Publications

2019

• Fabrication of porous anodic alumina (PAA) templates with straight pores and with hierarchical structures through exponential voltage decrease technique
  
  • Sacco Leandro
  • Florea Ileana
  • Cojocaru Costel Sorin
  Surface and Coatings Technology, Elsevier, 2019, 364, pp.248-255. The oxide barrier layer at the bottom of the pores has been successfully thinned by applying an exponential voltage decrease process followed by a wet chemical etching. The impact of the potential drop on the porous anodic alumina (PAA) structure has been deeply investigated, as well as the electrolyte temperature, the number of potential steps and the exponential decay rate. The results presented herein evidence that straight pores can be obtained and simultaneously remove the dielectric layer in spite of applying the exponential voltage decay during the PAA synthesis, through a smart adjustment between the anodization conditions and exponential voltage decay parameters. Additionally, the PAA structure can be tuned to fabricate hierarchically nanoporous templates with secondary pores ranging from 2 up to 10 branches. The presented simple procedure aims to become a standard step for the fabrication of the next generation PAA templates based devices. (10.1016/j.surfcoat.2019.02.086)
  DOI : 10.1016/j.surfcoat.2019.02.086
• Low-cost high-efficiency system for solar-driven conversion of CO 2 to hydrocarbons
  
  • Huan Tran Ngoc
  • Alves Dalla Corte Daniel
  • Lamaison Sarah
  • Karapinar Dilan
  • Lutz Lukas
  • Menguy Nicolas F
  • Foldyna Martin
  • Turren-Cruz Silver-Hamill
  • Hagfeldt Anders
  • Bella Federico
  • Fontecave Marc
  • Mougel Victor
  Proceedings of the National Academy of Sciences of the United States of America, National Academy of Sciences, 2019, 116 (20), pp.201815412. Conversion of carbon dioxide into hydrocarbons using solar energy is an attractive strategy for storing such a renewable source of energy into the form of chemical energy (a fuel). This can be achieved in a system coupling a photovoltaic (PV) cell to an electrochemical cell (EC) for CO2 reduction. To be beneficial and applicable, such a system should use low-cost and easily processable photovoltaic cells and display minimal energy losses associated with the catalysts at the anode and cathode and with the electrolyzer device. In this work, we have considered all of these parameters altogether to set up a reference PV–EC system for CO2 reduction to hydrocarbons. By using the same original and efficient Cu-based catalysts at both electrodes of the electrolyzer, and by minimizing all possible energy losses associated with the electrolyzer device, we have achieved CO2 reduction to ethylene and ethane with a 21% energy efficiency. Coupled with a state-of-the-art, low-cost perovskite photovoltaic minimodule, this system reaches a 2.3% solar-to-hydrocarbon efficiency, setting a benchmark for an inexpensive all–earth-abundant PV–EC system. (10.1073/pnas.1815412116)
  DOI : 10.1073/pnas.1815412116
• Experimental Determination of Optical Constants from Martian Analog Materials Using a Spectro-Polarimetric Approach
  
  • Alemanno G.
  • Garcia-Caurel E.
  • Carter J.
  • Brunetto R.
  • Poulet F.
  • Aleon-Toppani A.
  • Urso R.
  • Mivumbi O.
  • Boukari C.
  • Godard V.
  , 2019. We present our experimental approach to derive the optical constants of some martian analogue materials based on the infrared ellipsometry technique.
• Direct evidence of 2H hexagonal Si in Si nanowires
  
  • He Zhanbing
  • Maurice Jean-Luc
  • Li Qikai
  • Pribat Didier
  Nanoscale, Royal Society of Chemistry, 2019, 11 (11), pp.4846-4853. (10.1039/c8nr10370d)
  DOI : 10.1039/c8nr10370d
• Organic electronics and photovoltaics
  
  • Yassar Abderrahim
  , 2019.
• Optical phantoms for biomedical polarimetry: a review
  
  • Chue-Sang Joseph
  • Gonzalez Mariacarla
  • Pierre Angie
  • Laughrey Megan
  • Saytashev Ilyas
  • Novikova Tatiana
  • Ramella-Roman Jessica
  Journal of Biomedical Optics, Society of Photo-optical Instrumentation Engineers, 2019, 24 (03), pp.1. (10.1117/1.JBO.24.3.030901)
  DOI : 10.1117/1.JBO.24.3.030901
• Greater magnitude tibiofemoral contact forces are associated with reduced prevalence of osteochondral pathologies 2–3 years following anterior cruciate ligament reconstruction
  
  • Saxby David John
  • Bryant Adam
  • van Ginckel Ans
  • Wang Yuanyuan
  • Wang Xinyang
  • Modenese Luca
  • Gerus Pauline
  • Konrath Jason
  • Fortin Karine
  • Wrigley Tim
  • Bennell Kim
  • Cicuttini Flavia
  • Vertullo Christopher
  • Feller Julian
  • Whitehead Tim
  • Gallie Price
  • Lloyd David
  Knee Surgery, Sports Traumatology, Arthroscopy, Springer Verlag, 2019, 27 (3), pp.707-715. (10.1007/s00167-018-5006-3)
  DOI : 10.1007/s00167-018-5006-3
• Optical phantoms for biomedical polarimetry: a review
  
  • Chue-Sang Joseph
  • Gonzalez Mariacarla
  • Pierre Angie
  • Laughrey Megan
  • Saytashev Ilyas
  • Novikova Tatiana
  • Ramella-Roman Jessica
  Journal of Biomedical Optics, Society of Photo-optical Instrumentation Engineers, 2019, 24 (03), pp.1. (10.1117/1.JBO.24.3.030901)
  DOI : 10.1117/1.JBO.24.3.030901
• Optical transmission during mid-infrared femtosecond laser pulses ablation of fused silica
  
  • Liang Qingqing
  • Zhong Yue
  • Fan Zhengquan
  • Diao Hanhu
  • Jukna Vytautas
  • Chen Wanghua
  • Houard Aurélien
  • Zeng Zhinan
  • Li Ruxin
  • Liu Yi
  Applied Surface Science, Elsevier, 2019, 471, pp.506-515. We report on the optical transmission of near-infrared (1.8 μm) femtosecond laser pulses during multiple pulses laser ablation of fused silica surface. In addition to the previously reported ciliary white light phenomenon (Phys. Rev. Lett. 110, 097601 (2013)), two new optical transmission phenomena were observed for relatively low energy laser pulses. We systemically examined the damage morphologies of the ablation site as a function of laser pulse energy and laser shot number. Laser induced periodic surface structures (LIPSS) with different periods and orientations were observed for different pulse energy regimes. Comparison of the damage morphologies and the optical transmission reveals that the two new optical transmission phenomena origin from the refraction of the incident near-infrared pulses on the LIPSS covered damage surface followed by nonlinear propagation of the beamlets and even filamentation if the laser energy was high enough. We found that the interference of the neighboring white light emissions gives rise to radially orientated optical fringes. Based on this observation, we proposed another interpretation for the ciliary white light phenomenon. (10.1016/j.apsusc.2018.11.192)
  DOI : 10.1016/j.apsusc.2018.11.192
• Tuning bimetallic catalysts for a selective growth of SWCNTs
  
  • Forel Salomé
  • Castan Alice
  • Amara Hakim
  • Florea Ileana
  • Fossard Frédéric
  • Catala Laure
  • Bichara Christophe
  • Mallah Talal
  • Huc Vincent
  • Loiseau Annick
  • Cojocaru Costel-Sorin
  Nanoscale, Royal Society of Chemistry, 2019, 11 (9), pp.4091-4100. Recent advances in structural control during the synthesis of SWCNTs have in common the use of bimetallic nanoparticles as catalysts, despite the fact that their exact role is not fully understood. We therefore analyze the effect of the catalyst's chemical composition on the structure of the resulting SWCNTs by comparing three bimetallic catalysts (FeRu, CoRu and NiRu). A specific synthesis protocol is designed to impede the catalyst nanoparticle coalescence mechanisms and stabilize their diameter distributions throughout the growth. Owing to the ruthenium component which has a limited carbon solubility, tubes grow in tangential mode and their diameter is close to that of their seeding nanoparticle. By using as-synthesized SWCNTs as a channel material in field effect transistors, we show how the chemical composition of the catalysts and temperature can be used as parameters to tune the diameter distribution and semiconducting-to-metallic ratio of SWCNT samples. Finally, a phenomenological model, based on the dependence of the carbon solubility as a function of catalyst nanoparticle size and nature of the alloying elements, is proposed to interpret the results. (10.1039/c8nr09589b)
  DOI : 10.1039/c8nr09589b
• Instrument-dependent method for obtaining a nondepolarizing estimate from an experimental Mueller matrix
  
  • Ossikovski Razvigor
  • Arteaga Oriol
  Optical Engineering, SPIE, 2019, 58 (08), pp.1. (10.1117/1.OE.58.8.082409)
  DOI : 10.1117/1.OE.58.8.082409
• Heteroepitaxial growth of silicon on GaAs via low-temperature plasma-enhanced chemical vapor deposition
  
  • Hamon Gwenaëlle
  • Vaissière Nicolas
  • Lausecker Clément
  • Cariou Romain
  • Chen Wanghua
  • Alvarez J
  • Maurice Jean-Luc
  • Patriarche Gilles J
  • Largeau Ludovic
  • Decobert Jean
  • Kleider Jean-Paul
  • Roca I Cabarrocas Pere
  , 2019, 10926. We present an innovative approach for the growth of crystalline silicon on GaAs using plasma-enhanced chemical vapor deposition (PECVD). In this process the substrate is kept at low temperature (175 °C) and epitaxial growth is obtained via the impact of charged silicon clusters which are accelerated towards the substrate by the plasma-potential and melt upon impact. Therefore, this is a nanometer size epitaxial process where the local temperature (nm scale) rises above the melting temperature of silicon for extremely short times (in the range from ps to ns). This allows obtaining epitaxial growth even on relatively rough GaAs films, which have been cleaned in-situ using a SiF4 plasma etching. We present in-plane X-Ray Diffraction (XRD) measurements which are consistent with the hypothesis that the epitaxial growth happens at a local high temperature. Indeed, the tetragonal structure observed and the low in-plane lattice parameter determined from XRD can only be explained by the thermal mismatch induced by a high growth temperature. The effect of the plasma on the underlying GaAs properties, in particular the formation of hydrogen complexes with GaAs dopants (C, Si, Te) is studied in view of the integration of the c-Si epi-layers into devices (10.1117/12.2511174)
  DOI : 10.1117/12.2511174
• Toward Efficient Radial Junction Silicon Nanowire-Based Solar Mini-Modules
  
  • Al-Ghzaiwat Mutaz
  • Foti Antonino
  • Nuesslein André
  • Halagacka Lukas
  • Meot Jacques
  • Labouret Anne
  • Ossikovski Razvigor
  • Roca I Cabarrocas Pere
  • Foldyna Martin
  physica status solidi (RRL) - Rapid Research Letters (pss RRL), Wiley-VCH Verlag, 2019, 13 (2), pp.1800402. (10.1002/pssr.201800402)
  DOI : 10.1002/pssr.201800402
• Self-Assembled Magnetically Isolated Co Nanoparticles Embedded Inside Carbon Nanotubes
  
  • Prischepa Serghej L
  • Danilyuk Alexander L
  • Kukharev Andrei V
  • Le Normand François
  • Cojocaru Costel Sorin
  IEEE Transactions on Magnetics, Institute of Electrical and Electronics Engineers, 2019, 55 (2), pp.1-4. We investigate the influence of carbon nanotubes (CNTs) aligned array on the magnetic properties of an ensemble of densely packed Co nanoparticles (NPs) embedded inside CNTs. Samples are synthesized by chemical vapor deposition activated by current discharge plasma and hot filament. Each CNT contained only one NP of Co, which had preliminarily been formed on the surface of the SiO 2 /Si substrate. Co NPs are elongated along the CNT axis. The reference Co NPs ensemble and Co NPs embedded inside CNTs behave differently in a magnetic field. In the former case, Co NPs are strongly coupled by the dipole-dipole interaction (DDI); the easy axis plane is oriented parallel to the substrate. For Co-CNT samples, Co NPs are magnetically isolated. The reason for suppressing the contribution of the DDI is the magnetic anisotropy. It increases significantly because of the peculiar morphology of Co embedded in CNT and stresses. We evaluate the values of shape, magnetocrystalline, and magnetoelastic anisotropy constants. The magnetoelastic anisotropy is estimated for both the crystalline structures of Co, fcc and hcp, observed in Co NPs. The maximum stresses are reached in the case of hcp Co, when the hexagonal axis is oriented along the radial CNT direction. The influence of stresses onto the magnetic structure of Co inclusions is investigated by the micromagnetic simulations. Index Terms-Carbon nanotubes (CNTs), dipole-dipole interaction (DDI), magnetic anisotropy, magnetoelasticity, nanosized cobalt. (10.1109/TMAG.2018.2864692)
  DOI : 10.1109/TMAG.2018.2864692
• Microarcing-enhanced tungsten nano and micro-particles formation in low pressure high-density plasma
  
  • Ouaras K.
  • Lombardi G.
  • Couedel L.
  • Arnas Cécile
  • Hassouni K.
  Physics of Plasmas, American Institute of Physics, 2019, 26 (2), pp.023705.
• Microcrystalline silicon thin film deposition from silicon tetrafluoride: Isolating role of ion energy using tailored voltage waveform plasmas
  
  • Wang Junkang
  • Daineka Dmitri
  • Elyaakoubi Mustapha
  • Johnson Erik
  Solar Energy Materials and Solar Cells, Elsevier, 2019, 190, pp.65-74. The energy of ions during plasma enhanced chemical vapor deposition (PECVD) is known to impact material quality, but isolating this effect from other process parameters (plasma density, pressure) in a capacitively coupled plasma (CCP) is not straightforward. In this work, we utilize a novel radio-frequency (RF) excitation technique-tailored voltage waveforms (TVW)-as a solution to achieve ion flux-energy decoupling through the electrical asymmetry effect. This makes it possible to independently study the impact of ion energy on material deposition. We study the impact of ion energy-more precisely the maximum ion bombardment energy (IBEmax) before collisions-on the PECVD of hydrogenated microcrystalline silicon (µc-Si:H) thin films from an SiF4/H2/Ar chemistry. Through structural and electronic analysis, we find that the variation of IBEmax directly translates into material quality, even at relatively high process pressure. Better material properties (crystalline grain features, material density and photoelectronic response) are obtained for films deposited with moderate values of IBEmax around 45-55 eV. Above this range, a deterioration in material quality is observed, presumably due to more effective bulk atomic displacements induced by the silicon-containing ions. These results are consistent with the performance of single-junction µc-Si:H solar cell devices using these materials as active layers. Optimum performance is obtained for devices with an absorber layer deposited using a plasma excitation resulting in IBEmax in the range of ~45-55 eV. The variation in device performance is mainly due to changes in the open circuit voltage. (10.1016/j.solmat.2018.10.014)
  DOI : 10.1016/j.solmat.2018.10.014
• Influence of Disorder and Anharmonic Fluctuations on the Dynamical Rashba Effect in Purely Inorganic Lead-Halide Perovskites
  
  • Marronnier Arthur
  • Roma Guido
  • Carignano Marcelo
  • Bonnassieux Yvan
  • Katan Claudine
  • Even Jacky
  • Mosconi Edoardo
  • de Angelis Filippo
  Journal of Physical Chemistry C, American Chemical Society, 2019, 123 (1), pp.291–298. Doping organic metal-halide perovskites with cesium could be the best solution to stabilize highly-efficient perovskite solar cells. The understanding of the respective roles of the organic molecule, on one hand, and the inorganic lattice, on the other, is thus crucial in order to be able to optimize the physical properties of the mixed-cation structures. In particular, the study of the recombination mechanisms is thought to be one of the key challenges towards full comprehension of their working principles. Using molecular dynamics and frozen phonons, we evidence sub-picosecond anharmonic fluctuations in the fully inorganic CsPbI3 perovskite. We reveal the effect of these fluctuations, combined with spin-orbit coupling, on the electronic band structure, evidencing a dynamical Rashba effect. Our study shows that under certain conditions space disorder can quench the Rashba effect. As for time disorder, we evidence a dynamical Rashba effect which is similar to what was found for MAPbI3 and which is still sizable despite temperature disorder, the large investigated supercell, and the absence of the organic cations’ motion. We show that the spin texture associated to the Rashba splitting cannot be deemed responsible for a consistent reduction of recombination rates, although the spin mismatch between valence and conduction band increases with the ferroelectric distortion causing the Rashba splitting. (10.1021/acs.jpcc.8b11288)
  DOI : 10.1021/acs.jpcc.8b11288
• Low Temperature Solution-Processable 3D-Patterned Charge Recombination Layer for Organic Tandem Solar Cells
  
  • Choi Jin Woo
  • Jin Jong Woo
  • Tondelier Denis
  • Bonnassieux Yvan
  • Geffroy Bernard
  Materials, MDPI, 2019. We propose a novel method to pattern the charge recombination layer (CRL) with a low-temperature solution-processable ZnO layer (under 150 • C) for organic solar cell applications. Due to the optimal drying process and thermal annealing condition, ZnO sol-gel particles formed a three-Dimensional (3D) structure without using a high temperature or ramping method. The generated 3D nano-ripple pattern showed a height of around 120 nm, and a valley-to-valley distance of about 500 nm. Based on this newly developed ZnO nano-ripple patterning technique, it was possible to pattern the CRL without damaging the underneath layers in tandem structure. The use of nano-ripple patterned ZnO as the part of CRL, led to the concomitant improvement of the power conversion efficiency (PCE) of about 30%, compared with non-patterned CRL device. (10.3390/ma12010162)
  DOI : 10.3390/ma12010162
• Defect State Analysis in Ion‐Irradiated Amorphous‐Silicon Heterojunctions by HAXPES
  
  • Lee Min-I
  • Defresne Alice
  • Plantevin Olivier
  • Céolin Denis
  • Rueff Jean-Pascal
  • Roca I Cabarrocas Pere
  • Tejeda Antonio
  physica status solidi (RRL) - Rapid Research Letters (pss RRL), Wiley-VCH Verlag, 2019, 13 (5), pp.1800655. The efficiency in HIT (Heterojunction with Intrinsic Thin film) solar cells strongly depends on the passivation of dangling bonds at the a-Si:H/c-Si interface by hydrogen, introduced in the plasma enhanced CVD process. Here in, we study controlled defects that are introduced by Ar ion irradiation. We observe by hard X-ray photoemission spectroscopy (HAXPES) that during Ar ion implantation, Si-H bonds in the a-Si:H layer are broken and become dangling bonds. We quantify the number of dangling bonds in the a-Si:H layer, and we identify the electronic states associated to them, which explains previously observed photoluminescence transitions. (10.1002/pssr.201800655)
  DOI : 10.1002/pssr.201800655
• Aggregate-driven reconfigurations of carbon nanotubes in thin networks under strain: in-situ characterization
  
  • Bodelot Laurence
  • Pavic Luka
  • Hallais Simon
  • Charliac Jérôme
  • Lebental Bérengère
  Scientific Reports, Nature Publishing Group, 2019, pp.11p. This work focuses on the in-situ characterization of multi-walled carbon nanotube (CNT) motions in thin random networks under strain. Many fine-grain models have been devised to account for CNT motions in carbon nanotube networks (CNN). However, the validation of these models relies on mesoscopic or macroscopic data with very little experimental validation of the physical mechanisms actually arising at the CNT scale. In the present paper, we use in-situ scanning electron microscopy imaging and high resolution digital image correlation to uncover prominent mechanisms of CNT motions in CNNs under strain. Results show that thin and sparse CNNs feature stronger strain heterogeneities than thicker and denser ones. It is attributed to the complex motions of individual CNTs connected to aggregates within thin and sparse CNNs. While the aggregates exhibit a collective homogeneous deformation, individual CNTs connecting them are observed to fold, unwind or buckle, seemingly to accommodate the motion of these aggregates. In addition, looser aggregates feature internal reconfgurations via cell closing, similar to foam materials. Overall, this suggests that models describing thin and sparse CNN deformation should integrate multiphase behaviour (with various densities of aggregates in addition to individual CNTs), heterogeneity across surface, as well as imperfect substrate adhesion. (10.1038/s41598-019-41989-2)
  DOI : 10.1038/s41598-019-41989-2
• Stern-Gerlach experiment with light: separating photons by spin with the method of A. Fresnel
  
  • Arteaga Oriol
  • Garcia-Caurel Enric
  • Ossikovski Razvigor
  Optics Express, Optical Society of America - OSA Publishing, 2019. In 1822 A. Fresnel described an experiment to separate a beam of light into its right-and left-circular polarization components using chiral interfaces. Fresnel's experiment combined three crystalline quartz prisms of alternating handedness to achieve a visible macroscopic separation between the two circular components. Such quartz polyprisms were rather popular optical components in XIXth century but today remain as very little known optical devices. This work shows the analogy between Fresnel's experiment and Stern-Gerlach experiment from quantum mechanics since both experiments produce selective deflection of particles (photons in case of Fresnel's method) according to their spin angular momentum. We have studied a historical quartz polyprism with eight chiral interfaces producing a large spatial separation of light by spin. We have also constructed a modified Fresnel biprism to produce smaller separations and we have examined the analogy with Stern-Gerlach apparatus for both strong and weak measurements. The polarimetric analysis of a Fresnel polyprism reveals that it acts as a spin angular momentum analyzer. (10.1364/OE.27.004758)
  DOI : 10.1364/OE.27.004758
• Anisotropic integral decomposition of depolarizing Mueller matrices
  
  • Ossikovski Razvigor
  • Kuntman Ali
  • Arteaga Oriol
  OSA Continuum, OSA Publishing, 2019. We propose a novel, computationally efficient integral decomposition of depolarizing Mueller matrices allowing for the obtainment of a nondepolarizing estimate, as well as for the determination of the elementary polarization properties, in terms of mean values and variances-covariances of their fluctuations, of a weakly anisotropic depolarizing medium. We illustrate the decomposition on experimental examples and compare its performance to those of alternative decompositions. (10.1364/OSAC.2.001900)
  DOI : 10.1364/OSAC.2.001900
• Erratum: Multi frequency matching for voltage waveform tailoring <A href="/abs/">(2018 Plasma Sources Sci. Technol. 27 095012</A>)
  
  • Schmidt Frederik
  • Schulze Julian
  • Johnson Erik
  • Booth Jean-Paul
  • Keil Douglas
  • French David M.
  • Trieschmann Jan
  • Mussenbrock Thomas
  Plasma Sources Science and Technology, IOP Publishing, 2019, 28, pp.019601. (10.1088/1361-6595/aaeb4b)
  DOI : 10.1088/1361-6595/aaeb4b
• Spectral dependence of femtosecond laser induced circular optical properties in silica
  
  • Tian Jing
  • Li Rubing
  • Yoo Sang Hyuk
  • Poumellec Bertrand
  • Garcia-Caurel Enric
  • Ossikovski Razvigor
  • Stchakovsky Michel
  • Eypert Céline
  • Canning John
  • Lancry Matthieu
  OSA Continuum, OSA Publishing, 2019, 2 (4), pp.1233. Transmission Mueller-matrix spectroscopic ellipsometry is applied to study femtosecond laser induced nanogratings in silica glass in a wide spectral range 250-1800 nm. By using differential decomposition of the Mueller matrix, the circular birefringence and dichroism of femtosecond laser irradiated SiO 2 are quantified for the first time in the UV and Near-IR range. A maximum value of the effective specific rotation of α ~ 860°/mm at 290 nm is found. In the near-IR range, we found a linear and circular dichroism band peaking around 1240 nm, which might be attributed to the formation of anisotropic species like the formation of oriented OH species and Si-O-Si bond. (10.1364/OSAC.2.001233)
  DOI : 10.1364/OSAC.2.001233
• Complete Mueller matrix from a partial polarimetry experiment: the 12-element case
  
  • Arteaga Oriol
  • Ossikovski Razvigor
  Journal of the Optical Society of America. A Optics, Image Science, and Vision, Optical Society of America, 2019. Conventional generalized ellipsometry instrumentation is capable of measuring 12 out of the 16 elements of the Mueller matrix of the sample. The missing column (or row) of the experimental partial Mueller matrix can be analytically determined under additional assumptions. We identify the conditions necessary for completing the partial Mueller matrix to a full one. More specifically, such a completion is always possible if the sample is non-depolarizing; the fulfillment of additional conditions, such as the Mueller matrix exhibiting symmetries or being of a special two-component structure, are necessary if the sample is depolarizing. We report both algebraic and numerical procedures for completing the partial 12-element Mueller matrix in all tractable cases and validate them on experimental examples. (10.1364/JOSAA.36.000416)
  DOI : 10.1364/JOSAA.36.000416