Gwan-Hyoung Lee group (Seoul National University) demonstrated dimensionality-driven phase engineering of molybdenum ditelluride (MoTe2) in van der Waals heterostructure by using encapsulation annealing. They observed stepwise increase of phase transition temperature in 2H-to-Td phase transition of ultrathin layered MoTe2: higher transition temperature for smaller number of layers (Thinner film). This finding is totally contary to the behavior of the conventional nanoparticles that the smaller nanoparticles have the lower phase transition temperature. This work was published on Advanced Functional Materials.