yasin ekinci | Swiss Federal Institute of Technology (ETH) (original) (raw)

Papers by yasin ekinci

Applied Physics Letters, 2009

We report on a simple and high-throughput method for the fabrication of gold and silver nanoparti... more We report on a simple and high-throughput method for the fabrication of gold and silver nanoparticle dimers with extremely small gaps and extending over large areas, using colloidal lithography and shadow thermal-evaporation techniques. The plasmon resonances of the individual dimers with various structural parameters were studied, as well as their coupling phenomena in the nearly touching regime. The method presented enables fabrication of efficient and low-cost plasmonics structures for applications such as surface-enhanced Raman scattering, plasmon-enhanced fluorescence, and biosensing.

Optics Letters, 2010

We report an experimental and theoretical study of the optical properties of two-dimensional arra... more We report an experimental and theoretical study of the optical properties of two-dimensional arrays of aluminum nanoparticle in-tandem pairs. Plasmon resonances and effective optical constants of these structures are investigated and strong magnetic response as well as negative permeability are observed down to 400 nm wavelength. Theoretical calculations based on the finite-difference time-domain method are performed for various particle dimensions and lattice parameters, and are found to be in good agreement with the experimental results. The results show that metamaterials operating across the whole visible wavelength range are feasible.

Nano Letters, 2008

We numerically study the effect of structural asymmetry in a plasmonic metamaterial made from gol... more We numerically study the effect of structural asymmetry in a plasmonic metamaterial made from gold nanowires. It is reported that optically inactive (i.e., optically dark) particle plasmon modes of the symmetric wire lattice are immediately coupled to the radiation field, when a broken structural symmetry is introduced. Such higher order plasmon resonances are characterized by their subradiant nature. They generally reveal long lifetimes and distinct absorption losses. It is shown that the near-field interaction strongly determines these modes.

Microelectronic Engineering, 2007

An evaluation of hydrogen silsesquioxane (HSQ) for EUV lithography is presented. The effects of b... more An evaluation of hydrogen silsesquioxane (HSQ) for EUV lithography is presented. The effects of bake temperature and developer concentration on the ultimate resolution, sensitivity and contrast are investigated. It is demonstrated that HSQ as a negative-tone photoresist provides patterns with half-pitches as small as 20 nm with EUV interference lithography. SEM micrographs show that the low line-edge roughness of the patterns is accompanied with the high-quality cross-sectional profiles. This high resolution and pattern quality are achieved through development in high-concentration developers for long development times, which is in line with previous results obtained with e-beam lithography.

In this paper the contrast behavior of photoresists upon EUV exposure is addressed. During a lith... more In this paper the contrast behavior of photoresists upon EUV exposure is addressed. During a lithographic exposure, the intended shape undergoes contrast loss which can be divided into two portions. One part is assigned to exposure tool induced contrast loss (e.g. aberrations of the exposure optics, mechanical stability of the system), while the other part is due to chemical processes in the resist during exposure and development. Both contributors have to be decoupled from each other in order to solely analyze the resist contrast loss. The method presented here is based on an experimental evaluation of dense line/space patterns obtained from EUV exposures. For decoupling of the resist induced contrast loss from the exposure tool contrast, the aerial image has to be determined. As an alternative EUV exposure tool the EUV interference lithography (EUV-IL) beamline at Paul Scherrer Institute is applied for resist qualification. The theoretical description of the sinusoidal aerial image of the EUV-IL tool is presented as well as the experimental method applied to analyze resist patterns in terms of resist contrast. Finally, the results are compared with data obtained from ASML's ADT EUV scanner.

Acta Materialia, 2007

Gold is an ideal material for wires and electrodes on the nanoscale because of its corrosion resi... more Gold is an ideal material for wires and electrodes on the nanoscale because of its corrosion resistance and biocompatibility. For system integration the mechanical properties of gold nanowires are highly important. In this paper, a study on the deformation behavior of parallel line arrays of gold on polyimide substrates is presented. Arrays of 45-60 nm nanolines were produced by extreme ultraviolet interference lithography, evaporation of gold and a subsequent lift-off process. Tensile testing of these samples was performed by using an in situ synchrotron-based technique, which allows for the fast acquisition of diffraction peaks. The samples show yield stresses of about 400 MPa. This is comparable to thin films of similar thickness, but significantly lower than previously reported results on single electrodeposited wires deformed in bending. The differences are explained in terms of strain gradient plasticity theory.

Optics Letters, 2007

We investigated the extraordinary optical transmission phenomenon in the UV range by fabricating ... more We investigated the extraordinary optical transmission phenomenon in the UV range by fabricating largearea, free-standing aluminum hole arrays using extreme UV interference lithography and shadow thermal evaporation. Transmission spectra show strong peaks in the UV region resulting from both surface plasmon polariton and localized surface plasmon excitations. The results indicate that the high plasmon frequency of Al is directly responsible for the presence of strong resonance peaks in the UV region, which supports the role of plasmonic phenomena in the extraordinary transmission. The simple fabrication method enables large-area production of such structures for research and industrial production purposes.

We report an experimental and theoretical study of the optical properties of two-dimensional arra... more We report an experimental and theoretical study of the optical properties of two-dimensional arrays of aluminum nanoparticle in-tandem pairs. Plasmon resonances and effective optical constants of these structures are investigated and strong magnetic response as well as negative permeability are observed down to 400 nm wavelength. Theoretical calculations based on the finite-difference time-domain method are performed for various particle dimensions and lattice parameters, and are found to be in good agreement with the experimental results. The results show that metamaterials operating across the whole visible wavelength range are feasible.

We study the fluorescence enhancement of a single emitter coupled to two spherical gold nanoparti... more We study the fluorescence enhancement of a single emitter coupled to two spherical gold nanoparticles and discuss the differences with respect to coupling to a single one. We also show that by changing the aspect ratio of the nanoparticles we can easily tune the plasmon-mediated enhancement from the infrared to the visible range. We present the fabrication of our nanoantennae by two alternative methods, namely X-ray interference lithography followed by focused ion beam milling and electron beam lithography. The manufactured structures are characterized individually by confocal microscopy.

Optics Letters, 2011

We fabricate computer generated holograms for the generation of phase singularities at extreme ul... more We fabricate computer generated holograms for the generation of phase singularities at extreme ultraviolet (EUV) wavelengths using electron beam lithography and demonstrate their ability to generate optical vortices in the nonzero diffraction orders. To this end, we observe the characteristic intensity distribution of the vortex beam and verify the helical phase structure interferometrically. The presented method forms the basis for further studies on singular light fields in the EUV frequency range, i.e., in EUV interference lithography. Since the method is purely achromatic, it may also find applications in various fields of x ray optics.

Nano Letters, 2007

Modern nanotechnology offers routes to create new artificial materials, widening the functionalit... more Modern nanotechnology offers routes to create new artificial materials, widening the functionality of devices in physics, chemistry, and biology. Templated self-organization has been recognized as a possible route to achieve exact positioning of quantum dots to create quantum dot arrays, molecules, and crystals. Here we employ extreme ultraviolet interference lithography (EUV-IL) at a wavelength of λ ) 13.5 nm for fast, large-area exposure of templates with perfect periodicity. Si(001) substrates have been patterned with two-dimensional hole arrays using EUV-IL and reactive ion etching. On these substrates, three-dimensionally ordered SiGe quantum dot crystals with the so far smallest quantum dot sizes and periods both in lateral and vertical directions have been grown by molecular beam epitaxy. X-ray diffractometry from a sample volume corresponding to about 3.6 × 10 7 dots and atomic force microscopy (AFM) reveal an up to now unmatched structural perfection of the quantum dot crystal and a narrow quantum dot size distribution. Intense interband photoluminescence has been observed up to room temperature, indicating a low defect density in the three-dimensional (3D) SiGe quantum dot crystals. Using the Ge concentration and dot shapes determined by X-ray and AFM measurements as input parameters for 3D band structure calculations, an excellent quantitative agreement between measured and calculated PL energies is obtained. The calculations show that the band structure of the 3D ordered quantum dot crystal is significantly modified by the artificial periodicity. A calculation of the variation of the eigenenergies based on the statistical variation in the dot dimensions as determined experimentally (±10% in linear dimensions) shows that the calculated electronic coupling between neighboring dots is not destroyed due to the quantum dot size variations. Thus, not only from a structural point of view but also with respect to the band structure, the 3D ordered quantum dots can be regarded as artificial crystal.

Microelectronic Engineering, 2008

Nearly defect-free arrays of several 10 4 gold dots of 12 ± 3 nm in diameter inside 10 nm deep ca... more Nearly defect-free arrays of several 10 4 gold dots of 12 ± 3 nm in diameter inside 10 nm deep cavities were fabricated for immobilization of proteins. Extreme ultraviolet interference lithography (EUV-IL) at the XIL-beamline of the Swiss Light Source was used to produce 140 nm period arrays of 50 nm holes in a 40 nm thick PMMA layer on oxidized silicon wafers. The size of the openings was reduced by glancing angle deposition (GLAD) of metals such as chromium and silver. Reactive ion etching of the underlying substrate, followed by deposition of a few nanometers of gold, lift-off and thermal annealing resulted in perfectly ordered arrays of small gold nanoparticles with well-defined size distribution. The combination of passivation of the silica surface with polyethylene glycol (PEG) derivatives and functionalization of gold with thiols enables the preparation of large area arrays of well separated functional protein molecules.

Nano Letters, 2008

We numerically study the effect of structural asymmetry in a plasmonic metamaterial made from gol... more We numerically study the effect of structural asymmetry in a plasmonic metamaterial made from gold nanowires. It is reported that optically inactive (i.e., optically dark) particle plasmon modes of the symmetric wire lattice are immediately coupled to the radiation field, when a broken structural symmetry is introduced. Such higher order plasmon resonances are characterized by their subradiant nature. They generally reveal long lifetimes and distinct absorption losses. It is shown that the near-field interaction strongly determines these modes.

Microelectronic Engineering, 2006

This paper describes extreme ultraviolet (EUV) resist screening results that have been obtained o... more This paper describes extreme ultraviolet (EUV) resist screening results that have been obtained on an interference printer at the Swiss Light Source. Imaging performance of a variety of chemically amplified resists has been studied. The main focus of the work has been on evaluating ultimate resolution and exposure latitudes of various materials and on improving their process parameters. The chemically amplified resists have also been compared with non-chemically amplified PMMA. The resolution of the latter is clearly superior to that of the chemically amplified materials. Below 40-35 nm half-pitch all chemically amplified materials at best show modulation in resist, a limitation that is attributed to acid diffusion. However, PMMA shows clean profiles on the interference printer down to about 20 nm.

Surface Science, 2007

Templated self-organization has been used to prepare two-dimensional arrays as well as three-dime... more Templated self-organization has been used to prepare two-dimensional arrays as well as three-dimensional quantum dot crystals (QDC) containing Ge dots in a Si host crystal. Si(1 0 0) substrates have been patterned with two-dimensional hole gratings using extreme ultra-violet interference lithography (EUV-IL) and reactive ion etching. The EUV-IL was realized by multiple beam diffraction using Cr gratings on SiN x membranes fabricated by e-beam lithography. Si/Ge overgrowth was performed by molecular beam epitaxy. The impact of the microscopic shape and size of the prepattern using the mask design and the EUV-IL exposure dose as parameters on the Ge dot nucleation has been studied with atomic force microscopy, transmission electron microscopy and photoluminescence measurements. Adjusting the growth parameters in multiple layer deposition the initial two-dimensional configuration was transferred into three-dimensional QDC.

Physical Review B, 2007

We analyze the influence of near-field coupling on the formation of collective plasmon modes in a... more We analyze the influence of near-field coupling on the formation of collective plasmon modes in a multilayer metallic nanowire array. It is shown that the spectral interference between super-and subradiant normal modes results in characteristic line shape modifications which are directly controlled by the spacing as well as the alignment of the stacked lattice planes. Moreover, a distinct near-field-induced reversal of particle plasmon hybridization is reported. Our numerical findings are in excellent agreement with experimental results.

We study the formation of complex pattern geometries and beam shapes in diffraction-based extreme... more We study the formation of complex pattern geometries and beam shapes in diffraction-based extreme ultraviolet interference lithography. In particular, we demonstrate numerically as well as experimentally the potential of interfering multiple beams with well-controlled relative phase relations for the fabrication of high resolution periodic and quasiperiodic nanostructures.

Journal of Photopolymer Science and Technology, 2006

... From this study, it was concluded that the differences in profiles between MET and PSI are ca... more ... From this study, it was concluded that the differences in profiles between MET and PSI are caused by the combined effect of different ... We would like to thank Koen Van Ingen-Schenau (ASML), Cyril Vannuffel and Amandine Jouve (CEA-Leti) for the joint experiments and many ...

Optics Express, 2006

We have fabricated, characterized and theoretically analyzed the performance of bilayer (or stack... more We have fabricated, characterized and theoretically analyzed the performance of bilayer (or stacked) metallic wire-grids. The samples with 100 nm period were fabricated with extreme-ultraviolet interference lithography. Transmission efficiency over 50% and extinction ratios higher than 40 dB were measured in the visible range with these devices. Simulations using a finite-difference time-domain algorithm are in agreement with the experimental results and show that the transmission spectra are governed by Fabry-Perot interference and near-field coupling between the two layers of the structure. The simple fabrication method involves only a single lithographic step without any etching and guarantees precise alignment and separation of the two wire-grids with respect to each other.

Scripta Materialia, 2008

... Thumbnails - selected | Full-Size images. Thumbnails - selected | Full-Size images. Article. ... more ... Thumbnails - selected | Full-Size images. Thumbnails - selected | Full-Size images. Article. Article - selected. ... The grain size of the lines was found to be in the range of 20–30 nm [8]. Details of the fabrication procedure are described in Ref. [10]. ...

Applied Physics Letters, 2009

We report on a simple and high-throughput method for the fabrication of gold and silver nanoparti... more We report on a simple and high-throughput method for the fabrication of gold and silver nanoparticle dimers with extremely small gaps and extending over large areas, using colloidal lithography and shadow thermal-evaporation techniques. The plasmon resonances of the individual dimers with various structural parameters were studied, as well as their coupling phenomena in the nearly touching regime. The method presented enables fabrication of efficient and low-cost plasmonics structures for applications such as surface-enhanced Raman scattering, plasmon-enhanced fluorescence, and biosensing.

Optics Letters, 2010

We report an experimental and theoretical study of the optical properties of two-dimensional arra... more We report an experimental and theoretical study of the optical properties of two-dimensional arrays of aluminum nanoparticle in-tandem pairs. Plasmon resonances and effective optical constants of these structures are investigated and strong magnetic response as well as negative permeability are observed down to 400 nm wavelength. Theoretical calculations based on the finite-difference time-domain method are performed for various particle dimensions and lattice parameters, and are found to be in good agreement with the experimental results. The results show that metamaterials operating across the whole visible wavelength range are feasible.

Nano Letters, 2008

We numerically study the effect of structural asymmetry in a plasmonic metamaterial made from gol... more We numerically study the effect of structural asymmetry in a plasmonic metamaterial made from gold nanowires. It is reported that optically inactive (i.e., optically dark) particle plasmon modes of the symmetric wire lattice are immediately coupled to the radiation field, when a broken structural symmetry is introduced. Such higher order plasmon resonances are characterized by their subradiant nature. They generally reveal long lifetimes and distinct absorption losses. It is shown that the near-field interaction strongly determines these modes.

Microelectronic Engineering, 2007

An evaluation of hydrogen silsesquioxane (HSQ) for EUV lithography is presented. The effects of b... more An evaluation of hydrogen silsesquioxane (HSQ) for EUV lithography is presented. The effects of bake temperature and developer concentration on the ultimate resolution, sensitivity and contrast are investigated. It is demonstrated that HSQ as a negative-tone photoresist provides patterns with half-pitches as small as 20 nm with EUV interference lithography. SEM micrographs show that the low line-edge roughness of the patterns is accompanied with the high-quality cross-sectional profiles. This high resolution and pattern quality are achieved through development in high-concentration developers for long development times, which is in line with previous results obtained with e-beam lithography.

In this paper the contrast behavior of photoresists upon EUV exposure is addressed. During a lith... more In this paper the contrast behavior of photoresists upon EUV exposure is addressed. During a lithographic exposure, the intended shape undergoes contrast loss which can be divided into two portions. One part is assigned to exposure tool induced contrast loss (e.g. aberrations of the exposure optics, mechanical stability of the system), while the other part is due to chemical processes in the resist during exposure and development. Both contributors have to be decoupled from each other in order to solely analyze the resist contrast loss. The method presented here is based on an experimental evaluation of dense line/space patterns obtained from EUV exposures. For decoupling of the resist induced contrast loss from the exposure tool contrast, the aerial image has to be determined. As an alternative EUV exposure tool the EUV interference lithography (EUV-IL) beamline at Paul Scherrer Institute is applied for resist qualification. The theoretical description of the sinusoidal aerial image of the EUV-IL tool is presented as well as the experimental method applied to analyze resist patterns in terms of resist contrast. Finally, the results are compared with data obtained from ASML's ADT EUV scanner.

Acta Materialia, 2007

Gold is an ideal material for wires and electrodes on the nanoscale because of its corrosion resi... more Gold is an ideal material for wires and electrodes on the nanoscale because of its corrosion resistance and biocompatibility. For system integration the mechanical properties of gold nanowires are highly important. In this paper, a study on the deformation behavior of parallel line arrays of gold on polyimide substrates is presented. Arrays of 45-60 nm nanolines were produced by extreme ultraviolet interference lithography, evaporation of gold and a subsequent lift-off process. Tensile testing of these samples was performed by using an in situ synchrotron-based technique, which allows for the fast acquisition of diffraction peaks. The samples show yield stresses of about 400 MPa. This is comparable to thin films of similar thickness, but significantly lower than previously reported results on single electrodeposited wires deformed in bending. The differences are explained in terms of strain gradient plasticity theory.

Optics Letters, 2007

We investigated the extraordinary optical transmission phenomenon in the UV range by fabricating ... more We investigated the extraordinary optical transmission phenomenon in the UV range by fabricating largearea, free-standing aluminum hole arrays using extreme UV interference lithography and shadow thermal evaporation. Transmission spectra show strong peaks in the UV region resulting from both surface plasmon polariton and localized surface plasmon excitations. The results indicate that the high plasmon frequency of Al is directly responsible for the presence of strong resonance peaks in the UV region, which supports the role of plasmonic phenomena in the extraordinary transmission. The simple fabrication method enables large-area production of such structures for research and industrial production purposes.

We report an experimental and theoretical study of the optical properties of two-dimensional arra... more We report an experimental and theoretical study of the optical properties of two-dimensional arrays of aluminum nanoparticle in-tandem pairs. Plasmon resonances and effective optical constants of these structures are investigated and strong magnetic response as well as negative permeability are observed down to 400 nm wavelength. Theoretical calculations based on the finite-difference time-domain method are performed for various particle dimensions and lattice parameters, and are found to be in good agreement with the experimental results. The results show that metamaterials operating across the whole visible wavelength range are feasible.

We study the fluorescence enhancement of a single emitter coupled to two spherical gold nanoparti... more We study the fluorescence enhancement of a single emitter coupled to two spherical gold nanoparticles and discuss the differences with respect to coupling to a single one. We also show that by changing the aspect ratio of the nanoparticles we can easily tune the plasmon-mediated enhancement from the infrared to the visible range. We present the fabrication of our nanoantennae by two alternative methods, namely X-ray interference lithography followed by focused ion beam milling and electron beam lithography. The manufactured structures are characterized individually by confocal microscopy.

Optics Letters, 2011

We fabricate computer generated holograms for the generation of phase singularities at extreme ul... more We fabricate computer generated holograms for the generation of phase singularities at extreme ultraviolet (EUV) wavelengths using electron beam lithography and demonstrate their ability to generate optical vortices in the nonzero diffraction orders. To this end, we observe the characteristic intensity distribution of the vortex beam and verify the helical phase structure interferometrically. The presented method forms the basis for further studies on singular light fields in the EUV frequency range, i.e., in EUV interference lithography. Since the method is purely achromatic, it may also find applications in various fields of x ray optics.

Nano Letters, 2007

Modern nanotechnology offers routes to create new artificial materials, widening the functionalit... more Modern nanotechnology offers routes to create new artificial materials, widening the functionality of devices in physics, chemistry, and biology. Templated self-organization has been recognized as a possible route to achieve exact positioning of quantum dots to create quantum dot arrays, molecules, and crystals. Here we employ extreme ultraviolet interference lithography (EUV-IL) at a wavelength of λ ) 13.5 nm for fast, large-area exposure of templates with perfect periodicity. Si(001) substrates have been patterned with two-dimensional hole arrays using EUV-IL and reactive ion etching. On these substrates, three-dimensionally ordered SiGe quantum dot crystals with the so far smallest quantum dot sizes and periods both in lateral and vertical directions have been grown by molecular beam epitaxy. X-ray diffractometry from a sample volume corresponding to about 3.6 × 10 7 dots and atomic force microscopy (AFM) reveal an up to now unmatched structural perfection of the quantum dot crystal and a narrow quantum dot size distribution. Intense interband photoluminescence has been observed up to room temperature, indicating a low defect density in the three-dimensional (3D) SiGe quantum dot crystals. Using the Ge concentration and dot shapes determined by X-ray and AFM measurements as input parameters for 3D band structure calculations, an excellent quantitative agreement between measured and calculated PL energies is obtained. The calculations show that the band structure of the 3D ordered quantum dot crystal is significantly modified by the artificial periodicity. A calculation of the variation of the eigenenergies based on the statistical variation in the dot dimensions as determined experimentally (±10% in linear dimensions) shows that the calculated electronic coupling between neighboring dots is not destroyed due to the quantum dot size variations. Thus, not only from a structural point of view but also with respect to the band structure, the 3D ordered quantum dots can be regarded as artificial crystal.

Microelectronic Engineering, 2008

Nearly defect-free arrays of several 10 4 gold dots of 12 ± 3 nm in diameter inside 10 nm deep ca... more Nearly defect-free arrays of several 10 4 gold dots of 12 ± 3 nm in diameter inside 10 nm deep cavities were fabricated for immobilization of proteins. Extreme ultraviolet interference lithography (EUV-IL) at the XIL-beamline of the Swiss Light Source was used to produce 140 nm period arrays of 50 nm holes in a 40 nm thick PMMA layer on oxidized silicon wafers. The size of the openings was reduced by glancing angle deposition (GLAD) of metals such as chromium and silver. Reactive ion etching of the underlying substrate, followed by deposition of a few nanometers of gold, lift-off and thermal annealing resulted in perfectly ordered arrays of small gold nanoparticles with well-defined size distribution. The combination of passivation of the silica surface with polyethylene glycol (PEG) derivatives and functionalization of gold with thiols enables the preparation of large area arrays of well separated functional protein molecules.

Nano Letters, 2008

We numerically study the effect of structural asymmetry in a plasmonic metamaterial made from gol... more We numerically study the effect of structural asymmetry in a plasmonic metamaterial made from gold nanowires. It is reported that optically inactive (i.e., optically dark) particle plasmon modes of the symmetric wire lattice are immediately coupled to the radiation field, when a broken structural symmetry is introduced. Such higher order plasmon resonances are characterized by their subradiant nature. They generally reveal long lifetimes and distinct absorption losses. It is shown that the near-field interaction strongly determines these modes.

Microelectronic Engineering, 2006

This paper describes extreme ultraviolet (EUV) resist screening results that have been obtained o... more This paper describes extreme ultraviolet (EUV) resist screening results that have been obtained on an interference printer at the Swiss Light Source. Imaging performance of a variety of chemically amplified resists has been studied. The main focus of the work has been on evaluating ultimate resolution and exposure latitudes of various materials and on improving their process parameters. The chemically amplified resists have also been compared with non-chemically amplified PMMA. The resolution of the latter is clearly superior to that of the chemically amplified materials. Below 40-35 nm half-pitch all chemically amplified materials at best show modulation in resist, a limitation that is attributed to acid diffusion. However, PMMA shows clean profiles on the interference printer down to about 20 nm.

Surface Science, 2007

Templated self-organization has been used to prepare two-dimensional arrays as well as three-dime... more Templated self-organization has been used to prepare two-dimensional arrays as well as three-dimensional quantum dot crystals (QDC) containing Ge dots in a Si host crystal. Si(1 0 0) substrates have been patterned with two-dimensional hole gratings using extreme ultra-violet interference lithography (EUV-IL) and reactive ion etching. The EUV-IL was realized by multiple beam diffraction using Cr gratings on SiN x membranes fabricated by e-beam lithography. Si/Ge overgrowth was performed by molecular beam epitaxy. The impact of the microscopic shape and size of the prepattern using the mask design and the EUV-IL exposure dose as parameters on the Ge dot nucleation has been studied with atomic force microscopy, transmission electron microscopy and photoluminescence measurements. Adjusting the growth parameters in multiple layer deposition the initial two-dimensional configuration was transferred into three-dimensional QDC.

Physical Review B, 2007

We analyze the influence of near-field coupling on the formation of collective plasmon modes in a... more We analyze the influence of near-field coupling on the formation of collective plasmon modes in a multilayer metallic nanowire array. It is shown that the spectral interference between super-and subradiant normal modes results in characteristic line shape modifications which are directly controlled by the spacing as well as the alignment of the stacked lattice planes. Moreover, a distinct near-field-induced reversal of particle plasmon hybridization is reported. Our numerical findings are in excellent agreement with experimental results.

We study the formation of complex pattern geometries and beam shapes in diffraction-based extreme... more We study the formation of complex pattern geometries and beam shapes in diffraction-based extreme ultraviolet interference lithography. In particular, we demonstrate numerically as well as experimentally the potential of interfering multiple beams with well-controlled relative phase relations for the fabrication of high resolution periodic and quasiperiodic nanostructures.

Journal of Photopolymer Science and Technology, 2006

... From this study, it was concluded that the differences in profiles between MET and PSI are ca... more ... From this study, it was concluded that the differences in profiles between MET and PSI are caused by the combined effect of different ... We would like to thank Koen Van Ingen-Schenau (ASML), Cyril Vannuffel and Amandine Jouve (CEA-Leti) for the joint experiments and many ...

Optics Express, 2006

We have fabricated, characterized and theoretically analyzed the performance of bilayer (or stack... more We have fabricated, characterized and theoretically analyzed the performance of bilayer (or stacked) metallic wire-grids. The samples with 100 nm period were fabricated with extreme-ultraviolet interference lithography. Transmission efficiency over 50% and extinction ratios higher than 40 dB were measured in the visible range with these devices. Simulations using a finite-difference time-domain algorithm are in agreement with the experimental results and show that the transmission spectra are governed by Fabry-Perot interference and near-field coupling between the two layers of the structure. The simple fabrication method involves only a single lithographic step without any etching and guarantees precise alignment and separation of the two wire-grids with respect to each other.

Scripta Materialia, 2008

... Thumbnails - selected | Full-Size images. Thumbnails - selected | Full-Size images. Article. ... more ... Thumbnails - selected | Full-Size images. Thumbnails - selected | Full-Size images. Article. Article - selected. ... The grain size of the lines was found to be in the range of 20–30 nm [8]. Details of the fabrication procedure are described in Ref. [10]. ...