Substrate temperature-dependent thermoelectric figure of merit of nanocrystalline Bi2Te3 and Bi2Te2.7Se0.3 prepared using pulsed laser deposition supported by DFT study. Issue 15 (15th October 2020)

• Record Type: Journal Article
• Authors: Wudil, Y.S.; Gondal, M.A.; Rao, S.G.; Kunwar, S.; Alsayoud, A.Q.
• Is Part Of: Ceramics international. Volume 46:Issue 15(2020)
• Page Start: 24162
• Page End: 24172
• Publication Date: 2020-10-15
• Subjects: Thermoelectric -- Bi2Te2.7Se0.3 -- Density functional theory -- Pulsed laser deposition -- Bi2Te3 -- Substrate-temperature dependent performance; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.06.196
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: This work reports the pulsed laser deposition of n-type selenium (Se) doped bismuth telluride (Bi2 Te2.7 Se0.3 ) and n-type bismuth telluride (Bi2 Te3 ) nanostructures under varying substrate temperatures. The influence of the substrate temperature during deposition on the structural, morphological and thermoelectric properties for each phase was investigated. Density functional theory (DFT) simulations were employed to study the electronic structures of the unit-cells of the compounds as well as their corresponding partial and total densities of states. Surface and structural characterization results revealed highly crystalline nanostructures with abundant grain boundaries. Systematic comparative analysis to determine the effect of Se inclusion into the Bi2 Te3 matrix on the thermoelectric properties is highlighted. The dependence of the thermoelectric figure of merit (ZT) of the nanostructures on the substrate temperatures during deposition was demonstrated. The remarkable room temperature thermoelectric power factor (PF) of 2765 μW/mK 2 and 3179 μW/mK 2 for pure and Se-doped Bi2 Te3 compounds respectively, signifies their potential of being useful in cooling and power generation purposes. The room temperature ZT values of the Se-doped Bi2 Te3 was found to be 0.92, about 30% enhancement as compared with the pure phase, which evidently results from the suppressed thermal conductivity in the doped species caused by phonon scattering at the interfaces.