Large Enhancement of Thermal Conductivity and Lorenz Number in Topological Insulator Thin Films

ACS Nano ◽  
2018 ◽  
Vol 12 (2) ◽  
pp. 1120-1127 ◽  
Author(s):  
Zhe Luo ◽  
Jifa Tian ◽  
Shouyuan Huang ◽  
Mithun Srinivasan ◽  
Jesse Maassen ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Topological Insulator ◽  
Lorenz Number ◽  
Large Enhancement

Pseudo-Superlattices of Bi2Te3 Topological Insulator Films with Enhanced Thermoelectric Performance

2011 ◽  
Vol 1344 ◽  
Author(s):  
V. Goyal ◽  
D Teweldebrhan ◽  
A.A. Balandin
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Topological Insulator ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Laser Flash ◽  
Thermoelectric Efficiency ◽  
Thermoelectric Figure ◽  
Surface Transport ◽  
Film Thinning

ABSTRACTIt was recently suggested theoretically that atomically thin films of Bi2Te3 topological insulators have strongly enhanced thermoelectric figure of merit. We used the “graphene-like” exfoliation process to obtain Bi2Te3 thin films. The films were stacked and subjected to thermal treatment to fabricate pseudo-superlattices of single crystal Bi2Te3 films. Thermal conductivity of these structures was measured by the “hot disk” and “laser flash” techniques. The room temperature in-plane and cross-plane thermal conductivity of the stacks decreased by a factor of ∼2.4 and 3.5 respectively as compared to that of bulk. The strong decrease of thermal conductivity with preserved electrical properties translates to ∼140-250% increase in the thermoelectric figure if merit. It is expected that the film thinning to few-quintuples, and tuning of the Fermi level can lead to the topological insulator surface transport regime with the theoretically predicted extraordinary thermoelectric efficiency.

Thermal and Electrical Properties of 3.2 nm Thin Gold Films Coated on Alginate Fiber

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Hua Dong ◽  
Ranran Chen ◽  
Yongqiang Mu ◽  
Shouting Liu ◽  
Jingkui Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Electron Scattering ◽  
Bulk Material ◽  
Gold Films ◽  
Metallic Thin Films ◽  
Lorenz Number ◽  
Electrical Conductivities ◽  
Thermal And Electrical Properties ◽  
Alginate Fiber

The thermal transport in metallic thin films can be reduced by the electron scattering and there are very little available knowledge that can be used to explain the mechanism. In this work, we characterized the thermal and electron transport of 3.2 nm thin gold films coated on alginate fiber by the transient electrothermal (TET) technique. The results reveal that the thermal and electrical conductivities are reduced significantly from the respective values of bulk material by 76.2% and 93.9%. At the same time, the Lorenz number is calculated as 8.66 × 10−8 W Ω K−2 and it is almost three times increased from the value of bulk material. The intrinsic thermal diffusivity of alginate fiber is 3.25 × 10−7 m2 s−1 and the thermal conductivity is 0.51 W m−1 K−1.

Cross-plane thermal conductivity of thin films characterized by Flash DSC measurement

2019 ◽  
Vol 677 ◽  
pp. 21-25 ◽  
Author(s):  
Yucheng He ◽  
Xiaoheng Li ◽  
Ling Ge ◽  
Qinyun Qian ◽  
Wenbing Hu
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Conductivity Of Thin Films

scholarly journals Reduction of thermal conductivity in ferroelectric SrTiO3 thin films

2020 ◽  
Vol 4 (5) ◽  
Author(s):  
Alexandros Sarantopoulos ◽  
Dipanjan Saha ◽  
Wee-Liat Ong ◽  
César Magén ◽  
Jonathan A. Malen ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity

Determination of Thermal Conductivity of Amorphous Silicon Thin Films via Non-Contacting Optical Probing

2006 ◽  
Vol 326-328 ◽  
pp. 689-692
Author(s):  
Seung Jae Moon
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Amorphous Silicon ◽  
Optical Transmission ◽  
Film Deposition ◽  
Transmission Measurement ◽  
Conductive Heat ◽  
Optical Transmission Measurement

The thermal conductivity of amorphous silicon (a-Si) thin films is determined by using the non-intrusive, in-situ optical transmission measurement. The thermal conductivity of a-Si is a key parameter in understanding the mechanism of the recrystallization of polysilicon (p-Si) during the laser annealing process to fabricate the thin film transistors with uniform characteristics which are used as switches in the active matrix liquid crystal displays. Since it is well known that the physical properties are dependent on the process parameters of the thin film deposition process, the thermal conductivity should be measured. The temperature dependence of the film complex refractive index is determined by spectroscopic ellipsometry. A nanosecond KrF excimer laser at the wavelength of 248 nm is used to raise the temperature of the thin films without melting of the thin film. In-situ transmission signal is obtained during the heating process. The acquired transmission signal is fitted with predictions obtained by coupling conductive heat transfer with multi-layer thin film optics in the optical transmission measurement.

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