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Progress in Natural Science:Materials International 2020年第3期30卷 432-436页

作者： Konrad Kosiba André Rothkirch Junhee Han Liang Deng Benjamin Escher Gang Wang Uta Kühn Jozef Bednarcik Leibniz IFW Dresden Institute for Complex Materials DESY Photon Science 3. Korea institute of Industrial Technology (KITECH) Korea Institute for Rare Metals 4. Fraunhofer Institute for Photonic Microsystems IPMS Department of Engineering 5. Laboratory for Microstructures Institute of Materials Shanghai University 6. J. Safarik University in Kosice Institute of Physics Department of Condensed Matter Physics

The biocompatible Ti40Cu34Pd14Zr10Sn2bulk metallic glass was rapidly heated,also known as flash-annealed,at varying heating rates up to 1579 K/***,the phase formation was characterized via advanced in-situ highenergy X-ray *** has been found that the evolving kinetic constraints can be used as a tool to deliberately alter the crystalline phase *** novel processing route permits to select phases to crystallize to a predefined fraction and,thus,to potentially design the microstructure of materials according to a specified ***,flash-annealing poses a unique synthesis route to design materials with,for instance,good biomechanical compatibility.

关键词： High-energy X-ray diffraction Flash-annealing Phase formation Metallic glass Biocompatible Ti alloy

Coulomb-actuated microbeams revisited: experimental and numerical modal decomposition of the saddle-node bifurcation

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microsystems & Nanoengineering 2021年第3期7卷 111-123页

作者： Anton Melnikov Hermann A.G.Schenk Jorge M.Monsalve Franziska Wall Michael Stolz Andreas Mrosk Sergiu Langa Bert Kaiser fraunhofer institute for photonic microsystems ipms Dresden 01109Germany Arioso Systems GmbH Dresden 01109Germany Brandenburg University of Technology Cottbus-Senftenberg Cottbus 03046Germany

Electrostatic micromechanical actuators have numerous applicati ons in scie nee and *** many applications,they are operated in a narrow frequency range close to resonanee and at a drive voltage of low ***,new applications,such as microelectromechanical systems(MEMS)microspeakers(μSpeakers),have emerged that require operation over a wide frequency and dynamic *** the dynamic performance under such circumstances is still highly ***-of-the-art finite element analysis struggles with pull-in instability and does not deliver the necessary in formation about un stable equilibrium states *** lumped-parameter models amenable to direct physical interpretation are *** inhibits the in dispensable in-depth analysis of the dynamic stability of such *** this paper,we take a major step towards mending the *** combining the finite element method(FEM)with an arc-length solver,we obtain the full bifurcation diagram for electrostatic actuators based on prismatic Euler-Bernoulli beams.A subsequent modal analysis then shows that within very narrow error margins,it is exclusively the lowest Euler-Bernoulli eigenmode that dominates the beam physics over the entire relevant drive voltage *** experiment directly recording the deflection profile of a MEMS microbeam is performed and confirms the numerical findings with astonishing *** enables modeling the system using a single spatial degree of freedom.

关键词： bifurcation modal narrow

Galvanically induced potentials to enable minimal tribochemical wear of stainless steel lubricated with sodium chloride and ionic liquid aqueous solution

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Friction 2018年第2期6卷 230-242页

作者： Tobias AMANN Felix GATTI Natalie OBERLE Andreas KAILER Jürgen RüHE fraunhofer institute for Mechanics of Materials IWM institute for Macromolecular Chemistry University of Freiburg IMTEK-Department of microsystems Engineering University of Freiburg

The effect of galvanically induced potentials on the friction and wear behavior of a 1 RK91 stainless steel regarding to tribocorrosion was investigated using an oscillating ball-on-disk tribometer equipped with an electrochemical cell. The aim of this investigation is to develop a water-based lubricant. Therefore 1 molar sodium chloride(NaCl) and 1% 1-ethyl-3-methylimidazolium chloride [C_2 mim][Cl] water solutions were used. Tribological performance at two galvanically induced potentials was compared with the non-polarized state: cathodic potential-coupling with pure aluminum- and anodic potential-coupling with pure copper. Frictional and electrochemical response was recorded during the tests. In addition, wear morphology and chemical composition of the steel were analyzed using scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS), respectively. The galvanically induced cathodic polarization of the stainless steel surface results in electrochemical corrosion protection and the formation of a tribolayer. Cations from the electrolyte(sodium Na^+ and 1-ethyl- 3-methylimidazolium [C_2 mim]^+) interact and adhere on the surface. These chemical interactions lead to considerably reduced wear using 1 NaC l(86%) and 1% 1-ethyl-3-methylimidazolium chloride [C_2 mim][Cl](74%) compared to the nonpolarized system. In addition, mechanical and corrosive part of wear was identified using this electrochemical technique. Therefore this method describes a promising method to develop water-based lubricants for technical applications.

关键词： sliding wear tribochemistry potential controlled friction and wear galvanic coupling ionic liquids tribolayer formation

LED-pumped whispering-gallery laser

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photonics Research 2017年第6期5卷 36-40页

作者： SIMON J.HERR KARSTEN BUSE INGO BREUNIG Laboratory for Optical Systems Department of Microsystems Engineering University of Freiburg fraunhofer institute for Physical Measurement Techniques IPM

A low-cost light-emitting diode(LED) is sufficient to pump a quasi-continuous-wave bidirectional high-Q whispering-gallery resonator laser made of Nd:YVO_4. This is remarkable because of the very limited spatial and spectral coherence of an LED. The LED, delivering up to 3.5 W, centered around 810 nm, is turned on in intervals of 100 μs duration, and for these periods a laser output exceeding 0.8 mW has been ***, 0.1-s-long laser pulses are demonstrated. To the best of our knowledge, this is the first demonstration of an LED-pumped high-Q whispering-gallery laser. The concept can be extended easily to other laser active materials. A prospect is also to pump several of such lasers with a single LED.

关键词： LED-pumped whispering-gallery laser Nd

Combining thermal scanning probe lithography and dry etching for grayscale nanopattern amplification

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microsystems & Nanoengineering 2024年第1期10卷 335-344页

作者： Berke Erbas Ana Conde-Rubio Xia Liu Joffrey Pernollet Zhenyu Wang Arnaud Bertsch Marcos Penedo Georg Fantner Mitali Banerjee Andras Kis Giovanni Boero Juergen Brugger microsystems Laboratory École Polytechnique Fédérale de Lausanne(EPFL)Lausanne 1015Switzerland Center of MicroNanoTechnology(CMi) EPFLLausanne 1015Switzerland Laboratory of Nanoscale Electronics and Structures École Polytechnique Fédérale de Lausanne(EPFL)Lausanne 1015Switzerland Laboratory for Bio-and Nano-Instrumentation École Polytechnique Fédérale de Lausanne(EPFL)Lausanne 1015Switzerland Laboratory of Quantum Physics Topology and CorrelationsÉcole Polytechnique Fédérale de Lausanne(EPFL)Lausanne 1015Switzerland Present address:institute of Materials Science of Barcelona ICMAB-CSIC Campus UABBellaterra 08193Spain Present address:School of Integrated Circuits and Electronics MIIT Key Laboratory for Low-Dimensional Quantum Structure and DevicesBeijing Institute of TechnologyBeijing 100081China

Grayscale structured surfaces with nanometer-scale features are used in a growing number of applications in optics and *** scanning probe lithography achieves a lateral resolution below 10 nm and a vertical resolution below 1 nm,but its maximum depth in polymers is ***,we present an innovative combination of nanowriting in thermal resist and plasma dry etching with substrate cooling,which achieves up to 10-fold amplification of polymer nanopatterns into SiO_(2) without proportionally increasing surface *** nanopatterns in SiO_(2) with 400 nm pitch and 150 nm depth are fabricated free of shape distortion after dry *** exemplify the possible applications of the proposed method,grayscale dielectric nanostructures are used for scalable manufacturing through nanoimprint lithography and for strain nanoengineering of 2D *** a method for aspect ratio amplification and smooth grayscale nanopatterning has the potential to find application in the fabrication of photonic and nanoelectronic devices.

关键词： lithography thermal pattern

The push-pull principle:an electrostatic actuator concept for low distortion acoustic transducers

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microsystems & Nanoengineering 2022年第6期8卷 181-194页

作者： Bert Kaiser Hermann A.G.Schenk Lutz Ehrig Franziska Wall Jorge M.Monsalve Sergiu Langa Michael Stolz Anton Melnikov Holger Conrad David Schuffenhauer Harald Schenk fraunhofer institute for photonic microsystems ipms DresdenGermany Arioso Systems GmbH since Sep.1st 2022:BOSCH Sensortec GmbHDresdenGermany Chair of Micro and Nano Systems Brandenburg University of Technology Cottbus-SenftenbergCottbusGermany

Electrostatic actuators are of particular interest for microsystems(MEMS),and in particular for MEMS audio transducers for use in advanced true wireless *** are attractive because of their typically low electrical capacitance and because they can be fabricated from materials that are compatible with standard complementary metal-oxide semiconductor(CMOS)*** high audio performance and in particular low harmonic distortion(THD)the implementation of the push-pull principle provides strong *** an arrangement of three electrodes in a conjunct moving configuration on a beam,we demonstrate here for the first time a balanced bending actuator incarnating the push-pull principle operating at low *** first design already exhibits a harmonic distortion as low as 1.2%at 79 dB using a signal voltage of only 6 V_(p) and a constant voltage of only±10 V_(dc) in a standard acoustic measurement ***,exceeding our previously reported approach in all three key performance indications at the same *** expect that our novel electrode configurations will stimulate innovative electrostatic actuator developments for a broad range of *** this paper we report the basic theory,the fabrication and the performance of our novel actuator design acting as an audio transducer.

关键词： distortion push electrostatic

photonic integrated circuit components based on amorphous silicon-on-insulator technology

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photonics Research 2016年第3期4卷 126-134页

作者： Timo Lipka Lennart Moldenhauer Jorg Muller Hoc Khiem Trieu institute of microsystems Technology Hamburg University of Technology

We present integrated-optic building blocks and functional photonic devices based on amorphous siliconon-insulator technology. Efficient deep-etched fiber-to-chip grating couplers, low-loss single-mode photonic wire waveguides, and compact power splitters are presented. Based on the sub-μm photonic wires, 2 × 2 Mach–Zehnder interferometers and add/drop microring resonators(MRRs) with low device footprints and high finesse up to 200 were realized and studied. Compact polarization rotators and splitters with ≥10 d B polarization extinction ratio were fabricated for the polarization management on-chip. The tuning and trimming capabilities of the material platform are demonstrated with efficient microheaters and a permanent device trimming method, which enabled the realization of energy-efficient photonic circuits. Wavelength multiplexers in the form of cascaded filter banks and 4 × 4 routers based on MRR switches are presented. Fabrication imperfections were analyzed and permanently corrected by an accurate laser-trimming method, thus enabling eight-channel multiplexers with record low metrics of sub-m W static power consumption and ≤1°C temperature overhead. The high quality of the functional devices, the high tuning efficiency, and the excellent trimming capabilities demonstrate the potential to realize low-cost, densely integrated, and ultralow-power 3D-stacked photonic circuits on top of CMOS microelectronics.

关键词： photonic integrated circuit components based on amorphous silicon-on-insulator technology SOI MRR OADM

Concept and proof for an all-silicon MEMS micro speaker utilizing air chambers

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microsystems & Nanoengineering 2019年第1期5卷 196-206页

作者： Bert Kaiser Sergiu Langa Lutz Ehrig Michael Stolz Hermann Schenk Holger Conrad Harald Schenk Klaus Schimmanz David Schuffenhauer fraunhofer-institute for photonic microsystems 01109 DresdenGermany Chair of Micro and Nano Systems Brandenburg University of Technology Cottbus-Senftenberg03013 CottbusGermany

MEMS-based micro speakers are attractive candidates as sound transducers for smart devices,particularly wearables and *** such devices,high sound pressure levels,low harmonic distortion and low power consumption are required for industrial,consumer and medical *** ability to integrate with microelectronic circuitry,as well as scalable batch production to enable low unit costs,are the key factors benchmarking a *** Nanoscopic Electrostatic Drive based,novel micro speaker concept presented in this work essentially comprises inplane,electrostatic bending actuators,and uses the chip volume rather than the its surface for sound *** describe the principle,design,fabrication,and first characterization *** design options and governing equations are given and *** a standard acoustical test setup(ear simulator),a MEMS micro speaker generated a sound pressure level of 69 dB at 500 Hz with a total harmonic distortion of 4.4%,thus proving the *** potential on sound pressure as well as linearity improvement is *** expect that the described methods can be used to enhance and design other MEMS devices and foster modeling and simulation approaches.

关键词： sound utilizing distortion

Resonant cavity-enhanced quantum dot field-effect transistor as a single-photon detector

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Chinese Physics B 2014年第10期23卷 162-167页

作者：董宇王广龙王红培倪海桥陈建辉高凤岐乔中涛杨晓红牛智川 Laboratory of Nanotechnology and microsystems Mechanical Engineering College institute of Semiconductors Chinese Academy of Sciences

A resonant cavity-enhanced （RCE） quantum dot （QD） field-effect transistor （RCEQDFET） is designed for single- photon detection in this paper. Adding distributed Bragg reflection （DBR） mirrors to the single-photon detector （SPD）, we improve the light absorption efficiency of the SPD. The effects of the reflectivity of the mirrors, the thickness and light absorption coefficient of the absorbing layer on the detector＇s light absorption efficiency are investigated, and the resonant cavity is determined by using the air/semiconductor interface as the mirror on the top. Through analyzing the relationship between the refractive index of AlxGal_xAs and A1 component, we choose A1As/Alo.15Gao.85As as the material of the mirror on the bottom. The pairs of A1As/Alo.15Gao.85As film are further determined to be 21 by calculating the reflectivity of the mirror. The detector is fabricated from semiconductor heterostructures grown by molecular beam epitaxy. The reflection spectrum, photoluminescence （PL） spectrum, photocurrent response, and channel current of the detector are tested and the results show that the RCEQDFET-SPD designed in this paper has better performances in photonic response and wavelength selection.

关键词： single-photon detector quantum dot field-effect transistor resonant cavity enhanced

Near-field launching and mapping unidirectional surface plasmon polaritons using an automated dual-tip scanning near-field optical microscope

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photonics Research 2022年第11期10卷 2628-2641页

作者： NAJMEH ABBASIRAD ANGELA BARREDA YI-JU CHEN JER-SHING HUANG ISABELLE STAUDE FRANK SETZPFANDT THOMAS PERTSCH institute of Applied Physics Abbe Center of PhotonicsFriedrich Schiller University Jena07745 JenaGermany institute of Solid State Physics Friedrich Schiller University Jena07743 JenaGermany Research Department of Nanooptics Leibniz Institute of Photonic Technology07745 JenaGermany fraunhofer-institute for Applied Optics and Precision Engineering IOF 07745 JenaGermany

The spatial distribution of electromagnetic fields emitted from the aperture tip of a scanning near-field optical microscope(SNOM), which is called the emission pattern, depends on the geometry of the apex and the material composition of the tip’s coating. In previous works, experimental measurements of the emission pattern from the aperture tip were performed mostly in the far field. Moreover, the corresponding theoretical models were also developed based on these far-field measurements. Here, we have used the automated dual-tip SNOM to systematically characterize the emission from the aperture tip in the near field. In this regard, we have considered three different pairs of excitation and detection tips with distinct geometries. The emission patterns of the excitation tips were mapped using detection tips. Unidirectional surface plasmon polaritons(SPPs) at the surface of a gold platelet were launched by an excitation tip and measured in the near field by the detection tip. The experimental results were numerically reproduced by means of the Bethe–Bouwkamp model. This work puts into evidence the applicability of the automated dual-tip SNOM as the only available characterization technique to measure the emission from aperture tips in the near field. The reported asymmetric SPP radiation patterns can find applications in photonic integrated circuits or in biological and chemical sensing.

关键词： optical excitation field