The influence of precursor on rhenium incorporation into Re-doped MoS2 (Mo1−xRexS2) thin films by aerosol-assisted chemical vapour deposition (AACVD)

Abstract

The molecular precursors [Mo(S₂CNEt₂)₄] (1), [Re(S₂CC₆H₅)(S₃CC₆H₅)₂] (2), and [Re₂(μ-S)₂(S₂CNEt₂)₄] (3) were used to deposit thin films of Re-doped MoS₂ at 550 °C by aerosol assisted chemical vapour Deposition (AACVD). ICP-OES was used to quantify the amount of Re dopant in each film which range from ca. 2–17 at% Re, with greater incorporation of Re from films using precursor (3). In general, lightly doped films show evidence of elemental homogeneity and retention of structure from EDX spectroscopy mapping and p-XRD measurements. However, Raman spectroscopy suggests that the MoS₂ structure is lost upon heavy doping (ca. >4–7 at% Re) by the disappearance of the E_2g and A_1g optical phonons of MoS₂, which we attribute to the introduction of intralayer Re-Re bonding caused by the larger 5d orbitals of Re. Electron microscopy shows that inclusion of Re dopant atoms also dramatically influences the morphology of the films produced, ranging from lamellar structures to clusters and florets, though at similar doping level the morphologies are similar for films made from both Re precursors.