Study of surface oxidation and recovery of clean MoTe₂ films

Transporting the sample through different characterization units while maintaining its integrity is crucial if multiple surface sensitive probes are to be employed. In this context, the layered transition metal dichalcogenides (TMDs) are known to be extremely susceptible to ambient degradation, leading to the formation of protrusions and particles on the films. Compared to MoS₂ and MoSe₂, MoTe₂ is one of the most reactive surfaces to ambient conditions. Therefore, understanding its surface oxidation and how to recover a clean surface is very important. In this paper, we report the MBE synthesis of single phase of 2H-MoTe2 with good stoichiometric films on graphene terminated 6H-SiC(0001) substrates and are able to recover the clean surface after exposure to air under properly protected conditions. Our films are analyzed in detail by reflection high energy electron diffraction (RHEED), X-ray photoemission spectroscopy (XPS), and scanning tunneling microscopy (STM).