Design, fabrication and characterization of porous silicon multilayer optical devices

Thesis: DESIGN, FABRICATION AND CHARACTERIZATION OF POROUS SILICON MULTILAYER OPTICAL DEVICESAuthor: Elisabet Xifré PérezDirectors: Lluís F. Marsal Garví i Josep Pallarès Marzal Aquesta tesi està centrada en el disseny i fabricació de dispositius òptics multicapa realitzats en silici porós. El silici porós és un material dielèctric que s'obté amb l'atac electroquímic del silici mitjançant solucions d'àcid fluorhídric. Aquest material té unes excel·lents propietats mecàniques i tèrmiques i és totalment compatible amb la tecnologia del silici. És un material molt adient per a la fabricació de multicapes ja que l'índex de refracció i el gruix de cadascuna de les capes que les formen es determinen durant el procés de fabricació. Escollint de forma adient aquests dos paràmetres de les capes, es poden fabricar diferents dispositius òptics. Per a assolir el principal objectiu d'aquesta tesi que és la fabricació de dispositius òptics multicapa de silici porós per aplicacions en el camp de les telecomunicacions s'han realitzat els següents passos. En primer lloc s'han realitzat programes de simulació per a l'estudi teòric del comportament òptic de les multicapes. Amb aquests programes s'ha realitzat l'estudi i el disseny de diversos dispositius òptics: Distributed Bragg Reflectors, microcavitats, miralls omnidireccionals i guies d'ona tant basades en reflexió total interna com basades en les propietats dels cristalls fotònics. Una vegada simulats i dissenyats, aquests dispositius òptics de silici porós s'han fabricat. S'ha posat en marxa un sistema complert de fabricació de silici porós i s'ha realitzat la seva calibració. Amb aquest sistema s'han fabricat monocapes i multicapes de silici porós que s'han caracteritzat física i òpticament mitjançant diversos mètodes: SEM, espectroscopia FTIR i el·lipsometria espectroscòpica. Un d'aquests mètodes de caracterització, l'el·lipsometria, s'ha dut a terme durant una estada predoctoral de tres mesos a l'Ecole Polytechnique de Paris. Aquest mètode es diferencia de tots els altres utilitzats en que ha permès analitzar l'anisotropia de les capes en funció de la porositat. Tots aquests passos han estat necessaris per assolir l'objectiu final d'aquesta tesi que és la fabricació de dispositius òptics multicapa. Els dispositius de silici porós fabricats han estat Distributed Bragg Reflectors, microcavitats (amb aplicacions de sensor d'humitat) i miralls omnidireccionals amb estructures diferents a les utilitzades fins ara que optimitzen les seves característiques òptiques. Les aportacions científiques del treball desenvolupat durant la realització d'aquesta tesi han estat: - el disseny i desenvolupament de noves estructures multicapa que permeten obtenir miralls omnidireccionals amb una amplada de banda omnidireccional independent de les limitacions que fins ara presentava el material i amb una baixa complexitat de fabricació.- la fabricació d'aquestes estructures mirall el que implica la introducció de les multicapes de silici porós en aplicacions làsers i de guies d'ona- el disseny i anàlisi de guies d'ona basades en cristalls fotònics (miralls omnidireccionals).- la introducció de multicapes de silici porós com a sensors òptics d'humitat.- la creació de programes de simulació de multicapes que són utilitzats actualment pel grup NePhos- la posta en marxa i calibració d'un sistema de fabricació de silici porós al Departament d'Enginyeria Electrònica, Elèctrica i Automàtica (DEEEA), que serà utilitzat en un futur pròxim per a realitzar el treball de nous doctorands sobre noves aplicacions del silici porós, - l'anàlisi el·lipsomètric de multicapes de silici porós iniciant les relacions entre el DEEEA i el LPICM de l'Ecole Polytechnique de París. Aquest anàlisi ha determinat el comportament anisotròpic del silici porós i iniciant una nova línia de simulació de multicapes de materials anisòtrops. Del treball desenvolupat durant la tesi s'han realitzat 7 publicacions a revistes internacionals, 7 comunicacions a congressos internacionals i 6 comunicacions a congressos nacionals. Cal destacar que una part del treball realitzat s'ha dut a terme durant una estada de tres mesos a la Universitat Ecole Polytechnique (Palaiseau, Paris) de França. Thesis: DESIGN, FABRICATION AND CHARACTERIZATION OF POROUS SILICON MULTILAYER OPTICAL DEVICESAuthor: Elisabet Xifré PérezDirectors: Lluís F. Marsal Garví i Josep Pallarès Marzal This thesis is focused on the design and fabrication of multilayer optical devices based on porous silicon. Porous silicon is a dielectric material obtained with the electrochemical etching of silicon with hydrofluoric acid solutions. This material has excellent mechanical and thermal properties and is completely compatible with the well-established silicon technology. It is a very suitable material for the fabrication of multilayers because the refractive index and the thickness of each of the layers of the multilayer are determined during the fabrication process. Selecting, in an appropriate way, these two parameters of the layers different optical devices can be fabricated. In order to achieve the main objective of this thesis that is the fabrication of multilayer optical devices made of porous silicon, different steps have been realized. Firstly, different simulation programs have been developed to theoretically study the optical behavior of the multilayers. With these simulation programs, it has been realized the study and design of different optical devices: Distributed Bragg Reflectors, microcavities, omnidirectional mirrors, and waveguides not only based on total internal reflection but also based on the photonic crystal properties. Once simulated and designed, these porous silicon multilayer devices have been fabricated. For this purpose, a fabrication system has been established and calibrated and several porous silicon monolayers and multilayers have been fabricated. These fabricated layers have been characterized to determine their physical and optical properties using different methods: SEM, FTIR spectrometry, and spectroscopic ellipsometry. One of these methods, the ellipsometry, has been carried out during a three-month predoctoral stage at the Ecole Polytechnique in Paris. This method has allowed the analysis of the anisotropy of the porous silicon layers. All these steps were necessary to achieve our main and final objective: the fabrication of porous silicon multilayer optical devices. The optical devices fabricated with porous silicon multilayers are Distributed Bragg Reflectors, microcavities (with applications as humidity sensors) and omnidireccional mirrors with structures different to the ones used until this moment that optimize their optical characteristics. The scientific contributions derived from the work realized during this thesis are: - the design and development of new multilayer structures that permitted to obtain omnidirectional mirrors with a low fabrication complexity and with an omnidirectional bandgap width independent of the limitations that the material presented until this moment.- the fabrication of these mirror structures that introduces porous silicon multilayers for laser applications and waveguides.- the design and analysis of waveguides based on the photonic crystals properties (omnidirectional mirrors).- the introduction of porous silicon multilayers for humidity sensors applications.- the creation of programs for the simulation of multilayers, that are used nowadays by the NePhos group.- the establishment and calibration of a porous silicon fabrication system at the Departament d'Enginyeria Electrònica, Elèctrica i Automàtica (DEEEA), that will be used in a near future by new doctoral students for new applications of porous silicon. - the ellipsometric analysis of porous silicon multilayers beginning the relations between the DEEEA and the LPICM at the Ecole Polytechnique in Paris. This analysis has determined the anisotropic behavior of porous silicon and started a new simulation line of multilayers with anisotropic materials. From the work realized during this thesis 7 publications in international journals, 7 communications to international conferences and 6 communications to national conferences have been realized. It is worth to emphasize that one part of the work has been realized during a stage at the Ecole Polytechnique (Palaiseau, Paris) in France

All silicon waveguide spherical microcavity coupler device

[EN] This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/ 10.1364/OE.19.003185. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawA coupler based on silicon spherical microcavities coupled to silicon waveguides for telecom wavelengths is presented. The light scattered by the microcavity is detected and analyzed as a function of the wavelength. The transmittance signal through the waveguide is strongly attenuated (up to 25 dB) at wavelengths corresponding to the Mie resonances of the microcavity. The coupling between the microcavity and the waveguide is experimentally demonstrated and theoretically modeled with the help of FDTD calculations. © 2011 Optical Society of America.The authors wish to acknowledge financial support from projects FIS2009-07812; Consolider Nanolight.es 2007/0046 and Nº 1841; the Spanish Education and Science Ministry, TEC2008- 06145; the Generalitat Valenciana, project PROMETEO/2008/092 and PROMETEO/2010/043; and project Apoyo a la investigación 2009 from Universidad Politecnica de Valencia, nº reg. 4325. E. Xifré-Pérez acknowledges the financial support from the program Juan de la Cierva (Spanish Ministerio de Educación y Ciencia). J. D. Doménech acknowledges the FPI research grant BES-2009-018381. Finally we thank Prof. J. Garcia de Abajo for providing us with the MESME theoretical program we have used in the calculation of electric field intensity distribution of the Mie modes.Xifre Perez, E.; Doménech Gómez, JD.; Fenollosa Esteve, R.; Muñoz Muñoz, P.; Capmany Francoy, J.; Meseguer Rico, FJ. (2011). All silicon waveguide spherical microcavity coupler device. Optics Express. 19(4):3185-3192. https://doi.org/10.1364/OE.19.003185S31853192194Cai, M., Painter, O., Vahala, K. J., & Sercel, P. C. (2000). Fiber-coupled microsphere laser. Optics Letters, 25(19), 1430. doi:10.1364/ol.25.001430Knight, J. C., Dubreuil, N., Sandoghdar, V., Hare, J., Lefèvre-Seguin, V., Raimond, J. M., & Haroche, S. (1995). Mapping whispering-gallery modes in microspheres with a near-field probe. Optics Letters, 20(14), 1515. doi:10.1364/ol.20.001515Lefèvre-Seguin, V., & Haroche, S. (1997). Towards cavity-QED experiments with silica microspheres. 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O., Demir, A., Kurt, A., & Serpenguzel, A. (2005). Optical channel dropping with a silicon microsphere. IEEE Photonics Technology Letters, 17(8), 1662-1664. doi:10.1109/lpt.2005.850896Almeida, V. R., Barrios, C. A., Panepucci, R. R., & Lipson, M. (2004). All-optical control of light on a silicon chip. Nature, 431(7012), 1081-1084. doi:10.1038/nature02921Noda, S., Chutinan, A., & Imada, M. (2000). Trapping and emission of photons by a single defect in a photonic bandgap structure. Nature, 407(6804), 608-610. doi:10.1038/35036532Fenollosa, R., Meseguer, F., & Tymczenko, M. (2008). Silicon Colloids: From Microcavities to Photonic Sponges. Advanced Materials, 20(1), 95-98. doi:10.1002/adma.200701589Xifré-Pérez, E., García de Abajo, F. J., Fenollosa, R., & Meseguer, F. (2009). Photonic Binding in Silicon-Colloid Microcavities. Physical Review Letters, 103(10). doi:10.1103/physrevlett.103.103902Conwell, P. R., Barber, P. W., & Rushforth, C. K. (1984). Resonant spectra of dielectric spheres. 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Dielectric nanoantenna as an efficient and ultracompact demultiplexer for surface waves

Nanoantennas for highly efficient excitation and manipulation of surface waves at nanoscale are key elements of compact photonic circuits. However, previously implemented designs employ plasmonic nanoantennas with high Ohmic losses, relatively low spectral resolution, and complicated lithographically made architectures. Here we propose an ultracompact and simple dielectric nanoantenna (silicon nanosphere) allowing for both directional launching of surface plasmon polaritons on a thin gold film and their demultiplexing with a high spectral resolution. We show experimentally that mutual interference of magnetic and electric dipole moments supported by the dielectric nanoantenna results in opposite propagation of the excited surface waves whose wavelengths differ by less than 50 nm in the optical range. Broadband reconfigurability of the nanoantennas operational range is achieved simply by varying the diameter of the silicon sphere. Moreover, despite subwavelength size ($<\lambda/3$) of the proposed nanoantennas, they demonstrate highly efficient and directional launching of surface waves both in the forward and backward directions with the measured front-to-back ratio having a contrast of almost two orders of magnitude within a 50 nm spectral band. Our lithography-free design has great potential as highly efficient, low-cost, and ultracompact demultiplexer for advanced photonic circuits.Comment: added relevant references; fixed typos in Supplementary eq. 8,9,1

Medically Biodegradable Hydrogenated Amorphous Silicon Microspheres

[EN] Hydrogenated amorphous silicon colloids of low surface area (<5 m(2)/g) are shown to exhibit complete in-vitro biodegradation into orthosilicic acid within 10-15 days at 37 degrees C. When converted into polycrystalline silicon colloids, by high temperature annealing in an inert atmosphere, microparticle solubility is dramatically reduced. The data suggests that amorphous silicon does not require nanoscale porosification for full in-vivo biodegradability. This has significant implications for using a-Si:H coatings for medical implants in general, and orthopedic implants in particular. The high sphericity and biodegradability of submicron particles may also confer advantages with regards to contrast agents for medical imaging.This work has been partially supported by the Spanish CICyT projects, FIS2009-07812, Consolider CSD2007-046, MAT2009-010350 and PROMETEO/2010/043.Shabir, Q.; Pokale, A.; Loni, A.; Johnson, DR.; Canham, L.; Fenollosa Esteve, R.; Tymczenko, MK.... (2011). Medically Biodegradable Hydrogenated Amorphous Silicon Microspheres. Silicon. 3(4):173-176. https://doi.org/10.1007/s12633-011-9097-4S17317634Salonen J, Kaukonen AM, Hirvonen J, Lehto VP (2008) J Pharmaceutics 97:632–53Anglin EJ, Cheng L, Freeman WR, Sailor MJ (2008) Adv Drug Deliv Rev 60:1266–77O’Farrell N, Houlton A, Horrocks BR (2006) Int J Nanomedicine 1:451–72Canham LT (1995) Adv Mater 7:1037, PCT patent WO 97/06101,1999Park JH, Gui L, Malzahn G, Ruoslahti E, Bhatia SN, Sailor MJ (2009) Nature Mater 8:331–6Cullis AG, Canham LT, Calcott PDJ (1997) J Appl Phys 82:909–66Canham LT, Reeves CR (1996) Mat Res Soc Symp 414:189–90Edell DJ, Toi VV, McNeil VM, Clark LD (1992) IEEE Trans Biomed Eng 39:635–43Fenollosa R, Meseguer F, Tymczenko M (2008) Adv Mater 20:95Fenollosa R, Meseguer F, Tymczenko M, Spanish Patent P200701681, 2007Pell LE, Schricker AD, Mikulec FV, Korgel BA (2004) Langmuir 20:6546Xifré-Perez E, Fenollosa R, Meseguer F (2011) Opt Express 19:3455–63Fenollosa R, Ramiro-Manzano F, Tymczenko M, Meseguer F (2010) J Mater Chem 20:5210Xifré-Pérez E, Domenech JD, Fenollosa R, Muñoz P, Capmany J, Meseguer F (2011) Opt Express 19–4:3185–92Rodriguez I, Fenollosa R, Meseguer F, Cosmetics & Toiletries 2010;42–49Ramiro-Manzano F, Fenollosa R, Xifré-Pérez E, Garín M, Meseguer F (2011) Adv Mater 23:3022–3025. doi: 10.1002/adma.201100986Iler RK (1979) Chemistry of silica: solubility, polymerization, colloid & surface properties & biochemistry. Wiley, New YorkTanaka K, Maruyama E, Shimado T, Okamoto H (1999) Amorphous silicon. Wiley, New York, NYPatterson AL (1939) Phys Rev 56:978–82Canham LT, Reeves CL, King DO, Branfield PJ, Gabb JG, Ward MC (1996) Adv Mater 8:850–2Iler RK In: Chemistry of silica: solubility, polymerization, colloid & surface properties &Biochemistry. Wiley, New York, NYFinnie KS, Waller DJ, Perret FL, Krause-Heuer AM, Lin HQ, Hanna JV, Barbe CJ (2009) J Sol-Gel Technol 49:12–8Zhao D, Huo Q, Feng J, Chmelka BF, Stucky GD (1998) J Am Chem Soc 120:6024–36Fan D, Akkaraju GR, Couch EF, Canham LT, Coffer JL (2010) Nanoscale 1:354–61Tasciotti E, Godin B, Martinez JO, Chiappini C, Bhavane R, Liu X, Ferrari M (2011) Mol Imaging 10:56–

Sustained, Controlled and Stimuli-Responsive Drug Release Systems Based on Nanoporous Anodic Alumina with Layer-by-Layer Polyelectrolyte

DOI: 10.1186/s11671-016-1585-4 URL: http://nanoscalereslett.springeropen.com/articles/10.1186/s11671-016-1585-4 Filiació URV: SIControlled drug delivery systems are an encouraging solution to some drug disadvantages such as reduced solubility, deprived biodistribution, tissue damage, fast breakdown of the drug, cytotoxicity, or side effects. Self-ordered nanoporous anodic alumina is an auspicious material for drug delivery due to its biocompatibility, stability, and controllable pore geometry. Its use in drug delivery applications has been explored in several fields, including therapeutic devices for bone and dental tissue engineering, coronary stent implants, and carriers for transplanted cells. In this work, we have created and analyzed a stimuli-responsive drug delivery system based on layer-by-layer pH-responsive polyelectrolyte and nanoporous anodic alumina. The results demonstrate that it is possible to control the drug release using a polyelectrolyte multilayer coating that will act as a gate

Photonic Binding in Silicon-Colloid Microcavities

Photonic binding between two identical silicon-colloid-based microcavities is studied by using a generalized multipolar expansion. In contrast with previous works, we focus on low-order cavity modes that resemble low-energy electronic orbitals. For conservative light intensities, the interaction between cavity modes with moderate Q factors produces extremely large particle acceleration values. Optical forces dominate over vanderWaals, gravity, and Brownian motion, and they show a binding-antibinding behavior in analogy to electronic binding. As these photonic forces are associated with relatively broad Mie mode resonances and they are not strongly influenced by sample absorption, our study opens a plausible avenue towards manipulation of high-refractive-index colloidal assemblies. © 2009 The American Physical Society.This work has been partially supported by the Spanish CICyT (Projects MAT2006-03097, MAT2007-66050, TEC2006-06531, and Consolider CSD2007-046) and by the EU (NMP4-SL-2008-213669-ENSEMBLE).Peer Reviewe

Supported Ultra-Thin Alumina Membranes with Graphene as Efficient Interference Enhanced Raman Scattering Platforms for Sensing

© 2020 by the authors.The detection of Raman signals from diluted molecules or biomaterials in complex media is still a challenge. Besides the widely studied Raman enhancement by nanoparticle plasmons, interference mechanisms provide an interesting option. A novel approach for amplification platforms based on supported thin alumina membranes was designed and fabricated to optimize the interference processes. The dielectric layer is the extremely thin alumina membrane itself and, its metallic aluminum support, the reflecting medium. A CVD (chemical vapor deposition) single-layer graphene is transferred on the membrane to serve as substrate to deposit the analyte. Experimental results and simulations of the interference processes were employed to determine the relevant parameters of the structure to optimize the Raman enhancement factor (E.F.). Highly homogeneous E.F. over the platform surface are obtained, typically 370 ± (5%), for membranes with ~100 nm pore depth, ~18 nm pore diameter and the complete elimination of the Al2O3 bottom barrier layer. The combined surface enhanced Raman scattering (SERS) and interference amplification is also demonstrated by depositing ultra-small silver nanoparticles. This new approach to amplify the Raman signal of analytes is easily obtained, low-cost and robust with useful enhancement factors (~400) and allows only interference or combined enhancement mechanisms, depending on the analyte requirements.The research leading to these results has received funding from Ministerio de Ciencia, Innovación y Universidades (RTI2018-096918-B-C41) and RTI2018-094040-B-I00) and by the Agency for Management of University and Research Grants (AGAUR) 2017-SGR-1527. S.C. acknowledges the grant BES-2016-076440 from MINECO.Peer reviewe

3D-FDTD modelling of optical biosensing based on gold-coated nanoporous anodic alumina

The suitability of using gold-coated nanoporous anodic alumina structures as a platform for reflectometry-based plasmonic biosensors is investigated by numerical simulation. Reflectance spectra of such structures has been obtained using 3D-FDTD while the sensing capabilities have been evaluated as the change in spectra upon the adsorption of a layer of a biological-related molecule (biolayer) on the gold coating and inner pore surface. Results show that the gold-coated nanoporous structure enables the coupling of normally incident light to a localized surface plasmon resonance, and that such resonance shifts upon the adsorption of the biolayer. A sensitivity can be defined as the resonance wavelength shift with the biolayer refractive index. It is demonstrated that smaller gold coating thicknesses result in an increase in sensitivity, but at the cost of a decrease in the resonance sharpness, what suggests the existence of an optimal gold coating thickness. Keywords: FDTD simulation, Gold-coated nanoporous anodic alumina, Reflectometry-based plasmonic biosensor, Biolaye