scholarly journals Thermal Models for Determining Thermal Conductivity and Thermal Boundary Conductance Using Pump-Probe Thermoreflectance Techniques

2009 ◽  
Author(s):  
Patrick E. Hopkins ◽  
Justin R. Serrano ◽  
Leslie M. Phinney
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Probe Signal ◽  
Pump Probe ◽  
Thermal Models ◽  
Thermal Boundary Conductance ◽  
Advantages And Disadvantages ◽  
Heating Event ◽  
Lock In ◽  
Thermal Conductivity Λ

Pump-probe transient thermoreflectance (TTR) techniques are powerful tools for measuring thermophysical properties of thin films, such as thermal conductivity, Λ, or thermal boundary conductance, G. TTR experimental setups rely on lock-in techniques to detect the response of the probe signal relative to the pump heating event. The temporal decays of the lock-in signal are then compared to thermal models to deduce the Λ and G in and across various materials. There are currently two thermal models that are used to relate the measured signals from the lock-in to the Λ and G in the sample of interest. In this work, the thermal models, their assumptions, and their ranges of applicability are compared. The advantages and disadvantages of each technique are elucidated from the results of the thermophysical property measurements.

High thermal conductivity and thermal boundary conductance of homoepitaxially grown gallium nitride (GaN) thin films

2021 ◽  
Vol 5 (10) ◽  
Author(s):  
Yee Rui Koh ◽  
Md Shafkat Bin Hoque ◽  
Habib Ahmad ◽  
David H. Olson ◽  
Zeyu Liu ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Gallium Nitride ◽  
High Thermal Conductivity ◽  
Thermal Boundary Conductance

Dimensionality Analysis of Thermal Transport in Multilayer Thin Film Systems

2009 ◽  
Author(s):  
Patrick E. Hopkins ◽  
Justin R. Serrano ◽  
Leslie M. Phinney ◽  
Sean P. Kearney ◽  
Thomas W. Grasser ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Transport ◽  
Modulation Frequency ◽  
3D Models ◽  
Dimensional Error ◽  
Pump Probe ◽  
One Dimensional ◽  
Thermal Boundary Conductance ◽  
Dimensionality Analysis ◽  
Thermal Conductivity Λ

Pump-probe transient thermoreflectance (TTR) techniques are powerful tools for measuring thermophysical properties of thin films, such as thermal conductivity, Λ, or thermal boundary conductance, G. This paper examines the assumption of one-dimensional heating on Λ and G determination in nanostructures using a pump-probe transient thermoreflectance technique. The traditionally used one dimensional and radial (3D) models are reviewed. To test the assumptions of the thermal models, experimental data from Al films on bulk substrates (Si and glass) are taken with the TTR technique. This analysis is extended to thin film multilayer structures. Results show that at 11 MHz modulation frequency, thermal transport is indeed one dimensional. Error among the various models arises due to pulse accumulation and not accounting for residual heating.

Confined Transducer Geometries to Enhance Sensitivity to Thermal Boundary Conductance in Frequency-Domain Thermoreflectance Measurements

2021 ◽  
Author(s):  
Ronald J. Warzoha ◽  
Adam A. Wilson ◽  
Brian F. Donovan ◽  
Andy Clark ◽  
Xuemei Cheng ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Frequency Domain ◽  
Optical Pump ◽  
Pump Probe ◽  
Thermal Boundary Conductance ◽  
Buried Interfaces ◽  
Thermal Penetration Depth ◽  
Numerical Fitting ◽  
Measurement Resolution ◽  
Heating Event

Abstract Quantifying the resistance to heat flow across well-bonded, planar interfaces is critical in modern electronics packaging architectures, particularly as device length scales are reduced and power demands continue to grow unabated. However, very few experimental techniques are capable of measuring the thermal resistance across such interfaces due to limitations in the required measurement resolution provided by the characterization technique (i.e., Rth < 0.1 mm2·K/W in steady-state configurations) and restrictions on the thermal penetration depth that can be achieved as a result of the heating event that is typically imposed on a sample’s surface (for optical pump-probe thermoreflectance techniques). A recent numerical fitting routine for Frequency-domain Thermoreflectance (FDTR) developed by the authors1 offers a potential avenue to rectify these issues if the transducer’s geometry can be confined. This work utilizes numerical simulations to evaluate the sensitivity of FDTR to a range of thermal boundary resistance (TBR) values as a function of the thermal resistance of adjacent material layers. Experimental measurements are performed across a handful of different material systems to validate our computational results and to demonstrate the the extent to which confined transducer geometries can improve our sensitivyt to the TBR across so-called “buried” interfaces when characterized with FDTR.

Criteria for Cross-Plane Dominated Thermal Transport in Multilayer Thin Film Systems During Modulated Laser Heating

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Patrick E. Hopkins ◽  
Justin R. Serrano ◽  
Leslie M. Phinney ◽  
Sean P. Kearney ◽  
Thomas W. Grasser ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Transport ◽  
Modulation Frequency ◽  
Multilayer Thin Film ◽  
Axially Symmetric ◽  
Dimensional Error ◽  
Pump Probe ◽  
One Dimensional ◽  
Thermal Boundary Conductance ◽  
Thermal Conductivity Λ

Pump-probe transient thermoreflectance (TTR) techniques are powerful tools for measuring the thermophysical properties of thin films, such as thermal conductivity, Λ, or thermal boundary conductance, G. This paper examines the assumption of one-dimensional heating on, Λ and G, determination in nanostructures using a pump-probe transient thermoreflectance technique. The traditionally used one-dimensional and axially symmetric cylindrical conduction models for thermal transport are reviewed. To test the assumptions of the thermal models, experimental data from Al films on bulk substrates (Si and glass) are taken with the TTR technique. This analysis is extended to thin film multilayer structures. The results show that at 11 MHz modulation frequency, thermal transport is indeed one dimensional. Error among the various models arises due to pulse accumulation and not accounting for residual heating.

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

scholarly journals Giant Photoluminescence Enhancement and Carrier Dynamics in MoS2 Bilayers with Anomalous Interlayer Coupling

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1994
Author(s):  
Han Li ◽  
Yating Ma ◽  
Zhongjie Xu ◽  
Xiang’ai Cheng ◽  
Tian Jiang
Keyword(s):  
Optical Properties ◽  
Transition Metal Dichalcogenides ◽  
Interlayer Coupling ◽  
Carrier Dynamics ◽  
Probe Signal ◽  
Exciton Resonance ◽  
Pump Probe ◽  
Metal Dichalcogenides ◽  
Photoluminescence Enhancement ◽  
Probe Measurements

Fundamental researches and explorations based on transition metal dichalcogenides (TMDCs) mainly focus on their monolayer counterparts, where optical densities are limited owing to the atomic monolayer thickness. Photoluminescence (PL) yield in bilayer TMDCs is much suppressed owing to indirect-bandgap properties. Here, optical properties are explored in artificially twisted bilayers of molybdenum disulfide (MoS2). Anomalous interlayer coupling and resultant giant PL enhancement are firstly observed in MoS2 bilayers, related to the suspension of the top layer material and independent of twisted angle. Moreover, carrier dynamics in MoS2 bilayers with anomalous interlayer coupling are revealed with pump-probe measurements, and the secondary rising behavior in pump-probe signal of B-exciton resonance, originating from valley depolarization of A-exciton, is firstly reported and discussed in this work. These results lay the groundwork for future advancement and applications beyond TMDCs monolayers.

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