Thickness-Dependent Thermal Conductivity of Suspended Two-Dimensional Single-Crystal In₂Se₃ Layers Grown by Chemical Vapor Deposition

Using micro-Raman spectroscopy and finite-element simulations, we determine the in-plane thermal conductivity of suspended two-dimensional single-crystal In₂Se₃ grown by chemical vapor deposition. The thermal conductivity shows a strong dependence on the layer thickness: it reaches ∼60 W/m·K at the thickness of 35 nm, and it decreases to ∼4 W/m·K for the 5 nm thick layer. This dependence demonstrates the significance of phonon surface scattering and also indicates changes to the phonon dispersion relations as the layer thickness decreases. The determination of the thickness-dependent thermal conductivity provides an important practical basis for advancing 2D In₂Se₃-based device technologies and, more generally, also enables fundamental insight into the limiting mechanisms for 2D thermal transport.