Session: 04-01-01: Advanced Materials for Energy

Paper Number: 145862

145862 - Investigation of Thermal Conductivity of Partial Periodic Si/ge Superlattice in Si Nanowire 

In recent decades, there has been an increasing interest in developing nanostructured materials for use in thermos-electrics, thermal interface materials, thermal management applications, and macro-electronics such as composites and superlattices. Simultaneously, a growing body of research has been conducted to develop a deeper comprehension of thermal transport in these materials and to predict their effective thermal conductivity. The two most common and widely used thermoelectric materials are silicon (Si) and germanium (Ge). Due to their potential applications in thermoelectric energy conversion, the thermal transport properties of silicon/germanium (Si/Ge)-based nanomaterials have been the subject of much study. Nanowires' thermal conductivities (TC) are significantly lower than those of bulk materials. Because of this, nanowires are obtaining a growing amount of interest in the scientific sector. In addition to this, they have a higher thermal efficiency due to their lower thermal conductivity. In addition, SiNWs are a desirable option due to their perfect interface compatibility with conventional Si-based technology.

Non-equilibrium molecular dynamics simulation (NEMD) is used to look at the thermal conductivity (TC) of partial periodic Si/Ge superlattice nanowires (SLNW). Compared to bulk Si, Si nanowire has lower thermal conductivity. Doping of Ge atoms as periodic bands lowers the thermal conductivity of the system from both Si and Ge systems of the same dimension respectively. To comprehend the relationship between thermal conductivity and the position of the superlattice structure, the thermal conductivity for two partial Si/Ge superlattice layers put in various places has been examined. The SL band's midway location is where thermal conductivity is at its lowest. In accordance with where the Si/Ge bands are located, thermal conductivity needs to be examined. As the band's location gradually changed from being close to the heat sink to the heat source, thermal conductivity gradually decreased. Thermal conductivity can be reduced by 30%–40%, depending on where the band is located. The length given for the partial SL bands has then been determined to have an optimal period length for a certain system, allowing for the achievement of the lowest thermal conductivity. The activation of phonons of various energies at various places and the phonon scattering at the Si/Ge contact are what cause these effects of the SL structure in the Si nanowire. The Vibrational Density of States (VDOS) analysis of the phonon at various frequencies explains these phonon behaviors, which in turn explains the various thermal conductivity results for various systems in this study. According to the findings, there is a practical and efficient technique to lower the thermal conductivity of semiconductor materials for a variety of thermoelectric applications.

Presenting Author: Titan C. Paul University of South Carolina Aiken

Presenting Author Biography: The presenter is an Associate Professor of Engineering at the University of South Carolina Aiken.

Authors:

Kamrul Hasan Rafi Bangladesh University of Engineering and Technology
Azmir Hasan Mojumder Bangladesh University of Engineering and Technology
A. K. M. Monjur Morshed Bangladesh University of Engineering and Technology,
Titan C. Paul University of South Carolina Aiken