How to Advertise
Home | This Week's Contents  |  C&EN ClassifiedsSearch C&EN Online

 
 
Related Story
Playing It Cool
[C&EN, April 3, 2000]
Related People
Rama Venkatasubramanian

Ali Shakouri

E-mail this article to a friend
Print this article
E-mail the editor
 
 
 
 
 Table of Contents
 C&EN Classifieds
 News of the Week
 Cover Story
 Editor's Page
 Business
 Government & Policy
 Science/Technology
 Concentrates
  Business
  Government & Policy
  Science/Technology
 Education
 ACS News
 Calendars
 Books
 Digital Briefs
 ACS Comments
 Career & Employment
 Special Reports
 Letters
 Newscripts
 Nanotechnology
 What's That Stuff?
 Pharmaceutical Century

 Hot Articles
 Safety  Letters
 Chemcyclopedia

 Back Issues

 How to Subscribe
 Subscription Changes
 About C&EN
 Copyright Permission
 E-mail webmaster
NEWS OF THE WEEK
SCIENCE
October 15, 2001
Volume 79, Number 42
CENEAR 79 42 p. 8
ISSN 0009-2347
[Previous Story] [Next Story]

EFFICIENT MINIATURE REFRIGERATORS
Jump in performance of thermoelectric coolers may broaden applications

SOPHIE WILKINSON

A new composite material promises to significantly improve the performance of thermoelectric cooling devices.

Unlike conventional compressor-based refrigerators, thermoelectric coolers made from semiconductors have no moving mechanical parts and can be miniaturized. However, they require a lot of energy, and their performance--which is quantified as "ZT"--isn't as good as conventional cooling technology.

Despite years of research, ZT of thermoelectric coolers as measured at room temperature has barely exceeded 1, notes Rama Venkatasubramanian, senior program director of Research Triangle Institute's (RTI) Center for Semiconductor Research. But according to Ali Shakouri, an assistant professor of electrical engineering at UC Santa Cruz who studies thin-film thermoelectric coolers, Venkatasubramanian and his colleagues have now achieved "an important breakthrough. They improved room-temperature ZT" significantly for the first time in almost 40 years.

The RTI researchers achieved a ZT of 2.4 in p-type lattices built by alternating engineered thin films of bismuth telluride and antimony telluride and a ZT of 1.4 in n-type lattices of bismuth telluride and bismuth telluride selenide [Nature, 413, 597 (2001)]. The ZT of a thermoelectric device can be approximated by averaging the ZT of its n- and p-type components. Once the average ZT reaches 1.5, Venkatasubramanian says, it "opens the door to a huge number of applications." These include temperature control for a lab on a chip, automotive heating and cooling applications, and cooling of computer chips. Because the production temperature for these thermoelectric devices is below 300 °C, they can be built on silicon chips after the chips have been processed. They can also be used for high-speed cooling for applications such as fiber-optic switches.

Shakouri cautions that reliability of the system must be tested, "since very high current densities are needed to operate thin-film coolers."

[Previous Story] [Next Story]



Top


Chemical & Engineering News
Copyright © 2001 American Chemical Society


How to Advertise
Home | Table of Contents | News of the Week | Cover Story
Business | Government & Policy | Science/Technology
Chemical & Engineering News
Copyright © 2001 American Chemical Society - All Right Reserved
1155 16th Street NW • Washington DC 20036 • (202) 872-4600 • (800) 227-5558


CASChemPortChemCenterPubs Page