 in Nizhny Tagil, Russia, according to his facts page. The 2010 press release says Novoselov first worked with Geim as a PhD student in the Netherlands and followed him to the United Kingdom, where both became professors at the University of Manchester. They shared the 2010 Nobel Prize in Physics "for groundbreaking experiments regarding the two-dimensional material graphene".
What were Geim's "Friday night experiments"?
In his Nobel lecture, Random walk to graphene, Geim describes pouring water into a powerful electromagnet in Nijmegen, "allegedly, on a Friday night", just to see what happened. Water, and later a live frog, floated in the field. That experiment earned Geim and Michael Berry the 2000 Ig Nobel Prize.
He then made such detours a habit and called them "Friday night experiments": short projects far from his main work, given a few months at most. "Next, you give it a try, and normally you fail," he writes in the lecture PDF. Novoselov, who came to Nijmegen as a PhD student in 1999, took part in many of them.
How did sticky tape produce graphene?
Geim first gave a PhD student a graphite tablet and suggested a polishing machine. Months later the student showed him a speck about 10 micrometres thick; he had polished away the whole tablet to get it. A colleague who used scanning tunnelling microscopes then brought over a piece of tape that, Geim writes, he had fished out of a bin. Microscopists cleaned graphite surfaces by peeling off the top layer with tape and threw the tape away. On it, Geim found flakes much thinner than the polished speck. In his words: "Polishing was dead, long live Scotch tape!"
The Nobel Committee's popular information explains the next steps. Repeating the tape trick 10 to 20 times gave thinner and thinner flakes. Placing them on oxidised silicon made the thinnest ones visible under an ordinary microscope as shades of colour, like oil on water. Their 2004 paper in Science reported films a few atoms thick that were stable in air, metallic and of high quality.
Worked example: how thin is one layer?
The NCERT Class 10 chapter on carbon describes graphite as hexagonal sheets of carbon stacked in layers, each atom bonded to three others in the same plane. Graphene is one of those sheets.
Layer spacing. The popular information says 1 mm of graphite holds about three million layers. Spacing = 1 × 10⁻³ m / 3 × 10⁶ = 3.3 × 10⁻¹⁰ m, or about 0.33 nm.
How many peels? An idealised model with sample numbers: suppose each peel splits a flake in half and you start with a flake 3,000 layers thick (about 1 micrometre). You need 2ⁿ ≥ 3,000. Since 2¹¹ = 2,048 and 2¹² = 4,096, that is 12 peels, in the same range as the 10 to 20 repeats described.
Electron speed. The popular information says electrons in graphene move at a constant speed of one million metres per second. That is 3 × 10⁸ / 1 × 10⁶ = 300 times slower than light in vacuum. To cross a 10-micrometre flake takes 1 × 10⁻⁵ m / 1 × 10⁶ m/s = 1 × 10⁻¹¹ s, or 10 picoseconds.
What mistakes do students make with graphite and graphene?
Treating 2D as zero thickness. A single layer is still about 0.33 nm thick; "two-dimensional" means electrons move only in the plane.
Mixing up the allotropes. Diamond has each carbon bonded to four others; graphite and graphene to three in a flat hexagonal array.
Dropping powers of ten. Write every length in metres before dividing.
If the difference between graphite's layers and diamond's network is fuzzy, the Fermi Concept Library has every concept in physics, chemistry, biology, mathematics and computing, each with its own lesson and its place in the map. Our post on carbon compounds for Class 10 covers the allotropes in more detail.
What can a student take from how they worked?
Protect time for small side projects. Geim gave them months, not years, so failure was cheap.
Look at what others throw away. The thin flakes were on tape that went into the bin.
Find a way to see your result. Without the oxidised silicon trick, the flakes would have stayed invisible.
Keep working with good people. The press release notes that Geim and Novoselov had worked together for a long time.
Try it: rework step 2 for a starting flake 100,000 layers thick and see how many more peels you need.
