Thermo-electric figure of merit of quasi-two-dimensional Bi2Te3 nano-structures. (11th April 2018)

• Record Type: Journal Article
• Authors: Singh, M P
• Is Part Of: Journal of physics communications. Volume 2:Number 4(2018)
• Publication Date: 2018-04-11
• Subjects: quantum well -- quantum size effect -- figure of merit; 72.10.-d -- 72.15.jf -- 72.20.pa; Physics -- Periodicals; 530.05
• DOI: 10.1088/2399-6528/aaaee3
• Languages: English
• ISSNs: 2399-6528

Abstract

Abstract: Quasi-two dimensional nano-structures are characterized by radical changes in electron and phonon properties. Electron behavior in Q-2D nano-structures is modified by the presence of multiple sub-bands. For well widths smaller than 50 Å simplified model calculations based on the assumption of electrons occupying the lowest sub-band appears to be quite reasonable. For larger width others, parabolic sub-bands need to be considered. The present paper investigates the thermoelectric figure-of-merit of bismuth telluride which is five layered (Te-Bi-Te-Bi-Te) crystal with hexagonal symmetry with six equivalent valleys, in the range 40–300 Å and observe that for 100 Å well width three sub-band model and for 200 Å well width six sub-band model are good approximation at room temperature. Further it is observed that optimum carrier density for 200 Å well width is 3.2 × 10 24 m − 3 and maximum of ZT shifts towards lower concentration; and discusses the acceptability of single band approximation.