Challenges of fabrication of a large-area-uniform molybdenum disulfide layered thin film at low growth temperature by atmospheric-pressure solution-based mist CVD

Abstract

A MoS2 layered thin film was grown by atmospheric-pressure solution-based mist CVD on a 30 mm2 large-area substrate at 400 °C, which is a significantly lower growth temperature than that of conventional CVD. The film formation was reliably confirmed by Raman spectroscopy, grazing incidence X-ray diffraction (GIXD), and transmission electron microscope (TEM). Possibly, film formation energy was decreased by dissolving (NH3)6Mo7O24 ∙ 4H2O in methanol owing to formation of an intermediate product, whose decomposition temperature was lower than 760 °C — the decomposition temperature observed in thermogravimetric-differential thermal analysis (TG-DTA). Optical constants were derived by spectroscopic ellipsometry measurements, whose results indicate the reasonably good quality of MoS2 and the suitability of mist CVD in response to the large-area low-temperature growth request from industry.

Giant change of MoS2 optical properties along amorphous–crystalline transition: broadband spectroscopic study including the NIR therapeutic window

“…Table 1), are generally interpreted as electronic transitions between the valence band and conduction and exited bands of BZ in its high symmetry points. 20,21 A different number of oscillators (for example, two 20,22 or four 21,30 ) were used in the literature to parameterize the 2H MoS 2 electric permittivity in this spectral range. The assignment of these transition energies depends on spectra deconvolution and is, in general, difficult due to the complex nature of the excited bands of MoS 2 BZ.…”

“…The model dielectric function (MDF) of MoS 2 in the NIR-VIS-UV range is usually constructed by a sum of oscillators of various types (for example, Gauss, Lorentz, or Tauc-Lorentz), the number of which depends on the available spectral range and spectral resolution. [19][20][21][22] Appropriateness of oscillator type selection is discussed in 19 . Nevertheless, other mathematical functions specifically designed for electronic transitions in the vicinity of MoS 2 band structure critical points and rich excitonic features were employed as well.…”

“…The model dielectric function (MDF) of MoS 2 in the NIR-VIS-UV range is usually constructed by a sum of oscillators of various types (for example, Gauss, Lorentz, or Tauc-Lorentz), the number of which depends on the available spectral range and spectral resolution. [19][20][21][22] The appropriateness of oscillator type selection is discussed in ref. 19.…”

Growth mechanism under the supply-limited regime in mist chemical vapor deposition: presumption of mist droplet state in high-temperature field

“…Focusing on the high degree of freedom, mist CVD has enabled the uniformity of large areas in atomiclevel-controlled high-quality functional thin films fabricated by the precise control of the mist flow (2nd G mist CVD). [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] Part of this principle was already reported in Ref. 15.…”

Growth mechanism of zinc oxide thin film by mist chemical vapor deposition via the modulation of [H2O]/[Zn] ratios

“…In the 3rd G mist CVD system, the problem of mixed precursors can be avoided due to the low probability of collision between droplets (LPCD) and the existence of the Leidenfrost state droplets (ELSD); thus, it is possible to precisely control the amount of H 2 O and Zn source supply. [8][9][10][11][12][13][14][15][16][17][18] Herein, we investigated the influence of [H 2 O]/[Zn] ratios on ZnO film growth rates, crystal orientations, surface morphologies, and chemical states in the films. Finally, the ZnO film growth mechanism was proposed based on the systematic investigation of the relationship between these experimental results.…”