MoS2 박막의 구조와 광학적 특성

Structural and Optical Properties of MoS2 Films

MoS2 films were deposited on the glass substrates by spray pyrolysis. Crystal structure, surface morphology and chemical composition of MoS2 films were investigated by x-ray diffraction(XRD), scanning electron microscope(SEM) and energy dispersive x-ray spectroscopy(EDS). The optical absorption spectra of the samples were measured at 293 K using the UV-NIR spectrophotometer. The crystal structure of MoS2 films deposited at 400 ℃ was hexagonal with lattice constant ao = 3.160 Å, co = 12.295 Å. The grain size of MoS2 films were increased with increasing the deposition temperature of the samples. The chemical composition of Mo and S of the samples were identified as 33.4 and 66.6 at.% in the limits of detector resolution for measuring EDS spectra. The optical energy band gap of the MoS2 films deposited at 400 ℃ was found to be 3.138 eV for the direct transition and 2.775 eV for the indirect transition at 293 K. The optical energy band gaps of the MoS2 films were decreased with increasing growth temperature of the samples.