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Nanoscale size-selective deposition of nanowires by micrometer scale hydrophilic patterns.

He Y, Nagashima K, Kanai M, Meng G, Zhuge F, Rahong S, Li X, Kawai T, Yanagida T - Sci Rep (2014)

Bottom Line: The diameter size of deposited nanowires was strongly limited by the width of hydrophilic patterns, exhibiting the nanoscale size selectivity of nanowires deposited onto micrometer scale hydrophilic patterns.Such size selectivity was due to the nanoscale height variation of a water layer formed onto the micrometer scale hydrophilic patterns.We successfully demonstrated the sequential alignment of different sized nanowires on the same substrate by applying this size selective phenomenon.

View Article: PubMed Central - PubMed

Affiliation: The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan.

ABSTRACT
Controlling the post-growth assembly of nanowires is an important challenge in the development of functional bottom-up devices. Although various methods have been developed for the controlled assembly of nanowires, it is still a challenging issue to align selectively heterogeneous nanowires at desired spatial positions on the substrate. Here we report a size selective deposition and sequential alignment of nanowires by utilizing micrometer scale hydrophilic/hydrophobic patterned substrate. Nanowires dispersed within oil were preferentially deposited only at a water/oil interface onto the hydrophilic patterns. The diameter size of deposited nanowires was strongly limited by the width of hydrophilic patterns, exhibiting the nanoscale size selectivity of nanowires deposited onto micrometer scale hydrophilic patterns. Such size selectivity was due to the nanoscale height variation of a water layer formed onto the micrometer scale hydrophilic patterns. We successfully demonstrated the sequential alignment of different sized nanowires on the same substrate by applying this size selective phenomenon.

No MeSH data available.


(a) Typical dark field optical microscopy and (b) magnified images of aligned 625 nm diameter nanowire on 3 μm width of hydrophilic patterns. (c) Deposition probability data of nanowires when varying hydrophilic pattern width. The data for nanowires with the diameters of 100 nm and 625 nm were shown. (d) Deposition probability data of nanowires when varying nanowire diameters. The data for the hydrophilic pattern widths of 2 μm and 10 μm were shown. The coating cycles are 20 for the experiments in Figure 2 (c) and (d).
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f2: (a) Typical dark field optical microscopy and (b) magnified images of aligned 625 nm diameter nanowire on 3 μm width of hydrophilic patterns. (c) Deposition probability data of nanowires when varying hydrophilic pattern width. The data for nanowires with the diameters of 100 nm and 625 nm were shown. (d) Deposition probability data of nanowires when varying nanowire diameters. The data for the hydrophilic pattern widths of 2 μm and 10 μm were shown. The coating cycles are 20 for the experiments in Figure 2 (c) and (d).

Mentions: Fig. 2a and b shows the typical dark field optical microscopy images of aligned Si nanowires. In this experiment, the nanowire diameter, the pattern size (width × length), the coating speed, the coating cycles and temperature were 625 nm, 3 μm × 10 μm, 10 mm/s, 100 and 20°C, respectively. The employed Si nanowires were fabricated by metal-assisted chemical etching method424344. In Fig. 2a, the deposition probability of nanowires for a pattern was 98%. The deposition probability is defined as the number probability of patterns where the nanowire exists. Fig. 2c and 2d show the deposition probability of nanowires when varying the pattern width and the nanowire diameter. For the experiments in Fig. 2c, the nanowires with the diameter of 100 nm and 625 nm were used. As seen in Fig. 2c, the deposition probability of nanowires with the diameter of 625 nm decreased from 100% to 2.7% when decreasing the pattern width from 10 μm to 0.5 μm. On the other hand, the deposition probability of nanowires with the diameter of 100 nm was kept to be almost 100% even varying the width of patterns. For the experiments in Fig. 2d, the hydrophilic patterns with the widths of 2 μm and 10 μm were employed. When increasing the nanowire diameters from 100 nm to 625 nm for the constant width of pattern-2 μm, the deposition probability decreased from 100% to 9.3%, as shown in Fig. 2d. For the pattern width of 10 μm, the deposition probability of nanowires was almost 100% independent of the nanowire diameter. Thus these results of Fig. 2c and 2d clearly highlight the occurrence of the size selective deposition of nanowires using micrometer scale hydrophilic/hydrophobic patterned substrate.


Nanoscale size-selective deposition of nanowires by micrometer scale hydrophilic patterns.

He Y, Nagashima K, Kanai M, Meng G, Zhuge F, Rahong S, Li X, Kawai T, Yanagida T - Sci Rep (2014)

(a) Typical dark field optical microscopy and (b) magnified images of aligned 625 nm diameter nanowire on 3 μm width of hydrophilic patterns. (c) Deposition probability data of nanowires when varying hydrophilic pattern width. The data for nanowires with the diameters of 100 nm and 625 nm were shown. (d) Deposition probability data of nanowires when varying nanowire diameters. The data for the hydrophilic pattern widths of 2 μm and 10 μm were shown. The coating cycles are 20 for the experiments in Figure 2 (c) and (d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4120308&req=5

f2: (a) Typical dark field optical microscopy and (b) magnified images of aligned 625 nm diameter nanowire on 3 μm width of hydrophilic patterns. (c) Deposition probability data of nanowires when varying hydrophilic pattern width. The data for nanowires with the diameters of 100 nm and 625 nm were shown. (d) Deposition probability data of nanowires when varying nanowire diameters. The data for the hydrophilic pattern widths of 2 μm and 10 μm were shown. The coating cycles are 20 for the experiments in Figure 2 (c) and (d).
Mentions: Fig. 2a and b shows the typical dark field optical microscopy images of aligned Si nanowires. In this experiment, the nanowire diameter, the pattern size (width × length), the coating speed, the coating cycles and temperature were 625 nm, 3 μm × 10 μm, 10 mm/s, 100 and 20°C, respectively. The employed Si nanowires were fabricated by metal-assisted chemical etching method424344. In Fig. 2a, the deposition probability of nanowires for a pattern was 98%. The deposition probability is defined as the number probability of patterns where the nanowire exists. Fig. 2c and 2d show the deposition probability of nanowires when varying the pattern width and the nanowire diameter. For the experiments in Fig. 2c, the nanowires with the diameter of 100 nm and 625 nm were used. As seen in Fig. 2c, the deposition probability of nanowires with the diameter of 625 nm decreased from 100% to 2.7% when decreasing the pattern width from 10 μm to 0.5 μm. On the other hand, the deposition probability of nanowires with the diameter of 100 nm was kept to be almost 100% even varying the width of patterns. For the experiments in Fig. 2d, the hydrophilic patterns with the widths of 2 μm and 10 μm were employed. When increasing the nanowire diameters from 100 nm to 625 nm for the constant width of pattern-2 μm, the deposition probability decreased from 100% to 9.3%, as shown in Fig. 2d. For the pattern width of 10 μm, the deposition probability of nanowires was almost 100% independent of the nanowire diameter. Thus these results of Fig. 2c and 2d clearly highlight the occurrence of the size selective deposition of nanowires using micrometer scale hydrophilic/hydrophobic patterned substrate.

Bottom Line: The diameter size of deposited nanowires was strongly limited by the width of hydrophilic patterns, exhibiting the nanoscale size selectivity of nanowires deposited onto micrometer scale hydrophilic patterns.Such size selectivity was due to the nanoscale height variation of a water layer formed onto the micrometer scale hydrophilic patterns.We successfully demonstrated the sequential alignment of different sized nanowires on the same substrate by applying this size selective phenomenon.

View Article: PubMed Central - PubMed

Affiliation: The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka Ibaraki, Osaka, 567-0047, Japan.

ABSTRACT
Controlling the post-growth assembly of nanowires is an important challenge in the development of functional bottom-up devices. Although various methods have been developed for the controlled assembly of nanowires, it is still a challenging issue to align selectively heterogeneous nanowires at desired spatial positions on the substrate. Here we report a size selective deposition and sequential alignment of nanowires by utilizing micrometer scale hydrophilic/hydrophobic patterned substrate. Nanowires dispersed within oil were preferentially deposited only at a water/oil interface onto the hydrophilic patterns. The diameter size of deposited nanowires was strongly limited by the width of hydrophilic patterns, exhibiting the nanoscale size selectivity of nanowires deposited onto micrometer scale hydrophilic patterns. Such size selectivity was due to the nanoscale height variation of a water layer formed onto the micrometer scale hydrophilic patterns. We successfully demonstrated the sequential alignment of different sized nanowires on the same substrate by applying this size selective phenomenon.

No MeSH data available.