Bali, Ashoka and Chetty, Raju and Sharma, Amit and Rogl, Gerda and Heinrich, Patrick and Suwas, Satyam and Misra, Dinesh Kumar and Rogl, Peter and Bauer, Ernst and Mallik, Ramesh Chandra
(2016)
Thermoelectric properties of In and I doped PbTe.
Journal of Applied Physics, 120 (17).
ISSN 0021-8979
Abstract
A systematic study of structural, microstructural, and thermoelectric properties of bulk PbTe doped with indium (In) alone and co-doped with both indium and iodine (I) has been done. X-ray diffraction results showed all the samples to be of single phase. Scanning electron microscopy (SEM) results revealed the particle sizes to be in the range of micrometers, while high resolution transmission electron microscopy was used to investigate distinct microstructural features such as interfaces, grain boundaries, and strain field domains. Hall measurement at 300K revealed the carrier concentration similar to 10(19) cm(-3) showing the degenerate nature which was further seen in the electrical resistivity of samples, which increased with rising temperature. Seebeck coefficient indicated that all samples were n-type semiconductors with electrons as the majority carriers throughout the temperature range. A maximum power factor similar to 25 mu W cm(-1) K-2 for all In doped samples and Pb0.998In0.003Te1.000I0.003 was observed at 700 K. Doping leads to a reduction in the total thermal conductivity due to enhanced phonon scattering by mass fluctuations and distinct microstructure features such as interfaces, grain boundaries, and strain field domains. The highest zT of 1.12 at 773K for In doped samples and a zT of 1.1 at 770K for In and I co-doped samples were obtained.
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