Improvement of thermoelectric properties induced by uniquely ordered lattice field in Bi2Se0.5Te2.5 pillar array

• Published in: Journal of solid state chemistry 2014-07, Vol.215, p.219-224
• Main Authors: Tan, Ming, Hao, Yanming, Wang, Gangzhi
• Format: Article
• Language: English
• Subjects: Bi2Se0.5Te2.5 film; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductivity phenomena in semiconductors and insulators; Cross-disciplinary physics: materials science; rheology; Crystalline state (including molecular motions in solids); Electronic transport in condensed matter; Exact sciences and technology; Ion and electron beam-assisted deposition; ion plating; Ion beam assisted deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Ordered lattice field; Physics; Pillar array; Structure of solids and liquids; crystallography; Theory of crystal structure, crystal symmetry; calculations and modeling; Thermoelectric and thermomagnetic effects; Thermoelectric properties
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2014.04.005

In this study, it was found that uniquely ordered lattice field favors transport of carriers but hinder that of phonons. The n-Bi2Se0.5Te2.5 pillar array film was successfully achieved by a simple ion beam assisted deposition technique. This oriented pillar array structure is clear with pillar diameter of about 30nm, exhibiting a uniquely ordered lattice field. The properties of the ordered Bi2Se0.5Te2.5 pillar array were greatly enhanced in comparison with those of the ordinary film. The Bi2Se0.5Te2.5 pillar array with a thermoelectric dimensionless figure-of-merit ZT=1.28 was obtained at room temperature. The in-plane transport mechanisms of the ordered pillar array and the ordinary structures, lattice field model, are proposed and investigated. The specially ordered lattice field is the main reason for the properties enhancement observed in the Bi2Se0.5Te2.5 film. Introduction of such ordered lattice field into TE films is therefore a very promising approach. In this study, it was found that uniquely ordered lattice field favors transport of carriers but hinder that of phonons. The Bi2Se0.5Te2.5 pillar array film with a thermoelectric dimensionless figure-of-merit ZT=1.28 was obtained at room temperature. The in-plane transport mechanisms of the ordered pillar array and the ordinary structures, the lattice field model, are proposed and investigated. The specially ordered lattice field is the main reason for the properties enhancement observed in the Bi2Se0.5Te2.5 pillar array. Introduction of such uniquely ordered lattice field into TE films is therefore a very promising approach. In (a) TEM and (b) HRTEM images of the ordered Bi2Se0.5Te2.5 column array. [Display omitted] •Uniquely ordered Bi2Se0.5Te2.5 pillar array was achieved by an IBAD method.•The pillar array with an ordered lattice field exhibits attractive TE property.•The transport mechanism of such ordered pillar array is proposed and investigated.•Introduction of such ordered lattice field into film is a very promising approach.