High Quality MoS2 Layered Thin Films Obtained by Ionized Jet Deposition Investigated by X-ray Absorption Spectroscopy at S L2,3 and Mo M2,3 Edges

Abstract

We present a comparative soft x-ray absorption spectroscopy (XAS) study of the sulfur L₂,₃ and molybdenum M₂,₃ absorption edges in MoS₂ prepared by different fabrication routes, including bulk crystallization, mechanical exfoliation, chemical vapor deposition (CVD), and ionized jet deposition (IJD). The S L₂,₃ edges reveal pronounced differences in pre-edge and main-edge fine structure that sensitively reflect the degree of structural order, dimensionality, and electronic hybridization between S 3p and Mo 4d states. Bulk, exfoliated, and CVD-grown samples exhibit well-resolved multiple features characteristic of layered and ordered two-dimensional (2D) MoS₂, whereas as-deposited IJD-grown films display broadened, weakly structured spectra consistent with an amorphous phase and poorly defined stoichiometry. Upon moderate annealing at 250°C, IJD-grown films develop clear spectral signatures of layered MoS₂, indicating the formation of an ordered crystalline 2H-MoS₂ phase. Complementary analysis of the Mo M₂,₃ edges shows a concomitant narrowing and energy shift of the M₃ feature toward values typical of well-ordered 2D MoS₂. These results demonstrate that S L₂,₃ and Mo M₂,₃ XAS provide a sensitive probe of synthesis-dependent electronic structure in MoS₂ and confirm IJD as a viable, low-temperature route to electronically ordered 2D MoS₂ phases.