کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5426496 | 1395890 | 2007 | 5 صفحه PDF | دانلود رایگان |
Structural and electronic properties of self-assembled monolayer with 4-(4-amino-phenylazo) benzoic acid (APABA) on the Si(0Â 0Â 1)-(4Â ÃÂ 2) surface are investigated by ab initio calculation based on density functional theory. For the APABA chemisorption on the silicon surface, we have assumed two different binding sites: (i) amino group of molecule and (ii) carboxyl group of molecule. Considering amino-site, we have assumed two possible models for the chemisorption of molecules on the Si(0Â 0Â 1)-(4Â ÃÂ 2) surface: (i) an intrarow position between two neighboring Si dimers in the same dimer row (Model I), (ii) on-dimer position (Model II). We have found that Model II is 1.10Â eV energetically more favorable than Model I. The Si-N bond length was calculated as 1.85Â Ã which is in excellent agreement with the sum of the corresponding covalent radii of 1.87Â Ã . Considering carboxyl-site, we have assumed exactly the same model as mentioned above. Again we have found that Model II is energetically favorable than Model I. The calculated bond lengths for Si-O and O-C are 1.76 and 1.35Â Ã , respectively.
Journal: Surface Science - Volume 601, Issue 18, 15 September 2007, Pages 3760-3764