Application of Thin Film Thermoelectrics

The objective of this program is to develop a thin/thick film materials deposition process technology which will reliably provide high quality materials for constructing Peltier thermo-elements with a high figure of merit over the temperature range of 250-350 Deg K. The study will focus on the materials system consisting of (B1, Sb)2(Te, Se)3 alloys for both p- and n-type thermo-elements. Literature shows that specific compositions in this alloy system have provided high figures of merit (3.2 - 3.4 x IO-3/Deg K at 3OOK) with a maximum Peltier cooling of 77 Deg K. Recently investigators at the University of Virginia reported a high figure of merit of 3.7 x 10-3/K for p- type (Bi, Sb)2(Te, Sb)3 alloy. The process selected for depositing the films in the proposed program will be a unique, high rate Microwave Enhanced CVO process (MECVD) developed at Energy Conversion Devices, Inc. ECD has achieved deposition rates as high as 3OO Deg. A/sec for amorphous Si-H alloys using this technique, and this process has been developed for depostion on large area surfaces. Large area thin/thick film thermoelectric modules will be attractive for applications which require heating/cooling ability in a single, light-weight module.