Effect of thermal annealing on thermoelectric properties of BixSb2−xTe3 thin films grown by sputtering

Abstract

The present study focuses on the enhancement of the Seebeck coefficient (S) of BiSbTe alloy thin films on post-deposition annealing. It is demonstrated that thermal treatment leads to about twofold enhancement in the S of BiSbTe alloy thin films deposited using DC magnetron sputtering. Investigation of the enhanced thermoelectric properties has been done by studying their phase, compositional, and structural properties. The x-ray diffraction patterns show the presence of a mixed BixSb2 − xTe3 phase, which crystallizes in the Sb-rich phase on annealing. The surface morphology of the as-deposited samples exhibit spherical features that grow in the form of hexagonal rods on increasing the annealing temperature to 300 °C. However, on further increasing the annealing time to 3 h at 300 °C, distorted cubical microstructures were observed. The microstructures had a higher Sb/Bi ratio, implying that these structures were Sb rich. The thermoelectric properties of the nanostructured BixSb2 − xTe3 films were studied as a function of annealing temperature and time. An enhancement of about two orders of magnitude is observed both in the S and power factor for the samples annealed at 300 °C for 3 h. This enhancement is attributed to the energy filtering of charge carriers at the junction of the BixSb2 − xTe3 matrix and Sb-rich inclusions. These results indicate that annealing is an efficient way of tuning the growth of microstructures and the S of BixSb2 − xTe3 thin films.

Role of topological surface states and mirror symmetry in topological crystalline insulator SnTe as an efficient electrocatalyst

“…As can be seen in the top spectra in Figure S27a, which is obtained before Ar + sputtering, a peak appears on the left-hand side of the two Te core levels. These two peaks can be assigned to Te in TeO2 because their binding energies are close to the reported standard values of 576.4 eV (Te 3d5/2) and 586.8 (Te 3d3/2) of this oxide (71,72). It can also be seen that the intensities of the two major peaks in Figure S27a increase while their full width at half maximums (FWHM) get narrower with the sputter time.…”

“…These two peaks can be assigned to Te in TeO 2 because their binding energies are close to the reported standard values of 576.4 eV (Te 3d 5/2 ) and 586.8 (Te 3d 3/2 ) of this oxide. 44,45 It can also be seen that the intensities of the two major peaks in Fig. S28a † increase while their full width at half maxima (FWHM) get narrower with the sputter time.…”

Polymer-mixed Sb2Te3/Te nanocomposites exhibiting p-type to n-type conduction reversal and thermal conductivity reduction

“…Polymer-based thermoelectric materials are gaining much attention because of the ability of the polymer in altering the microstructure which can help in tuning the thermoelectric properties [3]. The TE properties of materials, Seebeck coefficient (S), electrical conductivity (σ), and thermal conductivity (κ) are dependent on the quenching medium, i.e., the cooling rate of melt solidification [4][5][6], annealing treatment [7,8], the synthesis process [9,10], and sintering process [11,12]. Knowledge of the phase diagram is important in choosing the appropriate composition and process temperature.…”

“…In recent years, polymer-based composites such as poly (3,4-ethylene dioxythiophene) (PEDOT) [3,4], polyaniline (PANI) [5,6], and polythiophene [7] have been applied as TE materials due to their versatile processability, low density, and low thermal conductivity, all of which are critical in improving TE properties. Recent research has concentrated on the synthesis of hybrid Sb 2 Te 3 composites by the blending of inorganic and organic ingredients to increase their application [29].…”