Studies on phase formation behavior and thermoelectric transport properties of Cu-doped Bi2Te3–Bi2S3 system

Kyu Hyoung Lee, Yurian Kim, Dong Ho Kim, Chul Oh Park, Hyun Sik Kim, Sang il Kim

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Herein, we investigated the influence of sulfur (S) addition on the phase formation behavior and thermoelectric transport properties of n-type Cu0.008Bi2Te3. A complete single phase of rhombohedral Bi2Te3 was formed in Cu0.008Bi2Te2.8S0.2, whereas a mixture of Bi2Te3 and Bi2Te2S1 phases was generated at higher S contents. We elucidated the complex effects of S substitution at Te-site on transport properties of Cu0.008Bi2Te3; (1) increase in density-of-states effective mass, (2) decrease in weighted mobility ratio, (3) reduction in lattice thermal conductivity, and (4) reduction in bipolar thermal conductivity. Despite the slight deterioration in electronic transport properties, a maximum thermoelectric figure of merit (zT) of 0.82 was achieved at 400 K in Cu0.008Bi2Te2.8S0.2 due to the synergetic effect of intensified point defect phonon scattering in a wide temperature range and suppressed bipolar thermal conduction at elevated temperatures.

Original languageEnglish
Pages (from-to)4781-4789
Number of pages9
JournalJournal of Materials Research and Technology
Volume15
DOIs
StatePublished - 1 Nov 2021

Keywords

  • BiS
  • BiTe
  • Composite
  • Phase formation
  • Thermoelectric

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