Staff directory
- ORCID: 0000-0002-6491-4763
Publications
2024
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Design and fabrication of an opto-mechanical antenna in the NIR range
Maram, Daniyal Khosh; Borris, Xavier; Garcia-Garcia, Joan; Ruiz, Raul; Cartoixa, Xavier; Abadal, Gabriel Micro And Nano Engineering; 23: 100241. 2024. 10.1016/j.mne.2024.100241.
2023
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Imaging of Antiferroelectric Dark Modes in an Inverted Plasmonic Lattice
Rodriguez-Alvarez, J; Labarta, A; Idrobo, JC; Dell'Anna, R; Cian, A; Giubertoni, D; Borrise, X; Guerrero, A; Perez-Murano, F; Rodriguez, AF; Batlle, X Acs Nano; 17 (9): 8123 - 8132. 2023. 10.1021/acsnano.2c11016. IF: 17.100
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In-plane thermal diffusivity determination using beam-offset frequency-domain thermoreflectance with a one-dimensional optical heat source
Xu, K; Guo, JL; Raciti, G; Goni, AR; Alonso, MI; Borrise, X; Zardo, I; Campoy-Quiles, M; Reparaz, JS International Journal Of Heat And Mass Transfer; 214: 124376. 2023. 10.1016/j.ijheatmasstransfer.2023.124376. IF: 5.200
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L-band Lithium Niobate-On-Insulator SH0 Resonators Avoiding Transverse Spurious Modes through Electrode Apodization
Acosta, L; Guerrero, E; Caballero, C; Verdú, J; Guerrero, A; Borrisé, X; Esteve, J; de Paco, P 2023 53rd European Microwave Conference, Eumc; : 287 - 290. 2023. 10.23919/EuMC58039.2023.10290237.
2021
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An inverted honeycomb plasmonic lattice as an efficient refractive index sensor
Rodríguez-álvarez J., Gnoatto L., Martínez-Castells M., Guerrero A., Borrisé X., Rodríguez A.F., Batlle X., Labarta A. Nanomaterials; 11 (5, 1217) 2021. 10.3390/nano11051217. IF: 5.076
We present an efficient refractive index sensor consisting of a heterostructure that contains an Au inverted honeycomb lattice as a main sensing element. Our design aims at maximizing the out-of-plane near-field distributions of the collective modes of the lattice mapping the sensor sur-roundings. These modes are further enhanced by a patterned SiO2 layer with the same inverted honeycomb lattice, an SiO2 spacer, and an Au mirror underneath the Au sensing layer that contrib-ute to achieving a high performance. The optical response of the heterostructure was studied by numerical simulation. The results corresponding to one of the collective modes showed high sensitivity values ranging from 99 to 395 nm/RIU for relatively thin layers of test materials within 50 and 200 nm. In addition, the figure of merit of the sensor detecting slight changes of the refractive index of a water medium at a fixed wavelength was as high as 199 RIU−1. As an experimental proof of concept, the heterostructure was manufactured by a simple method based on electron beam lithography and the measured optical response reproduces the simulations. This work paves the way for improving both the sensitivity of plasmonic sensors and the signal of some enhanced surface spec-troscopies. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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Decoupling the effects of defects on efficiency and stability through phosphonates in stable halide perovskite solar cells
Xie H., Wang Z., Chen Z., Pereyra C., Pols M., Gałkowski K., Anaya M., Fu S., Jia X., Tang P., Kubicki D.J., Agarwalla A., Kim H.-S., Prochowicz D., Borrisé X., Bonn M., Bao C., Sun X., Zakeeruddin S.M., Emsley L., Arbiol J., Gao F., Fu F., Wang H.I., Tielrooij K.-J., Stranks S.D., Tao S., Grätzel M., Hagfeldt A., Lira-Cantu M. Joule; 5 (5): 1246 - 1266. 2021. 10.1016/j.joule.2021.04.003. IF: 41.248
Understanding defects is of paramount importance for the development of stable halide perovskite solar cells (PSCs). However, isolating their distinctive effects on device efficiency and stability is currently a challenge. We report that adding the organic molecule 3-phosphonopropionic acid (H3pp) to the halide perovskite results in unchanged overall optoelectronic performance while having a tremendous effect on device stability. We obtained PSCs with ∼21% efficiency that retain ∼100% of the initial efficiency after 1,000 h at the maximum power point under simulated AM1.5G illumination. The strong interaction between the perovskite and the H3pp molecule through two types of hydrogen bonds (H…I and O…H) leads to shallow point defect passivation that has a significant effect on device stability but not on the non-radiative recombination and device efficiency. We expect that our work will have important implications for the current understanding and advancement of operational PSCs. © 2021 Elsevier Inc.
2020
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Plasmonic enhanced photodetectors for near infra-red light detection
Giubertoni D., Paternoster G., Acerbi F., Borrise X., Cian A., Filippi A., Gola A., Guerrero A., Murano F.P., Romanato F., Scattolo E., Bellutti P. 2020 43rd International Convention on Information, Communication and Electronic Technology, MIPRO 202; (9245437): 1876 - 1880. 2020. 10.23919/MIPRO48935.2020.9245437. IF: 0.000
Silicon based single photon avalanche diodes (SPAD) are able to detect single photons in the visible part of the spectrum with high detection efficiency and high timing resolution. They also provide both single-photon sensitivity and fast responsivity in large-area detectors if arranged in extended arrays as Silicon Photomultipliers (SiPM). However, in applications exploiting near infrared light like light detection and ranging (LiDAR), the detector performance is hindered by the limited Si absorption coefficient. The latter implies absorption depths much larger than the typical active thickness of these devices (10-100 μm against few micrometers) resulting in a quantum efficiency (QE) too low for most of the previous applications. The exploitation of Surface Plasmon Polaritrons (SPP) can convert light in highly-confined modes and enhance the absorption of NIR photons. In this contribution, the first results on the integration of plasmonics nanostructures on thin silicon photodiodes are reported. Electro-optical measurements were carried out and the QE has been measured in the full 400-1100 nm spectrum. The resulting QE on the first prototypes is higher than 7% at 950 nm, an enhancement of about 45% with respect to the reference structure, paving the way for the application of metallic nanograting to SPADs and SiPMs devices. © 2020 Croatian Society MIPRO.
2018
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Arrays of suspended silicon nanowires defined by ion beam implantation: Mechanical coupling and combination with CMOS technology
Llobet J., Rius G., Chuquitarqui A., Borrisé X., Koops R., Van Veghel M., Perez-Murano F. Nanotechnology; 29 (15, 155303) 2018. 10.1088/1361-6528/aaac67. IF: 3.404
We present the fabrication, operation, and CMOS integration of arrays of suspended silicon nanowires (SiNWs). The functional structures are obtained by a top-down fabrication approach consisting in a resistless process based on focused ion beam irradiation, causing local gallium implantation and silicon amorphization, plus selective silicon etching by tetramethylammonium hydroxide, and a thermal annealing process in a boron rich atmosphere. The last step enables the electrical functionality of the irradiated material. Doubly clamped silicon beams are fabricated by this method. The electrical readout of their mechanical response can be addressed by a frequency down-mixing detection technique thanks to an enhanced piezoresistive transduction mechanism. Three specific aspects are discussed: (i) the engineering of mechanically coupled SiNWs, by making use of the nanometer scale overhang that it is inherently-generated with this fabrication process, (ii) the statistical distribution of patterned lateral dimensions when fabricating large arrays of identical devices, and (iii) the compatibility of the patterning methodology with CMOS circuits. Our results suggest that the application of this method to the integration of large arrays of suspended SiNWs with CMOS circuitry is interesting in view of applications such as advanced radio frequency band pass filters and ultra-high-sensitivity mass sensors. © 2018 IOP Publishing Ltd.
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Design, fabrication, and characterisation of wire grid polarizers for the deep UV spectral range
Rodríguez-De Marcos L., Ong Bin L., Citra Asmara T., Heussler S.P., Guerrero A., Mas R., Borrise X., Breese M.B.H., Rusydi A. Proceedings of SPIE - The International Society for Optical Engineering; 10691 ( 1069124) 2018. 10.1117/12.2314459. IF: 0.000
In this communication, we show preliminary results on transmissive TiO2 wire-grid polarizers (WGP) operating in the deep ultraviolet (DUV) range. WGP are devices based on strips of materials with large values of the modulus of the dielectric constant along with high absorption in the operational range. The merit function I is introduced as a new tool to find the optimum material for WGPs in a given spectral range. The experimental dielectric constant of TiO2 thin films deposited by pulsed laser deposition are obtained through spectroscopic ellipsometry, and the function indicates that TiO2 is the best candidate for WGP in the DUV range when it is compared with other oxides. Once the material selection for WGP is done, we present and compare two different design approaches for WGP: one using an effective medium theory for the periodic structure, and the second using finite-difference time-domain (FDTD) analysis. A prototype of WGP is fabricated by electron beam (e-beam) lithography followed by lift-off process; the topography of the sample is analyzed by AFM, and we found noticeable deviations in the grating from the designed values. In preliminary characterization work the effective dielectric constant in two perpendicular orientations is obtained by ellipsometry and the contrast is compared with the design. © 2018 COPYRIGHT SPIE.
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Geometric frustration in a hexagonal lattice of plasmonic nanoelements
Conde-Rubio A., Rodríguez A.F., Borrisé X., Perez-Murano F., Batlle X., Labarta A. Optics Express; 26 (16): 20211 - 20224. 2018. 10.1364/OE.26.020211. IF: 3.356
We introduce the concept of geometric frustration in plasmonic arrays of nanoelements. In particular, we present the case of a hexagonal lattice of Au nanoasterisks arranged so that the gaps between neighboring elements are small and lead to a strong near-field dipolar coupling. Besides, far-field interactions yield higher-order collective modes around the visible region that follow the translational symmetry of the lattice. However, dipolar excitations of the gaps in the hexagonal array are geometrically frustrated for interactions beyond nearest neighbors, yielding the destabilization of the low energy modes in the near infrared. This in turn results in a slow dynamics of the optical response and a complex interplay between localized and collective modes, a behavior that shares features with geometrically frustrated magnetic systems. © 2018 Optical Society of America.
2017
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Metamirrors Based on Arrays of Silicon Nanowires with Height Gradients
Otte M.A., Garcia-Martin A., Borrise X., Sepulveda B. Advanced Optical Materials; 5 (4, 1600933) 2017. 10.1002/adom.201600933. IF: 6.875
[No abstract available]
2015
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Activity-tunable nanocomposites based on dissolution and in situ recrystallization of nanoparticles on ion exchange resins
Alonso A., Vigués N., Rodríguez-Rodríguez R., Borrisé X., Muñoz M., Muraviev D.N., Mas J., Muñoz-Berbel X. RSC Advances; 5 (109): 89971 - 89975. 2015. 10.1039/c5ra16081b. IF: 3.840
This work proposes the use of cationic ion exchange resins as a platform for in situ formation and recrystallization of nanoparticles as a way to dynamically modulate their activity by changing their structure/composition. Here applied to Ag@Co-nanoparticles in cationic resins, this protocol may be expanded to other materials, opening the possibility to modulate activity with a simple and economic approach. This journal is © The Royal Society of Chemistry 2015.
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Au cylindrical nanocup: A geometrically, tunable optical nanoresonator
Kovylina M., Alayo N., Conde-Rubio A., Borrisé X., Hibbard G., Labarta A., Batlle X., Pérez-Murano F. Applied Physics Letters; 107 (3, 033102) 2015. 10.1063/1.4927053. IF: 3.302
The optical response of Au cylindrical metallic nanostructures (nanocups) with very thin walls is studied by means of finite difference time domain simulations. The simulations predict that, by changing the geometry of the nanocups, they behave as tunable optical nanoresonators with strong near-field enhancement. This opens up the possibility to use them simultaneously as container and field enhancer. Nanocups have been produced by an on-purpose designed fabrication route that combines nanoimprint lithography, definition of an intermediate hard mask, and metal lift-off. The fabrication route offers a manifold of supplementary advantages: thorough control of geometrical parameters; versatility of compositional design, including multishell nanocups; precise positioning of nanocups over the substrate; and low-cost and fast manufacturing of large areas of desirable density without loss of resolution, all processes being compatible with high throughput, low cost production, thus enabling future commercial applications. © 2015 AIP Publishing LLC.
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Creation of guiding patterns for directed self-assembly of block copolymers by resistless direct e-beam exposure
Evangelio L., Fernandez-Regulez M., Borrise X., Lorenzoni M., Fraxedas J., Perez-Murano F. Proceedings of SPIE - The International Society for Optical Engineering; 9423 (942326) 2015. 10.1117/12.2085830. IF: 0.000
We present a novel approach for the creation of guiding patterns to direct the self-assembly of block copolymers. A neutral layer of a brush polymer is directly exposed by electrons, causing the cross-linking of the brush molecules, and thus changing its local affinity. The advantage relies on the achievable resolution and the reduction of the process steps in comparison with deep UV and conventional electron beam lithography, since it avoids the use of a resist. We envision that this method will be highly valuable for the investigation of novel high-chi DSA materials and complex guiding pattern designs, where pattern placement and resolution is becoming critical. © 2015 SPIE.
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Creation of guiding patterns for directed self-assembly of block copolymers by resistless direct e-beam exposure
Evangelio L., Fernández-Regúlez M., Borrisé X., Lorenzoni M., Fraxedas J., Pérez-Murano F. Journal of Micro/ Nanolithography, MEMS, and MOEMS; 14 (3, 033511) 2015. 10.1117/1.JMM.14.3.033511. IF: 1.428
We present an approach for the creation of guiding patterns to direct the self-assembly of block copolymers. A neutral layer of a brush polymer is directly exposed by electrons, causing the cross-linking of the brush molecules, and thus changing its local affinity. The advantage relies on the achievable resolution and the reduction of the process steps in comparison with deep UV and conventional electron beam lithography, since it avoids the use of a resist. We envision that this method will be highly valuable for the investigation of high-chi directed self-assembly materials and complex guiding pattern designs, where pattern placement and resolution are becoming critical. © 2015 Society of Photo-Optical Instrumentation Engineers (SPIE).
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Fabrication of functional electromechanical nanowire resonators by focused ion beam implantation
Llobet J., Gerbolés M., Sansa M., Bausells J., Borrisé X., Perez-Murano F. Journal of Micro/ Nanolithography, MEMS, and MOEMS; 14 (3, 15026SSP) 2015. 10.1117/1.JMM.14.3.031207. IF: 1.428
A fast and flexible fabrication method that allows the creation of silicon structures of various geometries is presented. It is based on the combination of focused ion beam local gallium implantation, selective silicon etching, and diffusive boron doping. The structures obtained by this resistless method are electrically conductive. Freely suspended mechanical resonators of different dimensions and geometries have been fabricated and measured. The resulting devices present a good electrical conductivity which allows the characterization of their high-frequency mechanical response by electrical read-out. © 2015 Society of Photo-Optical Instrumentation Engineers (SPIE).
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Manipulation of competing ferromagnetic and antiferromagnetic domains in exchange-biased nanostructures
Fraile Rodríguez A., Basaran A.C., Morales R., Kovylina M., Llobet J., Borrisé X., Marcus M.A., Scholl A., Schuller I.K., Batlle X., Labarta A. Physical Review B - Condensed Matter and Materials Physics; 92 (17, 174417) 2015. 10.1103/PhysRevB.92.174417. IF: 3.736
Using photoemission electron microscopy combined with x-ray magnetic circular dichroism we show that a progressive spatial confinement of a ferromagnet (FM), either through thickness variation or laterally via patterning, actively controls the domains of uncompensated spins in the antiferromagnet (AF) in exchange-biased systems. Direct observations of the spin structure in both sides of the FM/AF interface in a model system, Ni/FeF2, show that the spin structure is determined by the balance between the competing FM and AF magnetic energies. Coexistence of exchange bias domains, with opposite directions, can be established in Ni/FeF2 bilayers for Ni thicknesses below 10 nm. Patterning the Ni/FeF2 heterostructures with antidots destabilizes the FM state, enhancing the formation of opposite exchange bias domains below a critical antidot separation of the order of a few FeF2 crystal domains. The results suggest that dimensional confinement of the FM may be used to manipulate the AF spin structure in spintronic devices and ultrahigh-density information storage media. The underlying mechanism of the uncompensated AF domain formation in Ni/FeF2 may be generic to other magnetic systems with complex noncollinear FM/AF spin structures. ©2015 American Physical Society.
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Nanoparticles with tunable shape and composition fabricated by nanoimprint lithography
Alayo N., Conde-Rubio A., Bausells J., Borrisé X., Labarta A., Batlle X., Pérez-Murano F. Nanotechnology; 26 (44, 445302) 2015. 10.1088/0957-4484/26/44/445302. IF: 3.821
Cone-like and empty cup-shaped nanoparticles of noble metals have been demonstrated to provide extraordinary optical properties for use as optical nanoanntenas or nanoresonators. However, their large-scale production is difficult via standard nanofabrication methods. We present a fabrication approach to achieve arrays of nanoparticles with tunable shape and composition by a combination of nanoimprint lithography, hard-mask definition and various forms of metal deposition. In particular, we have obtained arrays of empty cup-shaped Au nanoparticles showing an optical response with distinguishable features associated with the excitations of localized surface plasmons. Finally, this route avoids the most common drawbacks found in the fabrication of nanoparticles by conventional top-down methods, such as aspect ratio limitation, blurring, and low throughput, and it can be used to fabricate nanoparticles with heterogeneous composition. © 2015 IOP Publishing Ltd.
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Tailored Height Gradients in Vertical Nanowire Arrays via Mechanical and Electronic Modulation of Metal-Assisted Chemical Etching
Otte M.A., Solis-Tinoco V., Prieto P., Borrisé X., Lechuga L.M., González M.U., Sepulveda B. Small; 11 (33): 4201 - 4208. 2015. 10.1002/smll.201500175. IF: 8.368
In current top-down nanofabrication methodologies the design freedom is generally constrained to the two lateral dimensions, and is only limited by the resolution of the employed nanolithographic technique. However, nanostructure height, which relies on certain mask-dependent material deposition or etching techniques, is usually uniform, and on-chip variation of this parameter is difficult and generally limited to very simple patterns. Herein, a novel nanofabrication methodology is presented, which enables the generation of high aspect-ratio nanostructure arrays with height gradients in arbitrary directions by a single and fast etching process. Based on metal-assisted chemical etching using a catalytic gold layer perforated with nanoholes, it is demonstrated how nanostructure arrays with directional height gradients can be accurately tailored by: (i) the control of the mass transport through the nanohole array, (ii) the mechanical properties of the perforated metal layer, and (iii) the conductive coupling to the surrounding gold film to accelerate the local electrochemical etching process. The proposed technique, enabling 20-fold on-chip variation of nanostructure height in a spatial range of a few micrometers, offers a new tool for the creation of novel types of nano-assemblies and metamaterials with interesting technological applications in fields such as nanophotonics, nanophononics, microfluidics or biomechanics. Based on metal-assisted chemical etching using a catalytic gold layer perforated with nanoholes, it is demonstrated how high aspect-ratio nanostructure arrays with directional height gradients can be accurately tailored by: i) control of mass transport through the nanohole array, ii) mechanical properties of the perforated metal layer, and iii) conductive coupling to the surrounding gold film to accelerate the local electrochemical etching process. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Tuning piezoresistive transduction in nanomechanical resonators by geometrical asymmetries
Llobet J., Sansa M., Lorenzoni M., Borrisé X., San Paulo A., Pérez-Murano F. Applied Physics Letters; 107 (7, 073104) 2015. 10.1063/1.4928709. IF: 3.302
The effect of geometrical asymmetries on the piezoresistive transduction in suspended double clamped beam nanomechanical resonators is investigated. Tapered silicon nano-beams, fabricated using a fast and flexible prototyping method, are employed to determine how the asymmetry affects the transduced piezoresistive signal for different mechanical resonant modes. This effect is attributed to the modulation of the strain in pre-strained double clamped beams, and it is confirmed by means of finite element simulations. © 2015 AIP Publishing LLC.
2014
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Determination of heterogeneous electron transfer rate constants at interdigitated nanoband electrodes fabricated by an optical mix-and-match process
Del Campo, F.J.; Abad, L.; Illa, X.; Prats-Alfonso, E.; Borrisé, X.; Cirera, J.M.; Bai, H.-Y.; Tsai, Y.-C. Sensors and Actuators, B: Chemical; 194: 86 - 95. 2014. 10.1016/j.snb.2013.12.016. IF: 3.840
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Enabling electromechanical transduction in silicon nanowire mechanical resonators fabricated by focused ion beam implantation
Llobet, J.; Sansa, M.; Gerbolés, M.; Mestres, N.; Arbiol, J.; Borrisé, X.; Pérez-Murano, F. Nanotechnology; 2014. 10.1088/0957-4484/25/13/135302. IF: 3.672