Experimental Investigation of Thermal Transport Mechanisms Through a Nanoscale Point Contact

2011 ◽  
Author(s):  
Michael Thompson Pettes ◽  
Li Shi
Keyword(s):  
Radiation Transport ◽  
Thermal Contact ◽  
Near Field ◽  
Temperature Drop ◽  
Point Contact ◽  
Dominant Mode ◽  
Large Temperature ◽  
Resistance Thermometer ◽  
Atomic Force ◽  
Field Radiation

Using a silicon nitride cantilever with an integral Si tip and a micro-fabricated Pt-C resistance thermometer placed close to the tip, we have measured the thermal contact resistance of a nanoscale Si point contact in an ultrahigh vacuum atomic force microscope at near room temperature. The temperature of the cantilever tip was observed to remain constant during approach to, while in contact with, and during retraction from the Si substrate, while a large temperature drop was observed at the points of contact and separation, suggesting negligible near-field radiation transport in the experiment reported here. Detailed contact mechanics calculations of the contact diameter and modeling of the nanocontact show that solid-solid conduction with phonon transmission coefficient of at least 0.12 is the dominant mode of heat transfer through the nanoscale contact.

A Reexamination of Phonon Transport Through a Nanoscale Point Contact in Vacuum

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Michael Thompson Pettes ◽  
Li Shi
Keyword(s):  
Contact Area ◽  
Room Temperature ◽  
Near Field ◽  
Point Contact ◽  
Thermal Conductance ◽  
Phonon Transport ◽  
Interfacial Resistance ◽  
Resistance Thermometer ◽  
Measurement Results ◽  
Interface Contact

Using a silicon nitride cantilever with an integral silicon tip and a microfabricated platinum–carbon resistance thermometer located close to the tip, a method is developed to concurrently measure both the heat transfer through and adhesion energy of a nanoscale point contact formed between the sharp silicon tip and a silicon substrate in an ultrahigh vacuum atomic force microscope at near room temperature. Several models are used to evaluate the contact area critical for interpreting the interfacial resistance. Near field-thermal radiation conductance was found to be negligible compared to the measured interface thermal conductance determined based on the possible contact area range. If the largest possible contact area is assumed, the obtained thermal interface contact resistance can be explained by a nanoconstriction model that allows the transmission of phonons from the whole Brillouin zone of bulk Si with an average finite transmissivity larger than 0.125. In addition, an examination of the quantum thermal conductance expression suggests the inaccuracy of such a model for explaining measurement results obtained at above room temperature.

Near-Field Radiation Between a Sphere and Substrates of Different Materials

2008 ◽  
Author(s):  
Sheng Shen ◽  
Arvind Narayanaswamy ◽  
Gang Chen
Keyword(s):  
Radiative Heat ◽  
Near Field ◽  
Dielectric Materials ◽  
Silica Microsphere ◽  
Polar Dielectric ◽  
Atomic Force ◽  
Surface Phonon Polaritons ◽  
Radiation Enhancement ◽  
Field Radiation ◽  
Afm Cantilever

In order to measure the near-field radiative heat transfer between a microsphere and a substrate, we have developed a sensitive technique using a bi-material atomic force microscope (AFM) cantilever. In this paper, we use this technique to measure the near-field radiation between a silica microsphere and substrates made of different materials (semiconductor, metal and polar dielectric materials). The resulting “Conductance-distance” curves show the presence of the near-field radiation enhancement caused by surface phonon-polaritons.

Reconstruct the PWM Signal of Switching Power Supplies from the Near Field Radiation

2013 ◽  
Vol 718-720 ◽  
pp. 1792-1796
Author(s):  
Zhong Qun Li ◽  
Kai Xie ◽  
Ying Hao Ye ◽  
Rong Bin Guo ◽  
Xu Fei Wang
Keyword(s):  
Pulse Width Modulation ◽  
Signal Reconstruction ◽  
Near Field ◽  
Buck Converter ◽  
Power Supplies ◽  
Switching Converters ◽  
Switching Power ◽  
Magnetic Components ◽  
Field Radiation ◽  
Switching Power Supplies

A non-contact testing method is proposed for encapsulation treated or insulation coated switching power supplies, which is implemented by reconstructing the pulse width modulation (PWM) signal of switching converters from the near field radiation of magnetic components. The radiation pattern of a buck converter is investigated, and the magnetic field sensing probe and PWM signal reconstruction circuit are also illustrated. The reconstruction testing is carried out on a buck converter; the duty cycle error of the reconstructed PWM signal is less than 0.2%, which validates the proposed method.

A new method to calculate near-field radiation excited by heterogeneous fault rupture

2007 ◽  
Vol 20 (6) ◽  
pp. 597-604
Author(s):  
Xue-feng Shang ◽  
Qi-ming Liu ◽  
Hai-ming Zhang ◽  
Xiao-fei Chen
Keyword(s):  
Near Field ◽  
New Method ◽  
Fault Rupture ◽  
Field Radiation

Heat Transfer Spectroscopy and “Heat Transfer-Distance” Curves

2008 ◽  
Author(s):  
Arvind Narayanaswamy ◽  
Sheng Shen ◽  
Gang Chen
Keyword(s):  
Heat Transfer ◽  
Radiative Transfer ◽  
Atomic Force Microscope ◽  
Near Field ◽  
Surface Force ◽  
Casimir Forces ◽  
Distance Curve ◽  
Transfer Distance ◽  
Atomic Force ◽  
Order Of Magnitude

Thermal radiative transfer between objects as well as near-field forces such as van der Waals or Casimir forces have their origins in the fluctuations of the electrodynamic field. Near-field radiative transfer between two objects can be enhanced by a few order of magnitude compared to the far-field radiative transfer that can be described by Planck’s theory of blackbody radiation and Kirchoff’s laws. Despite this common origin, experimental techniques of measuring near-field forces (using the surface force apparatus and the atomic force microscope) are more sophisticated than techniques of measuring near-field radiative transfer. In this work, we present an ultra-sensitive experimental technique of measuring near-field using a bi-material atomic force microscope cantilever as the thermal sensor. Just as measurements of near-field forces results in a “force distance curve”, measurement of near-field radiative transfer results in a “heat transfer-distance” curve. Results from the measurement of near-field radiative transfer will be presented.

scholarly journals Opto-mechanical probe for combining atomic force microscopy and optical near-field surface analysis

2014 ◽  
Vol 39 (16) ◽  
pp. 4800 ◽  
Author(s):  
C. H. van Hoorn ◽  
D. C. Chavan ◽  
B. Tiribilli ◽  
G. Margheri ◽  
A. J. G. Mank ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Analysis ◽  
Near Field ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mechanical Probe

Circularly polarized localized near-field radiation at the nanoscale

2009 ◽  
Vol 99 (1-2) ◽  
pp. 67-74 ◽  
Author(s):  
E. Öğüt ◽  
G. Kızıltaş ◽  
K. Şendur
Keyword(s):  
Near Field ◽  
Circularly Polarized ◽  
Field Radiation
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