Limits...
Fabrication of Nickel Nanostructure Arrays Via a Modified Nanosphere Lithography

View Article: PubMed Central - HTML - PubMed

ABSTRACT

In this paper, we present a modified nanosphere lithographic scheme that is based on the self-assembly and electroforming techniques. The scheme was demonstrated to fabricate a nickel template of ordered nanobowl arrays together with a nickel nanostructure array-patterned glass substrate. The hemispherical nanobowls exhibit uniform sizes and smooth interior surfaces, and the shallow nanobowls with a flat bottom on the glass substrate are interconnected as a net structure with uniform thickness. A multiphysics model based on the level set method (LSM) was built up to understand this fabricating process by tracking the interface between the growing nickel and the electrolyte. The fabricated nickel nanobowl template can be used as a mold of long lifetime in soft lithography due to the high strength of nickel. The nanostructure–patterned glass substrate can be used in optical and magnetic devices due to their shape effects. This fabrication scheme can also be extended to a wide range of metals and alloys.

No MeSH data available.


SEM images of the resultant nickel nanobowls array top inset: FFT pattern of the image; and bottom inset: EDX spectrum of the nanobowls.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211311&req=5

Figure 3: SEM images of the resultant nickel nanobowls array top inset: FFT pattern of the image; and bottom inset: EDX spectrum of the nanobowls.

Mentions: The resultant nickel master template of a bowl-shaped nanostructure is shown in Figure 3. The PS nanospheres were washed away during the removal process, and EDX spectrum (bottom inset) indicates that the bright regions in the image are gold residuals. The pitch and size of the nanobowl can be adjusted independently by selecting PS nanospheres with different sizes or by decreasing the PS nanosphere size with oxygen plasma etching after the self-assembly process. Fast Fourier Transformation (FFT) technique is an excellent method to study the periodicity of micro- and nanostructures configuration [23]. In this study, the regularity of nickel nanobowls array was analyzed by applying FFT to the SEM images. The top inset in Figure 3 shows that the hexagonal arrangement of nickel nanobowls is quite uniform, and the nickel nanobowls array is of a six-fold symmetry. Figure 4 shows a SEM image of the nickel nanobowl cross-section milled using FIB with an ion beam current of about 100 pA. The nanobowl size was calculated from the SEM images of nanobowl cross-section using an image processing technique. It was found that the curvature radius of the nanobowl is about 267 nm less than the estimated 300 nm, which is due to the misalignment between the cutting line and the center line of the nanobowl and also the image contrast induced edge detection error because each pixel of our SEM images represents approximately 5 nm in length. The profile of the FIB cut nanobowls can be more accurately reconstructed and errors can be minimized by positioning the cutting line through the center of nanobowl and by improving the contrast of SEM images.


Fabrication of Nickel Nanostructure Arrays Via a Modified Nanosphere Lithography
SEM images of the resultant nickel nanobowls array top inset: FFT pattern of the image; and bottom inset: EDX spectrum of the nanobowls.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211311&req=5

Figure 3: SEM images of the resultant nickel nanobowls array top inset: FFT pattern of the image; and bottom inset: EDX spectrum of the nanobowls.
Mentions: The resultant nickel master template of a bowl-shaped nanostructure is shown in Figure 3. The PS nanospheres were washed away during the removal process, and EDX spectrum (bottom inset) indicates that the bright regions in the image are gold residuals. The pitch and size of the nanobowl can be adjusted independently by selecting PS nanospheres with different sizes or by decreasing the PS nanosphere size with oxygen plasma etching after the self-assembly process. Fast Fourier Transformation (FFT) technique is an excellent method to study the periodicity of micro- and nanostructures configuration [23]. In this study, the regularity of nickel nanobowls array was analyzed by applying FFT to the SEM images. The top inset in Figure 3 shows that the hexagonal arrangement of nickel nanobowls is quite uniform, and the nickel nanobowls array is of a six-fold symmetry. Figure 4 shows a SEM image of the nickel nanobowl cross-section milled using FIB with an ion beam current of about 100 pA. The nanobowl size was calculated from the SEM images of nanobowl cross-section using an image processing technique. It was found that the curvature radius of the nanobowl is about 267 nm less than the estimated 300 nm, which is due to the misalignment between the cutting line and the center line of the nanobowl and also the image contrast induced edge detection error because each pixel of our SEM images represents approximately 5 nm in length. The profile of the FIB cut nanobowls can be more accurately reconstructed and errors can be minimized by positioning the cutting line through the center of nanobowl and by improving the contrast of SEM images.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

In this paper, we present a modified nanosphere lithographic scheme that is based on the self-assembly and electroforming techniques. The scheme was demonstrated to fabricate a nickel template of ordered nanobowl arrays together with a nickel nanostructure array-patterned glass substrate. The hemispherical nanobowls exhibit uniform sizes and smooth interior surfaces, and the shallow nanobowls with a flat bottom on the glass substrate are interconnected as a net structure with uniform thickness. A multiphysics model based on the level set method (LSM) was built up to understand this fabricating process by tracking the interface between the growing nickel and the electrolyte. The fabricated nickel nanobowl template can be used as a mold of long lifetime in soft lithography due to the high strength of nickel. The nanostructure–patterned glass substrate can be used in optical and magnetic devices due to their shape effects. This fabrication scheme can also be extended to a wide range of metals and alloys.

No MeSH data available.