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Catalytic growth of ZnO nanostructures by r.f. magnetron sputtering.

Arroyo-Hernández M, Alvaro R, Serrano S, Costa-Krämer JL - Nanoscale Res Lett (2011)

Bottom Line: The catalytic effect of gold seed particles deposited on a substrate prior to zinc oxide (ZnO) thin film growth by magnetron sputtering was investigated.The ZnO structures are subsequently deposited by r.f. magnetron sputtering in a UHV chamber, and possible morphological differences between the ZnO grown on top of the substrate and on the gold are investigated.The results indicate a moderate catalytic effect for a deposited gold underlayer of 4 nm, quite close to the gold thin film percolation thickness.

View Article: PubMed Central - HTML - PubMed

Affiliation: IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, Tres Cantos, Madrid 28760, Spain. maria.arroyo@imm.cnm.csic.es.

ABSTRACT
The catalytic effect of gold seed particles deposited on a substrate prior to zinc oxide (ZnO) thin film growth by magnetron sputtering was investigated. For this purpose, selected ultra thin gold layers, with thicknesses close to the percolation threshold, are deposited by thermal evaporation in ultra high vacuum (UHV) conditions and subsequently annealed to form gold nanodroplets. The ZnO structures are subsequently deposited by r.f. magnetron sputtering in a UHV chamber, and possible morphological differences between the ZnO grown on top of the substrate and on the gold are investigated. The results indicate a moderate catalytic effect for a deposited gold underlayer of 4 nm, quite close to the gold thin film percolation thickness.

No MeSH data available.


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SEM top views comparing the ZnO structures grown directly onto the substrate and onto an annealed ultra thin gold film of different thicknesses.
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Figure 3: SEM top views comparing the ZnO structures grown directly onto the substrate and onto an annealed ultra thin gold film of different thicknesses.

Mentions: To check a possible gold catalytic effect of the ZnO growth on gold, this was carried out for 2, 4 and 10 nm thin gold thicknesses. The morphology of the ZnO structures grown was inspected by SEM (Figure 3). We deliberately went above and below the gold percolation threshold to avoid irreproducible and drastic morphological and temperature dependencies inherent to percolation behaviour. To evaluate this possible catalytic effect of gold, the morphology of ZnO directly growth on sapphire (Figure 3, left) and on top of the annealed gold (Figure 3, right) were compared. As seen, there is no difference between both for 10 nm gold films. On the other hand, ZnO grown on 2 nm gold thickness shows a different structure depending on the material below, but only for 4 nm gold films marked differences are observed. In Figure 4, detailed images illustrating this effect are shown. The cross-sectional views clearly show a randomly oriented ZnO nanostructure when grown on 4 nm gold films, with lengths ranging from 80 to 220 nm. This confirms the moderate effect of gold for catalytic ZnO nanostructure formation.


Catalytic growth of ZnO nanostructures by r.f. magnetron sputtering.

Arroyo-Hernández M, Alvaro R, Serrano S, Costa-Krämer JL - Nanoscale Res Lett (2011)

SEM top views comparing the ZnO structures grown directly onto the substrate and onto an annealed ultra thin gold film of different thicknesses.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211855&req=5

Figure 3: SEM top views comparing the ZnO structures grown directly onto the substrate and onto an annealed ultra thin gold film of different thicknesses.
Mentions: To check a possible gold catalytic effect of the ZnO growth on gold, this was carried out for 2, 4 and 10 nm thin gold thicknesses. The morphology of the ZnO structures grown was inspected by SEM (Figure 3). We deliberately went above and below the gold percolation threshold to avoid irreproducible and drastic morphological and temperature dependencies inherent to percolation behaviour. To evaluate this possible catalytic effect of gold, the morphology of ZnO directly growth on sapphire (Figure 3, left) and on top of the annealed gold (Figure 3, right) were compared. As seen, there is no difference between both for 10 nm gold films. On the other hand, ZnO grown on 2 nm gold thickness shows a different structure depending on the material below, but only for 4 nm gold films marked differences are observed. In Figure 4, detailed images illustrating this effect are shown. The cross-sectional views clearly show a randomly oriented ZnO nanostructure when grown on 4 nm gold films, with lengths ranging from 80 to 220 nm. This confirms the moderate effect of gold for catalytic ZnO nanostructure formation.

Bottom Line: The catalytic effect of gold seed particles deposited on a substrate prior to zinc oxide (ZnO) thin film growth by magnetron sputtering was investigated.The ZnO structures are subsequently deposited by r.f. magnetron sputtering in a UHV chamber, and possible morphological differences between the ZnO grown on top of the substrate and on the gold are investigated.The results indicate a moderate catalytic effect for a deposited gold underlayer of 4 nm, quite close to the gold thin film percolation thickness.

View Article: PubMed Central - HTML - PubMed

Affiliation: IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, Tres Cantos, Madrid 28760, Spain. maria.arroyo@imm.cnm.csic.es.

ABSTRACT
The catalytic effect of gold seed particles deposited on a substrate prior to zinc oxide (ZnO) thin film growth by magnetron sputtering was investigated. For this purpose, selected ultra thin gold layers, with thicknesses close to the percolation threshold, are deposited by thermal evaporation in ultra high vacuum (UHV) conditions and subsequently annealed to form gold nanodroplets. The ZnO structures are subsequently deposited by r.f. magnetron sputtering in a UHV chamber, and possible morphological differences between the ZnO grown on top of the substrate and on the gold are investigated. The results indicate a moderate catalytic effect for a deposited gold underlayer of 4 nm, quite close to the gold thin film percolation thickness.

No MeSH data available.


Related in: MedlinePlus