van der Waals mediated interaction dynamics between individual nanostructures

Vanderbilt University, Nashville TN

Investigators

Abstract

CBET-1403456 Walker Modern microelectronic devices extensively used in telecommunications, computing, and energy conversion applications rely on ever shrinking feature sizes where materials are manipulated at atomic scale and exhibit new and extreme properties. As characteristic lengths decrease, interfaces between materials begin to dominate the performance of the materials, and hence the devices. Yet, our understanding of how charge and heat transmit through these interfaces is still limited. To create better materials and devices, we must study the effects of interfaces on carrier transport that are responsible for the extreme properties these highly scaled structures exhibit. This project will measure the flow of energy through several carefully controlled interfaces and predict the performance of those interfaces using atomistic-scale modeling. The combined theoretical and experimental approach will produce new design rules for creating and optimizing future devices. Consequently, the results of this project have far reaching implications and could lead to a reduced drain on our energy resources, faster computers, and increased communication bandwidth. The lack of thorough understanding of interfacial phonon transport is a current bottleneck in microelectronic cooling and thermal design of composite materials. This project aims at understanding the interaction dynamics of van der Waals interfaces between individual nanostructures, which determines the phonon transmission and scattering mechanisms at these interfaces. The interaction dynamics at the van der Waals interface will alter the phonon transmission coefficient, leading to different thermal conductivities between single and double ribbons. Therefore, our approach is to measure systematically the intrinsic thermal conductivity of individual silicon nanoribbons, silicon double nanoribbons, and silicon and boron double ribbons, and to perform corresponding atomic scale modeling. Comparison of results from different samples will provide new insights into how different factors, such as adhesion energy, acoustic impendence mismatch, and amorphous layers affect phonon transmission through van der Waals interfaces, which will provide new insights into manipulating thermal transport through these interfaces. Since van der Waals interfaces are one of the most common interfaces between individual nanostructures or nanostructures and substrates/host materials, the obtained fundamental understanding will shed light on how to better manage the heat dissipation in microelectronic devices and tune the thermal properties of nanocomposites.