Thermal transport in semiconductor nanostructures
The scaling of semiconductor devices also changed the way heat flows through these systems. Heat flows in semiconductors predominantly in the form of lattice vibrations also called `phonons'. The shrinking the devices shift the heat transfer from the particle nature to the wave nature and to investigate heat flow in such a regime requires new tools. The following ingredients have been developed for the investigating heat flow at nano-scale:
- Phonon model: To capture the lattice dynamics within harmonic limit a good phonon model is needed. Our phonon model is an extension and combination of the older Keating's VFF model and Junger's VFF model. We call it the Modified VFF model (Link to JCE paper).
- Landauer's model This allows to capture the heat flow processes in uniform nanostructures like nanowires, UTBs, etc., under small temperature differences.
- Phonon Green's function heat solver To understand the flow of heat is to understand the flow of phonons. Within the wave function formalism the phonon transport is solved to understand the thermal transport in rough nanowires, superlattice nanowires, etc.
- Thermal transport in SiGe superlattice nanowires Understand phonon transport in SiGe superlattice(SL) nanowire. Reduce lattice thermal conductivity by using different structures of nanowire
Group member involved:
- Modified valence force field approach for phonon dispersion: from zinc-blende bulk to nanowires Methodology and computational details, Abhijeet Paul, Mathieu Luisier and Gerhard Klimeck, Journal of Computational Electronics, 2010.
- Atomistic modeling of the phonon dispersion and lattice properties of free-standing (100) Si nanowires, Abhijeet Paul, Mathieu Luisier and Gerhard Klimeck, IWCE 2010. ( DOI: 10.1109/IWCE.2010.5677959)
- Tuning lattice thermal conductance by porosity control in ultra-scaled Si and Ge nanowires, Abhijeet Paul and Gerhard Klimeck, Applied Physics Letters 98(8). 2011. ( DOI: 10.1063/1.3556648)