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Real time scanning tunneling microscopy of anodic dissolution of copper
A183 Surface Science 246 (1991) 465-467 North-Holland
465
Direct determination of microstructures by IAP FIM II. W bcc lattice determined by a manual method D.M. Ren a, W. Liu b and B.Y. Hu b Center of Fundamental Physics, Unwersity of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China b Physics Department, Huazhong Normal University, Wuhan, Hubei 430070, People's Republic of China Received 31 July 1990; accepted for publication 27 August 1990 A manual procedure to determine the body-centered cubic structure of tungsten directly by its FIM micrographs and by field evaporation is reported here. It was performed to obtain a general method for determining the three-dimensional microstructure of FIM specimens, and as a first step of characterizing the method as well. It mainly consists of the following steps: The selection of the region of exploration; the localization of imaged atoms; the determination of the diameter of the tungsten atom model; simulation of the field ion micrographs; acquisition of the three-dimensional microstructure of the examined area.
468
Surface Science 246 (1991) 468-476 North-Holland
Real time scanning tunneling microscopy of anodic dissolution of copper Y.C. Wu a, H.W. Pickering a, D.S. Gregory a, S. Geh a and T. Sakurai b " Department of Materials Sciences and Engineering, The Pennsylvania State University, University Park, PA 16802, USA b University of Tol¢~,o, Tokyo and Tohoku Unwersity, Sendai, Japan Received 4 September 1990; accepted for publication 26 September 1990 Changes in surface topography of anodically dissolving surfaces have been examined by scanning tunneling microscopy (STM). Since aqueous solutions present the possibility of faradaic reactions during the STM examination, their effects on the tunneling current are discussed. When copper is anodically dissolved in the Tafel region, the initial mechanically polished surface (0.05 ~m A1203) is known to roughen and to form large scale (#m) facets of low index hkl planes. Real time STM shows, in addition, that the crystalline faces of the facet actually smoothen on a finer scale (10 and 100 nm) while the facets are forming. When Cu is selectively dissolved from Cu-Au alloy, pits (10 to 1002 nm diameter) and eventual porosity form. The spacing and diameter of the pits obtained by STM are in good agreement with scanning electron microscopy results. As expected, however, STM under estimates the depth of the pits except at the very initial stages of surface roughening.
465
Direct determination of microstructures by IAP FIM II. W bcc lattice determined by a manual method D.M. Ren a, W. Liu b and B.Y. Hu b Center of Fundamental Physics, Unwersity of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China b Physics Department, Huazhong Normal University, Wuhan, Hubei 430070, People's Republic of China Received 31 July 1990; accepted for publication 27 August 1990 A manual procedure to determine the body-centered cubic structure of tungsten directly by its FIM micrographs and by field evaporation is reported here. It was performed to obtain a general method for determining the three-dimensional microstructure of FIM specimens, and as a first step of characterizing the method as well. It mainly consists of the following steps: The selection of the region of exploration; the localization of imaged atoms; the determination of the diameter of the tungsten atom model; simulation of the field ion micrographs; acquisition of the three-dimensional microstructure of the examined area.
468
Surface Science 246 (1991) 468-476 North-Holland
Real time scanning tunneling microscopy of anodic dissolution of copper Y.C. Wu a, H.W. Pickering a, D.S. Gregory a, S. Geh a and T. Sakurai b " Department of Materials Sciences and Engineering, The Pennsylvania State University, University Park, PA 16802, USA b University of Tol¢~,o, Tokyo and Tohoku Unwersity, Sendai, Japan Received 4 September 1990; accepted for publication 26 September 1990 Changes in surface topography of anodically dissolving surfaces have been examined by scanning tunneling microscopy (STM). Since aqueous solutions present the possibility of faradaic reactions during the STM examination, their effects on the tunneling current are discussed. When copper is anodically dissolved in the Tafel region, the initial mechanically polished surface (0.05 ~m A1203) is known to roughen and to form large scale (#m) facets of low index hkl planes. Real time STM shows, in addition, that the crystalline faces of the facet actually smoothen on a finer scale (10 and 100 nm) while the facets are forming. When Cu is selectively dissolved from Cu-Au alloy, pits (10 to 1002 nm diameter) and eventual porosity form. The spacing and diameter of the pits obtained by STM are in good agreement with scanning electron microscopy results. As expected, however, STM under estimates the depth of the pits except at the very initial stages of surface roughening.