Thermoelectric properties of skutterudite CoSb3 thin films

Abstract

The thermoelectric properties of Co-Sb thin films with different Sb content and with a thickness of 30 nm were investigated with respect to the composition and the corresponding structural properties of these films. The films were prepared by molecular beam deposition either by codeposition on heated substrates or room temperature deposition followed by a post-annealing step. It was found that the prepared films exhibit bipolar conduction, indicated by a positive Hall constant and a negative Seebeck coefficient. The obtained results can be well explained by using the bipolar model, assuming heavy electrons and light holes, which was finally confirmed experimentally by the preparation of p-and n-type doped CoSb 3 thin films. Furthermore, variable range hopping was identified by temperature dependent transport measurements as dominant conduction mechanism at low temperatures.

Effect of Fe ion implantation on the thermoelectric properties and electronic structures of CoSb3 thin films

“…All samples crystallized in the body centred cubic space group Im 3 (#204). As obtained aer renement, the unit cell volume was 73.87 nm 3 . The Co metal ions are located at the 8c sites (1/4, 1/4, 1/ 4), while the pnictogen atom Sb occupied the 24g sites (0, y, z).…”

“…2 The enhancement in zT can be done either by increasing the power factor S 2 /r or by decreasing k. CoSb 3 is a low band gap skutterudite compound semiconductor with high S and high carrier mobility. 3 It has a cubic structure with the formula of MX 3 , where M is a metal ion, such as Co, Rh, and Ir, and X is any metalloid (such as As and Sb). Of the eight subcubes in a cubic unit cell, two cubes are voids that can accommodate guest atoms and rattle inside.…”

A review of CoSb3-based skutterudite thermoelectric materials

“…The decrease in κ is mainly due to the fact that the high-density nano-interfaces in the low dimensional materials enhance significantly the scattering of electrons and phonons. In the past ten years, TE properties of CoSb 3 materials have been improved significantly by the nanocrystallization of CoSb 3 -based materials [124][125][126][127][128][129][130][131][132][133][134][135][136][137][138][139][140] or the preparation of thin film materials [141][142][143][144][145][146][147]. Toprak et al [125] reported a novel chemical alloying method to prepare CoSb 3 materials with different nanoparticle sizes.…”

An enhanced power factor via multilayer growth of Ag-doped skutterudite CoSb3 thin films

“…20 Therefore, many studies on the synthesis of high performance thin films, including CoSb 3 films, have been investigated. [21][22][23][24][25][26] For example, A. Ahmed et al 27 obtained a power factor of 7.92 mW m K −2 for the CoSb 2 -containing mixed phase thin film and 1.26 mW m K −2 for the stoichiometric CoSb 3 thin film. However, TE properties of CoSb 3 thin films remain lower than those of bulk materials due to the difficulty of controlling precisely the composition of the thin films.…”