Birth of a nanotube

Researchers at Purdue University are using a rare type of electron microscope to see how structures like carbon nanotubes form at the atomic level. Information derived from the microscope will be crucial for nanotechnology to find practical applications in computing, electronics and other areas.

The new transmission electron microscope has been modified so that researchers can watch how atoms come together to form nanostructures as gases flow into a chamber in the presence of a metal catalyst. This is the same method used to make nanotubes in research labs and electronic devices in the semiconductor industry.

"Before we can consistently manufacture nanostructures that have the same specifications and qualities, we have to learn precisely how atoms interact and come together to form these structures," said Eric Stach, an associate professor of materials engineering who operates the microscope at the Birck Nanotechnology Center.

The $4 million FEI Titan microscope is equipped with an "environmental cell," in which gases such as acetylene or butane, which contain carbon, are passed over nanoparticles of metal, such as iron or nickel. The metal particles act as a catalyst for breaking down the gases and releasing carbon atoms during the reaction, which takes place in the cell at temperatures sometimes reaching more than 1,000 degrees Celsius, or more than 1,800 degrees Fahrenheit.