Performance Analysis of Micro-Raman Spectroscopy Models for Thermal Conductivity Calculation

2021 ◽  
Author(s):  
Taher Meydando ◽  
Nazli Donmezer
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Raman Spectroscopy ◽  
Phonon Scattering ◽  
Raman Laser ◽  
Current Approach ◽  
Slab Model ◽  
Boltzmann Transport ◽  
Micro Raman Spectroscopy ◽  
Thermal Conductivities

Abstract Micro-Raman spectroscopy has been preferred recently to measure the thermal conductivity of thin-films due to its nondestructive and non-contact nature. However, the thermal size effects originating from both localized heat generation from Raman laser and phonon scattering at boundaries may cause erroneous estimation of the thermal conductivities with the current approach. In this study, the gray phonon Boltzmann transport equation (BTE) is solved to improve the results of micro-Raman thermal conductivity measurements. Due to the frequency independence of single phonon mode in the gray BTE model, our method stays ahead of most theoretical methods in calculation time while giving adequate agreement with the literature data. The improved thermal conductivities are evaluated at various laser powers and focal lengths. Subsequently, the values of thermal conductivities are compared with a simple slab model in which the deduction of thermal conductivity in sub-micron thicknesses is calculated using reduced heat flux through the slab resulting from phonon directional energy densities. The results show that subsequent errors are present in measuring the thermal conductivity of relatively thick, thin films with this technique which are noticed by comparing with the simple slab model. Finally, a virtual micro-Raman thermography experiment is developed, and its validity is verified by the same slab model.

Thermal Conductivity of Nano-Porous Bismuth Antimony Telluride

2010 ◽  
Author(s):  
Saburo Tanaka ◽  
Masayuki Takashiri ◽  
Koji Miyazaki
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Phonon Scattering ◽  
Antimony Telluride ◽  
Bismuth Antimony Telluride ◽  
Porous Thin Films ◽  
Average Grain Size ◽  
Bismuth Antimony ◽  
Bulk Alloys ◽  
Thermal Conductivities

Bismuth antimony telluride (Bi0.4Te3.0Sb1.6) nano-porous thin films have been prepared and measured their thermal conductivities. The thin films exhibit an average grain size of 50 nm and random crystal orientation. The cross-plane thermal conductivity is measured by a differential 3ω method at temperature range from 100 to 300 K, and the determined thermal conductivities are from 0.09 to 0.18 W/(m·K). As compared with bulk alloys at the same atomic composition, the nano-porous thin films exhibit an eightfold reduction in the thermal conductivity. For more detail analysis, the reduction of the thermal conductivity is examined by a simplified phonon gas model on a single crystal of bulk Bi2Te3. The analytical model fairly agreed with the experimental results, and thus we consider that the thermal conductivity is reduced by the strong phonon scattering at the nano-pores.

Impact on Thermal Conductivities of Nanostructured Bismuth Telluride Based Thin Films

2011 ◽  
Author(s):  
Saburo Tanaka ◽  
Masayuki Takashiri ◽  
Koji Miyazaki
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Bismuth Telluride ◽  
Phonon Scattering ◽  
Omega Method ◽  
Average Grain Size ◽  
3 Omega ◽  
Bulk Alloys ◽  
Nanocrystalline Thin Films ◽  
Thermal Conductivities

Nanostructured bismuth telluride based thin films, including nanoparticle and nanocrystalline have been prepared and measured their thermal conductivities. These thin films exhibit an average grain size of from 10 nm to 150 nm. The cross-plane thermal conductivities are measured by 3-omega method at 300 K. The determined nanostructured bismuth telluride thermal conductivities are 0.18 W/(m·K) and nanoparticle bismuth telluride thin film thermal conductivities are from 0.61 W/(m·K) to 0.80 W/(m·K). As compared with bulk alloys at the same atomic composition, both the nanoparticle and nanocrystalline thin films exhibit a reduction in the thermal conductivity. For more detail analysis, the reduction of the thermal conductivity is examined by a simplified phonon gas model on single crystal of bulk bismuth telluride, antimony telluride and bismuth selenide, The analytical model is consistent with the experimental results, and thus we consider that the thermal conductivity is reduced by the strong phonon scattering.

Thermal Conductivity Anisotropy in Phonon Transport of Bi2Te3/Bi0.5Sb1.5Te3 Superlattice Film

2020 ◽  
Vol 15 (4) ◽  
pp. 463-467
Author(s):  
Soo-Young Kang ◽  
No-Won Park ◽  
Won-Yong Lee ◽  
Min-Sung Kang ◽  
Gil-Sung Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Electron Scattering ◽  
Phonon Scattering ◽  
Phonon Transport ◽  
Temperature Dependent ◽  
Conductivity Anisotropy ◽  
Large Anisotropy ◽  
Temperature Dependent Thermal Conductivity ◽  
Thermal Conductivities

Nanoscale superlattice thin films generally exhibit larger phonon and electron scattering at the interface in the direction of the cross-plane of the samples. Therefore, it is very important to further detailed study of especially phonon transport of the superlattice films. Here, we report temperature dependent thermal conductivity anisotropy in phonon transport of Bi2 Te3 /Bi0.5 Sb1.5 Te3 superlattice thin films at 200–500 K. Thermal conductivity of these thin films for in- and cross-plane thermal conductivities were determined to be approximately 0.74 and 0.4 W m–1 K–1 at 200–500 K, respectively, clearly indicating ∼185% suppression in- and cross-plane thermal conductivities of the superlattice thin films with a large anisotropic behavior. Such large anisotropy in the thermal conductivity can be attributed to enhanced phonon scattering occurring at the interface of the Bi2Te3 and Bi0.5Sb1.5Te3 layer.

Thermal Conductivity Reduction in Few-Layer Graphene

2011 ◽  
Author(s):  
Dhruv Singh ◽  
Jayathi Y. Murthy ◽  
Timothy S. Fisher
Keyword(s):  
Thermal Conductivity ◽  
Weak Coupling ◽  
Phonon Scattering ◽  
Single Layer ◽  
Acoustic Mode ◽  
Single Layer Graphene ◽  
Boltzmann Transport ◽  
Layer Graphene ◽  
Out Of Plane ◽  
Few Layer Graphene

Using the linearized Boltzmann transport equation and perturbation theory, we analyze the reduction in the intrinsic thermal conductivity of few-layer graphene sheets accounting for all possible three-phonon scattering events. Even with weak coupling between layers, a significant reduction in the thermal conductivity of the out-of-plane acoustic modes is apparent. The main effect of this weak coupling is to open many new three-phonon scattering channels that are otherwise absent in graphene. The highly restrictive selection rule that leads to a high thermal conductivity of ZA phonons in single-layer graphene is only weakly broken with the addition of multiple layers, and ZA phonons still dominate thermal conductivity. We also find that the decrease in thermal conductivity is mainly caused by decreased contributions of the higher-order overtones of the fundamental out-of-plane acoustic mode. Moreover, the extent of reduction is largest when going from single to bilayer graphene and saturates for four layers. The results compare remarkably well over the entire temperature range with measurements of of graphene and graphite.

scholarly journals Thermal conductivity of GaAs nanowires studied by micro-Raman spectroscopy combined with laser heating

2010 ◽  
Vol 97 (26) ◽  
pp. 263107 ◽  
Author(s):  
Martin Soini ◽  
Ilaria Zardo ◽  
Emanuele Uccelli ◽  
Stefan Funk ◽  
Gregor Koblmüller ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Raman Spectroscopy ◽  
Laser Heating ◽  
Micro Raman Spectroscopy ◽  
Gaas Nanowires

Raman Spectroscopy: A Unique Tool for the Study of Thin Films

2000 ◽  
Vol 615 ◽  
Author(s):  
Ingrid De Wolf
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Local Stress ◽  
Micro Raman Spectroscopy

ABSTRACTIn this paper, the different applications of Raman spectroscopy for the study of thin films is briefly discussed, using examples from microelectronics. Special attention is given to the application of micro-Raman spectroscopy for the measurement of local stress in and near films.

scholarly journals Localized Strain Measurement in Molecular Beam Epitaxially Grown Chalcogenide Thin Films by Micro-Raman Spectroscopy

ACS Omega ◽  
2020 ◽  
Vol 5 (14) ◽  
pp. 8090-8096
Author(s):  
Qiu Li ◽  
Yong Wang ◽  
Tiantian Li ◽  
Wei Li ◽  
Feifan Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Strain Measurement ◽  
Molecular Beam ◽  
Micro Raman Spectroscopy ◽  
Chalcogenide Thin Films

One- and two-phonon scattering processes in ZnSe/ZnSxSe1−xsuperlattices studied by micro-Raman spectroscopy

1994 ◽  
Vol 50 (7) ◽  
pp. 4988-4991 ◽  
Author(s):  
G. Scamarcio ◽  
V. Spagnolo ◽  
C. Corvasce ◽  
M. Lugará ◽  
I. Suemune
Keyword(s):  
Raman Spectroscopy ◽  
Phonon Scattering ◽  
Micro Raman Spectroscopy
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