Semiconductors inspired by nature

A connection between sea sponges and electronic materials may not be obvious, but the primitive marine creatures are proving an inspiration to chemists looking for new ways to fabricate semiconductor devices.

Traditional semiconductor manufacturing is a costly, energy-intensive and inefficient business. Nature, on the other hand, has evolved simple and elegant ways of making complex nano- and microstructures using only simple inorganic materials.

Daniel Morse holds a species of marine sponge commonly known as Venus' flower basket. (Photo © Gregg Segal)

Daniel Morse with sea sponge
Photo © Gregg Segal

The sea sponge’s solution is to extract silicic acid from seawater and convert it into silica, and Daniel Morse, a molecular biologist from the University of California, Santa Barbara, is fascinated to know how the sponge manages this remarkable feat of biological engineering.

Morse and his team are using knowledge gained from their study of sea sponges to make semiconductor devices that convert light into electricity, the idea being to make cheaper, more efficient solar cells. The problem with biology, however, is that it is messy, and electronics engineering requires ultra-pure materials.

When asked how biological specimens could possibly relate to electronic materials, Morse replied: “The advantages of controlled biological catalysis have been captured in a process dominated solely by chemical physics, without the use of organic molecules whose presence tends to degrade the electronic performance of the resulting semiconductors.”

It appears that behind the action of the sponge’s biological enzymes lies just ammonia and water. By combining the precursors of metal oxides with water, and exposing the mixture to ammonia gas, it is possible to create films of highly crystalline semiconductors with a complex nanostructure, which could improve the performance of photovoltaic devices.

Other applications include high-density batteries, ferroelectric random access memory (FeRAM) and high-resolution IR detectors. These technologies are currently under investigation by Morse’s group in collaboration with a number of industrial partners.

Daniel Morse was recently named by Scientific American magazine as one of the top 50 researchers of 2006.