Session: K9-10: NANOSCALE THERMAL TRANSPORT MODELING AND MACHINE LEARNING II

Paper Number: 130657

130657 - Molecular Dynamics Simulation of Thermal Conductivity of Gan 

Abstract: 

Wurtzite GaN (gallium nitride) is a technologically significant semiconductor material known for its diverse applications in the field of optoelectronics and high-power electronics. Understanding its thermal properties, specifically its thermal conductivity, is crucial for optimizing the performance and efficiency of GaN-based devices. Here, we aim to elucidate the thermal conductivity of wurtzite GaN along the [0001] crystallographic direction at 300 K. To achieve this, we employ two distinct computational methods, namely Non-Equilibrium Molecular Dynamics (NEMD) and Equilibrium Molecular Dynamics (EMD). NEMD is a powerful technique that directly simulates the heat transport within a material. Our approach utilizes application of a thermostat to control the temperature within the system. By applying heat to the GaN structure, we track the resulting temperature gradient and, in turn, calculate the material's thermal conductivity. This method allows us to examine how the thermal properties of GaN evolve in response to external thermal gradients, making it an essential tool for understanding heat transport at the nanoscale. In parallel, we utilize EMD to determine the thermal conductivity of GaN using the Green-Kubo formulation. EMD involves simulating the system at thermal equilibrium and analyzing the heat flux autocorrelation function. By studying the fluctuations in heat flow within the material, we can derive the thermal conductivity. This equilibrium approach provides valuable insights into the steady-state thermal behavior of GaN, complementing the dynamic perspective offered by NEMD. We present the size effects on thermal conductivity and discussion bulk conductiviy estimation using linear correlation of conductivity and length.  Our work contributes not only to the fundamental understanding of GaN but also to the development of more efficient and reliable GaN-based devices in various technological applications.

Presenting Author: Mustafa Ozsipahi U.S. DEVCOM Army Research Laboratory

Presenting Author Biography: Dr. Mustafa Ozsipahi currently holds the position of George F. Adam Distinguished Postdoctoral Fellow at the U.S. Army Research Laboratory. His research primarily centers around the application of thermo-fluid engineering techniques in the development of advanced electronic systems and sustainable energy solutions. He earned his Master's and Ph.D. degrees in Mechanical Engineering from Istanbul Technical University in 2014 and 2020, respectively. During his doctoral studies, Dr. Ozsipahi also held a visiting researcher position at TU Dresden. After successfully earning his Ph.D., he held the position of a postdoctoral researcher at Southern Methodist University from 2020 to 2022.

Authors:

Mustafa Ozsipahi U.S. DEVCOM Army Research Laboratory
Sophia Jean U.S. DEVCOM Army Research Laboratory
Adam A. Wilson U.S. DEVCOM Army Research Laboratory
Ali Beskok Southern Methodist University