Epitaxial growth of TiSe ₂ /TiO ₂ heterostructure

Abstract

Abstract Here we report that TiSe 2 thin films can be epitaxially grown on TiO 2 substrates despite different lattice symmetry between the two materials. The TiSe 2 thin films can be prepared on TiO 2 via molecular beam epitaxy (MBE) in two ways: by conventional co-deposition using selenium and titanium sources, and by evaporating just selenium on reconstructed surfaces of TiO 2 . Both growth methods yield crystalline thin films with similar electronic band structures. TiSe 2 films on TiO 2 substrates exhibit large electron doping and a lack of charge density wave (CDW) order, which is different from both bulk single crystal TiSe 2 and TiSe 2 thin films on graphene. These phenomena can be explained by selenium vacancies in the TiSe 2 films, which naturally occur when these films are grown on TiO 2 substrates. Our successful growth of transition metal dichalcogenide (TMDC) films on a transition metal oxide (TMO) substrate provides a platform to further tune the electrical and optical properties of TMDC thin films.