Resonant Doped Bismuth Telluride for Reliable, Efficient Cryocooling.
MARLOW INDUSTRIES INC DALLAS TX
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Todays cryogenic coolers that operate down to 77 K suffer from several problems. Their most serious difficulties are significant noise levels, excessive vibration and poor reliability. Thermoelectric coolers do not suffer any of these concerns. However, thermoelectric coolers are not presently capable of cooling to temperatures as low as 77 K. Development of thermoelectric materials capable of extending cooler performance to these temperatures would open up potential applications such as cryogenic cooling of infrared detectors and CCDs as well as removing heat from Joule-Thomson refrigerators. Presently, the best thermoelectric materials over the temperature range 200 K to 450 K and the most practical below 200 K, are solid solutions of Bi2Te3, Sb2Te3 andor Bi2Se3. These alloys yield a peak dimensionless figure of merit, ZT, of approximately one near 300 K. These materials often require doping in order to optimize the carrier concentration and figure of merit, Z. As reported by Ravich and Vedernikov, certain impurities can also be added to improve thermoelectric properties through a selective scattering mechanism.
- Physical Chemistry
- Metallurgy and Metallography
- Electricity and Magnetism