Fredrik Hansen
LENS group

• Heat to electricity or electricity to heat
• Three differerent effects
– Seebeck effect
– Peltier effect
– Thomson effect

• Figure of merit
2
• 𝛼 − 𝑆𝑒𝑒𝑏𝑒𝑐𝑘 𝑐𝑜𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝛼 = −
∆𝑉
∆𝑇
• 𝜎 − 𝐸𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑎𝑙 𝑐𝑜𝑛𝑑𝑢𝑐𝑡𝑖𝑣𝑖𝑡𝑦
• κ − 𝑇ℎ𝑒𝑟𝑚𝑎𝑙 𝑐𝑜𝑛𝑑𝑢𝑐𝑡𝑖𝑣𝑖𝑡𝑦

• Lower Thermal conductivity
– Phonons are main heat carrier in semiconductors
– Mean free path – more scattering
– Quantum thermal conductance
• Higher Seebeck coefficient
– Distribution of electron energies

• Total Voltage
𝑉
𝑇
= 𝑉
𝑅
+ 𝑉
• Cooling power
𝑆
1
𝑄 = 𝛼𝑇𝐼 −
• Seebeck voltage
2
= 𝐼𝑅 + 𝛼∆𝑇
𝐼 2 𝑅 − κ∆𝑇
𝑉
𝑆
= 𝛼∆𝑇 = 𝛼 ∗ 𝛼𝑇𝐼
κ
−
𝐼 2 𝑅
2κ
= 𝑉
𝑆𝑃
• Figure of merit
𝑍𝑇 =
𝑉
𝑉
𝑆𝑃
𝑅
= 𝛼 2
κ
𝑇𝐼 1
𝐼𝑅
= 𝛼 2
κ 𝜎𝑇
− 𝑉
𝑆𝐽

• What are Thermoelectrics?
– http://disalvo.chem.cornell.edu/thermotheory2.html
• Nanotechnology, Undestanding small systems, Second Edition
–
Ben Rogers, Sumita Pennathur, Jesse Adams
–
ISBN: 978-1-4398-4920-0
• Thermoelectricity: From Atoms to Systems
–
By Ali Shakouri Professor of Electrical and Computer Engineering Birck, Nanotechnology Center,
Purdue University
– https://nanohub.org/courses/TEAS/01a/asset/2028
• Modeling of transient thermoelectric transport in Harman method for films and nanowires
– Miguel Munoz Rojo, Juan Jose Romero, Daniel Ramos, Diana-Andra Borca-Tasciuc,Theodorian
Borca-Tasciuc, Marisol Martín Gonzalez
Available online 5 December 2014