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Great blue-shift of luminescence of ZnO nanoparticle array constructed from ZnO quantum dots.

Wang N, Yang Y, Yang G - Nanoscale Res Lett (2011)

Bottom Line: The cathodoluminescence measurements showed that there is a pronounced blue-shift of luminescence comparable to those of the bulk counterpart, which is suggested to originate from ZnO QDs with small size where the quantum confinement effect can work well.The fabrication mechanism of the ZnO nanoparticle array constructed from ZnO QDs was proposed, in which the immiscible-like interaction between ZnO nuclei and Si surface play a key role in the ZnO QDs cluster formation.These investigations showed the fabricated nanostructure has potential applications in ultraviolet emitters.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics & Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P, R, China. stsygw@mail.sysu.edu.cn.

ABSTRACT
ZnO nanoparticle array has been fabricated on the Si substrate by a simple thermal chemical vapor transport and condensation without any metal catalysts. This ZnO nanoparticles array is constructed from ZnO quantum dots (QDs), and half-embedded in the amorphous silicon oxide layer on the surface of the Si substrate. The cathodoluminescence measurements showed that there is a pronounced blue-shift of luminescence comparable to those of the bulk counterpart, which is suggested to originate from ZnO QDs with small size where the quantum confinement effect can work well. The fabrication mechanism of the ZnO nanoparticle array constructed from ZnO QDs was proposed, in which the immiscible-like interaction between ZnO nuclei and Si surface play a key role in the ZnO QDs cluster formation. These investigations showed the fabricated nanostructure has potential applications in ultraviolet emitters.

No MeSH data available.


Related in: MedlinePlus

Schematic illustration of the fabrication mechanism of the ZnO nanoparticle array constructed from ZnO QDs. ZnO molecules randomly diffusing on surface (a), ZnO clusters thermally diffusing on surface and the inset showing the contact angle θ (b), large clusters formation by small clusters continuously diffusing and colliding (c), and big particles formation (d).
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Figure 5: Schematic illustration of the fabrication mechanism of the ZnO nanoparticle array constructed from ZnO QDs. ZnO molecules randomly diffusing on surface (a), ZnO clusters thermally diffusing on surface and the inset showing the contact angle θ (b), large clusters formation by small clusters continuously diffusing and colliding (c), and big particles formation (d).

Mentions: According to our previous study [28,29], the fabrication mechanism of the nanoparticle array is suggested a vapor-solid process. First, ZnO molecules form the thermal chemical vapor transport of source deposit on the substrate and then thermally diffuse on surface. Second, many small ZnO clusters would form by ZnO molecules by ZnO molecules continuously diffusing and colliding as shown in Figure 5b. Then, these small ZnO clusters still thermally diffuse on the surface, because there is an immiscible-like interaction between ZnO cluster and Si surface. In the inset in Figure 5b, we can see that the contact angle between ZnO cluster and Si surface is about 110° [28-33]. Thus, this contact angle is so large that ZnO clusters could easily thermal diffuse on Si surface, which seems a driving force to push ZnO cluster moving on surface. Third, large ZnO clusters would form by small clusters continuously diffusing and colliding as shown in Figure 5c. Actually, the nucleation of ZnO could take place when the size of clusters reaches to that of the critical nucleus in this stage. Then, these small ZnO nuclei still thermally move on surface because of the immiscible-like interaction between ZnO cluster and Si surface. Finally, these particle constructed from small nuclei would stop moving on surface and grow up step by step when their size is sufficiently large as shown in Figure 5d. In other words, the large cluster will stand on surface when the immiscible-like interaction cannot provide sufficiently large driving force to push those big particles. In addition, Si surrounding ZnO QDs would be oxidized to form silicon oxides. Thus, we can see that the ZnO nanoparticles are half-embedded in the amorphous silicon monoxide.


Great blue-shift of luminescence of ZnO nanoparticle array constructed from ZnO quantum dots.

Wang N, Yang Y, Yang G - Nanoscale Res Lett (2011)

Schematic illustration of the fabrication mechanism of the ZnO nanoparticle array constructed from ZnO QDs. ZnO molecules randomly diffusing on surface (a), ZnO clusters thermally diffusing on surface and the inset showing the contact angle θ (b), large clusters formation by small clusters continuously diffusing and colliding (c), and big particles formation (d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211426&req=5

Figure 5: Schematic illustration of the fabrication mechanism of the ZnO nanoparticle array constructed from ZnO QDs. ZnO molecules randomly diffusing on surface (a), ZnO clusters thermally diffusing on surface and the inset showing the contact angle θ (b), large clusters formation by small clusters continuously diffusing and colliding (c), and big particles formation (d).
Mentions: According to our previous study [28,29], the fabrication mechanism of the nanoparticle array is suggested a vapor-solid process. First, ZnO molecules form the thermal chemical vapor transport of source deposit on the substrate and then thermally diffuse on surface. Second, many small ZnO clusters would form by ZnO molecules by ZnO molecules continuously diffusing and colliding as shown in Figure 5b. Then, these small ZnO clusters still thermally diffuse on the surface, because there is an immiscible-like interaction between ZnO cluster and Si surface. In the inset in Figure 5b, we can see that the contact angle between ZnO cluster and Si surface is about 110° [28-33]. Thus, this contact angle is so large that ZnO clusters could easily thermal diffuse on Si surface, which seems a driving force to push ZnO cluster moving on surface. Third, large ZnO clusters would form by small clusters continuously diffusing and colliding as shown in Figure 5c. Actually, the nucleation of ZnO could take place when the size of clusters reaches to that of the critical nucleus in this stage. Then, these small ZnO nuclei still thermally move on surface because of the immiscible-like interaction between ZnO cluster and Si surface. Finally, these particle constructed from small nuclei would stop moving on surface and grow up step by step when their size is sufficiently large as shown in Figure 5d. In other words, the large cluster will stand on surface when the immiscible-like interaction cannot provide sufficiently large driving force to push those big particles. In addition, Si surrounding ZnO QDs would be oxidized to form silicon oxides. Thus, we can see that the ZnO nanoparticles are half-embedded in the amorphous silicon monoxide.

Bottom Line: The cathodoluminescence measurements showed that there is a pronounced blue-shift of luminescence comparable to those of the bulk counterpart, which is suggested to originate from ZnO QDs with small size where the quantum confinement effect can work well.The fabrication mechanism of the ZnO nanoparticle array constructed from ZnO QDs was proposed, in which the immiscible-like interaction between ZnO nuclei and Si surface play a key role in the ZnO QDs cluster formation.These investigations showed the fabricated nanostructure has potential applications in ultraviolet emitters.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics & Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P, R, China. stsygw@mail.sysu.edu.cn.

ABSTRACT
ZnO nanoparticle array has been fabricated on the Si substrate by a simple thermal chemical vapor transport and condensation without any metal catalysts. This ZnO nanoparticles array is constructed from ZnO quantum dots (QDs), and half-embedded in the amorphous silicon oxide layer on the surface of the Si substrate. The cathodoluminescence measurements showed that there is a pronounced blue-shift of luminescence comparable to those of the bulk counterpart, which is suggested to originate from ZnO QDs with small size where the quantum confinement effect can work well. The fabrication mechanism of the ZnO nanoparticle array constructed from ZnO QDs was proposed, in which the immiscible-like interaction between ZnO nuclei and Si surface play a key role in the ZnO QDs cluster formation. These investigations showed the fabricated nanostructure has potential applications in ultraviolet emitters.

No MeSH data available.


Related in: MedlinePlus