کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5424510 | 1395827 | 2008 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Dissociative adsorption and thermal evolution of carbon tetrachloride on Si(1Â 1Â 1)7Â ÃÂ 7
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The adsorption of CCl4 on Si(1Â 1Â 1)7Â ÃÂ 7 at room temperature has been characterized by electronic and vibrational electron energy loss spectroscopy (EELS). CCl4 was found to adsorb dissociatively on Si(1Â 1Â 1)7Â ÃÂ 7 with the formation of SiCl bond and adsorbed CClx species. At high exposures, CCl4 appears to more readily undergo a greater degree of dechlorination. Using a Si16H18 cluster to model only the adatom-restatom site, our density functional theory calculations suggest two plausible adstructures involving the dissociated Cl and CCl3 fragments. The wavenumbers of the observed EELS features are found to be in general accord with the corresponding calculated wavenumbers. Thermal evolution of the adsorbed fragments has been followed by both vibrational and electronic EELS as a function of the sample annealing temperature. A new EELS feature at 920-960Â cmâ1 attributed to SiC film or alloy formation is found to emerge at 573Â K, while the SiCl stretch at 550Â cmâ1, corresponding to dissociated surface Cl, is removed upon annealing to â¼883Â K. Furthermore, the electronic EELS spectra reveal an energy loss at 9.3Â eV that can be assigned to a single-electron transition from the Cl(pz) bonding state to the Cl(pz) antibonding state produced by the SiCl bond.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 602, Issue 18, 15 September 2008, Pages 3000-3005
Journal: Surface Science - Volume 602, Issue 18, 15 September 2008, Pages 3000-3005
نویسندگان
V. Venugopal, M. Ebrahimi, Z.H. He, K.T. Leung,