Spontaneous shape transition of Mn_xGe_1−x islands to long nanowires

• S. Javad Rezvani,
• Luc Favre,
• Gabriele Giuli,
• Yiming Wubulikasimu,
• Isabelle Berbezier,
• Augusto Marcelli,
• Luca Boarino and
• Nicola Pinto

Beilstein J. Nanotechnol. 2021, 12, 366–374, doi:10.3762/bjnano.12.30

• lamellas were ultimately thinned during a last step using a FIB based on an inert-gas source working at low energy to prevent sample amorphization. HRTEM investigations were performed at the CP2M microanalysis center (Marseille, France) on a JEOL JEM 2010 F URP22 instrument using a 200 keV primary energy

Nickel nanoparticle-decorated reduced graphene oxide/WO₃ nanocomposite – a promising candidate for gas sensing

• Ilka Simon,
• Alexandr Savitsky,
• Rolf Mülhaupt,
• Vladimir Pankov and
• Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

• –carbon composite (Ni@rGO). Previous work with WO3 had used either NiO (as part of the WO3 lattice), solely carbon, Pd-surface decorated WO3 (Pd@WO3), or Pd or Pt@carbon@WO3. We demonstrate the gas response for pure WO3, rGO/WO3 and Ni@rGO/WO3 sensing elements towards NO2 and acetone in air as well as

• towards CO in N2. The addition of 0.35 wt % Ni@rGO composite to WO3 enables the increase of the sensory response by more than 1.6 times for NO2 vapors. The gas response towards acetone using 0.35 wt % Ni@rGO/WO3 composite was 1.5 times greater for 3500 ppm than for 35,000 ppm acetone. For 0.35 wt % Ni@rGO

• /WO3 composite and CO gas, a response time (Tres) of 7 min and a recovery time (Trec) of 2 min was determined. Keywords: gas sensing; magnetic measurements; nickel nanoparticles; reduced graphene oxide; tungsten oxide; Introduction Toxic gases as well as volatile organic compounds (VOC) are known air

Exploring the fabrication and transfer mechanism of metallic nanostructures on carbon nanomembranes via focused electron beam induced processing

• Christian Preischl,
• Linh Hoang Le,
• Elif Bilgilisoy,
• Armin Gölzhäuser and
• Hubertus Marbach

Beilstein J. Nanotechnol. 2021, 12, 319–329, doi:10.3762/bjnano.12.26

• molecules [32]. EBISA should also work with electrons of rather low energy fabricated by a flood gun instead of the focused electron beam. This macroscopic process is schematically depicted in Figure S6 (Supporting Information File 1). If the precursor gas dosage takes place directly after electron

• deactivation via interaction of active sites with residual gas molecules. At this point, it should be noted that a mixture of both effects appears to be most likely. However, the quantitative contribution is not known. As it was reported that free-standing hybrid structures consisting of metallic

• h at 70 °C. Then, a repetition of rinsing in DMF and ethanol was applied to the samples in order to remove physically absorbed TPT molecules. The samples were consequently dried by a stream of nitrogen gas and preserved in argon environment until use in FEBID experiments. The FEBIP experiments were

The patterning toolbox FIB-o-mat: Exploiting the full potential of focused helium ions for nanofabrication

• Victor Deinhart,
• Lisa-Marie Kern,
• Jan N. Kirchhof,
• Sabrina Juergensen,
• Joris Sturm,
• Enno Krauss,
• Thorsten Feichtner,
• Sviatoslav Kovalchuk,
• Michael Schneider,
• Dieter Engel,
• Bastian Pfau,
• Bert Hecht,
• Kirill I. Bolotin,
• Stephanie Reich and
• Katja Höflich

Beilstein J. Nanotechnol. 2021, 12, 304–318, doi:10.3762/bjnano.12.25

• , large ion doses lead to gas agglomeration and the formation of bubbles, manifesting as strong surface swelling [23]. Furthermore, the associated sputter rate of light ions is roughly an order of magnitude smaller than that of Ga ions [21][22]. In addition, the low ion mass has further implications. The

• typically described with a Gaussian profile in He ion microscopy [27]. It has to be mentioned that the beam parameters for a gas field ion source (GFIS) are strongly correlated and, thus, not independently adjustable. Due to the extremely small size of the source typical currents are only in the range of

• picoamperes. Varying the gas flux can finely adjust the beam current. However, too large gas fluxes lead to a reduced trimer lifetime. Otherwise, the current can be modified by the size of the selected aperture and by the location of the beam crossover relative to this aperture (named ‘spot control’ by the

Gold(I) N-heterocyclic carbene precursors for focused electron beam-induced deposition

• Cristiano Glessi,
• Aya Mahgoub,
• Cornelis W. Hagen and
• Mats Tilset

Beilstein J. Nanotechnol. 2021, 12, 257–269, doi:10.3762/bjnano.12.21

• nanostructures [1][2][3][4]. This mask-less nanofabrication technique uses gaseous molecules as precursors. The gas molecules are introduced in the specimen chamber of a scanning electron microscope (SEM), adsorb onto a substrate, and dissociate upon electron irradiation, leaving a solid deposit on the substrate

• and some volatile fragments. The technique has been employed in applications such as the fabrication of nanoconnectors [5], extreme ultra-violet lithography (EUVL) mask repair [6], AFM probe tips [7][8][9], nanodevices for plasmonics [10], gas sensors [11][12], optoelectronics [13], and magnetic [14

• temperatures of these precursors exceeded the maximum operating temperature of standard gas injection systems (GIS) in the SEM, an unconventional method was chosen to introduce the precursors from a custom-built reservoir mounted directly on top of a heated substrate on which also the deposits were directly

TiO_x/Pt₃Ti(111) surface-directed formation of electronically responsive supramolecular assemblies of tungsten oxide clusters

• Marco Moors,
• Yun An,
• Agnieszka Kuc and
• Kirill Yu. Monakhov

Beilstein J. Nanotechnol. 2021, 12, 203–212, doi:10.3762/bjnano.12.16

• W3O9. To stabilize and utilize different charge states of the cluster outside the gas phase, we have prepared a substrate material, which, on the one hand, offers a sufficient template effect for the self-organization of the nanoclusters and, on the other hand, exhibits a rather low electronic surface

• titanium oxide layer due to the formed W3O9 interlayer. In consequence, this only indirect bonding to the surface leads to an electronic state, which should be very near to that of an isolated molecule in the gas phase. Indeed, our experiments with the STM tip exhibited a behavior that had never been

• atoms remain in the oxidation state +VI and one is reduced to +IV (compare Figure 3c and Figure 3d). The latter one has less unoccupied electronic states and, therefore, is not resolved by scanning with a positive bias voltage. Our DFT calculations of W3O9 and of a hypothetical W3O8 molecule in the gas

Imaging of SARS-CoV-2 infected Vero E6 cells by helium ion microscopy

• Natalie Frese,
• Patrick Schmerer,
• Martin Wortmann,
• Matthias Schürmann,
• Matthias König,
• Michael Westphal,
• Friedemann Weber,
• Holger Sudhoff and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2021, 12, 172–179, doi:10.3762/bjnano.12.13

• electrons to excite and detect secondary electrons from the sample surface. Due to the high brightness and low energy spread of its atomically sharp gas field ion source, the smallest attainable focused spot size is about 0.3 nm [22]. With its significantly smaller convergence angle compared to SEM, HIM

• , residual gas as well as the specimen itself are considered the main contributors of hydrocarbons [32][33]. Due to the much larger mass of He+ ions compared to electrons, their sputter rate is typically much higher. Since organic compounds are ablated from the sample surface, hydrocarbon deposition is

A review on the green and sustainable synthesis of silver nanoparticles and one-dimensional silver nanostructures

• Sina Kaabipour and
• Shohreh Hemmati

Beilstein J. Nanotechnol. 2021, 12, 102–136, doi:10.3762/bjnano.12.9

• ” synthesis methods. Several physical methods for top-down synthesis of silver nanostructures including ball milling [105][106][107], laser ablation [108][109][110][111][112], evaporation–condensation [113][114], electromagnetic levitation gas condensation (ELGC) [115], ultrasonication [116][117][118][119

• chamber where the metal of interest is vaporized into a low-density gas phase, becomes supersaturated by decreasing temperature, and then is condensed to form nuclei which then grow into nanoparticles [113][137]. The chamber gas usually contains an inert gas such as helium or argon [113][224]. AgNPs

• the gas phase to the reactor chamber. Second, adsorption of the vapor on the substrate surface and establishment of medium compounds followed by formation of a layer. Third, nucleation and growth of the layer through heating [241]. The important factors that control the process and size of synthesized

Fusion of purple membranes triggered by immobilization on carbon nanomembranes

• René Riedel,
• Natalie Frese,
• Fang Yang,
• Martin Wortmann,
• Raphael Dalpke,
• Daniel Rhinow,
• Norbert Hampp and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2021, 12, 93–101, doi:10.3762/bjnano.12.8

• . Afterwards the sample was rinsed with ethanol, dried in a stream of nitrogen, and stored under argon gas. Sample characterization X-ray photoelectron spectroscopy (XPS) has been conducted in an Omicron Multiprobe UHV system (Scienta Omicron GmbH, Taunusstein, Germany) using monochromatic Al Kα irradiation, a

The role of gold atom concentration in the formation of Cu–Au nanoparticles from the gas phase

• Yuri Ya. Gafner,
• Svetlana L. Gafner,
• Darya A. Ryzkova and
• Andrey V. Nomoev

Beilstein J. Nanotechnol. 2021, 12, 72–81, doi:10.3762/bjnano.12.6

• using computer simulation methods of only one of the physical methods used for the production of binary Cu–Au nanoparticles (i.e, the synthesis from a high-temperature gas phase). For the first time, a detailed study of the dependence of the atomic ordering of Cu–Au particles on the concentration of

• and internal structure, and the main mechanisms involved in the formation of binary Cu–Au nanoparticles upon deposition from a gaseous medium. Computer Model Synthesis from the gas phase is one of the main physical methods used for producing nanopowders. However, since particle formation reactions

• corresponds to the stage of transporting the atoms from the evaporated substances using the buffer gas to the synthesis chamber. The equations of atomic motion were solved based on the Verlet velocity scheme [16] with an integration step of h = 1 fs. During nucleation and further growth of the particles from

Atomic layer deposited films of Al₂O₃ on fluorine-doped tin oxide electrodes: stability and barrier properties

• Hana Krýsová,
• Michael Neumann-Spallart,
• Hana Tarábková,
• Pavel Janda,
• Ladislav Kavan and
• Josef Krýsa

Beilstein J. Nanotechnol. 2021, 12, 24–34, doi:10.3762/bjnano.12.2

• the topic of the present work, in which atomic layer deposition (ALD) is used as the coating technique [1]. This method is a gas-phase process which relies on a molecular approach. Therefore, a conformal coating, which reaches the pores and crevasses of the sample, can be obtained. Protective coating

• precursor was 0.1 s with a purge time of 5 s and the pulse of H2O was 0.1 s with a purge time of 10 s. TMA and water were maintained at 22 °C. Nitrogen (99.999%, Linde) was used as a carrier gas. The deposition of aluminium oxide films on silicon or FTO was carried out by performing 30, 60, 120, and 200

Bio-imaging with the helium-ion microscope: A review

• Matthias Schmidt,
• James M. Byrne and
• Ilari J. Maasilta

Beilstein J. Nanotechnol. 2021, 12, 1–23, doi:10.3762/bjnano.12.1

• using the HIM for secondary ion mass spectroscopy (SIMS) they wrote: “[If] a heavier gas in addition to or in place of helium [would be used] the resulting beam [c]ould then be used to generate enough secondary ions to permit SIMS analysis.” Both ideas were quickly proven to be correct in the following

• HIM this is realised by the atomic level (or gas field) ion source, which, in essence, is a single tungsten atom at which the gas atoms are ionised [1][39]. The column optics projects an image of that atom onto the sample, which commonly is referred to as “beam spot”. The achievable lateral resolution

• routinely applied drying methods is given. (I) Freeze drying: Samples are frozen (e.g., using a plunge or high-pressure freezer) and then dried under vacuum. Uryu et al. suggested a pathway which includes plunge freezing for instantaneous immobilization followed by freeze drying in a cold nitrogen gas and

Towards 3D self-assembled rolled multiwall carbon nanotube structures by spontaneous peel off

• Jonathan Quinson

Beilstein J. Nanotechnol. 2020, 11, 1865–1872, doi:10.3762/bjnano.11.168

• piezoelectric generator, a quartz tube (2.2 cm inner diameter), a 50 cm long horizontal tube furnace, a gas flow controller, and an acetone gas trap. The total gas flow was 2500 sccm for all experiments. In order to obtain different compositions within the MWCNTs, different sequences of different precursors

• . First, a liquid precursor consisting of toluene (99.9%, Sigma-Aldrich) and 5 wt % of ferrocene (98%, Aldrich, purified via sublimation at 90 °C prior to use) was injected into the furnace with Ar gas flow at 2000 sccm in a first precursor line (Supporting Information File 1, Figure S3) for 3 min. In a

• second precursor line, 500 sccm of Ar were used. Next, while the same ferrocene and toluene mixture was injected into the furnace, ammonia (≥99.98%, BOC) was added to the carrier gas at 30 sccm for 15 min. Finally, acetylene (industrial grade, BOC) was used as a gas precursor at 100 sccm with hydrogen

Scanning transmission imaging in the helium ion microscope using a microchannel plate with a delay line detector

• Eduardo Serralta,
• Nico Klingner,
• Olivier De Castro,
• Michael Mousley,
• Santhana Eswara,
• Serge Duarte Pinto,
• Tom Wirtz and
• Gregor Hlawacek

Beilstein J. Nanotechnol. 2020, 11, 1854–1864, doi:10.3762/bjnano.11.167

• information. Therefore, the user can generate BF, ADF, or other DF images through post-processing the transmission data at will at any time. The experiments were conducted using the npSCOPE prototype, which is a high-vacuum instrument based on the gas field ion source (GFIS) column technology. This instrument

• Orion NanoFab chamber, with a reduced travel range. The images presented in this work in transmission mode, unless stated differently, were taken while operating the microscope at 30 kV acceleration voltage, with a 10 μm aperture, in spot control 6 (crossover position of −247 mm) and gun gas pressure of

• based on their gray levels. For this image we used 30 kV acceleration voltage, with a 5 μm aperture, in spot control 5, a gun gas pressure of 1.3 × 10−6 mbar, and 300 μs pixel dwell time. The sample comprises a 20 nm thick silicon nitride membrane used as a support layer. A 20 nm thick layer of silicon

Piezotronic effect in AlGaN/AlN/GaN heterojunction nanowires used as a flexible strain sensor

• Jianqi Dong,
• Liang Chen,
• Yuqing Yang and
• Xingfu Wang

Beilstein J. Nanotechnol. 2020, 11, 1847–1853, doi:10.3762/bjnano.11.166

• introduced during the epitaxial growth process [1][2][3]. Furthermore, the analysis of the internal polarization of the AlGaN/AlN/GaN heterojunction showed the existence of a 2D electron gas (2DEG), which effectively suppresses the degradation of the carrier mobility caused by the scattering at charge

Unravelling the interfacial interaction in mesoporous SiO₂@nickel phyllosilicate/TiO₂ core–shell nanostructures for photocatalytic activity

• Bridget K. Mutuma,
• Xiluva Mathebula,
• Isaac Nongwe,
• Bonakele P. Mtolo,
• Boitumelo J. Matsoso,
• Rudolph Erasmus,
• Zikhona Tetana and
• Neil J. Coville

Beilstein J. Nanotechnol. 2020, 11, 1834–1846, doi:10.3762/bjnano.11.165

• silica in mSiO2@NiPS/TiO2 (Supporting Information File 1, Figure S3). The textural properties of the core–shell nanostructures were evaluated using N2 physisorption analysis. Figure 2a shows that the nitrogen gas adsorption–desorption isotherms of mSiO2 and the mSiO2@NiPS core–shell nanostructure are of

• operating at 120 kV) and scanning electron microscopy (FEI Nova Nanolab 600 FIB/SEM). The N2 adsorption and desorption isotherms of the samples were recorded using a Micromeritics Tristar 3000 instrument at 77 K. Before running the experiment, the samples were degassed at 150 °C for 12 h in N2 gas. The

Electron beam-induced deposition of platinum from Pt(CO)₂Cl₂ and Pt(CO)₂Br₂

• Aya Mahgoub,
• Hang Lu,
• Rachel M. Thorman,
• Konstantin Preradovic,
• Titel Jurca,
• Lisa McElwee-White,
• Howard Fairbrother and
• Cornelis W. Hagen

Beilstein J. Nanotechnol. 2020, 11, 1789–1800, doi:10.3762/bjnano.11.161

• precursor gas into the vacuum chamber of an electron microscope [2][3]. At specific locations on the substrate exposed to the electron beam, the transiently adsorbed precursor molecules decompose, forming a deposit while the volatile byproducts of the reaction desorb into the vacuum [4][5][6][7]. One of the

• [17]. The typical issues to be addressed when testing novel precursors include: (i) precursor storage, (ii) gas injection system (GIS) loading, (iii) optimal precursor temperature for deposition, (iv) precursor volatility and transport from the SEM chamber, (v) ability of precursor to form solid

• rate of 10 °C/min. FEBID in the SEM Deposition was performed in a Thermo Fisher Scientific (TFS) Nova Nano Lab 650 dual-beam system. Standard TFS gas injection systems (GIS) were used to introduce the new precursors into the SEM chamber, using a separate GIS for each precursor. Since Pt(CO)2Cl2 and Pt

Molecular dynamics modeling of the influence forming process parameters on the structure and morphology of a superconducting spin valve

• Alexander Vakhrushev,
• Aleksey Fedotov,
• Vladimir Boian,
• Roman Morari and
• Anatolie Sidorenko

Beilstein J. Nanotechnol. 2020, 11, 1776–1788, doi:10.3762/bjnano.11.160

• the force field created through pair interactions and refines this value. This value is due to the presence of electron gas in the material and, in accordance with [33][34], can be calculated by the formula where Ai is an empirical force field parameter; is the value of sublimation energy; and is

Imaging and milling resolution of light ion beams from helium ion microscopy and FIBs driven by liquid metal alloy ion sources

• Nico Klingner,
• Gregor Hlawacek,
• Paul Mazarov,
• Wolfgang Pilz,
• Fabian Meyer and
• Lothar Bischoff

Beilstein J. Nanotechnol. 2020, 11, 1742–1749, doi:10.3762/bjnano.11.156

• resolution of Ne+ from a gas field ion source. The comparison allows one to select the best possible ion species for the specific demands in terms of resolution, beam current, and volume to be drilled. Keywords: focused ion beam; gas field ion source; liquid metal alloy ion source; resolution; Introduction

• resolution. This mass range is of interest due to the interaction of the ions with the near-surface region and, among other use cases, the application of these ions for indirect or resist-aided lithography [3]. The introduction of the helium ion microscope (HIM) [4], working with a gas field ion source (GFIS

• agreement with the ΔE ~ m1/3 dependence for single-charged monomers [2]. In the noble gas irradiation experiments described here, a GFIS in a helium ion microscope ORION NanoFab (Carl Zeiss) [5][28] was used. For irradiation with light metal ions, a LMAIS installed in a FIB/SEM VELION system (Raith) [2][18

Out-of-plane surface patterning by subsurface processing of polymer substrates with focused ion beams

• Serguei Chiriaev,
• Luciana Tavares,
• Vadzim Adashkevich,
• Arkadiusz J. Goszczak and
• Horst-Günter Rubahn

Beilstein J. Nanotechnol. 2020, 11, 1693–1703, doi:10.3762/bjnano.11.151

• interest within diverse fields of materials science and technology [1]. In recent years, the capabilities of FIBs have been substantially enhanced leading to a broad range of applications by the implementation of light ion beams (He+ and Ne+) emitted by a gas field ion source (GFIS). This has enabled

• and bulge the film. At higher fluence values (corresponding to the cells in row 3, Figure 4a), the bulges are almost inexistent, which can be explained by the appearance of holes in the irradiated regions (e.g., cells A3 and B3 in Figure 4a). This induces gas release and deflation of the bulges. These

• continuous films of low permeability cannot be patterned with the technique described here. In order to apply the technique, a gas-leakage path, for instance, in the form of an array of microholes, needs to be prefabricated in the films before irradiation. As an alternative to a continuous film, an array of

The influence of an interfacial hBN layer on the fluorescence of an organic molecule

• Christine Brülke,
• Oliver Bauer and
• Moritz M. Sokolowski

Beilstein J. Nanotechnol. 2020, 11, 1663–1684, doi:10.3762/bjnano.11.149

• excited electron from the LUMO into unoccupied metallic states and/or a filling of the HOMO by an electron from the metal. We note that the HOMO and LUMO for the chemisorbed molecule differ from those of the gas phase molecule. Thus, the LUMO that is drawn in Figure 1a is not identical to the LUMO in the

• gas phase. For a second molecular layer, even without significant overlap of the wave functions of metal and molecule, quenching is also possible, because the CT may occur from the second layer to the metal via states in the first layer [5]. In principle, the hybridization of molecular and metallic

• differential energies of the PTCDA orbitals remain unaltered in comparison to those of PTCDA in the gas phase, which points to a more physisorptive bonding to the hBN/Cu(111) surface [32]. The HOMO of PTCDA is found at ca. 2.6 eV [32]. Hence, we can expect that both the LUMO and the HOMO are placed within the

Selective detection of complex gas mixtures using point contacts: concept, method and tools

• Alexander P. Pospelov,
• Victor I. Belan,
• Dmytro O. Harbuz,
• Volodymyr L. Vakula,
• Lyudmila V. Kamarchuk,
• Yuliya V. Volkova and
• Gennadii V. Kamarchuk

Beilstein J. Nanotechnol. 2020, 11, 1631–1643, doi:10.3762/bjnano.11.146

• potential of quantum point-contact sensors to selectively detect components of a gas mixture in real time. To demonstrate the high efficiency of the proposed approach, we analyze the human breath, which is the most complex of the currently known natural gas mixtures with extremely low concentrations of its

• conduction channel. With this information we can unambiguously characterize the analyzed system, since knowing the energy parameters is key to successfully identifying and modeling the physicochemical properties of various quantum objects. Using the point-contact spectroscopic profile of a complex gas

• sensor to selectively detect components of a gas mixture in real time. The importance of using point-contact sensor devices to solve complex problems is highlighted by, at least, two facts. First, our analyzed medium, the human breath, is the most complex of the currently known natural gas mixtures

PTCDA adsorption on CaF₂ thin films

• Philipp Rahe

Beilstein J. Nanotechnol. 2020, 11, 1615–1622, doi:10.3762/bjnano.11.144

• view of the optimum adsorption geometry, including isosurfaces at ±0.01 e/Å3 of the electron density difference Δρ = ρfull − ρslab − ρPTCDA. This difference was calculated as a difference between the electron densities of the full (ρfull), CaF2 slab (ρslab), and PTCDA gas phase (ρPTCDA) systems. The

• well as the three lowest unoccupied molecular orbitals (LUMO, LUMO+1, and LUMO+2) as calculated with cp2k for the PTCDA/CaF2(111) system are depicted in Figure 4e–h. The orbital shapes largely resemble earlier calculations of a flat PTCDA molecule in the gas phase [10], although the LUMO+1 and LUMO+2

• states are here separated by about 0.1 eV and found in different order (in agreement with a previous study [10], a smaller LUMO+1/LUMO+2 energetic separation was calculated for the gas-phase molecule). The dominant contribution of the orbitals to the data shown in Figure 2 is deferred from the orbital

Oxidation of Au/Ag films by oxygen plasma: phase separation and generation of nanoporosity

• Abdel-Aziz El Mel,
• Said A. Mansour,
• Mujaheed Pasha,
• Atef Zekri,
• Janarthanan Ponraj,
• Akshath Shetty and
• Yousef Haik

Beilstein J. Nanotechnol. 2020, 11, 1608–1614, doi:10.3762/bjnano.11.143

• oxygen, solid-state diffusion in metal alloys as well as the Kirkendall effect. The nanoporous microspheres generated by the silver oxidation within the Au/Ag alloy film might have potential applications to the field of gas sensors and catalysis since those require nanoporous semiconductor materials with

Walking energy harvesting and self-powered tracking system based on triboelectric nanogenerators

• Mingliang Yao,
• Guangzhong Xie,
• Qichen Gong and
• Yuanjie Su

Beilstein J. Nanotechnol. 2020, 11, 1590–1595, doi:10.3762/bjnano.11.141

• excellent performance, which can be used as motion [35][36][37] and temperature sensors [38][39], UV detectors [40], tactile sensors [41][42][43], sensors for healthcare [44][45][46][47], humidity sensors, and gas sensors [48][49][50][51], for example. In this work, a flexible undulated electrode-based

• and deionized water were used to clean 50 μm thick PTFE films, which were then dried with nitrogen. During the etching process, DC sputtering was used on the surface of the PTFE film as a mask to deposit Au particles for 45 s. Next, a gas mixture containing O2, CF4, and Ar was introduced to the