The structure of monolayer SiO2 on Mo(112): A 2-D [Si–O–Si] network or isolated [SiO4] units?
نویسندگان
چکیده
In this letter, atomically resolved scanning tunneling microscopic (STM) images obtained from monolayer SiO2/Mo(112) are presented. The results are consistent with a previously proposed structural model of isolated [SiO4] units based on vibrational features observed by high-resolution electron energy loss spectroscopy (HREELS) and infrared reflection–absorption spectroscopy (IRAS), and oxygen species identified by ultra-violet photoemission spectroscopy (UPS). These results are inconsistent with a structural model that assumes a two-dimensional (2-D) [Si–O–Si] network. These data illustrate that a metal substrate, although coated with an oxide thin layer, can be directly imaged at the atomic-scale with STM. 2006 Elsevier B.V. All rights reserved.
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Reply to comment on ‘‘The structure of monolayer SiO2 on Mo(112): A 2-D [Si–O–Si] network or isolated [SiO4] units?’’
1 For a tetrahedral of [SiO4], the asymmetrical vibrations of Si–O should always be IR active. Unfortunately, these modes were assumed to be IR inactive in Refs. [5,6]. 2 In Refs. [5,6], TO modes were calculated and compared with those obtained from IRAS using p-polarized and grazing incidence IR light [3– 6]. However, it is well-established that for dielectric thin films only the TO mode is ob...
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