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Au nanostructure arrays for plasmonic applications: annealed island films versus nanoimprint lithography.

Lopatynskyi AM, Lytvyn VK, Nazarenko VI, Guo LJ, Lucas BD, Chegel VI - Nanoscale Res Lett (2015)

Bottom Line: Modelling of the optical response for nanostructures with typical shapes associated with these techniques (parallelepiped for NIL and semi-ellipsoid for annealed island films) was performed using finite-difference time-domain calculations.As an important point, the distribution of electric field at so-called 'hot spots' was considered.The application of island film thermal annealing method for nanochips fabrication can be considered as a possible cost-effective platform for various surface-enhanced spectroscopies; while the NIL-fabricated NSA looks like more effective for sensing of small-size objects.

View Article: PubMed Central - PubMed

Affiliation: Department of Functional Optoelectronics, V. E. Lashkaryov Institute of Semiconductor Physics NASU, 41 Nauki avenue, 03028 Kyiv, Ukraine.

ABSTRACT
This paper attempts to compare the main features of random and highly ordered gold nanostructure arrays (NSA) prepared by thermally annealed island film and nanoimprint lithography (NIL) techniques, respectively. Each substrate possesses different morphology in terms of plasmonic enhancement. Both methods allow such important features as spectral tuning of plasmon resonance position depending on size and shape of nanostructures; however, the time and cost is quite different. The respective comparison was performed experimentally and theoretically for a number of samples with different geometrical parameters. Spectral characteristics of fabricated NSA exhibited an expressed plasmon peak in the range from 576 to 809 nm for thermally annealed samples and from 606 to 783 nm for samples prepared by NIL. Modelling of the optical response for nanostructures with typical shapes associated with these techniques (parallelepiped for NIL and semi-ellipsoid for annealed island films) was performed using finite-difference time-domain calculations. Mathematical simulations have indicated the dependence of electric field enhancement on the shape and size of the nanoparticles. As an important point, the distribution of electric field at so-called 'hot spots' was considered. Parallelepiped-shaped nanoparticles were shown to yield maximal enhancement values by an order of magnitude greater than their semi-ellipsoid-shaped counterparts; however, both nanoparticle shapes have demonstrated comparable effective electrical field enhancement values. Optimized Au nanostructures with equivalent diameters ranging from 85 to 143 nm and height equal to 35 nm were obtained for both techniques, resulting in the largest electrical field enhancement. The application of island film thermal annealing method for nanochips fabrication can be considered as a possible cost-effective platform for various surface-enhanced spectroscopies; while the NIL-fabricated NSA looks like more effective for sensing of small-size objects.

No MeSH data available.


Related in: MedlinePlus

Measured extinction spectra of random NSA samples produced via thermal annealing of gold island films. Normal incidence unpolarized light extinction spectra for samples R1 to R9 with different initial gold island film thickness exhibit peaks located in the wavelength range from 576 to 809 nm. Inset: the table with respective NSA geometrical parameters.
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Fig3: Measured extinction spectra of random NSA samples produced via thermal annealing of gold island films. Normal incidence unpolarized light extinction spectra for samples R1 to R9 with different initial gold island film thickness exhibit peaks located in the wavelength range from 576 to 809 nm. Inset: the table with respective NSA geometrical parameters.

Mentions: As a result of spectrophotometric measurements, light extinction spectra of the samples in air atmosphere were obtained (Figure 3). It was found that the peak position in the unpolarized light extinction spectrum, which corresponds to the occurrence of LSPR, shifts towards longer wavelengths with an increase in the initial gold island film thickness (see Figure 3 and Table 1). Additionally, the direct relation between lateral dimensions and height of nanostructures produced after annealing and the initial gold island film thickness was revealed. Thus, it is possible to tune the LSPR spectral position in the wavelength range from 576 to 809 nm (see Figure 3), and the associated PE spectral profile, by changing the initial gold island film thickness. Obviously, considered PE nanochips fabrication technology based on gold island films with subsequent thermal annealing can be exploited while taking into account inherent technological limitations that hinder the preparation of geometrically ordered nanoparticle arrays.Figure 3


Au nanostructure arrays for plasmonic applications: annealed island films versus nanoimprint lithography.

Lopatynskyi AM, Lytvyn VK, Nazarenko VI, Guo LJ, Lucas BD, Chegel VI - Nanoscale Res Lett (2015)

Measured extinction spectra of random NSA samples produced via thermal annealing of gold island films. Normal incidence unpolarized light extinction spectra for samples R1 to R9 with different initial gold island film thickness exhibit peaks located in the wavelength range from 576 to 809 nm. Inset: the table with respective NSA geometrical parameters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385248&req=5

Fig3: Measured extinction spectra of random NSA samples produced via thermal annealing of gold island films. Normal incidence unpolarized light extinction spectra for samples R1 to R9 with different initial gold island film thickness exhibit peaks located in the wavelength range from 576 to 809 nm. Inset: the table with respective NSA geometrical parameters.
Mentions: As a result of spectrophotometric measurements, light extinction spectra of the samples in air atmosphere were obtained (Figure 3). It was found that the peak position in the unpolarized light extinction spectrum, which corresponds to the occurrence of LSPR, shifts towards longer wavelengths with an increase in the initial gold island film thickness (see Figure 3 and Table 1). Additionally, the direct relation between lateral dimensions and height of nanostructures produced after annealing and the initial gold island film thickness was revealed. Thus, it is possible to tune the LSPR spectral position in the wavelength range from 576 to 809 nm (see Figure 3), and the associated PE spectral profile, by changing the initial gold island film thickness. Obviously, considered PE nanochips fabrication technology based on gold island films with subsequent thermal annealing can be exploited while taking into account inherent technological limitations that hinder the preparation of geometrically ordered nanoparticle arrays.Figure 3

Bottom Line: Modelling of the optical response for nanostructures with typical shapes associated with these techniques (parallelepiped for NIL and semi-ellipsoid for annealed island films) was performed using finite-difference time-domain calculations.As an important point, the distribution of electric field at so-called 'hot spots' was considered.The application of island film thermal annealing method for nanochips fabrication can be considered as a possible cost-effective platform for various surface-enhanced spectroscopies; while the NIL-fabricated NSA looks like more effective for sensing of small-size objects.

View Article: PubMed Central - PubMed

Affiliation: Department of Functional Optoelectronics, V. E. Lashkaryov Institute of Semiconductor Physics NASU, 41 Nauki avenue, 03028 Kyiv, Ukraine.

ABSTRACT
This paper attempts to compare the main features of random and highly ordered gold nanostructure arrays (NSA) prepared by thermally annealed island film and nanoimprint lithography (NIL) techniques, respectively. Each substrate possesses different morphology in terms of plasmonic enhancement. Both methods allow such important features as spectral tuning of plasmon resonance position depending on size and shape of nanostructures; however, the time and cost is quite different. The respective comparison was performed experimentally and theoretically for a number of samples with different geometrical parameters. Spectral characteristics of fabricated NSA exhibited an expressed plasmon peak in the range from 576 to 809 nm for thermally annealed samples and from 606 to 783 nm for samples prepared by NIL. Modelling of the optical response for nanostructures with typical shapes associated with these techniques (parallelepiped for NIL and semi-ellipsoid for annealed island films) was performed using finite-difference time-domain calculations. Mathematical simulations have indicated the dependence of electric field enhancement on the shape and size of the nanoparticles. As an important point, the distribution of electric field at so-called 'hot spots' was considered. Parallelepiped-shaped nanoparticles were shown to yield maximal enhancement values by an order of magnitude greater than their semi-ellipsoid-shaped counterparts; however, both nanoparticle shapes have demonstrated comparable effective electrical field enhancement values. Optimized Au nanostructures with equivalent diameters ranging from 85 to 143 nm and height equal to 35 nm were obtained for both techniques, resulting in the largest electrical field enhancement. The application of island film thermal annealing method for nanochips fabrication can be considered as a possible cost-effective platform for various surface-enhanced spectroscopies; while the NIL-fabricated NSA looks like more effective for sensing of small-size objects.

No MeSH data available.


Related in: MedlinePlus