Effects Of Disorder On Thermoelectric Properties Of Semiconducting Polymers, Zlatan Aksamija, Dhandapani Venkataraman, Connor J. Boyle, Meenakshi Upadhyaya
Apr 2019
Effects Of Disorder On Thermoelectric Properties Of Semiconducting Polymers, Zlatan Aksamija, Dhandapani Venkataraman, Connor J. Boyle, Meenakshi Upadhyaya
Zlatan Aksamija
Organic materials have attracted recent interest as thermoelectric (TE) converters due to their low cost and ease of fabrication. We examine the effects of disorder on the TE properties of semiconducting polymers based on the Gaussian disorder model (GDM) for site energies while employing Pauli’s master equation approach to model hopping between localized sites. Our model is in good agreement with experimental results and a useful tool to study hopping transport. We show that stronger overlap between sites can improve the electrical conductivity without adversely affecting the Seebeck coefficient. We find that positional disorder aids the formation of new conduction …
Quantifying Thermal Boundary Conductance Of 2d–3d Interfaces, Zlatan Aksamija, Cameron J. Foss
Feb 2019
Quantifying Thermal Boundary Conductance Of 2d–3d Interfaces, Zlatan Aksamija, Cameron J. Foss
Zlatan Aksamija
Heat dissipation in next-generation electronics based on two-dimensional (2D) materials is a
critical issue in their development and implementation. A potential bottleneck for heat removal in
2D-based devices is the thermal pathway from the 2D layer into its supporting substrate. The choice
of substrate, its composition and structure, can strongly impact the thermal boundary conductance
(TBC). Here we investigate the temperature-dependent TBC of 42 interfaces formed between a
group of six 2D materials and seven crystalline and amorphous substrates. We use first-principles
density functional perturbation theory to calculate the full phonon dispersion of the 2D layers and
substrates and then …
Dynamical Thermal Conductivity Of Suspended Graphene Ribbons In The Hydrodynamic Regime, Zlatan Aksamija, Arnab K. Majee
Jul 2018
Dynamical Thermal Conductivity Of Suspended Graphene Ribbons In The Hydrodynamic Regime, Zlatan Aksamija, Arnab K. Majee
Zlatan Aksamija
The steady-state behavior of thermal transport in bulk and nanostructured semiconductors has been widely
studied, both theoretically and experimentally. On the other hand, fast transients and frequency dynamics of
thermal conduction has been given less attention. The frequency response of thermal conductivity has become
more crucial in recent years, especially in light of the constant rise in the clock frequencies in microprocessors
and terahertz sensing applications. Thermal conductivity in response to a time-varying temperature field starts
decaying when the frequency exceeds a cutoff frequency Omega_c, which is related to the inverse of phonon relaxation time τ, on the order of …
Power Dissipation Of Wse2 Field-Effect Transistors Probed By Low- Frequency Raman Thermometry, Zlatan Aksamija, Cameron J. Foss, Arnab K. Majee, Amin Salehi-Khojin
Jun 2018
Power Dissipation Of Wse2 Field-Effect Transistors Probed By Low- Frequency Raman Thermometry, Zlatan Aksamija, Cameron J. Foss, Arnab K. Majee, Amin Salehi-Khojin
Zlatan Aksamija
The ongoing shrinkage in the size of two-dimensional (2D) electronic circuitry results in high power densities during device operation, which could cause a significant temperature rise within 2D channels. One challenge in
Raman thermometry of 2D materials is that the commonly used high-frequency modes do not precisely represent the temperature rise in some 2D materials because of peak broadening and intensity weakening at elevated temperatures. In this work, we show that a low-frequency E2g 2 shear mode can be used to accurately extract temperature and measure thermal boundary conductance (TBC) in backgated tungsten diselenide (WSe2) field-effect transistors, whereas the high-frequency …
Interfacial Thermal Transport In Monolayer Mos2- And Graphene-Based Devices, Zlatan Aksamija
Dec 2017
Interfacial Thermal Transport In Monolayer Mos2- And Graphene-Based Devices, Zlatan Aksamija
Zlatan Aksamija
No abstract provided.
S41598-017-16744-0.Pdf, Zlatan Aksamija
Nov 2017
S41598-017-16744-0.Pdf, Zlatan Aksamija
Zlatan Aksamija
No abstract provided.
Interfacial Thermal Transport In Monolayer Mos2- And Graphene-Based Devices, Zlatan Aksamija, Amin Salehi-Khojin, Cameron J. Foss, Arnab K. Majee, Fatemeh Khalili-Araghi
Jul 2017
Interfacial Thermal Transport In Monolayer Mos2- And Graphene-Based Devices, Zlatan Aksamija, Amin Salehi-Khojin, Cameron J. Foss, Arnab K. Majee, Fatemeh Khalili-Araghi
Zlatan Aksamija
In many device architectures based on 2D materials, a major part of the heat generated in hot-spots dissipates in the through-plane direction where the interfacial thermal resistances can significantly restrain the heat removal
capability of the device. Despite its importance, there is an enormous (1–2 orders of magnitude) disagreement in the literature on the interfacial thermal transport characteristics of MoS2 and other transition metal dichalcogenides (TMDs) (0.1–14 MW m−2 K−1). In this report, the thermal boundary conductance (TBC) across MoS2 and graphene monolayers with SiO2/Si and sapphire substrates is systematically investigated using a
custom-made electrical thermometry platform followed by 3D …
Impact Of Mismatch Angle On Electronic Transport Across Grain Boundaries And Interfaces In 2d Materials, Zlatan Aksamija
Dec 2016
Impact Of Mismatch Angle On Electronic Transport Across Grain Boundaries And Interfaces In 2d Materials, Zlatan Aksamija
Zlatan Aksamija
We study the impact of grain boundaries (GB) and misorientation angles between grains on electronic
transport in 2-dimensional materials. Here we have developed a numerical model based on the firstprinciples
electronic bandstructure calculations in conjunction with a method which computes electron
transmission coefficients from simultaneous conservation of energy and momentum at the interface to
essentially evaluate GB/interface resistance in a Landauer formalism. We find that the resistance across
graphene GBs vary over a wide range depending on misorientation angles and type of GBs, starting
from 53 Ω μm for low-mismatch angles in twin (symmetric) GBs to about 1020 Ω μm …
