Simultaneous measurement of in-plane and interfacial thermal conductivity of isotopically labeled bilayer graphene

The thermal properties of bilayer graphene (BLG) play a crucial role in the advancement of its promising electronic devices. However, the measurement of thermal conductivity using current techniques faces obstacles due to the low temperature gradient both in plane and across the interface in the sample. Here we present an approach to simultaneously explore the in-plane and interfacial thermal conductivity of chemical vapor deposited AB-stacked BLG by utilizing an isotope labeling assisted Raman spectroscopic technique. By applying the modified heat diffusion model, we acquire the interfacial thermal conductivity of isotopically labeled AB-stacked BLG of $105\ifmmode\pm\else\textpm\fi{}3\phantom{\rule{0.16em}{0ex}}\mathrm{MW}/({\mathrm{m}}²\phantom{\rule{0.16em}{0ex}}\mathrm{K})$, whereas we find the in-plane thermal conductivity of each layer is reduced compared with their monolayers. This technique demonstrates strong support for advancing the BLG thermal engineering research as well as a potential of extending to other two-dimensional systems.