Facet-Dependent Interfacial Charge Transfer between T-Phase VS₂ Nanoflakes and Rutile TiO₂ Single Crystals

The hybridizations of two-dimensional (2D) metallic materials with semiconducting transition metal oxides (TMOs) register attractive heterojunctions, which can find various applications in photostimulated circumstances. In this work, we developed an ambient-pressure chemical vapor deposition method to directly grow T-VS₂ on atomically smooth rutile TiO₂ single crystals with different terminations and thus successfully constructed a heterojunction model of VS₂/TiO₂ with a well-defined clean interface. Detailed measurements with Kelvin probe force microscopy revealed the facet-dependent charge transfer occurring at the VS₂/TiO₂ interfaces, seeing variations not only in the amount and direction of the transferred electrons but also in the photoinduced surface potential changes and the dynamics of photogenerated charge carriers under ultraviolet irradiation. Interestingly, ultrathin T-VS₂ was found with considerable magnetism at room temperature, disregarding the charge exchange with the TiO₂ substrates. These results may bring deep insights into the photoinspired functionalities of the hybridized system combining metallic transition metal dichalcogenides and TMO materials.