Paint-on semiconductor

Researchers at the

have created a semiconductor device that outperforms today's conventional chips, and they made it by painting a liquid onto a piece of glass.

The finding represents the first time a so-called "wet" semiconductor device has outperformed traditional, more costly grown-crystal semiconductor devices.

"Traditional ways of making computer chips, fibre-optic lasers, digital camera image sensors – the building blocks of the information age – are costly in time, money, and energy," said Professor Ted Sargent of the Edward S. Rogers Sr. Department of Electrical and Computer Engineering and leader of the research group. Conventional semiconductors have produced spectacular results -- the personal computer, the Internet, digital photography -- but they rely on growing atomically perfect crystals at 1,000 degrees Celsius and above, he explained.

The Toronto team instead cooked up semiconductor particles in a flask containing extra-pure oleic acid, the main ingredient in olive oil. The team then placed a drop of solution on a glass slide patterned with gold electrodes and forced the drop to spread out into a smooth, continuous semiconductor film using a process called spin-coating. They then gave their film a two-hour bath in methanol. Once the solvent evaporated, it left an 800 nanometre-thick layer of the light-sensitive nanoparticles.