Frequency matters: Understanding and measuring heat transfer in micro- and nanoscale applications
Event details
| Date | 25.05.2016 |
| Hour | 14:15 › 15:15 |
| Speaker | Dr. Christian Monachon, Mechanical Engineering Department, University of California, Berkeley |
| Location | |
| Category | Conferences - Seminars |
Heat transfer at the micro- and nano-scale is critically important in current technologies. Direct applications include microprocessors, high performance heat sink technologies and thermal barrier coatings as they all exhibit size effects. Among these effects I will put a special emphasis on the presence of an ever-growing density of heterogeneous interfaces in these devices, which limits their efficiency by hampering waste heat extraction from them.
Concomitantly, in the past 20 years a class of techniques, using electrothermal and laser-based modulated heating, has been developed. They can access nanoscale properties through careful control of thermal penetration depth through modulation frequency adjustments. I will introduce these techniques and their capabilities, with a special focus on Time Domain Thermoreflectance (TDTR), which is a fs laser pump-probe thermoreflectance technique, and is capable of thermally probing properties of materials with dimensions down to a few nm or single interfaces.
I will then show how I used TDTR to measure thermal boundary conductance (TBC) of solid/solid interfaces. In particular, I will show that a comprehensive understanding of interfaces in terms of chemistry and interfacial work of adhesion is instrumental to obtain high TBCs, with up to 25-fold increases obtained in some cases. I will also present a new way of quantitatively estimating the TBC of strong interfaces at high temperatures, which makes it useful for engineering purposes. I will conclude by suggesting how insights into modulated heating can be applied in novel manufacturing techniques.
Bio: Christian Monachon earned his B. Sc. and M. Sc. Materials Science and Engineering in 2008 at the École Polytechnique Fédérale de Lausanne (EPFL), along with a minor in energy technologies and a Master thesis in mechanical metallurgy at Northwestern University in Chicago, USA. After earning his PhD in mechanical metallurgy from EPFL in 2013, he moved to work as a postdoctoral fellow at the Mechanical Engineering department at the University of California in Berkeley. His current interests are in understanding and measuring thermal transport at micro- and nanometer scale, with applications in thermal management, energy conversion and manufacturing.
Concomitantly, in the past 20 years a class of techniques, using electrothermal and laser-based modulated heating, has been developed. They can access nanoscale properties through careful control of thermal penetration depth through modulation frequency adjustments. I will introduce these techniques and their capabilities, with a special focus on Time Domain Thermoreflectance (TDTR), which is a fs laser pump-probe thermoreflectance technique, and is capable of thermally probing properties of materials with dimensions down to a few nm or single interfaces.
I will then show how I used TDTR to measure thermal boundary conductance (TBC) of solid/solid interfaces. In particular, I will show that a comprehensive understanding of interfaces in terms of chemistry and interfacial work of adhesion is instrumental to obtain high TBCs, with up to 25-fold increases obtained in some cases. I will also present a new way of quantitatively estimating the TBC of strong interfaces at high temperatures, which makes it useful for engineering purposes. I will conclude by suggesting how insights into modulated heating can be applied in novel manufacturing techniques.
Bio: Christian Monachon earned his B. Sc. and M. Sc. Materials Science and Engineering in 2008 at the École Polytechnique Fédérale de Lausanne (EPFL), along with a minor in energy technologies and a Master thesis in mechanical metallurgy at Northwestern University in Chicago, USA. After earning his PhD in mechanical metallurgy from EPFL in 2013, he moved to work as a postdoctoral fellow at the Mechanical Engineering department at the University of California in Berkeley. His current interests are in understanding and measuring thermal transport at micro- and nanometer scale, with applications in thermal management, energy conversion and manufacturing.
Practical information
- Informed public
- Free
- This event is internal
Organizer
- IGM
Contact
- Prof J. Botsis