Tuning the electronic properties of defect-rich MoS2.

Abstract

Transition metal dichalcogenides (TMDCs), including molybdenum disulfide (MoS₂), have emerged as a promising candidate for novel semiconducting devices. However, in many cases structural defects significantly affect the electronic properties of the material. The present study utilizes angle-resolved photoelectron spectroscopy (ARPES) and surface-sensitive core-level spectroscopy (SXPS, XAS) with synchrotron radiation to investigate the interfaces between defect-rich MoS₂ and perfluorinated cobalt phthalocyanine (CoPcF₁₆). Defects were introduced in synthetic MoS₂ bulk crystals by gentle argon and neon sputtering. Although the band structure is still visible after sputtering, especially SXPS reveals structural and electronic disturbances of the topmost MoS₂ layer. We show how the Fermi energy in such defect-rich MoS₂ can be tuned by the subsequent deposition of CoPcF₁₆, which is verified by a shift in Fermi level for the Ne sputtered surface, under complex charge rearrangements including a charge transfer from all the substrates towards the cobalt atom of the organic molecule.