Oxygen driven reconstruction dynamics of Ni(977) measured by time-lapse scanning tunneling microscopy

Autor:	T. P. Pearl, Steven J. Sibener
Rok vydání:	2001
Předmět:	Coalescence (physics) Chemistry Analytical chemistry General Physics and Astronomy chemistry.chemical_element Oxygen law.invention Overlayer law Chemical physics Monolayer Limiting oxygen concentration Physical and Theoretical Chemistry Scanning tunneling microscope Vicinal Surface reconstruction
Zdroj:	The Journal of Chemical Physics. 115:1916-1927
ISSN:	1089-7690 0021-9606
DOI:	10.1063/1.1381532
Popis:	Time-lapse scanning tunneling microscopy (STM) has been used to observe the oxygen induced reconstruction behavior of Ni(977), a stepped metallic surface. Previous studies using helium atom diffraction resolved the macroscopic kinetics for the reversible step-doubling and -singling of this vicinal surface. Sequential STM imaging recorded at elevated temperature has now elucidated atomic-level mechanistic details for the merging of steps in the presence of small amounts of adsorbed oxygen, less than 2% of a monolayer. Point contact between neighboring steps decorated with chemisorbed oxygen facilitates rapid step coalescence by means of zippering. An optimal oxygen concentration of step edge saturation was found to enable the step merging to proceed most rapidly. Excess oxygen was found to hinder the coalescence of neighboring steps through the possible growth of overlayer structures on the terraces. At sufficiently high temperatures, the surface is driven back to single steps due to oxygen dissolution. Th...
Databáze:	OpenAIRE
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