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Room-temperature nonequilibrium growth of controllable ZnO nanorod arrays.

Li Q, Cheng K, Weng W, Song C, Du P, Shen G, Han G - Nanoscale Res Lett (2011)

Bottom Line: In this study, controllable ZnO nanorod arrays were successfully synthesized on Si substrate at room temperature (approx. 25°C).It was found that the wettability and electrowetting behaviors of ZnO nanorod arrays could be tuned through variations of nanorods density and length.Moreover, its field emission property was also optimized by changing the nanorods density and dimension.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Materials Science & Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, People's Republic of China. wengwj@zju.edu.cn.

ABSTRACT
In this study, controllable ZnO nanorod arrays were successfully synthesized on Si substrate at room temperature (approx. 25°C). The formation of controllable ZnO nanorod arrays has been investigated using growth media with different concentrations and molar ratios of Zn(NO3)2 to NaOH. Under such a nonequilibrium growth condition, the density and dimension of ZnO nanorod arrays were successfully adjusted through controlling the supersaturation degree, i.e., volume of growth medium. It was found that the wettability and electrowetting behaviors of ZnO nanorod arrays could be tuned through variations of nanorods density and length. Moreover, its field emission property was also optimized by changing the nanorods density and dimension.

No MeSH data available.


Related in: MedlinePlus

Photographs of water droplet shape when voltage at 0 V: (a1) sample A; (b1) sample B; (c1) sample C; and (d1) ZnO seed-layer film; electrically induced transitions of water droplet shape when voltage at 60 V: (a2) sample A; (b2) sample B; (c2) sample C; and (d2) ZnO seed-layer film.
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Figure 8: Photographs of water droplet shape when voltage at 0 V: (a1) sample A; (b1) sample B; (c1) sample C; and (d1) ZnO seed-layer film; electrically induced transitions of water droplet shape when voltage at 60 V: (a2) sample A; (b2) sample B; (c2) sample C; and (d2) ZnO seed-layer film.

Mentions: The electrowetting relies on the modification of contact angle by the application of an electrical potential between the conducting substrate and the liquid droplet (Figure 7), which starts from the electrocapillarity phenomenon. For 3-μL droplets of deionized water, the contact angle changes of samples A, B, C, and ZnO seed-layer film were observed by adjusting voltages from 0 to 60 V. Figure 8a1-d1 and 8a2-d2 shows the performance of droplets when voltages at 0 and 60 V were added. As can be observed in Figure 8, the contact angle change of sample C after applying a voltage in the 0 to 60 V range is as large as 95° and the sample A with lower density and length exhibits a poor electrowetting property which only a 29.7° change can be seen. The electric field results in a distribution of charge that alters the surface free energy, causing the droplet to spread on the surface [38]. The lower density of ZnO nanorod array, the fewer free energy changes when apply a voltage, so that the electrowetting property of ZnO film seems to be limited (Figure 8d1,d2). The gradual electrowetting responses were recorded and shown in Figure 9. This gradual response has its advantage for applications such as electrooptics and so on [39].


Room-temperature nonequilibrium growth of controllable ZnO nanorod arrays.

Li Q, Cheng K, Weng W, Song C, Du P, Shen G, Han G - Nanoscale Res Lett (2011)

Photographs of water droplet shape when voltage at 0 V: (a1) sample A; (b1) sample B; (c1) sample C; and (d1) ZnO seed-layer film; electrically induced transitions of water droplet shape when voltage at 60 V: (a2) sample A; (b2) sample B; (c2) sample C; and (d2) ZnO seed-layer film.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211990&req=5

Figure 8: Photographs of water droplet shape when voltage at 0 V: (a1) sample A; (b1) sample B; (c1) sample C; and (d1) ZnO seed-layer film; electrically induced transitions of water droplet shape when voltage at 60 V: (a2) sample A; (b2) sample B; (c2) sample C; and (d2) ZnO seed-layer film.
Mentions: The electrowetting relies on the modification of contact angle by the application of an electrical potential between the conducting substrate and the liquid droplet (Figure 7), which starts from the electrocapillarity phenomenon. For 3-μL droplets of deionized water, the contact angle changes of samples A, B, C, and ZnO seed-layer film were observed by adjusting voltages from 0 to 60 V. Figure 8a1-d1 and 8a2-d2 shows the performance of droplets when voltages at 0 and 60 V were added. As can be observed in Figure 8, the contact angle change of sample C after applying a voltage in the 0 to 60 V range is as large as 95° and the sample A with lower density and length exhibits a poor electrowetting property which only a 29.7° change can be seen. The electric field results in a distribution of charge that alters the surface free energy, causing the droplet to spread on the surface [38]. The lower density of ZnO nanorod array, the fewer free energy changes when apply a voltage, so that the electrowetting property of ZnO film seems to be limited (Figure 8d1,d2). The gradual electrowetting responses were recorded and shown in Figure 9. This gradual response has its advantage for applications such as electrooptics and so on [39].

Bottom Line: In this study, controllable ZnO nanorod arrays were successfully synthesized on Si substrate at room temperature (approx. 25°C).It was found that the wettability and electrowetting behaviors of ZnO nanorod arrays could be tuned through variations of nanorods density and length.Moreover, its field emission property was also optimized by changing the nanorods density and dimension.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Materials Science & Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, People's Republic of China. wengwj@zju.edu.cn.

ABSTRACT
In this study, controllable ZnO nanorod arrays were successfully synthesized on Si substrate at room temperature (approx. 25°C). The formation of controllable ZnO nanorod arrays has been investigated using growth media with different concentrations and molar ratios of Zn(NO3)2 to NaOH. Under such a nonequilibrium growth condition, the density and dimension of ZnO nanorod arrays were successfully adjusted through controlling the supersaturation degree, i.e., volume of growth medium. It was found that the wettability and electrowetting behaviors of ZnO nanorod arrays could be tuned through variations of nanorods density and length. Moreover, its field emission property was also optimized by changing the nanorods density and dimension.

No MeSH data available.


Related in: MedlinePlus