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This article explores the challenges and solutions in the physical characterization of materials at the microscale using robotized systems, with a specific focus on manipulating and characterizing micrometer-sized particles with different and complex 3D shapes and internal sub-micrometer structures. In this paper, the studied particles are Molybdenum diSulfide (MoS2) based materials generated within the contact interface during friction.These particles are being studied because they offer a particularly promising solution for reducing mechanical friction and the associated high energy losses. However, they are distributed randomly within the contact area and possess intricate sub-micrometer structures. Characterization demands precise manipulation techniques in an in-situ Scanning Electron Microscope(SEM) environment. To address these challenges, existing commercial micro and nanomanipulation tools are integrated within a vacuum SEM chamber, and robotics strategies are investigated to enable the whole process from particle preparation, and manipulation setup definition, to effective MoS 2 particle characterization all in-situ SEM. A set of several complementary experimental investigations are done and involve force measurement and deformation estimation studies, leading to the first qualitative results on MoS 2 based particles directly from the friction track. The work contributes to advancements in both microscale manipulation and characterization. It also has implications for lubrication research. [ABSTRACT FROM AUTHOR]

Robotics and 3D printing pave the way for future methodologies in many industries, but they can also be used for original artistic projects, including technological challenges. Imagine a film studio smaller than the size of your finger, an actor whose height is smaller than the thickness of your fingernail, and a camera using electrons instead of photons: these are the ingredients of the innovative film Stardust Odyssey. Several years of development were necessary to propose highprecision miniaturized robots able to position 3D-printed microfigurines in a scanning electronic microscope (SEM) to produce the film, which was released on 27 November 2019. This original film is available online [1]-[3]. The film, which pays tribute to David Bowie, holds the Guinness world record for the smallest 3D stop-motion animation character in the world [5]. [ABSTRACT FROM AUTHOR]

Aluminum nitride is an excellent electrical insulator and important piezoelectric material making it suitable for a wide range of applications in electronics and optoelectronics. However, to exhibit and preserve those piezoelectric properties, care has to be taken during manufacturing process. Indeed, the c-axis crystalline orientation of AlN is a necessary condition for piezoelectricity. Therefore, the goal of this paper is to compare AlN films grown on (100) silicon substrate by pulsed reactive DC sputtering at 400 °C on top of three different metallic underlayer electrodes (Ti/Pt, Cr/Pt, and AlN/Cr/Pt) by preserving the crystalline properties not only at room temperature but also at high temperatures. Among all deposited AlN films on top of the metallic underlayer electrode, only AlN/Cr/Pt has kept its crystallinity up to 950 °C. [ABSTRACT FROM AUTHOR]

A sulfur hexafluoride based reactive ion etching process allowing to etch several micron deep holes with diameters of the order of a few microns in lithium niobate is reported. Etching of deep structures with aspect ratios up to 1.5 was made possible through the use of an electroplated nickel mask exhibiting a selectivity as high as 20 with respect to lithium niobate. Several crystallograpic orientations were investigated, although particular interest was paid to Y-axis oriented substrates. Photoresist as well as metal masks were also tested and their selectivity was compared. The influence of process parameters such as applied rf power or operating pressure on the sidewall slope angle of the etched patterns was investigated. The technique has been successfully applied to the fabrication of phononic crystals consisting of periodical arrays of 9 μm diameter, 10 μm deep holes, with a 10 μm period, and presenting sidewall angles as high as 73° etched in Y-axis oriented lithium niobate. [ABSTRACT FROM AUTHOR]

In this study, the authors have demonstrated that it is possible to realize several three-dimensional (3D) micro- and nanostructures, by the fabrication of the smallest microhouse using a dual beam scanning electron microscope (SEM)/focused ion beam (FIB) Auriga 60 from Zeiss together with a six degree of freedom robot built with SmarAct components. In this new type of nanolab, cutting, etching, folding, assembling, and then welding thin membranes of silica on top of a cleaved optical fiber SMF28, or production of micro- and nanostructures, like the microhouse, are possible. The authors have experimentally shown that FIB can be used, in this new generation of micro/nanofactory, in combination with SEM, and gas injection system, in order to fabricate three-dimensional microstructures: a microhouse in this study, with ultrahigh accuracy assembly down to 10 nm. By using the theory of sputtering, the authors are able to propose a model of folding thin membranes of numerous materials such as metals, polymers, or crystals, i.e., silica, silicon, potassium tantalite, or lithium niobate. This method is usually described as origami in the literature [W. J. Aroa, H. I. Smith, and G. Barbastathis, Microelectron. Eng. 84, 1454 (2007); W. J. Aroa et al., J. Vac. Sci. Technol., B 25, 2184 (2007); and K. Chalapat et al., Adv. Mater. 25, 91 (2013)]. The experimental results indicate that the introduction of a microrobot inside the SEM vacuum chamber will provide the means to enlarge the scope of clean room facilities to build complex and smart 3D microsystems with heterogeneous materials, especially on the facet of an optical fiber in the lab on fiber new field. The authors propose a new way to easily manufacture many kinds of optical functions for light trapping based on nanoantennas, nanophotonic crystal, axicon or lattice, 3D biosensor with origami, and nanopatterning surfaces or carbon nanotubes, etc. [ABSTRACT FROM AUTHOR]

Emphasis on effect of oxygen on structural and ferroelectric properties of lead zirconia titanate thin film is reported. The thin film is prepared using RF sputtering and annealed in air atmosphere to introduce oxygen vacancies. The photoelectron spectroscopy data reveal lead rich film, which decreases with annealing temperature, while oxygen content decreases from 59.32–55.82% after annealing. The decrease in oxygen causes pyrochlore formation along with perovskite phase in annealed film. The polarization graph shows reduction in domain wall mobility and film polarization due to oxygen vacancy. The pure perovskite phase is achieved using CFA by inserting O2in annealing chamber. [ABSTRACT FROM AUTHOR]

This paper presents a method to determine the mechanical properties of piezoelectric thin films. The vibrational behavior of microcantilevers and clamped-clamped beams actuated by aluminum nitride (AlN) piezoelectric films were analyzed in order to investigate the suitability of these devices as characterization tools. Different geometries of resonators composed of a free-standing structure made up of a TiPt/AlN/TiPt piezoelectric stack were tested. The out-of-plane motion of the resonators was assessed by laser Doppler vibrometry. An AlN Young's modulus of about 200 GPa was extracted from resonance-frequency measurements by means of Comsol software simulations that allow taking into account AlN underetching. This value of Young's modulus was compared to the one measured by a nanoindentation technique. The quality of crystallinity was also assessed using X-ray diffraction (XRD) measurements. We then estimated the residual stress (about 200 MPa) using an interferometry measurement. [ABSTRACT FROM AUTHOR]

We present an optimization process to improve the rejection ratio in integrated beam combiners by locking the dark fringe and then monitoring its intensity. The method proposed here uses the electro-optic effect of lithium niobate in order to lock the dark fringe and to real-time balance the photometric flux by means of a twostage Mach--Zehnder interferometer waveguide. By applying a control voltage on the output Y-junction, we are able to lock the phase and stay in the dark fringe, while an independent second voltage is applied on the firststage intensity modulator, to finely balance the photometries. We have obtained a rejection ratio of 4600 (36.6 dB) at 3.39 µm in transverse electric polarization, corresponding to 99.98% fringe contrast, and shown that the system can compensate external phase perturbations (a piston variation of 100 nm) up to around 1 kHz. We also show the preliminary results of this process on wide-band modulation, where a contrast of 38% in 3.25- to 3.65-µm spectral range is obtained. These preliminary results on wide-band need to be optimized, in particular, for reducing scattered light of the device at the Y-junction. We expect this active method to be useful in high-contrast interferometry, in particular, for astronomical spatial projects actually under study. [ABSTRACT FROM AUTHOR]

A 3 : 1 composition of functional monomer (FM)-multifunctional acrylate was spin-coated and later crosslinked under the influence of oxygen plasma on the surface of poly(dimethyl siloxane) (PDMS) to generate a surface-anchored crosslinked network bearing functional moieties. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and wetting angle measurements were used to analyze the crosslinked monomer surfaces. Scanning electron microscopy was used to visualize the surface of the film after modification. The results of the surface reconstruction of the FM surfaces and plasma-treated PDMS reveal that long-term hydrophilic surfaces were achieved. Thus, the surface architecture could be favorably manipulated with this remarkable technique with a suitable combination of FMs and crosslinkers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [ABSTRACT FROM AUTHOR]

Tungsten oxide WO3 thin films are deposited by DC reactive magnetron sputtering. The Reactive Gas Pulsing Process (RGPP) associated with the GLancing Angle Deposition method (GLAD) are implemented to produce zigzag columnar structures. The oxygen injection time (tON time) and the pulsing period are kept constant. Three tilt angles α are used: 75, 80, and 85° and the number of zigzags N is progressively changed from N = 0.5, 1, 2, 4, 8 to 16. For each film, refractive index, extinction coefficient, and absorption coefficient are calculated from optical transmission spectra of the films measured in the visible region from wavelength values only. Absorption and extinction coefficients monotonously drop as the number of zigzags increases. Refractive indices are the lowest for the most grazing tilt angle α = 85°. The highest refractive index is nevertheless obtained for a number of zigzags close to four. This optimized optical property is directly correlated to changes of the microstructure, especially a porous architecture, which is favored for high tilt angles, and tunable as a function of the number of zigzags. [ABSTRACT FROM AUTHOR]

This paper reports on an original architecture of microfabricated alkali vapor cell designed for miniature atomic clocks. The cell combines diffraction gratings with anisotropically etched single-crystalline silicon sidewalls to route a normally-incident beam in a cavity oriented along the substrate plane. Gratings have been specifically designed to diffract circularly polarized light in the first order, the latter having an angle of diffraction matching the (111) sidewalls orientation. Then, the length of the cavity where light interacts with alkali atoms can be extended. We demonstrate that a longer cell allows to reduce the beam diameter, while preserving the clock performances. As the cavity depth and the beam diameter are reduced, collimation can be performed in a tighter space. This solution relaxes the constraints on the device packaging and is suitable for wafer-level assembly. Several cells have been fabricated and characterized in a clock setup using coherent population trapping spectroscopy. The measured signals exhibit null power linewidths down to 2.23 kHz and high transmission contrasts up to 17%. A high contrast-to-linewidth ratio is found at a linewidth of 4.17 kHz and a contrast of 5.2% in a 7-mm-long cell despite a beam diameter reduced to 600 μm. [ABSTRACT FROM AUTHOR]

The constant improvement of industrial needs to face modern telecommunication challenges leads to the development of novel transducer principles as alternatives to SAW and BAW solutions. The main technological limits of SAW (short-circuit between electrodes) and BAW (precise thickness control) solutions can be overcome by a new kind of transducer based on periodically poled ferroelectric substrate. The approach proposed in this paper exploits a ridge structure combined with a periodically poled transducer (PPT), allowing for the excitation of highly coupled modes unlike previously published results on planar PPTs. High-aspect-ratio ridges showing micrometer dimensions are achieved by dicing PPT plates with a diamond-tipped saw. An adapted metallization is achieved to excite acoustic modes exhibiting electromechanical coupling in excess of 15% with phase velocities up to 10 000 m?s?1. Theoretical predictions show that these figures may reach values up to 20% and 18 000 m?s?1, respectively, using an appropriate design. [ABSTRACT FROM AUTHOR]