Experimental Micro/Nanoscale Thermal Transport

This book covers the new technologies on micro/nanoscale thermal characterization developed in the Micro/Nanoscale Thermal Science Laboratory led by Dr. Xinwei Wang. Five new non-contact and non-destructive technologies are introduced: optical heating and electrical sensing technique, transient electro-thermal technique, transient photo-electro-thermal technique, pulsed laser-assisted thermal relaxation technique, and steady-state electro-Raman-thermal technique. These techniques feature significantly improved ease of implementation, super signal-to-noise ratio, and have the capacity of measuring the thermal conductivity/diffusivity of various one-dimensional structures from dielectric, semiconductive, to metallic materials.

Autorentext

XINWEI WANG, PHD, is a Full Professor in the Department of Mechanical Engineering at Iowa State University, where he is also the Director of the Micro/Nanoscale Thermal Science Laboratory. His current research focuses on SPM-based thermal probing and thermal transport in biomaterials.

Klappentext
A unique focus on experimental techniques for the characterization of thermal transport in micro/nanoscale materials In the rapidly evolving field of nanotechnology, it ultimately comes down to experiments and measurement techniques to obtain and validate data on the thermophysical properties of nanoscale and nanostructured materials for various engineering applications. Experimental Micro/Nanoscale Thermal Transport details techniques developed in the author's own laboratory that boast significantly reduced experimental time, superior signal-to-noise ratio, and high-accuracy measurement results. The book walks readers through the entire process of setting up and implementing advanced new technologies, including physical principles and data analysis for measuring the thermal conductivity/diffusivity of micro/nanoscale films and wires, while giving clear instructions on how to conduct experiments, assess uncertainties, and interpret physical results. Highlights of Experimental Micro/Nanoscale Thermal Transport include:

• The introduction of the superior optical heating and electrical thermal sensing (OHETS) technique, along with other techniques in the frequency domain
• Highly efficient methods for accurate transient measurement in the time domain, such as transient electro-thermal (TET), transient photo-electro-thermal (TPET), and pulsed laser-assisted-thermal relaxation (PLTR) techniques
• Measurement of full-spectrum thermophysical properties using the generalized electro-thermal (GET) technique, one of the most advanced technologies available
• Novel temperature differential measurement using Raman spectroscopy to achieve direct evaluation of the local thermal resistance at material interface The first of its kind to focus on thermal characterization of the thermophysical properties of micro/nanoscale materials, this book will help researchers in material design and characterization tackle challenging thermal transport problems, quickly establish their own measurement techniques, and gain invaluable insight into experimental design.

Inhalt
Preface xi

1 Introduction 1

1.1 Unique Feature of Thermal Transport in Nanoscale and Nanostructured Materials 1

1.1.1 Thermal Transport Constrained by Material Size 2

1.1.2 Thermal Transport Constrained by Time 6

1.1.3 Thermal Transport Constrained by the Size of Physical Process 8

1.2 Molecular Dynamics Simulation of Thermal Transport at Micro/Nanoscales 10

1.2.1 Equilibrium MD Prediction of Thermal Conductivity 11

1.2.2 Nonequilibrium MD Study of Thermal Transport 15

1.2.3 MD Study of Thermal Transport Constrained by Time 18

1.3 Boltzmann Transportation Equation for Thermal Transport Study 21

1.4 Direct Energy Carrier Relaxation Tracking (DECRT) 32

1.5 Challenges in Characterizing Thermal Transport at Micro/Nanoscales 44

References 45

2 Thermal Characterization in Frequency Domain 47

2.1 Frequency Domain Photoacoustic (PA) Technique 47

2.1.1 Physical Model 48

2.1.2 Experimental Details 50

2.1.3 PA Measurement of Films and Bulk Materials 52

2.1.4 Uncertainty of the PA Measurement 55

2.2 Frequency Domain Photothermal Radiation (PTR) Technique 57

2.2.1 Experimental Details of the PTR Technique 57

2.2.2 PTR Measurement of Micrometer-Thick Films 58

2.2.3 PTR with Internal Heating of Desired Locations 60

2.3 Three-Omega Technique 62

2.3.1 Physical Model of the 3 **Technique for One-Dimensional Structures 62

2.3.2 Experimental Details 65

2.3.3 Calibration of the Experiment 67

2.3.4 Measurement of Micrometer-Thick Wires 69

2.3.5 Effect of Radiation on Measurement Result 70

2.4 Optical Heating Electrical Thermal Sensing (OHETS) Technique 73

2.4.1 Experimental Principle and Physical Model 73

2.4.2 Effect of Nonuniform Distribution of Laser Beam 74

2.4.3 Experimental Details and Calibration 77

2.4.4 Measurement of Electrically Conductive Wires 79

2.4.5 Measurement of Nonconductive Wires 81

2.4.6 Effect of Au Coating on Measurement 83

2.4.7 Temperature Rise in the OHETS Experiment 84

2.5 Comparison Among the Techniques 85

References 86

3 Transient Technologies in the Time Domain 87

3.1 Transient Photo-Electro-Thermal (TPET) Technique 87

3.1.1 Experimental Principles 88

3.1.2 Physical Model Development 88

3.1.3 Effect of Nonuniform Distribution and Finite Rising Time of the Laser Beam 90

3.1.4 Experimental Setup 92

3.1.5 Technique Validation 93

3.1.6 Thermal Characterization of SWCNT Bundles and Cloth Fibers 95

3.2 Transient Electrothermal (TET) Technique 98

3.2.1 Physical Principles of the TET Technique 98

3.2.2 Methods for Data Analysis to Determine the Thermal Diffusivity 100

3.2.3 Effect of Nonconstant Electrical Heating 101

3.2.4 Experimental Details 102

3.2.5 Technique Validation 104

3.2.6 Measurement of SWCNT Bundles 105

3.2.7 Measurement of Polyester Fibers 107

3.2.8 Measurement of Micro/Submicroscale Polyacrylonitrile Wires 109

3.3 Pulsed Laser-Assisted Thermal Relaxation Technique 113

3.3.1 Experimental Principles 113

3.3.2 Physical Model for the PLTR Technique 114

3.3.3 Methods to Determine the Thermal Diffusivity 116

3.3.4 Experimental Setup and Technique Validation 117

3.3.5 Measurement of Multiwalled Carbon Nanotube (MWCNT) Bundles 118

3.3.6 Measurement of Individual Microscale Carbon Fibers 122

3.4 Super Channeling Effect for Thermal Transport in Micro/Nanoscale Wires 123

3.5 Multidimensional Thermal Characterization 128

3.5.1 Sample Preparation 129

3.5.2 Thermal Characterization Design 130

3.5.3 Thermal Transport Along the Axial Direction of Amorphous TiO2 Nanotubes 131

3.5.4 Thermal Transport in the Cross-Tube Direction of Amorphous TiO2 Nanotubes 133 3.5.5 Evaluatio...