1. Carbon monoxide adsorption on cobalt overlayers on a Si(1 1 1) surface studied by STM and XPS
- Author
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Yong Yang, Kai Wu, J.W. Niemantsverdriet, Dan Luo, Yong-Wang Li, Jian Xu, C.J. Weststrate, Yang He, and Xiaodong Wen
- Subjects
Materials science ,Silicon ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Dissociation (chemistry) ,Surfaces, Coatings and Films ,law.invention ,Chemical state ,Adsorption ,chemistry ,X-ray photoelectron spectroscopy ,law ,Crystallite ,Scanning tunneling microscope ,Cobalt - Abstract
We report on the structure and reactivity of the Co-Si polycrystalline surfaces that form at room temperature (RT). Scanning tunneling microscopy (STM) was used to examine the surface morphology while X-ray photoelectron spectroscopy (XPS) was used to detect the chemical states of cobalt and silicon as a function of cobalt coverage. Moreover, XPS measurements after exposing the Co-Si(1 1 1) samples to CO gas provide information about CO adsorption and dissociation. When 5 ML, an indication that Co-rich silicides and metallic Co present. The CO adsorption capacity increases with cobalt dose up to 30 ML after which it levels off, an indication that metallic cobalt sites are dominantly exposed on the surface. Furthermore, a closed metal film is formed for 200 ML dose. Some dissociation of CO was observed during heating of the CO-covered samples for Co doses ≥30 ML.
- Published
- 2021