The influence of a Te-depleted surface on the thermoelectric transport properties of Bi2Te3 nanowires

Hamdou B, Beckstedt A, Kimling J, Dorn A, Akinsinde L, Baessler S, Pippel E, Nielsch K (2014)

Publication Type: Journal article

Publication year: 2014

Journal

Nanotechnology Institute of Physics: Hybrid Open Access

Book Volume: 25

Article Number: 365401

Journal Issue: 36

DOI: 10.1088/0957-4484/25/36/365401

Abstract

We report on thermoelectric transport measurements along the basal plane of several individual, single-crystalline Bi2Te3 nanowires (NWs) with different cross-sectional areas, grown by a vapor-liquid-solid method. Lithographically defined microdevices allowed us to determine the Seebeck coefficient S, electrical conductivity σ, and thermal conductivity κ of individual NWs. The NWs studied show near intrinsic transport properties with low electrical conductivities of around σ = (3.2±0.9)× 104 Ω-1 m-1 at room temperature. We observe a transition of the Seebeck coefficient from positive to negative values (S=+133 μVK-1 to S=-87 μVK -1) with increasing surface-to-volume ratio at room temperature, which can be explained by the presence of an approximately 5 nm thick Te-depleted layer at the surface of the NWs. The thermal conductivities of our NWs are in the range of κ=(1.4±0.4) Wm-1 K-1 at room temperature, which is lower than literature values for bulk Bi 2Te3. We attribute this suppression in thermal conductivity to enhanced scattering of phonons at the surface of the NWs. Despite their reduced thermal conductivities, the NWs investigated only show a moderate figure of merit between 0.02 and 0.18 due to their near intrinsic transport properties. © 2014 IOP Publishing Ltd.

Involved external institutions

Universität Hamburg (UHH) DE Germany (DE) Max-Planck-Institut für Mikrostrukturphysik (MSP) / Max Planck Institute for Microstructure Physics DE Germany (DE)

How to cite

APA:

Hamdou, B., Beckstedt, A., Kimling, J., Dorn, A., Akinsinde, L., Baessler, S.,... Nielsch, K. (2014). The influence of a Te-depleted surface on the thermoelectric transport properties of Bi2Te3 nanowires. Nanotechnology, 25(36). https://dx.doi.org/10.1088/0957-4484/25/36/365401

MLA:

Hamdou, Bacel, et al. "The influence of a Te-depleted surface on the thermoelectric transport properties of Bi2Te3 nanowires." Nanotechnology 25.36 (2014).

BibTeX: Download