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1. Revenue Management for Parallel Services with Fully Observable Queues

Author

Vanden Bussche, Caitlin, Devos, Arnaud, Wittevrongel, Sabine, Fiems, Dieter, Goos, Gerhard, Series Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Devos, Arnaud, editor, Horváth, András, editor, and Rossi, Sabina, editor

Published
2025
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6. Fano Resonance between Stokes and Anti-Stokes Brillouin Scattering

Author

Lai, KwanTo, Finkelstein-Shapiro, Daniel, Devos, Arnaud, and Mante, Pierre-Adrien

Subjects
Physics - Optics
Abstract

In recent years, the manipulation of Fano resonances in the time domain has unlocked deep insights into a broad spectrum of systems' coherent dynamics. Here, inelastic scattering of light with coherent acoustic phonons is harnessed to achieve complex Fano resonances. The sudden change of phonon momentum during reflection leads to a transition from anti-Stokes to Stokes light scattering, producing two different resonances that interfere in the measurement process. We highlight the conditions necessary to achieve such interference, revealing an underlying symmetry between photons and phonons, and verify the theory experimentally. Then, we demonstrate the possibility to characterize energy and coherence losses at rough interfaces, thus providing a mechanism for nondestructive testing of interface quality. Our results describe numerous unexplained observations in ultrafast acoustics and can be generalized to the scattering of light with any waves.

Published
2020
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7. A Product-Form Solution for a Two-Class Queue with Random Routing and Randomly Alternating Service

Author

Devos, Arnaud, De Muynck, Michiel, Bruneel, Herwig, Walraevens, Joris, Akan, Ozgur, Editorial Board Member, Bellavista, Paolo, Editorial Board Member, Cao, Jiannong, Editorial Board Member, Coulson, Geoffrey, Editorial Board Member, Dressler, Falko, Editorial Board Member, Ferrari, Domenico, Editorial Board Member, Gerla, Mario, Editorial Board Member, Kobayashi, Hisashi, Editorial Board Member, Palazzo, Sergio, Editorial Board Member, Sahni, Sartaj, Editorial Board Member, Shen, Xuemin, Editorial Board Member, Stan, Mircea, Editorial Board Member, Jia, Xiaohua, Editorial Board Member, Zomaya, Albert Y., Editorial Board Member, Hyytiä, Esa, editor, and Kavitha, Veeraruna, editor

Published
2023
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8. Properties of Nanocrystalline Silicon Probed by Optomechanics

Author

Navarro-Urrios, Daniel, Colombano, Martin F., Maire, Jeremie, Chavez-Angel, Emigdio, Arregui, Guillermo, Capuj, Nestor E., Devos, Arnaud, Griol, Amadeu, Bellieres, Laurent, Martinez, Alejandro, Grigoras, Kestutis, Hakkinen, Teija, Saarilahti, Jaakko, Makkonen, Tapani, Sotomayor-Torres, Clivia M., and Ahopelto, Jouni

Subjects
Physics - Applied Physics, Condensed Matter - Materials Science, Physics - Optics
Abstract

Nanocrystalline materials exhibit properties that can differ substantially from those of their single crystal counterparts. As such, they provide ways to enhance and optimise their functionality for devices and applications. Here we report on the optical, mechanical and thermal properties of nanocrystalline silicon probed by means of optomechanical nanobeams to extract information of the dynamics of optical absorption, mechanical losses, heat generation and dissipation. The optomechanical nanobeams are fabricated using nanocrystalline films prepared by annealing amorphous silicon layers at different temperatures. The resulting crystallite sizes and the stress in the films can be controlled by the annealing temperature and time and, consequently, the properties of the films can be tuned relatively freely, as demonstrated here by means of electron microscopy and Raman scattering. We show that the nanocrystallite size and the volume fraction of the grain boundaries play a key role in the dissipation rates through non-linear optical and thermal processes. Promising optical (13000) and mechanical (1700) quality factors were found in the optomechanical cavity realised in the nanocrystalline Si resulting from annealing at 950 C. The enhanced absorption and recombination rates via the intra-gap states and the reduced thermal conductivity boost the potential to exploit these non-linear effects in applications, including NEMS, phonon lasing and chaos-based devices., Comment: 31 pages, 5 figures

Published
2019

11. Properties of nanocrystalline silicon probed by optomechanics

Author

Navarro-Urrios Daniel, Colombano Martín F., Maire Jeremie, Chávez-Ángel Emigdio, Arregui Guillermo, Capuj Néstor E., Devos Arnaud, Griol Amadeu, Bellieres Laurent, Martínez Alejandro, Grigoras Kestutis, Häkkinen Teija, Saarilahti Jaakko, Makkonen Tapani, Sotomayor-Torres Clivia M., and Ahopelto Jouni

Subjects
annealing, cavity optomechanics, nanocrystalline silicon, Physics, QC1-999
Abstract

Nanocrystalline materials exhibit properties that can differ substantially from those of their single crystal counterparts. As such, they provide ways to enhance and optimize their functionality for devices and applications. Here, we report on the optical, mechanical and thermal properties of nanocrystalline silicon probed by means of optomechanical nanobeams to extract information of the dynamics of optical absorption, mechanical losses, heat generation and dissipation. The optomechanical nanobeams are fabricated using nanocrystalline films prepared by annealing amorphous silicon layers at different temperatures. The resulting crystallite sizes and the stress in the films can be controlled by the annealing temperature and time and, consequently, the properties of the films can be tuned relatively freely, as demonstrated here by means of electron microscopy and Raman scattering. We show that the nanocrystallite size and the volume fraction of the grain boundaries play a key role in the dissipation rates through nonlinear optical and thermal processes. Promising optical (13,000) and mechanical (1700) quality factors were found in the optomechanical cavity realized in the nanocrystalline Si resulting from annealing at 950°C. The enhanced absorption and recombination rates via the intragap states and the reduced thermal conductivity boost the potential to exploit these nonlinear effects in applications including Nanoelectromechanical systems (NEMS), phonon lasing and chaos-based devices.

Published
2020
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13. An Approximate Analysis of a Bernoulli Alternating Service Model

Author

Devos, Arnaud, Fiems, Dieter, Walraevens, Joris, Bruneel, Herwig, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Phung-Duc, Tuan, editor, Kasahara, Shoji, editor, and Wittevrongel, Sabine, editor

Published
2019
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14. Explicit Solutions for Coupled Parallel Queues.

Author

Bruneel, Herwig and Devos, Arnaud

Subjects
*WAITING rooms, *GENERATING functions, *CONSUMERS, *PROBABILITY theory
Abstract

We consider a system of two coupled parallel queues with infinite waiting rooms. The time setting is discrete. In either queue, the service of a customer requires exactly one discrete time slot. Arrivals of new customers occur independently from slot to slot, but the numbers of arrivals into both queues within a slot may be mutually dependent. Their joint probability generating function (pgf) is indicated as A (z 1 , z 2) and characterizes the whole model. In general, determining the steady-state joint probability mass function (pmf) u (m , n) , m , n ≥ 0 or the corresponding joint pgf U (z 1 , z 2) of the numbers of customers present in both queues is a formidable task. Only for very specific choices of the arrival pgf A (z 1 , z 2) are explicit results known. In this paper, we identify a multi-parameter, generic class of arrival pgfs A (z 1 , z 2) , for which we can explicitly determine the system-content pgf U (z 1 , z 2) . We find that, for arrival pgfs of this class, U (z 1 , z 2) has a denominator that is a product, say r 1 (z 1) r 2 (z 2) , of two univariate functions. This property allows a straightforward inversion of U (z 1 , z 2) , resulting in a pmf u (m , n) which can be expressed as a finite linear combination of bivariate geometric terms. We observe that our generic model encompasses most of the previously known results as special cases. [ABSTRACT FROM AUTHOR]

Published
2024
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15. A Priority Retrial Queue with Constant Retrial Policy

Author

Devos, Arnaud, Walraevens, Joris, Bruneel, Herwig, Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Weikum, Gerhard, Series Editor, Takahashi, Yutaka, editor, Phung-Duc, Tuan, editor, Wittevrongel, Sabine, editor, and Yue, Wuyi, editor

Published
2018
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19. [Invited] Picosecond acoustics: from lab to fab

Author

Devos, Arnaud, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Physique - IEMN (PHYSIQUE - IEMN), and Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA)

Subjects
thickness control, adhesion, [SPI]Engineering Sciences [physics], thin-film, RF filters, picosecond acoustics, elasticity
Abstract

International audience; The main goal of this lecture is to give an outlook of the numerous and various applications that the picosecond acoustic technique has met in the industrial world. The story started a few years after its invention by Prof. H. Maris. Indeed, Rudolph Technologies (now ONTO) rapidly realized that such a technique was the missing one in the industrial world for controlling the thickness of thin metal films. That was the beginning of the Metapulse® story, a full automatized tool dedicated to microelectronics applications and that can be found in any production company worthy of the name. More recently, picosecond acoustics and especially its variant based on laser-tuning, the so-called Colored Picosecond Acoustics or APiC, have been shown to be very useful for many other industrial applications in topics as different as space mirror, radio-frequency filtering, flat and smart glass, solar cells,…

Published
2022

20. Colored Picosecond Acoustics Versus Scotch Tape Adhesion Test: Confrontation on a Series of Similar Samples With a Variable Adhesion

Author

Juarez, Alejandro Vital, Roffi, Laureline, Desmarres, Jean-Michel, Devos, Arnaud, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Centre National d'Études Spatiales [Toulouse] (CNES), Physique - IEMN (PHYSIQUE - IEMN), Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), labo commun STMicroelectronics IEMN, and Laboratoire commun STMicroelectronics-IEMN T3

Subjects
[SPI]Engineering Sciences [physics], sense organs
Abstract

International audience; The study of the bonding at interfaces between thin layers is of great importance in optical and electronic applications as well as in the field of space exploration. A large number of methods have been developed to characterize the adhesion of a thin film to a substrate. Among them, Scotch Tape test is still one of the most popular methods.Acoustic waves and especially ultra-high frequency acoustic waves are also sensitive to adhesion defects as they affect the way acoustic waves are reflected at the concerned interface.In this paper, we prepare a dedicated series of identical thin-film samples with a variable adhesion at the interface between the film and its substrate. For that several avenues have been explored: introduction of a weak layer between the film and the substrate; reinforcement of the weak layer adhesion using ion beam implantation. The samples are then characterized using two much different techniques: colored picosecond acoustics for measuring thickness and acoustic reflection coefficient at the interface and scotch tape test to have an independent evaluation of the adhesion. An excellent correlation is found between techniques regarding adhesion that confirms the capability of APiC to perform adhesion test in a totally non destuctive manner and furthermore locally.

Published
2022

22. Picosecond acoustics versus tape adhesion test: Confrontation on a series of similar samples with a variable adhesion

Author

Vital-Juarez, A., Roffi, L., Desmarres, J.-M., Devos, Arnaud, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Centre National d'Études Spatiales [Toulouse] (CNES), Physique - IEMN (PHYSIQUE - IEMN), Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), and French Space AgencyRégion Hauts de FranceNational Centre for Scientific Research

Subjects
[SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], Picosecond acoustics, Adhesion, Materials Chemistry, Reflection coefficient, Thin film, Surfaces and Interfaces, General Chemistry, [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph], Condensed Matter Physics, Surfaces, Coatings and Films
Abstract

International audience; A large number of methods have been developed to characterize the adhesion of a thin film to a substrate. Among them, tape test is still one of the most popular methods. Acoustic waves and especially ultra-high frequency acoustic waves are also sensitive to adhesion defects as they affect the way acoustic waves are reflected at such an interface. In this work, we first prepare a series of identical thin-film samples with a variable adhesion at the interface between the film and its substrate. To modulate adhesion of some samples, an ultrathin gold layer is deposited on the substrate before thin-film sputtering. Si+ ion implantation is also used to reinforce locally gold adhesion. The samples are then characterized using two much different techniques: picosecond acoustics (PA) for measuring thickness and acoustic reflection coefficient (R) at the interface and tape test to have an independent evaluation of the adhesion through the peeled area (P). On the samples series, R is found to vary from −0.46 the expected value for a perfectly bonded Ni/Si interface to almost −0.83 not far from −1 which corresponds to delamination. An excellent correlation is found between R and P: high |R| value samples are easily peeled off and P is large. That work demonstrates the capability of PA to perform adhesion test in a totally non-destructive manner and furthermore locally.

Published
2022
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28. Quantification of the adhesion of metal thin film interfaces by picosecond acoustics

Author

Juarez, Alejandro Vital, Devos, Arnaud, Desmarres, Jean-Michel, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Physique - IEMN (PHYSIQUE - IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Centre National d'Études Spatiales [Toulouse] (CNES), and Physique-IEMN (PHYSIQUE-IEMN)

Subjects
[PHYS.MECA.VIBR]Physics [physics]/Mechanics [physics]/Vibrations [physics.class-ph], Picosecond, adhesion, thin films, Acoustic, [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph]
Abstract

International audience; Thin films are widespread in numerous fields: engineering, electronics, optics, biomedical, space and many more. They are largely used and require a flawless quality. One of the most important parameters is the adhesion of a layer with the substrate. Different methods of measuring the adhesion are used with the purpose of ensuring the good quality of the material. These methods have the great disadvantage of being destructive and no repeatable [1]. Picosecond acoustics is an ultrasonic laser method suitable for thin films [2]. It works around a femtosecond laser that generates, by a thermoelastic effect, a very high frequency acoustic wave (between 10 - 300 GHz). It propagates inside the studied sample and provides informations about the elasticity and the thickness by measuring the time of flight of each echoes detected at the surface. A variation of the wavelength of the laser allows us to gain additional information. For instance, to be aware of the quality of the interface by measuring the reflection coefficient. The size of the value of this coefficient varies according to the quality of collage. A greater reflection means a poorly collage [3]. If a correlation between reflection coefficient and adhesion energy is possible, picosecond acoustics may become a non-destructive method of energy quantification. Measurements are made on nickel films deposited on various substrates using evaporation or sputtering and various parameters to influence adhesion between the film and the substrate. Adhesion of the same series of samples is then studied using two approaches: acoustic reflection using picosecond acoustics and adhesion energy as measured with the centrifuge technology [4]. In this work we present details of such a protocol and discuss the correlation between both approaches results.

Published
2020
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29. Scanning Acoustic Microscopy versus Colored Picosecond Acoustics to detect interface defects in hybrid wafer bonding

Author

Bossut, Solene, Devos, Arnaud, Lhostis, S, Deloffre, E, Euvrard, C, Dettoni, F, Chaton, C, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Physique-IEMN (PHYSIQUE-IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Physique - IEMN (PHYSIQUE - IEMN), and Laboratoire commun STMicroelectronics-IEMN T3

Subjects
Picosecond Acoustics, [PHYS.MECA.VIBR]Physics [physics]/Mechanics [physics]/Vibrations [physics.class-ph], Hybrid bonding, Scanning Acoustic Microscopy, [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph]
Abstract

International audience; Nowadays, microelectronics is making progress in miniaturization and diversification of chips by 3D integration: dies are stacked together to gain space and performances. The stacking used here is called hybrid bonding [1], as stacked surfaces are heterogeneous: part Cu and part oxide. After the bonding, it exists some defects at the interface which size can be milimetric to nanometric. Acoustic waves are very useful for detecting defects. In the field, the most used technique is the Scanning Acoustic Microscopy (SAM) which makes an image of the interface using ultrasonics (10-1000 MHz) with a XY resolution of 20 �m [2]. To detect smaller defects, Transmission Electron Microscopy (TEM) is used. Its resolution is about 0,1 nm, making this technic very local compared to SAM. Like the SAM, Colored Picosecond Acoustics (APiC) is based on acoustic waves but at higher frequencies (10-500 GHz) using of a femtosecond laser in a pump-probe scheme [3,4]. Such a technique is closer to TEM resolution. In this work, both acoustic techniques (SAM and APiC) are applied to the characterization of the same samples made of bonded wafers. APiC is first used to characterize the stack (thickness, velocity). Then, the interface contributions is focused on: Cu/Cu, Cu/oxide, oxide/oxide. As the technic makes a local measurement (typically 1-2 �m), the process is repeated at different points of the surface to get an interface image comparable to SAM result. In this work will be presented the APiC results obtained on wafers also studied by SAM to compare both approaches, especially about the resolution enhancement ApiC brings. The minimal size of the defects that APiC is able to detect will be explored.

Published
2020
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30. La publicité des jugements et l’accès à la jurisprudence dans un environnement numérique : quid agis ?

Author

UCL - SSH/JURI/PJPU - Droit public, Devos, Arnaud, Dewez, Samantha, Piérard, Olympe, Romainville, Céline, Rosic, Zorana, UCL - SSH/JURI/PJPU - Droit public, Devos, Arnaud, Dewez, Samantha, Piérard, Olympe, Romainville, Céline, and Rosic, Zorana

Abstract

Après avoir situé l’enjeu de l’accès à la jurisprudence et celui de la publicité des jugements au rang des principes fondamentaux d’un État de droit démocratique, nous revenons sur la révision de l’article 149 de la Constitution et la modification de l’article 782bis du Code judiciaire. En l’absence d’exécution du dispositif normatif introduit par cette dernière modification, nous effectuons ensuite un état des lieux de l’accès à la jurisprudence aujourd’hui en droit belge. Cet état des lieux révèle une carence en ce qui concerne le pouvoir judiciaire, et la nécessité d’organiser un accès informatisé à la jurisprudence. Ce constat pose un certain nombre de questions, qui ont été soumises au Ministre de la Justice lors d'un entretien.

Published
2021

33. Properties of nanocrystalline silicon probed by optomechanics

Author

Navarro Urrios, Daniel, Colombano Sosa, Martin, Maire, Jeremie, Chávez Ángel, Emigdio, Arregui Bravo, Guillermo, Capuj, Néstor E., Devos, Arnaud, Griol, Amadeu., Bellieres, Laurent, Martínez, Alejandro, Grigoras, Kestutis, Häkkinen, Teija, Saarilahti, Jaakko, Makkonen, Tapani, Sotomayor Torres, Clivia M., Ahopelto, Jouni, Navarro Urrios, Daniel, Colombano Sosa, Martin, Maire, Jeremie, Chávez Ángel, Emigdio, Arregui Bravo, Guillermo, Capuj, Néstor E., Devos, Arnaud, Griol, Amadeu., Bellieres, Laurent, Martínez, Alejandro, Grigoras, Kestutis, Häkkinen, Teija, Saarilahti, Jaakko, Makkonen, Tapani, Sotomayor Torres, Clivia M., and Ahopelto, Jouni

Abstract

Nanocrystalline materials exhibit properties that can differ substantially from those of their single crystal counterparts. As such, they provide ways to enhance and optimize their functionality for devices and applications. Here, we report on the optical, mechanical and thermal properties of nanocrystalline silicon probed by means of optomechanical nanobeams to extract information of the dynamics of optical absorption, mechanical losses, heat generation and dissipation. The optomechanical nanobeams are fabricated using nanocrystalline films prepared by annealing amorphous silicon layers at different temperatures. The resulting crystallite sizes and the stress in the films can be controlled by the annealing temperature and time and, consequently, the properties of the films can be tuned relatively freely, as demonstrated here by means of electron microscopy and Raman scattering. We show that the nanocrystallite size and the volume fraction of the grain boundaries play a key role in the dissipation rates through nonlinear optical and thermal processes. Promising optical (13,000) and mechanical (1700) quality factors were found in the optomechanical cavity realized in the nanocrystalline Si resulting from annealing at 950°C. The enhanced absorption and recombination rates via the intragap states and the reduced thermal conductivity boost the potential to exploit these nonlinear effects in applications including Nanoelectromechanical systems (NEMS), phonon lasing and chaos-based devices.

Published
2020

34. Properties of nanocrystalline silicon probed by optomechanics

Author

European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Ministerio de Economía y Competitividad (España), Navarro-Urrios, D., Colombano, Martin F., Maire, Jeremie, Chávez-Angel, Emigdio, Arregui, Guillermo, Capuj, Néstor E., Devos, Arnaud, Griol, Amadeu, Bellières, Laurent, Martínez, Alejandro, Grigoras, Kestutis, Häkkinen, Teija, Saarilahti, Jaakko, Makkonen, Tapani, Sotomayor Torres, C. M., Ahopelto, Jouni, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Ministerio de Economía y Competitividad (España), Navarro-Urrios, D., Colombano, Martin F., Maire, Jeremie, Chávez-Angel, Emigdio, Arregui, Guillermo, Capuj, Néstor E., Devos, Arnaud, Griol, Amadeu, Bellières, Laurent, Martínez, Alejandro, Grigoras, Kestutis, Häkkinen, Teija, Saarilahti, Jaakko, Makkonen, Tapani, Sotomayor Torres, C. M., and Ahopelto, Jouni

Abstract

Nanocrystalline materials exhibit properties that can differ substantially from those of their single crystal counterparts. As such, they provide ways to enhance and optimize their functionality for devices and applications. Here, we report on the optical, mechanical and thermal properties of nanocrystalline silicon probed by means of optomechanical nanobeams to extract information of the dynamics of optical absorption, mechanical losses, heat generation and dissipation. The optomechanical nanobeams are fabricated using nanocrystalline films prepared by annealing amorphous silicon layers at different temperatures. The resulting crystallite sizes and the stress in the films can be controlled by the annealing temperature and time and, consequently, the properties of the films can be tuned relatively freely, as demonstrated here by means of electron microscopy and Raman scattering. We show that the nanocrystallite size and the volume fraction of the grain boundaries play a key role in the dissipation rates through nonlinear optical and thermal processes. Promising optical (13,000) and mechanical (1700) quality factors were found in the optomechanical cavity realized in the nanocrystalline Si resulting from annealing at 950°C. The enhanced absorption and recombination rates via the intragap states and the reduced thermal conductivity boost the potential to exploit these nonlinear effects in applications including Nanoelectromechanical systems (NEMS), phonon lasing and chaos-based devices.

Published
2020

35. Analysis of the queue lengths in a priority retrial queue with constant retrial policy.

Author

Devos, Arnaud, Walraevens, Joris, Phung-Duc, Tuan, and Bruneel, Herwig

Subjects
QUEUING theory, NEW trials, GENERATING functions
Abstract

In this paper, we analyze a priority queueing system with a regular queue and an orbit. Customers in the regular queue have priority over the customers in the orbit. Only the first customer in the orbit (if any) retries to get access to the server, if the queue and server are empty (constant retrial policy). In contrast with existing literature, we assume different service time distributions for the high- and low-priority customers. Closed-form expressions are obtained for the probability generating functions of the number of customers in the queue and orbit, in steady-state. Another contribution is the extensive singularity analysis of these probability generating functions to obtain the stationary (asymptotic) probability mass functions of the queue and orbit lengths. Influences of the service times and the retrial policy are illustrated by means of some numerical examples. [ABSTRACT FROM AUTHOR]

Published
2020
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39. Mechanical characterization of thin films and interfaces using the colored picosecond ultrasonic technique

Author

Devos, Arnaud, Le Louarn, A., Emery, Patrick, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), and MENAPIC

Published
2014

40. Impact of the deposition process on the elastic properties of thin films measured by ultrafast acoustics

Author

Devos, Arnaud, Le Louarn, A., Emery, P., Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Published
2013

41. Comment on 'Visualizing coherent phonon propagation in the 100 GHz range: A broadband picosecond acoustic approach'

Author

Courtens, Eric, Ruffle, Benoit, Foret, Marie, Vacher, René, Devos, Arnaud, Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2011
Full Text
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42. Ta2O5/SiO2 insulating acoustic mirrors for AlN-based X-band BAW resonators

Author

Capilla Osorio, José, Olivares Roza, Jimena, Clement Lorenzo, Marta, Felmetsger, Valeriy, and Devos, Arnaud

Subjects
Telecomunicaciones
Abstract

This work describes the performance of AlN-based bulk acoustic wave resonators built on top of insulating acoustic reflectors and operating at around 8 GHz. The acoustic reflectors are composed of alternate layers of amorphous Ta2O5and SiO2 deposited at room temperature by pulsed-DC reactive sputtering in Ar/O2 atmospheres. SiO2 layers have a porous structure that provides a low acoustic impedance of only 9.5 MRayl. Ta2O5 films exhibit an acoustic impedance of around 39.5 MRayl that was assessed by the picoseconds acoustic technique These values allow to design acoustic mirrors with transmission coefficients in the centre of the band lower than -40 dB (99.998 % of reflectance) with only seven layers. The resonators were fabricated by depositing a very thin AlN film onto an iridium bottom electrode 180 nm-thick and by using Ir or Mo layers as top electrode. Resonators with effective electromechanical coupling factors of 5.7% and quality factors at the antiresonant frequency around 600 are achieved.

Published
2011

43. Phonons in nanoscale objects

Author

Devos, Arnaud, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), and Sattler K.D.

Abstract

ISBN 978-1-4200754-0-3

Published
2010

44. Ultrafast acoustics in 2D phononic crystals

Author

Devos, Arnaud, Mante, P.A., Robillard, J.F., Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Published
2009

45. Temperature coefficients measured by picosecond ultrasonics on materials in thin films for bulk acoustic wave technology

Author

Emery, P., Petit, D., Ancey, P., Devos, Arnaud, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Published
2007
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46. L'acoustique picoseconde : un outil de métrologie mécanique de couches minces appliqué à la microéléctronique

Author

Emery, P., Devos, Arnaud, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Published
2006

47. An improvement of the picosecond ultrasonic technique based on a tunable laser : application to bulk acoustic wave resonator characterizations

Author

Devos, Arnaud, Emery, P., Caruyer, G., Ancey, P., Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Published
2006
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48. Metrology of thin dielectric films using picosecond ultrasonics

Author

Devos, Arnaud, Cote, R., Caruyer, G., Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Published
2005

49. Picosecond ultrasonics : a powerful tool for materials characterization in Bulk Acoustic Wave resonators

Author

Devos, Arnaud, Caruyer, G., Emery, P., Ancey, P., Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Published
2005

50. Bulk Acoustic Wave (BAW) resonators and filters

Author

Dubus, Bertrand, Devos, Arnaud, Caruyer, G., Volatier, A., Defay, E., Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Published
2005

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