Fabrication of MoO/MoC-Layered Hybrid Structures by Direct Thermal Oxidation of MoC.

Two-dimensional (2D) MoC, as a new member of transition metal carbides, has many intriguing properties and potential applications in superconductors and electronic devices. The thermal stability of 2D materials is essential for the performance of the related devices, especially the ones with a vertical heterostructure. However, rare reports have demonstrated the thermal stability of MoC and the effects of thermal stability on its performance. Here, we propose a facile and controllable method to directly oxidize MoC to MoO, forming a MoO/MoC heterostructure. During the oxidization process, an in situ technique is employed to uncover the transformation and thermal stability of the MoC. The chemical vapor deposition MoC shows high structural stability below 550 °C in Ar or below 350 °C in O, which demonstrates the high thermal stability and antioxidation of the MoC film. The metallic MoC is gradually oxidized to semiconducting MoO as the temperature increases above 350 °C. The oxidization rate can be easily controlled by adjusting the oxidation temperature and time. Further, the obtained MoO/MoC vertical hybrid structure shows obvious Schottky junction behaviors, strongly indicating the perfect interfacial contact between the component layers. This work offers a new strategy for the controllable fabrication of high-quality 2D heterostructures.