Correlation of grain orientations and the thickness of gradient MoS2 films

Abstract

In this study, we synthesized gradient MoS₂ films with a home-made suspended mask and characterized them by transmission electron microscopy (TEM) and Raman spectroscopy. The advantage of using gradient films is to simultaneously produce numerous samples under the same growth condition but with different thicknesses. The cross-sectional TEM images and their Fourier transform spectra revealed the thickness dependency of the grain orientations for synthetic MoS₂ films. Combining the TEM results and the data of Raman A_1g and E¹_2g peaks, we found the correlation between the grain orientation and the A_1g/E¹_2g peak area ratio. We demonstrated the potential of using the non-polarized Raman Spectroscopy to characterize the grain structures of synthetic MoS₂ films.