Ultra low thermal conductivity of disordered layered p-type bismuth telluride

Abstract

Disordered layered p-type bismuth telluride was obtained by high pressure (1 GPa) and high strain deformation along the c-axis direction of commercially available single crystals. After initial deformation the p-type bismuth telluride flakes were subsequently fully densified by cold pressing (800 MPa at room temperature). As a result of the severe plastic deformation, the samples showed highly anisotropic electrical and thermal conductivities. In particular, the thermal conductivity measured along the pressing direction was as low as 0.34 W m À1 K À1 , which is one of the lowest values reported for fully dense ptype bismuth telluride. The full set of thermoelectric properties of the disordered bismuth antimony telluride is critically discussed.

Pre-oxidation effects on properties of bismuth telluride thermoelectric composites compacted by spark plasma sintering

“…Figure 5(e-g) show the total thermal conductivity (k or k T ), which is contributed by the electronic thermal conductivity (k e ) and lattice thermal conductivity (k L ), of the compacted samples as a function of the measurement temperatures. As observed in Figure 5(e), both of our samples had small changes in the total thermal conductivity even when the measurement temperature raised from 300 to 420 K. This is in agreement with the literature where thermal conductivity of Bi 2 Te 3 has a small temperature dependence [33]. For confirmation, we checked the electronic and lattice thermal conductivities of these samples.…”

Hybrid effect to possibly overcome the trade-off between Seebeck coefficient and electrical conductivity

“…These tradeoffs have traditionally made enhancing the figure of merit difficult. Recently, nanostructuring has been shown to be a powerful method to overcome the former problem [4][5][6][7][8][9][10][11][12]. This methodology utilizes the different mean free path length scales of electrical carriers and phonons, to selectively scatter phonons to lower the lattice thermal conductivity, and thereby enhance the ZT.…”

Effect of Thickness of Single-Phase Antimony and Tellurium Thin Films on Their Thermal Conductivities

“…36 Figure 2 reported XRD patterns for Te. 37 The average grain size of the thin film is calculated using the Debye-Scherrer equation D = k /Bcos , 38 where k is a constant (=0.89), is the wavelength of the radiation (=1.54058 Å), B is the full-width at half-maximum (FWHM) of the XRD pattern for each thin film, and is the diffraction angle from the XRD pattern. Using this formula, we obtain the average grain sizes to be approximately 36 nm and 40 nm for the Sb and Te thin films, respectively as shown in Figures 2(c) and (d).…”