Development of Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric Cryocooling Devices

Abstract : The research objective of this project at Alabama A&M University (AAMU), a leading HBCU, was to use nanoengineering and nanofabrication to develop nanostructured thermoelectric (TE) materials for application in high-efficiency thermoelectric power generators and solid-state micro cooling devices. Multi-nano-layered superlattice thin films based on Bi2Te3/Sb2Te3, SiO2/SiO2+CoSb, SiO2/SiO2+Au, Zn4Sb3/CeFe(4-x)CoxSb12, SiO2/SiO2+Ge, SiO2/SiO2+Cu, AgBiTe, AgSbTe, Si/Si+Sb, Si/Si+Ge, Zn4Sb4, and ZrNiSn were grown using ultra-high vacuum-based deposition methods. These thin films were further modified by MeV Si-ion beam bombardment to produce nanodots and nanoclusters for achieving high thermoelectric figure of merit (ZT). To the best of our knowledge, this research team is the only one using high-energy ion-beam technology to enhance the thermoelectric figure of merit. Excellent progress was made to significantly increase the ZT value by increasing the Seebeck coefficient and electrical conductivity while decreasing thermal conductivity for nano-power thermoelectric generators and thermoelectric coolers for achieving cryogenic temperatures. Arguably, Alabama A&M University currently has achieved the highest published room-temperature value of ZT, viz., 4.9, and successfully achieve the research objective. Numerous peer-reviewed papers were published and many presentations were made at conferences. A large number of students participated in this research project.