Review on Techniques for Thermal Characterization of Graphene and Related 2D Materials

Abstract

The discovery of graphene and its analog, such as MoS2, has boosted research. The thermal transport in 2D materials gains much of the interest, especially when graphene has high thermal conductivity. However, the thermal properties of 2D materials obtained from experiments have large discrepancies. For example, the thermal conductivity of single layer suspended graphene obtained by experiments spans over a large range: 1100–5000 W/m·K. Apart from the different graphene quality in experiments, the thermal characterization methods play an important role in the observed large deviation of experimental data. Here we provide a critical review of the widely used thermal characterization techniques: the optothermal Raman technique and the micro-bridge method. The critical issues in the two methods are carefully revised and discussed in great depth. Furthermore, improvements in Raman-based techniques to investigate the energy transport in 2D materials are discussed.

Remarkable Thermal Performance Enhancement of Micro Heat Pipes with Graphene-Nanoplatelet Nano-Wicks

“…The Raman spectrum shows the D band at 1354 cm −1 , G band at 1581 cm −1 and the 2D band at 2726 cm −1 . D band is a representation of structural defects associated with vacancies, grain boundaries and amorphous carbon species, while G bands relate to the sp 2 graphitic domains [ 60 , 61 ]. The small value of the intensity ratio of D and G bands, I D /I G = 0.23, indicates a minimal structural defect, revealing that the non-oxidized regions are dominant in the GNPs.…”

Layer Dependence of Thermally Induced Quantum Confinement and Higher Order Phonon Scattering for Thermal Transport in CVD-Grown Triangular MoS2

“…13,15 The nanosecond ET-Raman technique shows the k s value varying from 40 to 74 W m −1 K −1 for exfoliated MoS 2 as the thickness increases from 45 to 115 nm. 14 Among different thermal transport techniques, the optothermal Raman technique is a straightforward, nondestructive, and widely used technique to measure the interfacial thermal conductance and thermal conductivity of layered MoS 2 . 18 There are few reports on the thermal conductivity evaluation of exfoliated MoS 2 but very few on CVD-grown supported MoS 2 with varying thickness.…”

“…Recent reviews suggest that different experimental and theoretical techniques have been investigated previously to obtain the thermal conductivity of MoS 2 . − Theoretical evaluation of thermal conductivity of MoS 2 was mostly performed on the monolayer. , Theoretical simulation using PBTE calculations predicted the decrease in thermal conductivity for suspended MoS 2 with increasing thickness from single to three layers . The thermal conductivity in the range 44–50 W m –1 K –1 was obtained for 4L exfoliated MoS 2 using the thermal bridge method. , The nanosecond ET-Raman technique shows the k s value varying from 40 to 74 W m –1 K –1 for exfoliated MoS 2 as the thickness increases from 45 to 115 nm . Among different thermal transport techniques, the optothermal Raman technique is a straightforward, nondestructive, and widely used technique to measure the interfacial thermal conductance and thermal conductivity of layered MoS 2 .…”

Efficient modulation of thermal transport in two-dimensional materials for thermal management in device applications

“…And there are also many other excellent articles reviewing the thermal transport properties of 2D materials. [46][47][48] However, there is still a lack of systematic summary and discussion on the methods of regulating the thermal transport properties of 2D materials. Therefore, it is necessary to make a summary of the thermal management of 2D materials, to summarize the existing methods of regulation, to set out the advantages and disadvantages of various methods, and to propose possible methods for the future.…”