Large area arrays of metal nanowires

Auzelyté, Vaida; Solak, Harun H.; Ekinci, Yasin; MacKenzie, Robert; Vörös, János; Olliges, Sven; Spolenak, Ralph

doi:10.1016/j.mee.2008.01.064

Cited by 32 publications

(24 citation statements)

References 10 publications

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“…A similar process was previously used to obtain metal nanowire arrays. 17,18 However, sub-10 nm gap arrays with excellent homogeneity over large surfaces have not yet been reported. Gold and chromium, both of 99.99% purity, were deposited at angles a between 30 and 70 from the surface normal and with an azimuthal orientation perpendicular to the length of the nanowires (Fig.…”

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confidence: 99%

Fabrication of sub-10 nm gap arrays over large areas for plasmonic sensors

Siegfried

Ekinci

Solak³

et al. 2011

Applied Physics Letters

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We report a high-throughput method for the fabrication of metallic nanogap arrays with high-accuracy over large areas. This method, based on shadow evaporation and interference lithography, achieves sub-10 nm gap sizes with a high accuracy of 61.5 nm. Controlled fabrication is demonstrated over mm 2 areas and for periods of 250 nm. Experiments complemented with numerical simulations indicate that the formation of nanogaps is a robust, self-limiting process that can be applied to wafer-scale substrates. Surface-enhanced Raman scattering (SERS) experiments illustrate the potential for plasmonic sensing with an exceptionally low standard-deviation of the SERS signal below 3% and average enhancement factors exceeding 1 Â 10 6 . 1,2 This enhancement phenomenon relies on strongly confined electromagnetic fields generated by localized plasmons on metal nanostructures much smaller than the incident wavelength. 3,4 However, surface enhanced (SE) spectroscopic techniques are not yet routinely used at the industrial level. This is due to poor signal reproducibility, moderate average enhancement factors, and high costs. 5 To increase the signal enhancement, nanogap patterns are currently used: they produce extremely large electromagnetic fields for nano objects separated by a distance below 20 nm. 6 Local enhancement factors up to $10 9 have been reported with a one-dimensional (1D) nanogap pattern, 7 enabling single molecule detection. 8 The fabrication of nanogap arrays has been demonstrated with a variety of techniques. Electron-beam lithography (EBL) is used for direct writing 9 or patterning of shadow masks for angular evaporation. 10,11 With EBL, the pattern can be designed and realized with an exceptional degree of freedom. Due to proximity effects of the electron beam and limitations set by the photoresist liftoff, the resulting metal nanogap dimensions are limited to above roughly 10 nm and a metal layer thickness of below 30 nm. 9,12 The serial writing process of EBL makes this technique unfavorable for the fabrication of large area and low-cost sensors. Other lithography-based techniques have been used, including molecular rulers 13,14 or atomic layer deposition (ALD), 7 as effective methods to tune the nanogap size even below 2 nm. This, however, involves complicated multistep fabrication processes and produces local defects, which are found to cause fluctuations of the surface-enhanced Raman scattering (SERS) enhancement across the sensing area 7 or between different substrates.In this letter, we report the fabrication of homogeneous sub-10 nm gap arrays with high surface densities and over large areas. The fabrication scheme for our nanogap arrays consists of only two stages, lithography and metal layer deposition.In the first step, extreme ultraviolet interference lithography (EUV-IL) is used to provide a 1D line array on the substrate, which is typically float glass or silicon. Details of the EUV lithography, available at the Swiss Light Source, can be found elsewhere. 15 This technique provides high resolu...

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confidence: 99%

Fabrication of sub-10 nm gap arrays over large areas for plasmonic sensors

Siegfried

Ekinci

Solak³

et al. 2011

Applied Physics Letters

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“…Gold nanolines were produced on 125 m thick Kapton TM (polyimide) foil by extreme-ultra-violet interference lithography (EUV-IL) using the corresponding beamline at the Swiss Light Source (SLS) of the Paul Scherrer Institute in Villigen, Switzerland [22,23]. Patterns of parallel nanolines with a periodicity of 100 nm, about 40 nm width and 1 mm length were produced by exposure of PMMA/HSQ double layer photo resist by EUV interference patterns followed by etching of the photo resist layer.…”

Section: Methodsmentioning

confidence: 99%

Thermo mechanical properties and plastic deformation of gold nanolines and gold thin films

Olliges

Frank

Gruber

et al. 2011

Materials Science and Engineering: A

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“…This process was then optimized as further developments [123]. The PMMA/HSQ bilayer technique was further extended to broader applications [124][125][126][127], which is beyond the scope of this paper.…”

Section: Room Temperature Nanoimprint On Pmma/hsq For Metallic Chiralmentioning

confidence: 99%

Applications of nanoimprint lithography/hot embossing: a review

Chen

2015

Appl. Phys. A

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This review concentrates on the applications of nanoimprint lithography (NIL) and hot embossing for the fabrications of nanolectronic devices, nanophotonic metamaterials and other nanostructures. Technical challenges and solutions in NIL such as nanofabrication of templates, removal of residual resist, pattern displacement in thermal NIL arising from thermal expansion are first discussed. In the nanofabrication of templates, dry etch in plasma for the formation of multi-step structures and ultra-sharp tip arrays in silicon, nanophotonic chiral structures with high aspect ratio in SiC are demonstrated. A bilayer technique for nondestructive removal of residual resist in thermal NIL is described. This process is successfully applied for the fabrication of T-shape gates and functional high electron mobility transistors. However, pattern displacement intrinsically existing in thermal NIL/hot embossing owing to different thermal expansions in the template and substrate, respectively, limits its further development and scale-up. Low temperature even room temperature NIL (RTNIL) was then proposed on HSQ, trying to eliminate the pattern distortion by avoiding a thermal loop in the imprint. But, considerable pressure needed in RTNIL turned the major attentions to the development of UVcuring NIL in UV-curable monomers at low temperature. A big variety of applications by low-temperature UV-curing NIL in SU-8 are described, including high-aspect-ratio phase gratings, tagging technology by nanobarcode for DNA sequencing, nanofluidic channels, nanophotonic metamaterials and biosensors. Hot embossing, as a parallel technique to NIL, was also developed, and its applications on ferroelectric polymers as well as metals are reviewed. Therefore, it is necessary to emphasize that this review is mainly attempted to review the applications of NIL/embossing instead of NIL technique advances.

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Large area arrays of metal nanowires

Cited by 32 publications

References 10 publications

Fabrication of sub-10 nm gap arrays over large areas for plasmonic sensors

Fabrication of sub-10 nm gap arrays over large areas for plasmonic sensors

Thermo mechanical properties and plastic deformation of gold nanolines and gold thin films

Applications of nanoimprint lithography/hot embossing: a review

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