Effect of annealing temperature on microstructure and thermoelectric properties of bismuth–telluride multilayer thin films prepared by magnetron sputtering

Abstract

2015) Effect of annealing temperature on microstructure and thermoelectric properties of bismuth-telluride multilayer thin films prepared by magnetron sputtering, Materials Research Innovations, 19:sup10, S10-408-S10-412, N-type bismuth-telluride (Bi-Te) multilayer thin films with total thickness of about 900 nm were deposited on amorphous structure glass substrate by magnetron sputtering at room temperature. The films were annealed at different temperatures under Ar ambient for 1 hour. The effect of annealing temperature was investigated for Bi-Te multilayer thin films by surface topography, chemical composition, crystal structure and thermoelectric properties. The results show that the Bi-Te multilayer thin films are all transformed into Bi-Te-based compounds. With the annealing temperature increasing, the films undergo an island growth mode with column structure, and grain size increases from 16·4 to 23·1 nm; in addition, the electrical conductivity and carrier mobility increase monotonously. The maximum Seebeck coefficient (−98·5 μV K −1 ) and power factor (14·47 μW K −2 cm −1 ) can be obtained for stoichiometric Bi 2 Te 3 films annealed at 150°C.

A comprehensive review on Bi2Te3‐based thin films: Thermoelectrics and beyond

“…The presence of V Te vacancies answers the long‐standing puzzle of why nominally undoped Bi 2 Te 3 films have always shown n‐type conduction. [ 52,100,113 ] As summarized in Figure 3A, the carrier concentration n e of n‐type Bi 2 Te 3 films tends to increase with the increasing T sub . This upward trend in n e could be explained by progressively more intense re‐evaporation of Te and the generation of a greater density of V Te vacancies.…”

Static and Dynamic Postannealing Strategies for Roll-to-Roll Fabrication of DC Magnetron Sputtered Bismuth Telluride Thin Films onto Polymer Webs

“…The as-deposited film showed characteristic diffraction peaks at 2θ of 27.7, 38.2, 57.1, and 62.7°, corresponding to (0 1 5), (1 0 10), (2 0 10), and (1 1 15) planes, respectively, as expected in a standard Bi 2 Te 3 phase (ICSD #193330). XRD peaks (0 1 5) and (1 0 10) were observed for both hot and RT deposition of the Bi 2 Te 3 film on polymer/rigid substrates ,,,− due to their inherently strong reflection. Unlike with hot deposition on rigid substrates, ,, orientational growth (beneficial to the electrical property of films) was not observed in our study, consistent with the literature for RT deposition. , …”