Impacts of defects on the mechanical and thermal properties of SiC and GeC monolayers

K Ren and L Huang and HB Shu and GQ Zhang and WH Mu and HP Zhang and HS Qin and G Zhang, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 25, 32378-32386 (2023).

DOI: 10.1039/d3cp04538b

Defect engineering has been considered as an effective way for controlling the heat transport properties of two-dimensional materials. In this work, the effects of point vacancies and grain boundaries on the mechanical and thermal performances of SiC and GeC monolayers are investigated systematically by molecular dynamics calculations. The failure strength in SiC and GeC is decreased by introducing vacancies at room temperature, and the stress-strain relationship can be tuned significantly by different kinds of vacancies. When the grain boundary of 21.78 degrees is applied, the maximal fracture strengths can be as large as 27.56% for SiC and 23.56% for GeC. Also, the thermal properties of the two monolayers show a remarkable dependence on the vacancies and grain boundaries. The high vacancy density in SiC and GeC can induce disordered heat flow and the C/Ge point defect is crucial for thermal conductivity regulation for the Si/GeC monolayer. More importantly, the SiC and GeC monolayers with a grain boundary of 5.09 degrees show excellent interfacial thermal conductance. Our findings are of great importance in understanding SiC and GeC monolayers and seeking their potential applications. Defect engineering is an effective way to tune the mechanical and thermal properties of the SiC and GeC using as a promising thermal management of 2D devices.

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