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ZnSe nanotrenches: formation mechanism and its role as a 1D template.

Wang G, Lok SK, Sou IK - Nanoscale Res Lett (2011)

Bottom Line: High-resolution transmission electron microscopy was used to characterize the microstructures of ZnSe nanotrenches induced by mobile Au-alloy droplets.The contact side interfaces between the AuZnδ alloy droplets and the ZnSe as well as the four side walls of the resulting <011>-oriented nanotrenches were found all belong to the {111} plane family, with the front and back walls being the {111}A planes while the other two side walls being the {111}B planes.These findings offer a deeper understanding on the formation mechanism of the nanotrenches.

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Affiliation: Nano Science and Technology Program, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. phiksou@ust.hk.

ABSTRACT
High-resolution transmission electron microscopy was used to characterize the microstructures of ZnSe nanotrenches induced by mobile Au-alloy droplets. The contact side interfaces between the AuZnδ alloy droplets and the ZnSe as well as the four side walls of the resulting <011>-oriented nanotrenches were found all belong to the {111} plane family, with the front and back walls being the {111}A planes while the other two side walls being the {111}B planes. These findings offer a deeper understanding on the formation mechanism of the nanotrenches. Pure Au nanodashes were formed upon further deposition of Au on the nanotrenches.PACS: 61.46.Df, Structure of nanocrystals and nanoparticles. 81.16.Rf, Micro and nanoscale pattern formation. 68.37.Og, High resolution transmission electron microscopy.

No MeSH data available.


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Electron microscopic images of Au nanostructures being filled into the nanotrenches: (a) The plan-view SEM image. Inset displays one of the Au nanodashes of 140 nm in length; (b) the cross-sectional TEM image taken from a nanodash that has completely filled up the underlying nanotrench; (c) a nanodash located within a nanotrench with both the front and back surfaces being non-contacted. The viewing zone axis of (b, c) is perpendicular to the nanotrenches.
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Figure 4: Electron microscopic images of Au nanostructures being filled into the nanotrenches: (a) The plan-view SEM image. Inset displays one of the Au nanodashes of 140 nm in length; (b) the cross-sectional TEM image taken from a nanodash that has completely filled up the underlying nanotrench; (c) a nanodash located within a nanotrench with both the front and back surfaces being non-contacted. The viewing zone axis of (b, c) is perpendicular to the nanotrenches.

Mentions: Recently, Xue et al. [21] have demonstrated the fabrication of ultrafine protein arrays on Au nanowires arrays through the interactions of protein-mercaptoundecanoic acid and gold. In this study, using a sample with aligned nanotrenches as a template, further Au deposition of 9.1 Ǻ in nominal thickness was carried out at a lower growth temperature with the expectation that the deposited Au in the second growth step may fall into the nanotrenches to form 1D Au nanostructure. Figure 4a shows the SEM image of a typical resulting surface of this sample, which is named as sample #2. One can see that the resulting nanotrenches are partially filled with high-density nanostructures of which their top-view shapes are either square or rectangle with sharp corners, which are in high contrast with the spherical shape of the catalyst particles. Some of these nanostructures have higher aspect ratio, although they are rare. The inset in Figure 4a shows one of these "nanodashes" with a length of about 140 nm. Figure 4b displays the HRTEM images of a completely filled-in nanodash with both the front and back contact surfaces being the {111}A planes while Figure 4c displays one that is located within a nanotrench with both the front and back surfaces being non-contacted with arc shapes. The shapes of the contact surfaces and the non-contacted surfaces of the filled-in nanostructures shown in these images offer further evidence that the shape of the filled-in nanostructures is also driven by the minimization of the system energy. One thing is worth pointing out that both subsequent EDS analysis and a detailed study performed on the Fourier transform pattern taken at the regular lattice pattern of the nanodash shown in Figure 4c reveal that the filled in material is pure Au with epitaxial relationship of [100]Au//[100]ZnSe in contrast to the AuZnδ alloy phase and the lattice misalignment of the catalytic droplets. It is believed that the nanodashes filled in the nanotrenches are pure Au instead of AuZnδ alloy because a lower substrate temperature of 500°C was used for the secondary Au deposition that only lasts for 2.5 min, which lacks sufficient energy to initiate the Au-Zn alloying process, whereas the first Au deposition having been annealed at 550°C for 20 min is capable of resulting in the formation of AuZnδ alloy NPs. The formation of Au nanodashes demonstrated in this study indicates that it is indeed possible for using the ZnSe nanotrenches as a template to fill in other materials to form novel low-dimensional nanostructures.


ZnSe nanotrenches: formation mechanism and its role as a 1D template.

Wang G, Lok SK, Sou IK - Nanoscale Res Lett (2011)

Electron microscopic images of Au nanostructures being filled into the nanotrenches: (a) The plan-view SEM image. Inset displays one of the Au nanodashes of 140 nm in length; (b) the cross-sectional TEM image taken from a nanodash that has completely filled up the underlying nanotrench; (c) a nanodash located within a nanotrench with both the front and back surfaces being non-contacted. The viewing zone axis of (b, c) is perpendicular to the nanotrenches.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3211336&req=5

Figure 4: Electron microscopic images of Au nanostructures being filled into the nanotrenches: (a) The plan-view SEM image. Inset displays one of the Au nanodashes of 140 nm in length; (b) the cross-sectional TEM image taken from a nanodash that has completely filled up the underlying nanotrench; (c) a nanodash located within a nanotrench with both the front and back surfaces being non-contacted. The viewing zone axis of (b, c) is perpendicular to the nanotrenches.
Mentions: Recently, Xue et al. [21] have demonstrated the fabrication of ultrafine protein arrays on Au nanowires arrays through the interactions of protein-mercaptoundecanoic acid and gold. In this study, using a sample with aligned nanotrenches as a template, further Au deposition of 9.1 Ǻ in nominal thickness was carried out at a lower growth temperature with the expectation that the deposited Au in the second growth step may fall into the nanotrenches to form 1D Au nanostructure. Figure 4a shows the SEM image of a typical resulting surface of this sample, which is named as sample #2. One can see that the resulting nanotrenches are partially filled with high-density nanostructures of which their top-view shapes are either square or rectangle with sharp corners, which are in high contrast with the spherical shape of the catalyst particles. Some of these nanostructures have higher aspect ratio, although they are rare. The inset in Figure 4a shows one of these "nanodashes" with a length of about 140 nm. Figure 4b displays the HRTEM images of a completely filled-in nanodash with both the front and back contact surfaces being the {111}A planes while Figure 4c displays one that is located within a nanotrench with both the front and back surfaces being non-contacted with arc shapes. The shapes of the contact surfaces and the non-contacted surfaces of the filled-in nanostructures shown in these images offer further evidence that the shape of the filled-in nanostructures is also driven by the minimization of the system energy. One thing is worth pointing out that both subsequent EDS analysis and a detailed study performed on the Fourier transform pattern taken at the regular lattice pattern of the nanodash shown in Figure 4c reveal that the filled in material is pure Au with epitaxial relationship of [100]Au//[100]ZnSe in contrast to the AuZnδ alloy phase and the lattice misalignment of the catalytic droplets. It is believed that the nanodashes filled in the nanotrenches are pure Au instead of AuZnδ alloy because a lower substrate temperature of 500°C was used for the secondary Au deposition that only lasts for 2.5 min, which lacks sufficient energy to initiate the Au-Zn alloying process, whereas the first Au deposition having been annealed at 550°C for 20 min is capable of resulting in the formation of AuZnδ alloy NPs. The formation of Au nanodashes demonstrated in this study indicates that it is indeed possible for using the ZnSe nanotrenches as a template to fill in other materials to form novel low-dimensional nanostructures.

Bottom Line: High-resolution transmission electron microscopy was used to characterize the microstructures of ZnSe nanotrenches induced by mobile Au-alloy droplets.The contact side interfaces between the AuZnδ alloy droplets and the ZnSe as well as the four side walls of the resulting <011>-oriented nanotrenches were found all belong to the {111} plane family, with the front and back walls being the {111}A planes while the other two side walls being the {111}B planes.These findings offer a deeper understanding on the formation mechanism of the nanotrenches.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nano Science and Technology Program, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. phiksou@ust.hk.

ABSTRACT
High-resolution transmission electron microscopy was used to characterize the microstructures of ZnSe nanotrenches induced by mobile Au-alloy droplets. The contact side interfaces between the AuZnδ alloy droplets and the ZnSe as well as the four side walls of the resulting <011>-oriented nanotrenches were found all belong to the {111} plane family, with the front and back walls being the {111}A planes while the other two side walls being the {111}B planes. These findings offer a deeper understanding on the formation mechanism of the nanotrenches. Pure Au nanodashes were formed upon further deposition of Au on the nanotrenches.PACS: 61.46.Df, Structure of nanocrystals and nanoparticles. 81.16.Rf, Micro and nanoscale pattern formation. 68.37.Og, High resolution transmission electron microscopy.

No MeSH data available.


Related in: MedlinePlus