Influence of structural defect and sample size on thermal conductivity of gallium selenide/graphene

Abstract

The thermal conductivity (TC) of graphene-based vertical stacking material has recently attracted a lot of researchers based on its ability to help the thermal management of nanoelectronics devices due to the multifunctional properties of these engineered materials. Herein, we analyze the thermal conductivity of pristine/nanoporous gallium selenide/graphene heterostructure (GaSeGrHs) and gallium selenide (GaSe) using non-equilibrium molecular dynamics (NEMD) simulations. The influence of temperature difference/averaged temperature/sample length/pore shape on GaSeGrHs and GaSe was investigated. Due to the high graphene substrate's TC, the TC of the GaSeGrHs sheet is much bigger than the GaSe sheet. The results calculated by NEMD are similar to those calculated from the theoretical prediction formula and unaffected by temperature differences between the two thermal sources of hot and cold. Besides, the thermal conductivities of nanoporous GaSeGrHs are notably smaller than those of pristine ones. Also, the pore shapes can finely tune the TCs as well as the distribution of temperature around the membrane pore. Besides, the TC of pristine GaSeGrHs increases as the sample size rises from 10 to 70 nm and the temperature drops from 800 K to 100 K. In fact, with increasing average temperature, the GaSeGrHs TC drops 64 % and 54.7 % in ZZ and AC directions compared to the GaSe TC with 88.66 % and 89.66 %, respectively. Overall, the study would better understand the thermal conductivity of GaSeGrHs under various investigated conditions. It would extend its successful applications of these 2D materials in nanoelectronic, spintronic, and thermoelectric devices.