Haim Grebel, professor of electrical and computer engineering, heads a team of researchers who grow carbon nanotubes in the tiny spaces between the silica spheres that make up synthetic opals. These tiny tubes of carbon atoms, about 10,000 times thinner than a human hair, have unusual strength and unique electrical properties, and are extremely efficient conductors of heat, properties that make them potentially useful in extremely small scale electronic and mechanical applications. The team is testing the nanotubes to establish their optical, thermal and mechanical properties for potential use in communications and sensor systems. Read an article about his work. The team's work was reported in Applied Physics Letters (March 3, 2003).

The image above (left) shows self-assembled 245-nm silica nanospheres. These structures are later ion-implanted with Si, Ge. Nanoclusters of the guest material, approximately 5-nm in size, are formed within the silica nanospheres following annealing. The final result is 'nano  within nano'. The structures have been ion-implanted with Er ions as well. The image on the right show single-wall carbon nanotubes (SWCNT) grown in the voids of an artificial opal.