MoS2 Thin Films Grown by Sulfurization of DC Sputtered Mo Thin Films on Si/SiO2 and C-Plane Sapphire Substrates

• Published in: Journal of electronic materials 2021-03, Vol.50 (3), p.1452-1466
• Main Authors: Akcay, N., Tivanov, M., Ozcelik, S.
• Format: Article
• Language: English
• Subjects: Atomic beam spectroscopy; Atomic force microscopy; Characterization and Evaluation of Materials; Chemical vapor deposition; Chemistry and Materials Science; Crystal structure; Crystallization; Direct current; Electrical properties; Electronics and Microelectronics; Fourier transforms; Hexagonal phase; Infrared analysis; Instrumentation; Materials Science; Microscopy; Molybdenum disulfide; Optical and Electronic Materials; Optical properties; Original Research Article; Photoelectrons; Sapphire; Shielding; Silicon dioxide; Silicon substrates; Solid State Physics; Spectrum analysis; Sulfurization; Thickness; Thin films; X ray photoelectron spectroscopy; X ray spectra
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-020-08687-6

Here we report the growth of molybdenum disulfide (MoS 2 ) films with different thicknesses on silicon dioxide/silicon (SiO 2 /Si) and c-plane sapphire substrates by sulfurization of direct current (DC) sputtered Mo precursor films in a chemical vapor deposition furnace with sulfur powder at 900°C. The structural, morphological, optical, and electrical properties of the films on different substrates were investigated through a series of characterization in detail. X-ray diffraction (XRD) results showed that the grown films on sapphire substrates had better crystallization and a well-stacked layered structure than the films on SiO 2 /Si substrates. The frequency difference between the characteristic modes E 2 g 1 and A 1g of hexagonal phase MoS 2 was determined as ~ 26 cm −1 which is consistent with the typical value of bulk MoS 2 . Energy-dispersive x-ray (EDX) spectra exhibited that the films were near-stoichiometric. A small shift towards the lower binding energies in the Mo 3d 5/2 peak positions was observed due to the valency of Mo below +4 depending on the compositional ratios of the films in x-ray photoelectron spectroscopy (XPS) spectra. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis indicated that the films had smooth surfaces and a well-packed crystal structure. However, when the thickness of the films deposited on sapphire substrates increased, the strain between the sapphire substrate and MoS 2 film caused the formation of the micro-domes in the film. In addition, the films exhibited high absorption and reflection properties in the near-infrared (NIR) and mid-infrared (MIR) regions in Fourier transform infrared (FTIR) analysis. Therefore, it is considered that the films can be used for photodetector applications in these regions and infrared shielding coating applications.