Multilayer in-plane graphene/hexagonal boron nitride heterostructures: Insights into the interfacial thermal transport properties

Abstract

Combining both vertical and in-plane two-dimensional (2D) heterostructures opens up the possibility to create an unprecedented architecture using 2D atomic layer building blocks. The thermal transport properties of such mixed heterostructures, critical to various applications in nanoelectronics, however, have not been thoroughly explored. Herein, we construct two configurations of multilayer in-plane graphene/hexagonal boron nitride (Gr/h-BN) heterostructures (i.e. mixed heterostructures) via weak van der Waals (vdW) interactions and systematically investigate the dependence of their interfacial thermal conductance (ITC) on the number of layers using non-equilibrium molecular dynamics (NEMD) simulations. The computational results show that the ITC of two configurations of multilayer in-plane Gr/h-BN heterostructures (MIGHHs) decrease with increasing layer number n and both saturate at n = 3. And surprisingly, we find that the MIGHH is more advantageous to interfacial thermal transport than the monolayer in-plane Gr/h-BN heterostructure, which is in strong contrast to the commonly held notion that the multilayer structures of Gr and h-BN suppress the phonon transmission. The underlying physical mechanisms for these puzzling phenomena are probed through the analyses of heat flux, temperature jump, stress concentration factor, overlap of phonon vibrational spectra and phonon participation ratio. In particular, by changing the stacking angle of MIGHH, a higher ITC can be obtained due to the thermal rectification behavior. Furthermore, we find that the ITC in MIGHH can be well-regulated by controlling the coupling strength between layers. Our findings here are of significance for understanding the interfacial thermal transport behaviors of multilayer in-plane Gr/h-BN heterostructure, and are expected to attract extensive interest in exploring its new physics and applications. Graphene/hexagonal boron nitride (Gr/h-BN) heterostructure, which benefits from the small lattice mismatch between Gr and h-BN, has been successfully synthesized both vertical 22 -24 and coplanar 2 , 25 , 26 configurations, paving the way for constructing the mixed heterostructures. In parallel to the efforts on pursuing a more sophisticated synthesis method, the interfacial thermal transport properties of Gr/h-BN heterostructure, which play a pivotal role in the high-performance thermal interface materials (TIMs) and heterostructures devices, 27 -29 are urgently needed to be understood. Accordingly, using a transient heating technique, Zhang et al. 30 showed that the interfacial thermal resistance in the vertical Gr/h-BN heterostructure is affected by interatomic bond strength, heat flux direction and functionalization. Relatively, Chen et al. 31 , 32 found that the in-plane Gr/h-BN heterostructure exhibits a negative differential thermal resistance behavior, which is caused by the phonon resonance effect and the

Molecular Structure Effect of a Self-Assembled Monolayer on Thermal Resistance across an Interface

“…This is reasonable because the vibration frequency is roughly proportional to b K / m [23]. As the bond strength increased, the first peak of VDOS in the SAM no longer changed until the value of K was up to 30 To quantify the VDOS match between PEG and SAM, the overlap factor S [38] was defined as follows: To quantify the VDOS match between PEG and SAM, the overlap factor S [38] was defined as follows:…”

Nanoscale Thermal Cloaking in Silicon Film: A Molecular Dynamic Study

“…To better explain the cloaking phenomenon, we calculated the mode participation rate (MPR) [ 44 , 45 ]: where N represents the total number of atoms in the calculated domain, and according to Equation (7), PDOS i ( ω ) is the local density of states.…”

Thermal Transport in Two-Dimensional Heterostructures

“…More recently, (Ni et al, 2019) reported the dependence of thermal conductivity on interface composition diffusion in graphene/h-BN in-plane heterostructures, and demonstrated that the system's thermal conductivity is closely related to the interface composition diffusion length because of the Anderson localization of phonons. (Liang et al, 2020) found that the ITC decreases with the increase of layer number n and saturates at n 3 in multilayer in-plane graphen/h-BN heterostructures. Even so, the asymptotic value still surpasses that in monolayer heterostructures.…”