Hexagonal Boron Nitride–Graphene Heterostructures with Enhanced Interfacial Thermal Conductance for Thermal Management Applications

Abstract

Atomically thin monolayers of graphene show excellent electronic properties which have led to a great deal of research on their use in nanoscale devices. However, heat management of such nanoscale devices is essential in order to improve their performance. Graphene supported on hexagonal boron nitride (h-BN) substrate has been reported to show enhanced (opto)electronic and thermal properties as compared to extensively used SiO 2 /Si supported graphene. Motivated by this, we have performed temperature-and power-dependent Raman Spectroscopic measurements on four different types of (hetero)structures: (a) h-BN (BN), (b) graphene (Gr), (c) h-BN on graphene (BG), and (d) graphene encapsulated by h-BN layers from both top and bottom (BGB), all supported on SiO 2 /Si substrate. We have estimated the values of thermal conductivity (κ) and interfacial thermal conductance per unit area (g) of these four (hetero)structures to demonstrate the structure-activity (thermal) relationship. We report here the values of κ and g for h-BN supported on SiO 2 /Si as 280.0±58.0 Wm -1 K -1 and 25.6±0.4 MWm -2 K -1 , respectively. More importantly, we have observed an improvement in both thermal conductivity and interfacial thermal conductance per unit area in the heterostructures which ensures a better heat dissipation in devices. The κ and g of h-BN encapsulated graphene on SiO 2 /Si (BGB) sample was observed to be 850.0±81.0 Wm -1 K -1 and 105±1 MWm -2 K -1 , respectively, as opposed to 600.0±93.0 Wm -1 K -1 and 1.15±0.40 MWm -2 K -1 , respectively, for graphene on SiO 2 /Si substrate. Therefore, we propose that for graphene-based nanoscale devices, encapsulation with h-BN is a better alternative to address heat management issues.

Scanning Gate Microscopic Investigation of Graphene Nanoribbon Underneath Dielectric Layer

“…Upon applying V tip via the SGM tip, I DS of GNR was measured at V DS = 0.5 V, leading to an initial current level of 8.7 𝜇A. Notably, this initial I DS is influenced by dangling bonds on the SiO 2 substrate, and the current level can be improved using the ultraclean surface of a hexagonal boron nitride substrate [25,26].…”

Investigating the thermal transport in gold decorated graphene by opto-thermal Raman technique

“…This reduction is evident even for other 2D materials which were argued to be promising or even better candidates for device applications [9,10]. Recently, there have been experimental reports showing an enhanced thermal conductivity in chemical vapour deposited graphene with wrinkles [11] as well as in graphene encapsulated with other 2D materials like h-BN [12].…”