February 21, 2003 11:01 AM PST
Looking to nature to improve nanotech
The complex-shaped crystals of calcite were fabricated using a technique that involves depositing the mineral in a way that creates intricate microscopic patterns. The researchers described their approach in the latest issue of the journal Science, saying the technique may have broad implications for material science and nanotechnology.
Forming patterns on single crystals at a micron scale or smaller, and then integrating those crystals into optoelectronic circuits, creates components considered important in various electronic, sensory and optical devices.
Although the new approach may have an impact on how crystals are made in the future, a scientist at Bell Labs cautions that the work still needs to be refined.
"While many years from commercial use, this understanding could be very important to fabrication of nano-patterned materials," said Cherry Murray, senior vice president of physical sciences research at Bell Labs.
This new patterned crystal is the latest product inspired by biomimetics, an emerging field that takes engineering principles from nature and applies them to creating new materials and technologies.
"I have always been fascinated with nature's ability to perfect materials," said Joanna Aizenberg, the Bell Labs materials scientist who led the research. "We recently discovered that nature makes excellent micropatterned crystals, and we decided to see if we could copy the natural approach in the lab."
Aizenberg said her team made a surprising discovery two years ago when it found that thousands of calcite crystals are spread throughout the body of the brittlestar, a marine invertebrate, collectively forming a curious kind of eye for the animal. These microlenses naturally compensate for two types of distortions common in lenses: birefringence and spherical aberration.
The scientists began trying to mimic the design of the brittlestar crystals with the ultimate goal of building complex arrays of microlenses.
Most lenses today are built by carefully grinding down a piece of glass. The brittlestar takes a different approach, depositing successive layers of calcite onto an organic template with intricate patterns to form crystalline lenses.
Aizenberg and colleagues David Muller, John Grazul and Don Hamann studied biomineralization principles to develop a new approach that let them fabricate single crystals of calcite that have patterns which are approximately one-tenth the diameter of a human hair.
Bell Labs is the research arm of Lucent Technologies.