Page 13 - IOE_Winter 24
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NOVEL APPROACH TO
NANOSCALE HEAT TRANSFER
In the theory of heat transfer thermal energy depending on the material, photons and phonons
is conveyed by quantum particles known as will come together, and create something new
phonons, but in the nanoscale environment of called a ‘polariton’. It carries energy in its own
modern day semiconductors these phonons unique way, distinct from both photons and
are inadequate for effective heat removal. This phonons.
has prompted Purdue University to investigate
Phonons are like internal combustion vehicles,
the application of hybrid quasiparticles called
and photons are like electric vehicles. Polaritons
‘polaritons’ to achieve a solution.
are akin to a Toyota Prins. They are a hybrid of light
These ‘polaritons’ are conceptual models for and heat, retaining some properties of both, yet
energy exchange, as opposed to being tangible they are distinct.
particles and they have already been utilised in
Polaritons start to dominate heat transfer on any
certain optical applications, but according to the
surface thinner than 10 nanometres, which is
researchers their use in heat transfer has largely
about twice the size of transistors on an iPhone 15.
been overlooked, mainly because their effects
only become noticeable on very small scales. We’ve essentially added a new dimension to the
heat transfer mechanism. As semiconductors
In this project the researchers hope to be able
continue to shrink, it becomes increasingly
to demonstrate to chip manufacturers how
important to design them to utilise both phonons
polariton-based nanoscale heat transfer
and polaritons effectively.
principles can be applied to the physical design
of chips, considering the materials used and the At the Birck Nanotechnology Centre we have the
architecture of the layers. facilities to construct nanoscale experiments and
unique tools for validating our theories.”
Thomas Beechem, Associate Professor of
Mechanical Engineering at Purdue University, This work has been recognised as a featured
explains: article in the Journal of Applied Physics.
“ We have several ways of describing energy. [ Reference: West,P., ‘Opening a new Nanoscale
When we talk about light we describe it in terms of Lane on the Heat Transfer Highway’, Electronic
particles called ‘photons’. Heat also carries energy Specifier, 11th. December 2023 ]
in predictable ways, and we describe those
waves of energy as ‘phonons’. But sometimes,
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