Synthesis and Thermoelectric Study of Sb (III) Doped Bi2(Te1-Xsex)3 Thin Films by Apt

Abstract

Thermoelectric study of Sb (III) doped bismuth tellurium selenide ,Bi2-x Sbx(Te1-xSex)3 thin films were done.They are deposited by Arrested Precipitation Technique (APT). These thin films were prepared using a complexing agent triethanolamine (TEA) and a reducing agent sodium sulphite to avoid hydroxide formation of bismuth precursor Bi (NO3)3 and antimony precursor (SbCl3) in aqueous medium to favor the reaction with Te2- and Se2-chalcogen ions. The preparative conditions such as pH, concentration of precursors, temperature, rate of agitation and time were finalized at initial stages of deposition. As deposited films were annealed at constant temperature (373K) in muffle furnace and then characterized for optostructural, morphological, thermoelectric and figure of merit (ZT). The results demonstrate that the Bi2-x Sbx(Te1-xSex)3 thin films prepared by APT shows band gap in the range 1.46eV to 1.89eV. X-Ray Diffraction (XRD) pattern, Scanning Electron Microscopy (SEM) images reveals that Bi2-x Sbx(Te1-xSex)3 mixed metal chalcogenide films are of nanocrystalline nature and have rhombohedral structure and better morphology. EDAX study shows good stoichiometry. Electrical and TEP study shows Sb(III) doping in Bi2(Te1-xSex)3 mixed metal chalcogenide thin films are semiconducting having p-type conduction mechanism. The highest figure of merit obtained was 0.312 and 0.569 for D1 to D5 samples.