A Molecular Dynamics Study of Thermal conductivity in Monolayer GaN Nanoribbon

Abstract

Nowadays 2D materials like Graphene, Silicene, Stanene and single layer transition metal dichalcogenides (e.g., MoS2, WSe2,MoTe2,), are drawing significant attention in the research arena due to their superior electrical, thermal and opto-electronic properties to their bulk counterparts. In this study, we have investigated the thermal transport properties of single layer zigzag gallium nitride (GaN) nanoribbon using equilibrium molecular dynamics simulations. The calculated room temperature thermal conductivity of $20 \mathbf{nm} \times 2 \mathbf{nm}$ single layer GaN nanoribbon using tersoff inter-atomic potential is 2.04 W/m-K. The temperature and sample size dependence of thermal conductivity have also been studied. For a particular sample size, the thermal conductivity of GaN nanoribbon decreases with increasing temperatures. On the other hand, an opposite pattern is observed for length variation i.e. thermal conductivity increases with the increase in ribbon length keeping the temperature constant. Our study further includes the investigation of the thermal transport of defected GaN nanoribbon. The thermal conductivity of defected GaN sample has been estimated by incorporating defects of different concentration [1% to 5%] for different operating temperatures [100K to 500K]. Our study shows that the thermal conductivity reduces drastically with the increase of defect concentration. We have also calculated phonon density of states (PDOS) for pristine and defected GaN nanoribbon to provide better understanding of these phenomena. Our study would be helpful for further investigation of thermal transport in single layer GaN based devices.