Post-annealing effect on the structural and optical properties of electrophoretically coated 2D-Layered MoSe2

Temperature dependent changes in the structural, nanomorphological and optical characteristics of the 2D layered molybdenum diselenide (MoSe2), processed by electrophoretic coating (EPC) method, were examined. EPC processed MoSe2 was subjected to Raman spectroscopy confirming distinct active modes of A(1g), E-1g(1) and E-2u(2) at 240.9 cm(-1), 282.53 cm(-1) and 337.7 cm(-1), respectively. The in- and out-of plane vibrational modes observed in the Raman spectra were asserted as the 2H-MoSe2 phase which was not affected by the post annealing temperature. X-ray photoelectron spectroscopic measurements confirmed the states of Mo 3d at 228.9 eV and 232.1 eV, and of Se 3d at 54.5 eV and 55.3 eV. Studies on the surface morphology of the EPC processed MoSe2 showed significant changes due to the post-annealing treatment performed at 150 degrees C, 250 degrees C and 350 degrees C in terms of morphology, flake-size distribution and compactness of the film. The samples annealed at 150 degrees C and 250 degrees C showed a better optical absorption in the visible and the near infrared spectral regions with dominant characteristic peaks at 691.2 nm and 801.6 nm. Further studies assured that the EPC process yielded good quality and large area MoSe2 films with exotic structural, optical and nanomorphological characteristics that are highly suitable for functional devices. (C) 2020 The Authors. Publishing services by Elsevier B.V. on behalf of Vietnam National University, Hanoi.

Automated summary

Temperature-dependent changes in the structural, nanomorphological, and optical characteristics of 2D layered molybdenum diselenide processed by electrophoretic coating method were investigated. Post-annealing treatments at different temperatures affected the surface morphology, optical absorption, and film compactness of the MoSe2. The study confirmed that electrophoretic coating yielded high-quality MoSe2 films suitable for functional devices.