TY - GEN
T1 - Thermoelectricity of double doped strontium titanate
AU - Ravichandran, Jayakanth
AU - Siemons, Wolter
AU - Kardel, Justin
AU - Heijmerikx, Herman
AU - Chari, Arvind
AU - Oh, Dongwook
AU - Cahill, David G
AU - Ramesh, Ramamoorthy
AU - Majumdar, Arun
PY - 2010
Y1 - 2010
N2 - Lanthanum (La) doped Strontium Titanate (SrTiO3) is amongst the most promising n-type thermoelectric materials for power generation. We report a double doping method for thin films of SrTiO3 (STO), grown by Pulsed Laser Deposition (PLD), where doping of STO in the Sr-site by Lanthanum is accompanied by doping with oxygen vacancies. In the past theoretical predictions have shown that introducing oxygen vacancies in STO produces a high-effective mass defect band just below the conduction band edge, explaining the high seebeck coefficient observed in oxygen deficient STO. Based on careful transport measurements, we show that it is possible to obtain enhanced thermoelectric power factor by double doping, using La and oxygen vacancies in these thin films. With the aid of optical spectroscopic measurements, we establish the presence of the impurity band created by the vacancies and validate their role in the enhanced thermoelectric performance with structural and transport measurements. The presence of oxygen vacancies also serves to decrease the thermal conductivity due to effective phonon scattering.
AB - Lanthanum (La) doped Strontium Titanate (SrTiO3) is amongst the most promising n-type thermoelectric materials for power generation. We report a double doping method for thin films of SrTiO3 (STO), grown by Pulsed Laser Deposition (PLD), where doping of STO in the Sr-site by Lanthanum is accompanied by doping with oxygen vacancies. In the past theoretical predictions have shown that introducing oxygen vacancies in STO produces a high-effective mass defect band just below the conduction band edge, explaining the high seebeck coefficient observed in oxygen deficient STO. Based on careful transport measurements, we show that it is possible to obtain enhanced thermoelectric power factor by double doping, using La and oxygen vacancies in these thin films. With the aid of optical spectroscopic measurements, we establish the presence of the impurity band created by the vacancies and validate their role in the enhanced thermoelectric performance with structural and transport measurements. The presence of oxygen vacancies also serves to decrease the thermal conductivity due to effective phonon scattering.
UR - http://www.scopus.com/inward/record.url?scp=84860533582&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84860533582&partnerID=8YFLogxK
U2 - 10.1115/IHTC14-22352
DO - 10.1115/IHTC14-22352
M3 - Conference contribution
AN - SCOPUS:84860533582
SN - 9780791849392
T3 - 2010 14th International Heat Transfer Conference, IHTC 14
SP - 839
EP - 843
BT - 2010 14th International Heat Transfer Conference, IHTC 14
T2 - 2010 14th International Heat Transfer Conference, IHTC 14
Y2 - 8 August 2010 through 13 August 2010
ER -