Professor Zlatan Aksamija of our Electrical and Computer Engineering Department is a co-principal investigator for a multi-disciplinary team of researchers from the University of Illinois at Chicago (UIC), MIT, and UMass Amherst that has received a National Science Foundation (NSF) $1,999,966 grant to study the heterostructures of 2D materials and their thermal properties. The grant was awarded by the NSF’s Emerging Frontiers in Research and Innovation (EFRI) Program, and the research project is entitled “Thermal Transport in 2D Materials for Next Generation Nanoelectronics - From Fundamentals to Devices.”
As the research team’s research abstract explains, “This proposal seeks to comprehensively study the thermal transport dynamics of stacks of atomic layers of semiconductors, conductors, and insulators representative of future nano-electronic devices.”
The abstract concludes that the proposed research has a “transformative potential” and is of high relevance across many research fields. The broader impacts of this work will be significant in enabling the design of new classes of 2D heterogeneous materials for future electronics and optoelectronics from a thermal management perspective.
This EFRI award program specifically deals with “Two-Dimensional Atomic-layer Research and Engineering (2-DARE).” Professor Aksamija notes that to date only five 2-DARE awards out of about 122 pre-applications have been dispensed this year: one to Stanford, one to Yale, two to the University of Pennsylvania, and the grant awarded to the research team he belongs to involving UIC, MIT, and UMass Amherst. But he added that several more 2-Dare grants might be awarded.
In addition to Aksamija, the other members of the team are Amin Salehi-Khojin (principal investigator), Robert Klie (co-principal investigator), Fatemeh Khalili-Araghi (co-principal investigator), and Keith Nelson (co-principal investigator). The multidisciplinary team consists of an electrical engineer (Aksamija), a mechanical engineer, a chemist, and two physicists from the three different universities.
According to the researchers in their proposal abstract, computers and other current microelectronic devices based on silicon technology contain central processing units that produce surplus heat while performing calculations and other tasks. Consequently, this excess thermal energy is dissipated by fans or other means after it migrates to the surface of the silicon chip.
“However, as engineers seek to increase the transistor count per chip for greater computer power, silicon technology reaches its limit, and a different base material with a different hardware architecture will be needed,” as the researchers observe.
To this end, various sheets of material have recently been developed which are only one atomic layer thick and can function as semiconductors (transition metal dichalcogenides), conductors (graphene), or insulators (boron nitride), the main elements of any electronic device. By stacking these atomic layers in different sequences, scientists and engineers seek to develop entirely new classes of multi-functional materials, and have already developed assorted nanoscale transistors.
“However, the power density and tendency for such devices to overheat increase dramatically at such a small scale,” the researchers explain in their abstract.
Therefore, the researchers deduce, no practical devices from these materials will be possible until the physics of heat transfer at this scale is better understood and the heat dissipation problem is solved.
“The primary goal of this proposal is to provide the [scientific] community with a deeper understanding of the limits set by the kinetics of dissipation and heat removal through various junctions and interfaces in two-dimensional heterogeneous materials,” the researchers write. “The team aims to establish a multiscale thermal transport study through a closely coupled combination of material synthesis and device-level experiments, atomic-level characterization, thermal transport and phonon spectroscopy, theoretical modelling, and computational studies.”
Ultimately, the team will use synthesis/fabrication methods, such as chemical vapor deposition and atomic layer deposition, to produce hetero-structures of interest as fundamental components of any electronic devices.
EFRI, established by the NSF Directorate for Engineering in 2007, seeks high-risk, interdisciplinary research that has the potential to transform engineering and other fields. The grants demonstrate the EFRI goal to inspire and enable researchers to expand the limits of knowledge in service of grand engineering challenges and national needs. (August 2015)