The sticking probabilities of chloroethane-d5 and iodoethane-d5 in the same dissociative adsorption reaction system on a Si(100)-2x1 surface are found to be extremely different by temperature programmed desorption (TPD) experiments. The adsorption mechanism for both chloroethane-d5 and iodoethane-d5 on a clean Si(100)-2x1 surface is based on a dissociative chemisorption following halogen-carbon bond cleavage. The experimental study reveals that the exposure for the monolayer saturation of chloroethane-d5 is twenty times higher than that for iodoethane-d5. By analyzing the results of density functional theory (DFT) calculations, these differences are attributed to the stability of surface-mediated molecular adsorbates rather than to the differences in the dissociation barriers. Combining the calculation and experimental results, it is confirmed that the stability of the surface-mediated precursor state determined the efficiency of haloethane dissociation.

Temperature-programmed desorption (TPD) and density functional theory (DFT) study comparing the adsorption of ethyl halides on the Si(100) surface

254th National Meeting (2017)

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