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Morphological engineering of self-assembled nanostructures at nanoscale on faceted GaAs nanowires by droplet epitaxy.

Zha GW, Zhang LC, Yu Y, Xu JX, Wei SH, Shang XJ, Ni HQ, Niu ZC - Nanoscale Res Lett (2015)

Bottom Line: Here, we achieve morphological engineering in the form of novel quantum dots (QDs), 'square' quantum rings (QRs), 'rectangular' QRs, 3D QRs, crescent-shaped QRs, and nano-antidots.The evolution mechanisms for the peculiar morphologies of both NWs and nanostructures are modeled and discussed in detail.This work shows the potential of combining nano-structural engineering with NWs to achieve multifunctional properties and applications.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing, 100083 China ; Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 China.

ABSTRACT
Fabrication of advanced artificial nanomaterials is a long-term pursuit to fulfill the promises of nanomaterials and it is of utter importance to manipulate materials at nanoscale to meet urgent demands of nanostructures with designed properties. Herein, we demonstrate the morphological tailoring of self-assembled nanostructures on faceted GaAs nanowires (NWs). The NWs are deposited on different kinds of substrates. Triangular and hexagonal prism morphologies are obtained, and their corresponding {110} sidewalls act as platforms for the nucleation of gallium droplets (GDs). We demonstrate that the morphologies of the nanostructures depend not only on the annealing conditions but also on the morphologies of the NWs' sidewalls. Here, we achieve morphological engineering in the form of novel quantum dots (QDs), 'square' quantum rings (QRs), 'rectangular' QRs, 3D QRs, crescent-shaped QRs, and nano-antidots. The evolution mechanisms for the peculiar morphologies of both NWs and nanostructures are modeled and discussed in detail. This work shows the potential of combining nano-structural engineering with NWs to achieve multifunctional properties and applications.

No MeSH data available.


Related in: MedlinePlus

Representative SEM images of the obtained NWs. (a) Ion beam-sputtered (100) substrate, (b) magnetron-sputtered (100) substrate, and (c) magnetron-sputtered (111)B substrate. The inset in each panel is the magnified picture of NWs to illustrate the cross-sectional morphologies. (d) A schematic model for the triangular and hexagonal prism NWs on different substrates. The blue and yellow parts represent GaAs and SiO2, respectively. (e) TEM characterization of NWs in (a); insets are HRTEM image and its corresponding FFTs.
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Fig1: Representative SEM images of the obtained NWs. (a) Ion beam-sputtered (100) substrate, (b) magnetron-sputtered (100) substrate, and (c) magnetron-sputtered (111)B substrate. The inset in each panel is the magnified picture of NWs to illustrate the cross-sectional morphologies. (d) A schematic model for the triangular and hexagonal prism NWs on different substrates. The blue and yellow parts represent GaAs and SiO2, respectively. (e) TEM characterization of NWs in (a); insets are HRTEM image and its corresponding FFTs.

Mentions: Figure 1 is the representative scanning electron microscopy (SEM) images of the obtained NWs on different substrates with uniform average length of 4.5 μm and diameter of 260 nm. The difference lies in the existence or not of a preferential orientation of the NWs. Figure 1a shows that the NWs are grown in random orientations for ion beam-sputtered SiO2 surface. However, in the case of magnetron-sputtered samples (Figure 1b,c), most of the NWs align on the same orientations, with their growth axis following the <111> B azimuths of the underlying substrates. We suggest that the different sputtering energies adopted in these two systems are responsible for density discrepancy of SiO2 layer, and consequently, non-penetrating and penetrating pinholes are formed, respectively [19]. A dotted reflection high-energy electron diffraction pattern which is observed only on the magnetron-sputtered SiO2 layer confirmed this suggestion. Hereafter, the penetrating pinholes induce an epitaxial relationship between the obtained NWs and substrates with oriented NWs, while the non-penetrating ones, with the random-oriented NWs.Figure 1


Morphological engineering of self-assembled nanostructures at nanoscale on faceted GaAs nanowires by droplet epitaxy.

Zha GW, Zhang LC, Yu Y, Xu JX, Wei SH, Shang XJ, Ni HQ, Niu ZC - Nanoscale Res Lett (2015)

Representative SEM images of the obtained NWs. (a) Ion beam-sputtered (100) substrate, (b) magnetron-sputtered (100) substrate, and (c) magnetron-sputtered (111)B substrate. The inset in each panel is the magnified picture of NWs to illustrate the cross-sectional morphologies. (d) A schematic model for the triangular and hexagonal prism NWs on different substrates. The blue and yellow parts represent GaAs and SiO2, respectively. (e) TEM characterization of NWs in (a); insets are HRTEM image and its corresponding FFTs.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Fig1: Representative SEM images of the obtained NWs. (a) Ion beam-sputtered (100) substrate, (b) magnetron-sputtered (100) substrate, and (c) magnetron-sputtered (111)B substrate. The inset in each panel is the magnified picture of NWs to illustrate the cross-sectional morphologies. (d) A schematic model for the triangular and hexagonal prism NWs on different substrates. The blue and yellow parts represent GaAs and SiO2, respectively. (e) TEM characterization of NWs in (a); insets are HRTEM image and its corresponding FFTs.
Mentions: Figure 1 is the representative scanning electron microscopy (SEM) images of the obtained NWs on different substrates with uniform average length of 4.5 μm and diameter of 260 nm. The difference lies in the existence or not of a preferential orientation of the NWs. Figure 1a shows that the NWs are grown in random orientations for ion beam-sputtered SiO2 surface. However, in the case of magnetron-sputtered samples (Figure 1b,c), most of the NWs align on the same orientations, with their growth axis following the <111> B azimuths of the underlying substrates. We suggest that the different sputtering energies adopted in these two systems are responsible for density discrepancy of SiO2 layer, and consequently, non-penetrating and penetrating pinholes are formed, respectively [19]. A dotted reflection high-energy electron diffraction pattern which is observed only on the magnetron-sputtered SiO2 layer confirmed this suggestion. Hereafter, the penetrating pinholes induce an epitaxial relationship between the obtained NWs and substrates with oriented NWs, while the non-penetrating ones, with the random-oriented NWs.Figure 1

Bottom Line: Here, we achieve morphological engineering in the form of novel quantum dots (QDs), 'square' quantum rings (QRs), 'rectangular' QRs, 3D QRs, crescent-shaped QRs, and nano-antidots.The evolution mechanisms for the peculiar morphologies of both NWs and nanostructures are modeled and discussed in detail.This work shows the potential of combining nano-structural engineering with NWs to achieve multifunctional properties and applications.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing, 100083 China ; Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 China.

ABSTRACT
Fabrication of advanced artificial nanomaterials is a long-term pursuit to fulfill the promises of nanomaterials and it is of utter importance to manipulate materials at nanoscale to meet urgent demands of nanostructures with designed properties. Herein, we demonstrate the morphological tailoring of self-assembled nanostructures on faceted GaAs nanowires (NWs). The NWs are deposited on different kinds of substrates. Triangular and hexagonal prism morphologies are obtained, and their corresponding {110} sidewalls act as platforms for the nucleation of gallium droplets (GDs). We demonstrate that the morphologies of the nanostructures depend not only on the annealing conditions but also on the morphologies of the NWs' sidewalls. Here, we achieve morphological engineering in the form of novel quantum dots (QDs), 'square' quantum rings (QRs), 'rectangular' QRs, 3D QRs, crescent-shaped QRs, and nano-antidots. The evolution mechanisms for the peculiar morphologies of both NWs and nanostructures are modeled and discussed in detail. This work shows the potential of combining nano-structural engineering with NWs to achieve multifunctional properties and applications.

No MeSH data available.


Related in: MedlinePlus