SPIKY, four-legged crystals no bigger than the average virus are being grown to order in a chemistry lab in California. They are the most complicated nanoparticles that scientists have ever created under controlled conditions.
In the 1980s, nanoscientists learned to grow simple spheres from inorganic materials. Then they graduated to rods and discs. Now a group led by Paul Alivisatos at the University of California, Berkeley, has mastered the tetrapod. The crystals are made of a semiconductor material called cadmium telluride. They grow when cadmium and tellurium are stirred together with organic molecules into a solvent heated to 315 °C.…
