Quantitative Determination of the Imperfectness of a Cleaved MoS₂(001) Surface by Coaxial Impact-Collision Ion Scattering

R. Duszak, F. Ohtani, Y. Kadowaki, and H. Nozoye
[Surf. Sci., Vol. 324, pp.257-262, 1995]

Polar angle dependence of the Mo signal intensity in the case of CAICISS type scattering of 3 keV He and Ne ion beams from a cleaved (001) molybdenite surface have been obtained. The experimental results analyzed with the use of a recently developed computer simulation method allowed to determine quantitatively the incompleteness of the top, sulphur layer. A general method of CAICISS angular data fitting by normalization of the calculated second layer intensity contribution, to the background level at normal incidence is proposed. In addition, an approximate data treatment is suggested, which allows one to obtain an estimate of the surface roughness from the polar angle spectra.

Fig. 1(a). Molybdenum signal intensity for 3 keV Ne ion scattering from the MoS₂ (001) surface as a function of polar angle. Open circles: experimental data, solid line: fitting by the normalization to background at 90º, dashed line: best fit of the calculated intensity distribution, obtained by a standard fitting procedure.

Fig. 1(b). Molybdenum signal intensity for 3 keV He ion scattering from the MoS₂ (001) surface as a function of polar angle. Open circles: experimental spectrum, solid line: fitting by the normalization to the background level at 90º polar angle.