| 1. |
- Sadowski, Grzegorz, et al.
(författare)
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Structural evolution and thermoelectric properties of Mg3SbxBi2-x thin films deposited by magnetron sputtering
- 2023
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : A V S AMER INST PHYSICS. - 0734-2101 .- 1520-8559. ; 41:4
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Tidskriftsartikel (refereegranskat)abstract
- Mg3Bi2-based compounds are of great interest for thermoelectric applications near room temperature. Here, undoped p-type Mg3SbxBi2-x thin films were synthesized using magnetron sputtering (three elemental targets in Ar atmosphere) with a growth temperature of 200 ? on three different substrates, namely, Si as well as c- and r-sapphire. The elemental composition was measured with energy-dispersive x-ray spectroscopy and the structure by x-ray diffraction. The electrical resistivity and the Seebeck coefficient were determined under He atmosphere from room temperature to the growth temperature. All samples are crystalline exhibiting the La2O3-type crystal structure (space group P-3m1). The observed thermoelectric response is consistent with a semiconductive behavior. With increasing x, the samples become more electrically resistive due to the increasing bandgap. High Bi content (x < 1) is thus beneficial due to lower resistivity and a higher power factor near room temperature. Thermoelectric thin films synthesized at low temperatures may provide novel pathways to enable flexible devices on polymeric and other heat-sensitive substrates.
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| 2. |
- Shu, Rui, et al.
(författare)
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Solid-State Janus Nanoprecipitation Enables Amorphous-Like Heat Conduction in Crystalline Mg3Sb2-Based Thermoelectric Materials
- 2022
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Ingår i: Advanced Science. - : Wiley. - 2198-3844. ; 9:25
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Tidskriftsartikel (refereegranskat)abstract
- Solid-state precipitation can be used to tailor material properties, ranging from ferromagnets and catalysts to mechanical strengthening and energy storage. Thermoelectric properties can be modified by precipitation to enhance phonon scattering while retaining charge-carrier transmission. Here, unconventional Janus-type nanoprecipitates are uncovered in Mg3Sb1.5Bi0.5 formed by side-by-side Bi- and Ge-rich appendages, in contrast to separate nanoprecipitate formation. These Janus nanoprecipitates result from local comelting of Bi and Ge during sintering, enabling an amorphous-like lattice thermal conductivity. A precipitate size effect on phonon scattering is observed due to the balance between alloy-disorder and nanoprecipitate scattering. The thermoelectric figure-of-merit ZT reaches 0.6 near room temperature and 1.6 at 773 K. The Janus nanoprecipitation can be introduced into other materials and may act as a general property-tailoring mechanism.
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| 3. |
- Zheng, Zhijia, et al.
(författare)
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Photoluminescence properties of ZnO:Al films deposited on flexible PET substrate by RF reactive magnetron sputtering
- 2013
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Ingår i: Optoelectronics and Advanced Materials Rapid Communications. - 1842-6573 .- 2065-3824. ; 7:9-10, s. 676-679
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Tidskriftsartikel (refereegranskat)abstract
- Aluminium-doped ZnO (AZO) thin films have been deposited on flexible polyethylene terephthalate (PET) substrate by RF reactive magnetron sputtering process at low substrate temperature (room -100 degrees C), and their photoluminescence (PL) behavior at room temperature and the influence of O-2:Ar ratio, substrate temperature, and deposition time were investigated. The strong near band-edge UV emission and the weak blue emission were observed, while the defect-related deep-level green emission was nearly absent, indicating that high optical quality AZO films, grown on flexible PET substrate, were obtained using the RF reactive magnetron sputtering technique. The origin of the emissions is discussed.
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