Metal process makes heat chips

Researchers from the California Institute of Technology have found a way to make tiny thermoelectric devices that can be used to generate electrical power from heat and to cool very small areas.

The devices could eventually be used to very quickly cool tiny amounts of chemicals on labs-on-a-chip, to cool optoelectronics devices, and to power devices like wristwatches and portable electronics, according to the researchers.

The key to making the devices, which contain hundreds of separate pieces, is an electrochemical process that forms parts from several different types of metal and semiconductor materials. In contrast to commercial fabrication processes used to fashion the microscopic transistors that make up computer chips, the researchers' method allows for the use of metal.

The method involves using molds to deposit films of dissolved metals and semiconductors, then reducing the films to form solids. The molds, which are made from non-conducting material, allow the researchers to fabricate relatively tall structures from electrically-conducting materials.

The method could be used in practical cooling and power applications in two to five years, according to the researchers. The work appeared in the July 27, 2003 issue of Nature Materials.