In situ exploration of the thermodynamic evolution properties in the type II interface from the WSe₂-WS₂ lateral heterojunction

The mutual interaction of the type II heterointerface can be very susceptible to the variation of electron states, introducing differences into the band structure and the band alignment in comparison to their pristine states. Here, the thermal evolution of the exciton transition and electronic properties inside the covalently bonded type II interface of the atomically planar WSe₂-WS₂ lateral heterojunction has been studied. With the aid of luminescence and electronic evolution, it was found that the coupling at the heterointerface is strong, and that the change in the photon-electron transition with temperature is weak. Meanwhile, by employing some quantitative computational methods, the temperature variation of the extracted built-in electric field at the interface is unexpectedly pronounced, resulting from the thermodynamical spanning behaviors of the electrons, as well as the strains generated by the difference in the thermal expansion coefficient between the structural lattice. In addition, the electric contact at the interface shows a negative temperature correlation. The present findings provide a vital contribution to the photo-electron interaction-based application and evaluation paths of the electric contact in two-dimensional transition metal dichalcogenide-based devices.