Friday, June 20, 2008

Diamond Films from Tequila!

If you were looking for a new way to make semiconducting diamond, you might not have thought of starting with tequila. But the potent spirit turns out to be excellent raw material.
Diamond is normally an electrical insulator, but becomes a semiconductor when doped with the right impurities. Diamond film is tougher than silicon, so it could be useful for devices that must operate at high temperatures or under other harsh conditions.
However, diamond films are expensive and difficult to make. They are produced by vaporising organic material, and then controlling how the carbon atoms crystallise onto a surface. The process works best if the material contains carbon and oxygen in roughly equal parts, as well as some hydrogen.
Now a team of researchers led by Javier Morales of the University of Nueva Leon near Monterrey in Mexico have shown that ordinary tequila does the job nicely. They injected the heated vapour from 80-proof "tequila blanco" into a low-pressure chamber. Measurements confirmed that the carbon deposited on test surfaces had a diamond structure ( "Some kinds of tequila seem naturally to have the right mix of atoms," says Morales. Other forms of alcohol have also worked, although it's not clear if this is faster or more reliable than using common precursors such as acetone.
"The result is certainly funny, but the process seems reasonable," says physicist Rudolf Pfeiffer of the University of Vienna in Austria. "I don't know of any previous attempts to make diamonds from drinks."