Anisotropic in-plane thermal conductivity for multi-layer WTe₂

Improving thermal transport between substrate and transistors has become a vital solution to the thermal challenge in nanoelectronics. Recently 2D WTe₂ has sparked extensive interest because of heavy atomic mass and low Debye temperature. Here, the thermal transport of supported WTe₂ was studied via Raman thermometry with electrical heating. The supported 30 nm WTe₂ encased with 70 nm Al₂O₃ delivered 4.8 W·m^-1·K^-1 in-plane thermal conductivity along zigzag direction at room temperature, which was almost 1.6 times larger than that along armchair direction (3.0 W·m^-1·K^-1). Interestingly, the superior and inferior directions for thermal transport are just opposite of those for electrical transport. Hence, a heat manipulation model in WTe₂ FET device was proposed. Within the designed configuration, waste heat in WTe₂ would be mostly dissipated to metal contacts located along zigzag, relieving the local temperature discrepancy in the channel effectively and preventing degradation or breakdown. Our study provides new insight into thermal transport of anisotropic 2D materials, which might inspire energy-efficient nanodevices in the future.