Characterization of Laser Thinned Molybdenum Disulfide Nano Sheets

Transition Metals Dichalcogenide (TMDC) materials have attracted the scientific community due to their unique optical, mechanical, and electronic properties. Molybdenum disulfide (MoS$_{\mathrm{2}})$, an emerging 2D material, exhibit a tunable band gap that strongly depends on the numbers of layers, which makes MoS$_{\mathrm{2\thinspace }}$an attractive candidate for optoelectronic applications. However, recent reports have shown that engineering a monolayer using laser thinning can be an effective method without oxide formation, which can be a promising technique for various applications. Here, we investigate this laser thinning process using Raman spectroscopy, \textmu -XPS, and AFM measurements. Our results show that laser thinned MoS$_{\mathrm{2}}$ exhibit a large oxide on the surface of the flake. This oxide cannot be detected using \textmu -Raman spectroscopy, contrary to \textmu -XPS and AFM measurements. We also show that monolayer MoS$_{\mathrm{2}}$ exhibit distinctive phonon behavior compared to multilayer MoS$_{\mathrm{2}}$, which is readily reflected on the vibrational modes intensities. Our results shed light on the topology of laser thinned MoS$_{\mathrm{2}}$ flakes for future optoelectronic and electronic applications.