Surface structure of thin metallic films on mica as seen by scanning tunneling microscopy, scanning electron microscopy, and low-energy electron diffraction
- Max-Planck-Inst. fuer Polymerforschung, Mainz (West Germany)
- BASF AG Kunststofflaboratorium, Ludwigshafen (West Germany)
In this study silver, gold, palladium, and chromium films have been evaporated onto mica at substrate temperatures ranging from {minus}150C to +400C. Scanning tunneling microscopy (STM) images were obtained under ambient conditions. Silver and gold films exhibit an increasing grain size together with a grain flattening as the substrate temperature increases. At 275 and 400C for silver and gold, respectively, terraces with dimensions of the order of more than 100 nm are formed. However, also characteristic holes on the scale of a few 10 nm were always present. In addition, the gold films exhibit characteristic holes on the nanometer scale. While the larger holes are also visible on scanning electron microscopy micrographs, the small are not. Low-energy electron diffraction patterns prove the (111) orientation of both, silver and gold films; however, the quality of the silver patterns is better, consistent with the more perfect terraces as seen by STM. Palladium, evaporated at temperatures up to 350C did not exhibit similarly large and flat terraces. An improvement is achieved if prior to the palladium, silver is evaporated at elevated temperatures. Chromium, contrary to the fcc metals Ag, Au, and Pd crystallizes bcc, and forms a stable surface oxide under ambient conditions. The reproducibility of its STM images under ambient conditions depends on the applied bias and can be attributed to the surface oxide. Films evaporated at 50C exhibit a grainy structure. For the 350C films areas with columnar morphology have been observed. In conclusion, epitaxially grown Ag(111) films evaporated at 275C onto mica have been shown to exhibit large flat terraces suitable for nanoscale modifications and chemisorption studies with the STM.
- OSTI ID:
- 5232741
- Journal Information:
- Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States), Vol. 9:2; ISSN 0734-211X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHROMIUM
CRYSTAL STRUCTURE
GOLD
PALLADIUM
SILVER
ELECTRON DIFFRACTION
MICA
MICROSCOPY
SUBSTRATES
THIN FILMS
COHERENT SCATTERING
DIFFRACTION
ELEMENTS
FILMS
METALS
MINERALS
PLATINUM METALS
SCATTERING
SILICATE MINERALS
TRANSITION ELEMENTS
360102* - Metals & Alloys- Structure & Phase Studies