Publications

2021

• New insights into the reactivity of detonation nanodiamonds during the first stages of graphitization
  
  • Ducrozet Florent
  • Girard Hugues
  • Leroy Jocelyne
  • Larquet Eric
  • Florea Ileana
  • Brun Emilie
  • Sicard-Roselli Cécile
  • Arnault Jean-Charles
  Nanomaterials, MDPI, 2021, 11 (10), pp.2671. The present study aims to compare the early stages of graphitization of the same DND source for two annealing atmospheres (primary vacuum, argon at atmospheric pressure) in an identical set-up. DND samples are finely characterized by a combination of complementary techniques (FTIR, Raman, XPS, HR-TEM) to highlight the induced modifications for temperature up to 1100 °C. The annealing atmosphere has a significant impact on the graphitization kinetics with a higher fraction of sp$^2$-C formed under vacuum compared to argon for the same temperature. Whatever the annealing atmosphere, carbon hydrogen bonds are created at the DND surface during annealing according to FTIR. A “nano effect”, specific to the < 10 nm size of DND, exalts the extreme surface chemistry in XPS analysis. According to HR-TEM images, the graphitization is limited to the first outer shell even for DND annealed at 1100 °C under vacuum (10.3390/nano11102671)
  DOI : 10.3390/nano11102671
• In Situ Observation of Droplet Nanofluidics for Yielding Low-Dimensional Nanomaterials
  
  • Fan Zheng
  • Maurice Jean-Luc
  • Florea Ileana
  • Chen Wanghua
  • Yu Linwei
  • Guilet Stéphane
  • Cambril Edmond
  • Lafosse Xavier
  • Couraud Laurent
  • Bouchoule Sophie
  • Roca I Cabarrocas Pere
  Applied Surface Science, Elsevier, 2021, 573, pp.151510. Droplet based micro/nanofluidics has been demonstrated as a versatile tool in a wide range of fields. In particular, seeded growth of planar low-dimensional nanomaterials often relies on crawling metal droplets as catalytic media where nucleation and crystal growth proceed. However, direct observations of nanomaterials growth led by self-propelled droplet transport remain rare, which leaves many open questions on droplet behavior during growth. 2 Here, we report in situ observations of in-plane Si nanowires growth in a transmission electron microscope, where an indium droplet migrates on a silicon nitride membrane coated by a layer of hydrogenated amorphous silicon (a-Si:H), dissolves the a-Si:H coating film on the membrane, and results in the production of a crystalline Si nanowire in its trail. This in situ observation, combined with the geometric investigation of the nanowires, presents nice consistency with de Gennes' theoretic prediction of reactive wetting induced droplet motion. Interestingly, we recorded a nanoflake-to-nanowire transition when the growth rate was increased by heating the membrane from 350 °C to 400 °C. This work directly unveils rich transport mechanism of catalytic droplets, which is expected to be a new platform for producing diverse low-dimensional nanomaterials and promote their potential applications in nanoscience and technologies. (10.1016/j.apsusc.2021.151510)
  DOI : 10.1016/j.apsusc.2021.151510
• Constitutive Relations for Optically Active Anisotropic Media: A Review
  
  • Ossikovski Razvigor
  • Arteaga Oriol
  • Sturm Chris
  Advanced Photonics Research, Wiley, 2021, 2 (12). The formal description of optical activity (OA) (circular birefringence and dichroism) has more than a 200‐year‐old history, dating back to the pioneering experiments of Arago and Biot. Despite the numerous contributions to it, including several reviews, the formalism of OA has not been treated in a self‐consistent and deductive manner, to the best of authors’ knowledge. Worse, some literature sources report different, apparently contradictory and incompatible, approaches. Willing to provide a general comprehensive review, as well as to clarify all ambiguous points, a unified, systematic, and logical approach to this topic is advanced. By applying a general formal pattern based on the energy conservation principle, the various sets of constitutive relations for optically active media are derived. The relationships allowing for conversions between different sets are presented, in view of their use in the matrix methods for computing the polarimetric responses of stratified structures. The OA tensors of the optically active crystal classes are likewise reported, and the intimate relation existing between crystal point symmetries and physical manifestations of natural OA, namely, rotatory power and longitudinal effect, is discussed. As an illustration, the theoretical developments are applied to the practically important case of planar metamaterial structures. (10.1002/adpr.202100160)
  DOI : 10.1002/adpr.202100160
• Inverse problem of Mueller polarimetry for metrological applications
  
  • Novikova Tatiana
  • Bulkin Pavel
  Journal of Inverse and Ill-posed Problems, De Gruyter, 2021, 29 (5), pp.759-774. Abstract Inverse problem of Mueller polarimetry is defined as a determination of geometrical features of the metrological structures (i.e. 1D diffraction gratings) from its experimental Mueller polarimetric signature. This nonlinear problem was considered as an optimization problem in a multi-parametric space using the least square criterion and the Levenberg–Marquardt algorithm. We demonstrated that solving optimization problem with the experimental Mueller matrix spectra taken in conical diffraction configuration helps finding a global minimum and results in smaller variance values of reconstructed dimensions of the grating profile. (10.1515/jiip-2020-0140)
  DOI : 10.1515/jiip-2020-0140
• High Density of Quantum-Sized Silicon Nanowires with Different Polytypes Grown with Bimetallic Catalysts
  
  • Wang Weixi
  • Ngo Éric
  • Florea Ileana
  • Foldyna Martin
  • Roca I Cabarrocas Pere
  • Maurice Jean-Luc
  ACS Omega, ACS Publications, 2021. (10.1021/acsomega.1c03630)
  DOI : 10.1021/acsomega.1c03630
• Room temperature growth of silica nanowires on top of ultrathin Si nanowires synthesized with Sn‐Cu bimetallic seeds
  
  • Wang Weixi
  • Ngo Éric
  • Florea Ileana
  • Foldyna Martin
  • Roca I Cabarrocas Pere
  • Maurice Jean-Luc
  Physica Status Solidi A (applications and materials science), Wiley, 2021. (10.1002/pssa.202100409)
  DOI : 10.1002/pssa.202100409
• Synthesis and characterization of single-walled carbon nanotube via low-pressure chemical vapor deposition from FeMo catalyst
  
  • Truong Thi Thanh Loan
  • Michel Goncalves
  • Florea Ileana
  • Cojocaru Costel Sorin
  , 2021. Materials science of carbon nanotubes (CNTs) lies at the intersection of various paradigms from fundamental to applied physics and chemistry. However, understanding the mechanism of CNTs formation through different concepts remains a considerable challenge. Currently, to be able to use CNTs for specific applications,
• A multimodal nanopipette-based imaging platform for exploring brain communication
  
  • Papa Martina
  • Treussart François
  • Mothet Jean-Pierre
  • Güell Aleix
  , 2021. N-methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors that are critical for multiple aspects of brain physiology and pathology. They are essential for neural coding and transducing specific patterns of synaptic activity into long-term structural and functional changes of synapses and, therefore, vital to cognitive processes. Conversely, malfunction of these receptors is linked to the etiology of brain disorders such as Alzheimer disease and schizophrenia, for which there is no treatment. Therefore, interpreting mechanisms associated in their regulation is very important, however some of the molecular mechanisms governing the functioning of NMDARs are still unknown due to the lack of suitable techniques [1-2]. We are in particular interested in measuring the concentrations of NMDARs' coagonists, glycine and D-Serine, with high spatial resolution in order to understand their function in physiological and possible pathological conditions [3-4]. We propose the development of a multimodal tool based on the scanning ion conductance microscopy (SICM), a well established scanning probe microscopy technique that provides topographic information of biological samples and living tissues with high resolution [5]. Excitingly, in our imaging platform, the scanning probe will also be capable of measuring D-serine and glycine concentrations at synaptic and extra-synaptic nanodomains with a nanometer scale resolution, by means of an electrochemical enzymatic biosensors embedded in the tip of probe itself. The first step towards the employment of the platform for our purpose consisted of several tests to adapt the functioning of the setup for imaging two different cell types: neuron-like PC12 cells and MDCK cells. In parallel, first stages of the nano-pipette probes functionalization have been investigated to make it suitable for future inclusion of the enzymatic biosensor. Merging the imaging capabilities of the methodology and the advancements in tip engineering will allow to measure, in a network of mature neurons, the concentrations of the two co-agonists of NMDARs, while providing the topography of the synapses where these molecules are active. Bibliography 1. Traynelis, S. F. et al. Glutamate Receptor Ion Channels: Structure, Regulation, and Function. Pharmacological Reviews 62, 405{496 (2010) 2. Paoletti, P., Bellone, C. Zhou, Q. NMDA receptor subunit diversity: impact on receptor properties, synaptic plasticity and disease.Nature Reviews Neuroscience 14, 383-400 (2013) 3. Mothet, J.-P., le Bail, M. Billard, J.-M. Time and space profiling of NMDA receptor co-agonist functions. Journal of Neurochemistry 135,210-225 (2015). 4. Mothet, J.-P. et al. D-Serine is an endogenous ligand for the glycine site of the N-methyl-D-aspartate. receptor. Proceedings of the National Academy of Sciences 97, 4926-4931 (2000). 5. Zhu, C., Huang, K., Siepser, N. P., Baker, Scanning Ion Conductance Microscopy, Chemical Reviews 121, 11726-11768 (2021).
• Tin reduction from fluorine doped tin oxide for silicon nanowire-based solar energy harvesting and storage
  
  • Lukas Halagacka
  • Zuzana Gelnarova
  • Mutaz Al-Ghzaiwat
  • Ileana Florea
  • Jiri Hornicek
  • Kamil Postava
  • Martin Foldyna
  Optics Express, Optical Society of America - OSA Publishing, 2021, 29 (20), pp.31465. Hydrogen plasma reduction of fluorine doped tin oxide is a beneficial method to form tin nanodroplets on the sample surface directly in the plasma-enhanced chemical vapor deposition reactor. The formation of catalyst droplets is a crucial initial step for vapor-liquid-solid growth of silicon nanowires for radial junction solar cells and solar fuel cell technology. We present an original optical model which allows us to trace the formation process on fluorine doped tin oxide on soda-lime glass substrate from the in situ data and is in a good agreement with the spectroscopic ellipsometry data measured before and during the reduction process. The model reproduces well the phase shift introduced by a transition double layer in fluorine doped tin oxide which acts as a barrier against the sodium diffusion. Furthermore, we study the process of tin reduction from fluorine doped tin oxide in a real time and compare estimated amount of produced metallic tin with images from scanning electron microscopy.The proposed approach is very important for in situ real-time monitoring of the one-pump-down fabrication process used to grow nanowires and form radial junction devices. (10.1364/OE.435500)
  DOI : 10.1364/OE.435500
• Formation of inverse cones in crystalline silicon by selective etching of amorphous regions resulting from epitaxial breakdown
  
  • Mohsin H
  • Chen W
  • Daineka D
  • Roca I Cabarrocas P
  • Johnson E
  Journal of Physics D: Applied Physics, IOP Publishing, 2021, 54 (49), pp.495103. We report on a process to form micron-scale inverse cones in crystalline silicon without any masking steps using a selective, low temperature (<175°C) plasma process. The selectivity of the process originates from the use of a H 2 plasma that preferentially etches away amorphous cones, formed as a result of epitaxial breakdown, leaving the surrounding crystalline material behind. Efficient etching is realized by pre-coating the reactor walls with hydrogenated amorphous silicon oxide (a-SiO x :H) to prevent any chemical transport of silicon towards the substrate. The etch depth of the amorphous cones is linked directly to the time of exposure to plasma. When densely packed, such structures exhibit useful optical properties, such as specular reflectance as low as 2% (with the sample appearing visibly black in the high density and fully etched regions) and iridescence (in regions of partial etching). (10.1088/1361-6463/ac22d8)
  DOI : 10.1088/1361-6463/ac22d8
• Synthesis of novel π-conjugated functional organic semiconductors for optoelectronic applications
  
  • Ren Shiwei
  , 2021. Organic electronic devices have gained immense popularity in the last three decades because there are promising in terms of their tunable electronic properties, cost effectiveness, versatile functionalization, and processability. The key component of these devices is the organic semiconductor material, which acts as an active layer and determines the device performance. Discovering of novel high-performance building blocks and extending the library of organic semiconductors is one driving force in this filed. In this thesis, a series of novel π-conjugated materials were synthesized as n-type organic semiconductors and characterized by 1H NMR, 13C NMR spectroscopy, high resolution mass spectrometry, electrochemistry and UV-Vis spectroscopy. The manuscript consists of five chapters, and details of each chapter are as follows. Chapter 1 is a general introduction to organic semiconductors. Chapter 2 aims to further advances in the synthesis of organic semiconductors through a study of structure-property-morphology relationships in cross-conjugated 7,7’ disubstituted isoindigo materials. Oxindole is a key building block for the construction of isoindigo and chapter 3 explores the potential use of oxindole as a building block for the preparation of new A-D-A architecture based on π-conjugated bridge, with different bridge lengths. Our objective was to vary the conjugation length by different spacer groups and to alter the linkage position of the isatylidene malononitrile group (4 position vs. 6 position), to analyze the effect on its structural, photophysical and electrochemical properties. Chapter 4 aims to extend π-conjugation length of the isoindigo core, rather than its core-modification. This research is inspired by the renewed interest in the indophenine chemistry and targets to address the regioisomer issue. To this end we replaced the central double bond of isoindigo with quinoidal molecules based on EDOT units. These π-bridges are particularly suited since their provide π-spacer bridge together with good ability to act as conformational locking units to drive the formation of single isomer. In particular, in this chapter we describe the organic synthesis routes, the mechanisms of synthesis of products, physical characterization, UV-visible, electrochemistry, the structure property relationships within these molecules. With the help of 1H NMR experiments , 1H–1H COSY and 1H-1H NOESY analyses we showed a single isomer formation of these molecules. Last chapter demonstrates the fabrication of bio-interface for sensing. In fact, mixed ion/electron semiconducting polymers have recently emerged as promising materials for transducing signals at the interface between the biological elements and electronic devices. In this chapter we describe a study on a new bio-interface based on amphiphilic poly(3-hexylthiophene)-b-poly(3-triethylene-glycol-thiophene), for label-free impedimetric detection of Escherichia coli (E. coli). A set of amphiphilic conjugated random and block polythiophene that contain tetraethylene glycol side chains and possess mixed ionic and electronic conductivities have been synthesized, characterized and assessed as a bacteria biosensing material.
• Liquid-assisted vapor-solid-solid silicon nanowire growth mechanism revealed by in situ TEM when using Cu-Sn bimetallic catalysts
  
  • Ngo Eric
  • Wang Weixi
  • Bulkin Pavel
  • Florea Ileana
  • Foldyna Martin
  • Roca I Cabarrocas Pere
  • Maurice Jean-Luc
  Journal of Physical Chemistry C, American Chemical Society, 2021. The vapor-liquid-solid (VLS) and vapor-solid-solid (VSS) growth mechanisms are widely used to obtain silicon nanowires. In this paper, we report on a hybrid method based on the use of a dual-phase catalyst made of liquid Sn and solid Cu 3 Si, which results in a liquid-assisted VSS (LA-VSS) mechanism. The silicon atoms are brought by atomic hydrogen-assisted dissociation of silane molecules. We observe the growth in situ, in the transmission electron microscope, at (10.1021/acs.jpcc.1c05402)
  DOI : 10.1021/acs.jpcc.1c05402
• Detection of stable positive fixed charges in AlOx activated during annealing with in situ modulated PhotoLuminescence
  
  • Roca I Cabarrocas Pere
  • Desthieux Anatole
  • Sreng Mengkoing
  • Bulkin Pavel
  • Florea Ileana
  • Drahi Etienne
  • Bazer-Bachi Barbara
  • Vanel Jean-Charles
  • Silva François
  • Posada Jorge
  Solar Energy Materials and Solar Cells, Elsevier, 2021, 230, pp.111172. (10.1016/j.solmat.2021.111172)
  DOI : 10.1016/j.solmat.2021.111172
• Non-covalent functionalization of single walled carbon nanotubes with Fe-/co-porphyrin and Co-phthalocyanine for field-effect transistor applications
  
  • Bouanis Fatima
  • Bensifia Mohamed
  • Florea Ileana
  • Mahouche-Chergui Samia
  • Carbonnier Benjamin
  • Grande Daniel
  • Léonard Céline
  • Yassar Abderrahim
  • Pribat Didier
  Organic Electronics, Elsevier, 2021, 96, pp.106212. (10.1016/j.orgel.2021.106212)
  DOI : 10.1016/j.orgel.2021.106212
• Conversion photoélectrique : quelles sont les étapes de simulation les plus incertaines ?
  
  • Migan-Dubois Anne
  • Badosa Jordi
  • Bourdin Vincent
  • Torres Aguilar Moïra I.
  • Bonnassieux Yvan
  , 2021.
• Introduction of a 3 × 4 Mueller matrix decomposition method
  
  • Gonzalez Mariacarla
  • Ossikovski Razvigor
  • Novikova Tatiana
  • Ramella-Roman Jessica
  Journal of Physics D: Applied Physics, IOP Publishing, 2021, 54 (42), pp.424005. (10.1088/1361-6463/ac1622)
  DOI : 10.1088/1361-6463/ac1622
• Role of H 3 + ions in deposition of silicon thin films from SiH 4 /H 2 discharges: modeling and experiments
  
  • Zhang Tinghui
  • Orlac’h Jean-Maxime
  • Ghosh Monalisa
  • Giovangigli Vincent
  • Roca I Cabarrocas Pere
  • Novikova Tatiana
  Plasma Sources Science and Technology, IOP Publishing, 2021, 30 (7), pp.075024. (10.1088/1361-6595/ac0da2)
  DOI : 10.1088/1361-6595/ac0da2
• Polarimetric data-based model for tissue recognition
  
  • Rodríguez Carla
  • van Eeckhout Albert
  • Ferrer Laia
  • Garcia-Caurel Enrique
  • González-Arnay Emilio
  • Campos Juan
  • Lizana Angel
  Biomedical optics express, Optical Society of America - OSA Publishing, 2021, 12 (8), pp.4852. We highlight the potential of a predictive optical model method for tissue recognition, based on the statistical analysis of different polarimetric indicators that retrieve complete polarimetric information (selective absorption, retardance and depolarization) of samples. The study is conducted on the experimental Mueller matrices of four biological tissues (bone, tendon, muscle and myotendinous junction) measured from a collection of 157 ex-vivo chicken samples. Moreover, we perform several non-parametric data distribution analyses to build a logistic regression-based algorithm capable to recognize, in a single and dynamic measurement, whether a sample corresponds (or not) to one of the four different tissue categories. (10.1364/BOE.426387)
  DOI : 10.1364/BOE.426387
• Coupled Investigation of Contact Potential and Microstructure Evolution of Ultra-Thin AlOx for Crystalline Si Passivation
  
  • Zheng Zhen
  • An Junyang
  • Gong Ruiling
  • Zeng Yuheng
  • Ye Jichun
  • Yu Linwei
  • Florea Ileana
  • Roca I Cabarrocas Pere
  • Chen Wanghua
  Nanomaterials, MDPI, 2021, 11 (7), pp.1803. (10.3390/nano11071803)
  DOI : 10.3390/nano11071803
• La Transformation d’un Mouvement Politico-militaire en un Parti Politique : Cas du Mouvement Patriotique du Salut au Tchad 1990.
  
  • Moustapha Ousmane Abali
  , 2021.
• Direct in situ Electron Microscope synthesis of CNTs with applied electric Field and Field Emission
  
  • Vincent P.
  • Panciera F.
  • Florea I.
  • Ezzedine M.
  • Zamfir M.-R.
  • Perisanu S.
  • Cojocaru Costel Sorin
  • Blanchard Nicholas
  • Pribat D.
  • Purcell S.T.
  • Legagneux P.
  , 2021, pp.1-2. This work reports experiments on the oriented growth by electric field of free-standing carbon nanotubes(CNTs) by chemical vapor deposition (CVD) for field emission (FE) applications. The growths were observed in a scanning electron microscope (SEM) and in an environmental transmission electron microscope (ETEM) with the ETEM growths observed in real time. The effects of various applied voltage during growth will be presented. For high voltages, videos show that the maximum length of CNTs are limited either by the mechanical breakdown or FE induced thermal evaporation. Finally, the I(V) curves and current densities obtained will be presented with a focus on the different destruction mechanisms. (10.1109/IVNC52431.2021.9600790)
  DOI : 10.1109/IVNC52431.2021.9600790
• Negative Differential Resistance in Laser-Assisted Field Emission from Si Nanowires
  
  • Choueib M.
  • Derouet A.
  • Vincent P.
  • Ayari A.
  • Poncharal P.
  • Cojocaru Costel Sorin
  • Martel R.
  • Purcell S.T.
  , 2021, pp.1-2. (10.1109/IVNC52431.2021.9600693)
  DOI : 10.1109/IVNC52431.2021.9600693
• Silicon Nanowire Solar Cells with μc‐Si:H Absorbers for Radial Junction Devices
  
  • Dai Letian
  • Foldyna Martin
  • Alvarez J
  • Maurin Isabelle
  • Kleider Jean-Paul
  • Gacoin Thierry
  • Roca I Cabarrocas Pere
  Physica Status Solidi A (applications and materials science), Wiley, 2021, 218 (17), pp.2100231. (10.1002/pssa.202100231)
  DOI : 10.1002/pssa.202100231
• First-principles study on the role of silicon point defects on PERC solar cell degradation
  
  • Tejeda-Zacarias Elisa
  • Baranek Philippe
  • Vach Holger
  , 2021, pp.0809-0813. One of the causes of decrease in the performance of silicon-based solar pannels is linked to light and elevated temperature induced degradation (LeTID). Even if experimental evidence shows that different defects in the bulk material of the modules are involved in the mechanisms behind LeTID, its origins remain unresolved. First-principles methods result in powerful tools to understand this degradation at the nano and microscopic levels. In the present work we propose an approach to model LeTID precursors mechanisms by using ab initio methodology. (10.1109/PVSC43889.2021.9518589)
  DOI : 10.1109/PVSC43889.2021.9518589
• A Contactless Patterned Plasma Processing for Interdigitated Back Contact Silicon Heterojunction Solar Cells Fabrication
  
  • Wang Junkang
  • Ghosh Monalisa
  • Ouadjane Fatima
  • Carbonell Borja
  • Bulkin Pavel
  • Daineka Dmitri
  • Ouaras Karim
  • I Cabarrocas Pere Roca
  • Filonovich Sergej
  • Alvarez Jose
  • Johnson Erik
  , 2021, pp.0596-0601. We present results from the application of a novel, contactless patterning technique to form the doped fingers required for interdigitated back contact silicon heterojunction (IBC-SHJ) solar cells. The technique involves patterning the RF powered electrode in a custom-designed RF-PECVD chamber. The patterned powered electrode – which has 1 mm wide opening-slits in it - is brought in close proximity to the substrate surface, to localize the plasma and the process it performs. In this work, the localized plasma process being employed is an NF3/Ar etching, and is used to form doped fingers that are sub-mm wide and 60 mm long. The interdigitated structure (alternating electron and hole collection zones) is created by first uniformly depositing an intrinsic/n-type a-Si:H passivation stack, followed by an n-type/p-type µc-Si:H recombination junction on the rear side. A passivation layer is also deposited on the front side. The regions for the hole collection zones are then etched down to the intrinsic a-Si:H layer, and finally, a uniform p-type a-Si:H layer is deposited everywhere. The etched finger areas are first investigated by profilometry and spectroscopic ellipsometry, showing that the process can be controlled to leave as little as a few nanometers of passivating intrinsic a-Si:H. This fine control is achieved by pulsing the plasma, to slow the etching rate to a few Å/s. To evaluate the detailed opto-electronic properties of the structure, the samples are mapped out using two contactless techniques: Photoluminescence and Surface Photovoltage measurements (done with a macroscopic scanning Kelvin probe performed under dark and illuminated conditions). These measurements enable one to see both zones of degraded passivation, and the effectiveness of the doped regions in generating an open circuit voltage under illumination. (10.1109/PVSC43889.2021.9518831)
  DOI : 10.1109/PVSC43889.2021.9518831