Electric‐Field‐Assisted Growth of Vertical Graphene Arrays and the Application in Thermal Interface Materials

Abstract

Owing to the development of electronic devices moving toward high power density, miniaturization, and multifunction, research on thermal interface materials (TIMs) is become increasingly significant. Graphene is regarded as the most promising thermal management material owing to its ultrahigh in-plane thermal conductivity. However, the fabrication of high-quality vertical graphene (VG) arrays and their utilization in TIMs still remains a big challenge. In this study, a rational approach is developed for growing VG arrays using an alcohol-based electric-field-assisted plasma enhanced chemical vapor deposition. Alcohol-based carbon sources are used to produce hydroxyl radicals to increase the growth rate and reduce the formation of defects. A vertical electric field is used to align the graphene sheets. Using this method, high-quality and vertically aligned graphene with a height of 18.7 µm is obtained under an electric field of 30 V cm −1 . TIMs constructed with the VG arrays exhibit a high vertical thermal conductivity of 53.5 W m −1 K −1 and a low contact thermal resistance of 11.8 K mm 2 W −1 , indicating their significant potential for applications in heat dissipation technologies.

Vertically Aligned Graphene for Thermal Interface Materials

“…Top-down graphene nanoflakes [114] 10 ----rGO/epoxy composite [20] 2.65 ----VAGF [21] 614.86 -86.023 2.255 -GF/E-40 [23] 384.9 -910. 77 12.33 -AGAs [25] 6.57 -20/150 -GHF-2800 [24] 35.5 -406 --HLGP [16] 143 5.8-22.5 -0.87 -Bottom-up VG arrays [12] 53.5 11.8 ---VG [17] 680 ----…”

“…built-in electric field into the reaction system. [12] Moreover, they also found that the growth rate of VG increased with the electric field intensity.…”

“…The etching growth mechanism was beneficial to slowing down edge closure and promoting VG growth. [12,34,38] As shown in Figure 3e,f, the hydrogen atoms decomposed from alkanes or the hydroxyl groups decomposed from the alcohol could act as etchants to rapidly remove amorphous carbon for preventing the formation of secondary nucleation and removing crosslinking at the active edges, thus, promoting a continuous growth of highly crystalline graphene.…”

“…In this part, we mainly discuss the preparation methods of VG structures consisting of VG arrays, [ 12 ] VG monoliths, [ 16 ] VG aerogels, [ 18 ] etc. The preparation methods are divided into top‐down methods and bottom‐up methods according to the different approaches to assembling raw materials.…”

“…[ 13–16 ] On the contrary, the bottom‐up methods are mainly represented by plasma enhanced chemical vapor deposition (PECVD), by which VG with a specific morphology can be directly grown using different types of carbon sources as precursors. [ 12,17 ] This review attempts to summarize the state‐of‐the‐art research on the preparation of VG to provide guidelines on the design of VG structures and discusses the progress and advantages of VG‐based TIM applications to offer a perspective on the preparation of VG for TIM applications.…”