Highlights: What are the main findings? Grazing-incidence SEM strongly enhances surface-sensitive contrast in ultrathin MoS2 coatings. Sobel-based edge analysis quantitatively confirms increased morphological information content. MoS2 colloids predominantly contain mono- and few-layer nanosheets after settling. What are the implications of the main findings? Simple stage tilting enables surface-sensitive SEM without hardware modification. Method provides reliable morphological assessment of ultrathin 2D coatings. Approach is applicable to other layered coatings and nanostructured films. Ultrathin two-dimensional (2D) coatings exhibit functional properties that are strongly defined by morphological features such as sheet edges, fracture sites, overlaps, folds, and local thickness variations, which are often difficult to resolve using conventional scanning electron microscopy (SEM) configurations. Here, we introduce a grazing-incidence SEM approach based on controlled sample tilting close to 90° for enhancing surface sensitivity and morphological feature detectability in ultrathin coatings. The method is proved on colloidal MoS2 nanosheet coatings prepared by liquid-phase exfoliation. Optical absorption spectroscopy confirms the presence of mono- and few-layer MoS2 nanosheets in the dispersion, confirming the ultrathin nature of the deposited coating. Compared to standard 0° imaging, grazing-incidence SEM reveals clearer boundaries and discontinuities. Quantitative Sobel-based image analysis supports these observations, showing an increase in edge density from 5.9% to 7.6% and in average gradient magnitude from 0.151 to 0.172 a.u. under grazing incidence, indicating a higher amount of retrievable morphological information. The proposed approach relies only on standard stage tilting and provides a broadly applicable framework for the surface-sensitive morphological characterization of ultrathin 2D coatings and thin films.
Grazing-Incidence SEM Characterization of MoS2 Nanosheet Coatings Prepared by Liquid-Phase Exfoliation
Palomba, Mariano;Nicolais, Francesca;Giubileo, Filippo;Di Bartolomeo, Antonio;Carotenuto, Gianfranco
;Longo, Angela
2026
Abstract
Highlights: What are the main findings? Grazing-incidence SEM strongly enhances surface-sensitive contrast in ultrathin MoS2 coatings. Sobel-based edge analysis quantitatively confirms increased morphological information content. MoS2 colloids predominantly contain mono- and few-layer nanosheets after settling. What are the implications of the main findings? Simple stage tilting enables surface-sensitive SEM without hardware modification. Method provides reliable morphological assessment of ultrathin 2D coatings. Approach is applicable to other layered coatings and nanostructured films. Ultrathin two-dimensional (2D) coatings exhibit functional properties that are strongly defined by morphological features such as sheet edges, fracture sites, overlaps, folds, and local thickness variations, which are often difficult to resolve using conventional scanning electron microscopy (SEM) configurations. Here, we introduce a grazing-incidence SEM approach based on controlled sample tilting close to 90° for enhancing surface sensitivity and morphological feature detectability in ultrathin coatings. The method is proved on colloidal MoS2 nanosheet coatings prepared by liquid-phase exfoliation. Optical absorption spectroscopy confirms the presence of mono- and few-layer MoS2 nanosheets in the dispersion, confirming the ultrathin nature of the deposited coating. Compared to standard 0° imaging, grazing-incidence SEM reveals clearer boundaries and discontinuities. Quantitative Sobel-based image analysis supports these observations, showing an increase in edge density from 5.9% to 7.6% and in average gradient magnitude from 0.151 to 0.172 a.u. under grazing incidence, indicating a higher amount of retrievable morphological information. The proposed approach relies only on standard stage tilting and provides a broadly applicable framework for the surface-sensitive morphological characterization of ultrathin 2D coatings and thin films.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
