Tunable thermal expansion coefficient of transition-metal dichalcogenide lateral heterostructures

The thermal expansion effect plays an important role in governing the thermal stability or the stable configuration of quasi-two-dimensional atomic layers, where the difference between the thermal expansion coefficient of different kinds of atomic layer in lateral heterostructure may cause strong thermal rippling of the atomic layer. We investigate the thermal expansion phenomenon in the WSe₂-MoS₂ lateral heterostructure. We find that the thermal expansion coefficient can be enhanced by more than a factor of two via varying the ratio between the WSe₂ and MoS₂ components in the heterostructure. The underlying mechanism is disclosed to be the buckling of the WSe₂ region that is induced by the misfit strain at the coherent interface between WSe₂ and MoS₂. These findings shall be helpful in handling the thermal stability of functional devices based on the transition-metal dichalcogenide lateral heterostructures and other similar quasi-two-dimensional lateral heterostructures.