The growth and thermal properties of Au deposited on Rh(111) formation of ordered surface alloy /
Scanning tunnelling microscopy (STM), low energy ion scattering spectroscopy (LEIS), X-ray photoelectron spectroscopy (XPS) and high resolution electron energy loss spectroscopy (HREELS) were applied for studying Au on Rh(111) surface. Both the deposition of Au at different substrate temperatures (4...
Elmentve itt :
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| Dokumentumtípus: | Cikk |
| Megjelent: |
2016
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| Sorozat: | PHYSICAL CHEMISTRY CHEMICAL PHYSICS
18 |
| doi: | 10.1039/C6CP02128J |
| mtmt: | 3101262 |
| Online Access: | http://publicatio.bibl.u-szeged.hu/9833 |
| Tartalmi kivonat: | Scanning tunnelling microscopy (STM), low energy ion scattering spectroscopy (LEIS), X-ray photoelectron spectroscopy (XPS) and high resolution electron energy loss spectroscopy (HREELS) were applied for studying Au on Rh(111) surface. Both the deposition of Au at different substrate temperatures (400-800 K), and the effect of annealing the Au deposited at 500 K were investigated. Gold deposition at 500 K, checked by STM and LEIS methods, revealed that up to half monolayer Au the system exhibits clearly a layer-by layer growth; however, above this coverage a slight deviation was identified, mainly due to kinetic and morphologic effects. Continuous cover layer of Au was formed only above ~2.5 monolayers (ML). Below this coverage the pseudomorphic character of the Au overlayer was clearly proven by STM, but this feature disappears at 4 ML coverage. Indication of a moderate (5-10%) surface mixing of the two metals was observed only above 600 K, for both annealing the Au layer formed at lower temperatures and performing the deposition at elevated temperatures. Above 600 K a clear step-flow growth mechanism was verified. Depending on Au coverage, a more extended mixing of the top and the sublayer was observed at even higher temperatures. In this case nano-range ordering of the alloyed layer was detected by STM, where the lateral extension of the uniform commensurate (2[times]1) domains was around 4[times]4 nm2. In this case the local intralayer mixing of Rh and Au can locally reach the value of 50 %. The proposed structural model for the (2[times]1) alloy phase was corroborated also by HREELS investigations on CO adsorption. |
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| Terjedelem/Fizikai jellemzők: | 25230-25240 |
| ISSN: | 1463-9076 |