ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
High efficiency thermoelectric conversion is achieved by using materials with a maximum figure of merit Z=S2σ/k, where S is the Seebeck coefficient, σ and k, the electrical and thermal conductivities, respectively. High quality homogeneous thermoelectric materials, based on PbTe crystals, usually display an elevated value of Z over a narrow temperature range. A maximal value of figure of merit Z, as a function of electron density, is attained only for one specific location of the Fermi level, EF, with respect to the conduction band edge, EC. In order to maintain this optimal Z value, namely, maintain a constant location of the Fermi level, the electron density, which is determined by the dopant concentration, must increase with increasing temperature. We present a method for the generation of a dopant (indium) concentration profile in n-type PbTe crystals that gives rise to a constant location of the Fermi level, and hence, to an optimal value of Z over a wide temperature range. The resulting functionally graded material, based on PbTe〈In〉, displays a practically constant value of the Seebeck coefficient, over the 50–600 °C temperature range. © 2002 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1490152
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