Impact of Doping and Defects on Thermal Transport of Monolayer GaN Nanoribbons: A Molecular Dynamics Simulation Study

Monolayer gallium nitride (GaN), with its graphenelike honeycomb structure, has emerged as a promising material for nanoelectronics and optoelectronic applications. In this study, Equilibrium Molecular Dynamics (EMD) simulations using the Stillinger-Weber (SW) potential were employed to investigate the impact of doping as well as defects on the thermal conductivity of monolayer zigzag GaN nanoribbon (GaN-NR). The thermal transport in aluminum (Al) and indium (In) doped GaN-NR is explored, considering the substitution of both $\mathbf{G a}$ and nitrogen (N) atoms by the dopants. Ga replacement with In led to an increase in thermal conductivity from $11.51 \mathrm{~W} / \mathrm{m}-\mathrm{K}$ to 15.12 $\mathrm{W} / \mathrm{m}-\mathrm{K}$ at a $1 \%$ doping concentration. However, in all other cases, whether replacing $\mathbf{G a}$ or $\mathbf{N}$ with Al or replacing $\mathbf{N}$ with In, it shows an opposite trend, i.e., the thermal conductivity decreases. Furthermore, defects lead to a substantial reduction in thermal conductivity, with a decrease ranging from $68.9 \%$ to $77.4 \%$ observed at a $2 \%$ vacancy concentration across various defect shapes, from point vacancies to hexagon vacancies. We further examine the effect of defect concentrations and defect types on its thermal transport. The results provide valuable insights into the tunability of thermal conductivity in GaN nanostructures, illuminating future optimization for applications in optoelectronic and thermoelectric devices.