Electrostatic force spectroscopy revealing the degree of reduction of individual graphene oxide sheets

• Yue Shen,
• Ying Wang,
• Yuan Zhou,
• Chunxi Hai,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 1146–1155, doi:10.3762/bjnano.9.106

• methods, such as X-ray photoelectron spectroscopy (XPS) [8][9], Raman spectroscopy [10], and UV–vis absorption spectra [11][12], reflect the average information of rGO materials. However, they cannot characterize an isolated rGO sheet at the nanoscale. Optical observation [13] and transmission electron

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• of the RA SAM, even at room temperature. Additionally, photo-assisted electrical force microscopy, photo-assisted scanning Kelvin probe microscopy and Raman spectroscopy indicate a RA-induced graphene doping and photo-charge generation. Finally, the optical excitation of the RA monolayer generates

• potential histograms in dark from a pristine graphite microplate surface (G) – green line – and a thick amorphous retinoic acid layer (a-RA) – orange line – are also shown. Raman spectroscopy data. Raman spectra obtained from the same region of a graphene monolayer before (black) and after (blue) deposition

• photoelectrical characterization may shed some light on the dominant mechanisms. Finally, the charge transfer within the graphene/RA hybrid has also been investigated via Raman scattering experiments. Monolayer graphene, instead of graphite microplate, was chosen for this analysis due to the sensitivity of Raman

Cyclodextrin inhibits zinc corrosion by destabilizing point defect formation in the oxide layer

• Abdulrahman Altin,
• Maciej Krzywiecki,
• Adnan Sarfraz,
• Cigdem Toparli,
• Claudius Laska,
• Philipp Kerger,
• Aleksandar Zeradjanin,
• Karl J. J. Mayrhofer,
• Michael Rohwerder and
• Andreas Erbe

Beilstein J. Nanotechnol. 2018, 9, 936–944, doi:10.3762/bjnano.9.86

• detected with a hemispherical electron energy analyzer (SPECS PHOIBOS 150) with TOA = 50°. This configuration gives an information depth of ≈1.5 nm [43]. Raman spectroscopy was performed on samples prepared in the same manner as for SEM. Spectra were recorded using a Witec alpha300M confocal Raman

Facile chemical routes to mesoporous silver substrates for SERS analysis

• Elina A. Tastekova,
• Alexander Y. Polyakov,
• Anastasia E. Goldt,
• Alexander V. Sidorov,
• Alexandra A. Oshmyanskaya,
• Irina V. Sukhorukova,
• Dmitry V. Shtansky,
• Wolgang Grünert and
• Anastasia V. Grigorieva

Beilstein J. Nanotechnol. 2018, 9, 880–889, doi:10.3762/bjnano.9.82

• (meldonium; enhancement factor of ≈102) that is known for its ability to increase the endurance performance of athletes. Keywords: meldonium; mesoporous silver substrates; silver oxide; surface-enhanced Raman spectroscopy; Introduction Nowadays one of the largest sectors of the global chemical industry is

•  4b) [33]. The enhancement factor (EF) for the system was calculated as described according to the standard equation, namely, where ISERS and IRS are the corresponding SERS and Raman spectroscopy signal intensities and nSERS and nRS are the molar quantities of R6G in SERS and Raman experiments. As

• Foundation of Basic Research and Department of Science, Industrial Policy and Entrepreneurship of Moscow Government (15-33-70050-mol_a_mos) and Lomonosov Moscow State University Program of Development. The XRD and Raman spectroscopy experiments were performed using equipment of the Collective Scientific

Towards the third dimension in direct electron beam writing of silver

• Katja Höflich,
• Jakub Mateusz Jurczyk,
• Katarzyna Madajska,
• Maximilian Götz,
• Luisa Berger,
• Carlos Guerra-Nuñez,
• Caspar Haverkamp,
• Iwona Szymanska and
• Ivo Utke

Beilstein J. Nanotechnol. 2018, 9, 842–849, doi:10.3762/bjnano.9.78

• software Gwyddion 2.49. Confocal Raman spectroscopy was performed using an upright ND-MDT NTEGRA Raman microscope featuring a laser source with a wavelength of 532 nm and a 100× objective lens with a numerical aperture of 0.95. Spectra were recorded at a spectral resolution of 2.7 cm−1 with 5 s exposure

Graphene composites with dental and biomedical applicability

• Sharali Malik,
• Felicite M. Ruddock,
• Adam H. Dowling,
• Kevin Byrne,
• Wolfgang Schmitt,
• Ivan Khalakhan,
• Yoshihiro Nemoto,
• Hongxuan Guo,
• Lok Kumar Shrestha,
• Katsuhiko Ariga and
• Jonathan P. Hill

Beilstein J. Nanotechnol. 2018, 9, 801–808, doi:10.3762/bjnano.9.73

• ). Characterization The MLG and FLG material was characterized by Raman spectroscopy (Renishaw at 514 nm) and the AFM measurements were performed on a MultiMode V AFM (Veeco) in tapping mode under ambient conditions. RTESP silicon probes (Veeco) were used with a nominal tip radius of 10 nm and nominal spring constant

• 30 kV). In addition, FLG-polymer A and E were characterized by Raman Spectroscopy (JY T6400 at 514 nm) and SEM (Zeiss Ultra-Plus at 3 kV, EsB grid at 503 V). a) Raman spectra of MLG (ca. 10 layers, lower) and FLG (1–6 layers, upper) – both at 514 nm. b) Helium ion microscope (HeIM) overview of FLG, c

Heavy-metal detectors based on modified ferrite nanoparticles

• Urszula Klekotka,
• Ewelina Wińska,
• Elżbieta Zambrzycka-Szelewa,
• Dariusz Satuła and
• Beata Kalska-Szostko

Beilstein J. Nanotechnol. 2018, 9, 762–770, doi:10.3762/bjnano.9.69

• [15]. Therefore, the origin of these signals is most probable due to heavy ion adsorption. However, due to a lack of reference information, it is the only speculation on the origin of appearing new signals. Raman spectroscopy After every step (synthesis, surface modification, and heavy metal

• attachment) powdered samples of nanoparticles were analyzed using Raman spectroscopy giving additional information to IR spectroscopy. In Figure 5 selected spectra are presented. The Raman spectra show a set of peaks that are typical for inorganic cores (magnetite, maghemite/hematite) with accordingly

• adsorption was reported previously [15]. Figure 5C shows the modulation of Raman spectra by different compounds at the surface. A number of additional bands seen in case of PA are due to its specific chemical structure (Table 3). Considering all above-mentioned findings, Raman spectroscopy confirms the

The effect of atmospheric doping on pressure-dependent Raman scattering in supported graphene

• Egor A. Kolesov,
• Mikhail S. Tivanov,
• Olga V. Korolik,
• Olesya O. Kapitanova,
• Xiao Fu,
• Hak Dong Cho,
• Tae Won Kang and
• Gennady N Panin

Beilstein J. Nanotechnol. 2018, 9, 704–710, doi:10.3762/bjnano.9.65

• . Keywords: adsorption; doping; graphene; pressure; Raman spectroscopy; substrate; Introduction Graphene is a promising material for a variety of applications due to its unique physical properties [1]. Among its other outstanding features, one can distinguish its strong sensitivity to adsorbates, leading to

• adsorption properties of supported graphene. Raman spectroscopy is a versatile tool for studying graphene and graphene-based nanomaterials [9][10][11][12]. Several different parameters of graphene’s Raman spectra are affected by charge carrier density variations, such as the G and 2D peak positions and the

• Raman spectroscopy is a convenient tool for probing atmosphere-induced doping in graphene. Low-pressure behavior of adsorbates present on the graphene surface and concomitant charge carrier properties strongly depend on the substrate material, as well as graphene doping and number of layers. These

Anchoring Fe₃O₄ nanoparticles in a reduced graphene oxide aerogel matrix via polydopamine coating

• Błażej Scheibe,
• Radosław Mrówczyński,
• Natalia Michalak,
• Karol Załęski,
• Michał Matczak,
• Mateusz Kempiński,
• Zuzanna Pietralik,
• Mikołaj Lewandowski,
• Stefan Jurga and
• Feliks Stobiecki

Beilstein J. Nanotechnol. 2018, 9, 591–601, doi:10.3762/bjnano.9.55

• nanoparticles are present in agglomerated form. The vibrational properties of the prepared aerogel samples were analyzed by Raman spectroscopy. The typical rGO spectrum is featured by the presence of four main vibrational modes, namely: D, G, 2D and D+G (D+D’) [43]. In graphite-like materials, the G mode is

• , NovaNanoSEM 650). The diameter distribution of magnetite nanoparticles was determined using transmission electron microscopy (TEM) (Jeol, 1400, 120 kV). The vibrational properties of the investigated samples were examined by micro-Raman spectroscopy (Renishaw, inVia Raman microscope) operating at λ = 785 nm

Single-step process to improve the mechanical properties of carbon nanotube yarn

• Maria Cecilia Evora,
• Xinyi Lu,
• Nitilaksha Hiremath,
• Nam-Goo Kang,
• Kunlun Hong,
• Roberto Uribe,
• Gajanan Bhat and
• Jimmy Mays

Beilstein J. Nanotechnol. 2018, 9, 545–554, doi:10.3762/bjnano.9.52

• by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and scanning electron microscopy (SEM). The best improvement in mechanical properties was achieved on a sample treated with an aqueous solution of AA and subsequent irradiation. CNT yarn treatment with AA enhanced the strength (444.5

• composed of angled graphite sheets. In addition, VGCFs are different from CNTs in the method of production and they have few functional groups at the edges [35]. CNT yarns functionalized with AN and AA irradiated at 108 kGy Raman spectroscopy is a useful method to investigate the covalent sidewall

• to 21.5 ± 0.65 GPa. Deconvoluted XPS C 1s spectra of (a) pristine MWNT, (b) MWNT soaked in aqueous solution of 20% AN without irradiation, and (c) MWNT soaked in aqueous solution of 20% AN and irradiated at 27 kGy (c). Raman spectroscopy results for CNT yarn treated with aqueous solutions of 80% AN

Green synthesis of fluorescent carbon dots from spices for in vitro imaging and tumour cell growth inhibition

• Nagamalai Vasimalai,
• Vânia Vilas-Boas,
• Juan Gallo,
• María de Fátima Cerqueira,
• Mario Menéndez-Miranda,
• José Manuel Costa-Fernández,
• Lorena Diéguez,
• Begoña Espiña and
• María Teresa Fernández-Argüelles

Beilstein J. Nanotechnol. 2018, 9, 530–544, doi:10.3762/bjnano.9.51

• characterized by means of UV–vis, fluorescence, Fourier transform infrared and Raman spectroscopy, dynamic light scattering and transmission electron microscopy. The optical performance showed an outstanding ability for imaging purposes, with quantum yields up to 43.6%. Thus, the cytotoxicity of the above

• compounds present in the spices will partially remain inside or at the surface of the C-dots after the hydrothermal process, leading to different photoluminescent and biomedical properties. The synthesized C-dots have been extensively characterized with UV–vis, fluorescence, FTIR and Raman spectroscopy, DLS

• (PanAnalytical B.V, EA Almelo, The Netherlands) and Cu Kα radiation (λ = 0.15418 nm), and the samples were prepared on a Si substrate. Raman spectroscopy measurements were performed in Witec Alpha 300R confocal Raman Microscopy system with a 50× objective (WITec Wissenschaftliche Instrumente and Technologie GmbH

Ultralight super-hydrophobic carbon aerogels based on cellulose nanofibers/poly(vinyl alcohol)/graphene oxide (CNFs/PVA/GO) for highly effective oil–water separation

• Zhaoyang Xu,
• Huan Zhou,
• Sicong Tan,
• Xiangdong Jiang,
• Weibing Wu,
• Jiangtao Shi and
• Peng Chen

Beilstein J. Nanotechnol. 2018, 9, 508–519, doi:10.3762/bjnano.9.49

• previous studies [19][29], which is in agreement with the SEM results. FTIR can only be used to detect signals from molecules with infrared activity. Therefore, Raman spectroscopy analysis was studied to detect the stretching vibration characteristic peak of homonuclear diatomic pairs. The Raman spectrum

Engineering of oriented carbon nanotubes in composite materials

• Razieh Beigmoradi,
• Abdolreza Samimi and
• Davod Mohebbi-Kalhori

Beilstein J. Nanotechnol. 2018, 9, 415–435, doi:10.3762/bjnano.9.41

• ]) effects on the application and quality of composites. For this aim, many techniques have been developed such as Raman spectroscopy, Fourier-transforms infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Raman spectroscopy: Raman spectroscopy is a powerful tool to identify and quantify

• alignment direction, and 90° related to the laser light polarization direction where it is perpendicular to the CNT alignment direction). As indicated in the graph, the ratio of the G-mode to the D-mode (R) has increased [142]. The composites analyzed by Raman spectroscopy typically have very strong CNT

• signals that mask the signals of other organic components. In such cases, tunable UV Raman spectroscopy may be used, although this technique is rarely used. Fourier-transform infrared spectroscopy: FTIR is often used to characterize molecular bonding on the CNT surface and to determine the modification of

Blister formation during graphite surface oxidation by Hummers’ method

• Olga V. Sinitsyna,
• Georgy B. Meshkov,
• Anastasija V. Grigorieva,
• Alexander A. Antonov,
• Inna G. Grigorieva and
• Igor V. Yaminsky

Beilstein J. Nanotechnol. 2018, 9, 407–414, doi:10.3762/bjnano.9.40

• Hummers’ method and investigated by Raman spectroscopy and atomic force microscopy. HAPG was used as a graphite precursor because its surface after cleavage contains well-ordered millimeter-sized regions. The treatment resulted in graphite intercalation by sulfuric acid and blister formation all over the

• and hydrogen peroxide solution, the surface became gray and matte, which indicated a significant change in the surface roughness. Raman spectroscopy of the HAPG surface before and after the treatment Raman spectra, recorded from the ordered regions on the HAPG surface before and after the treatment

• Figure 5. The proposed mechanism may significantly influence the kinetics of pyrolytic graphite intercalation. Since molecules and ions diffuse through the system of pre-existing defects, the intercalation process can be reversible. The experimental data obtained in [20] by Raman spectroscopy proved that

Synthesis and characterization of electrospun molybdenum dioxide–carbon nanofibers as sulfur matrix additives for rechargeable lithium–sulfur battery applications

• Ruiyuan Zhuang,
• Shanshan Yao,
• Maoxiang Jing,
• Xiangqian Shen,
• Jun Xiang,
• Tianbao Li,
• Kesong Xiao and
• Shibiao Qin

Beilstein J. Nanotechnol. 2018, 9, 262–270, doi:10.3762/bjnano.9.28

• using an electrospinning technique followed by calcination, using sol–gel precursors and polyacrylonitrile (PAN) as a processing aid. The resulting samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Brunauer–Emmet–Teller (BET

• known to be active in numerous reactions associated with noble metals, such as CO2 hydrogenation, water gas shift, alcohol synthesis and hydrazine decomposition. Here, CH4/H2 atmosphere was not used during calcination, which was much safer and facile when compared to other methods [27]. Raman

• spectroscopy is a very useful tool for the characterization of carbon-based nanostructures. The Raman spectra of the products excited with a 532 nm laser line are shown in Figure 1b. Two characteristic peaks at around 1355 and 1580 cm−1 correspond to disordered carbon (D-band) and graphite carbon (G-band

BN/Ag hybrid nanomaterials with petal-like surfaces as catalysts and antibacterial agents

• Konstantin L. Firestein,
• Denis V. Leybo,
• Alexander E. Steinman,
• Andrey M. Kovalskii,
• Andrei T. Matveev,
• Anton M. Manakhov,
• Irina V. Sukhorukova,
• Pavel V. Slukin,
• Nadezda K. Fursova,
• Sergey G. Ignatov,
• Dmitri V. Golberg and
• Dmitry V. Shtansky

Beilstein J. Nanotechnol. 2018, 9, 250–261, doi:10.3762/bjnano.9.27

• utilized toward the development of cutting-edge hybrid nanostructures. For example, BN/noble metal (Pt, Au, Ag) hybrid nanomaterials are envisaged to be the promising components of highly active catalysts, drug delivery systems, molecular probe sensors, surface enhanced Raman spectroscopy techniques, and

Gas-assisted silver deposition with a focused electron beam

• Luisa Berger,
• Katarzyna Madajska,
• Iwona B. Szymanska,
• Katja Höflich,
• Mikhail N. Polyakov,
• Jakub Jurczyk,
• Carlos Guerra-Nuñez and
• Ivo Utke

Beilstein J. Nanotechnol. 2018, 9, 224–232, doi:10.3762/bjnano.9.24

• . Raman spectroscopy was performed with an upright ND-MDT NTEGRA Raman microscope featuring a laser source with a wavelength of 532 nm and a 100× objective lens with a numerical aperture of 0.90. The acquisition time of 1–5 s was enough to record the surface enhanced Raman signal from the silver deposits

Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting: combining renewable raw materials with clean fuels

• Stefanie Krüger,
• Michael Schwarze,
• Otto Baumann,
• Christina Günter,
• Michael Bruns,
• Christian Kübel,
• Dorothée Vinga Szabó,
• Rafael Meinusch,
• Verónica de Zea Bermudez and
• Andreas Taubert

Beilstein J. Nanotechnol. 2018, 9, 187–204, doi:10.3762/bjnano.9.21

• . Data analysis was done with the ThermoFisher Omnic 8.1.11 software. Raman spectroscopy was performed on a WITec alpha300 confocal Raman microscope with an upright optical microscope. Laser wavelength was 532 nm and laser power was 14 mW. The laser was coupled into a single mode optical fiber and

• as IR and Raman spectroscopy (Table S4, Supporting Information File 1, Figure 2, Table S3, Supporting Information File 1, Figure S7, Supporting Information File 1, Figure 6) and the data consistently show that the TS samples contain slightly more organic (i.e., silk) material. The deviations in the

Comparative study of post-growth annealing of Cu(hfac)₂, Co₂(CO)₈ and Me₂Au(acac) metal precursors deposited by FEBID

• Marcos V. Puydinger dos Santos,
• Aleksandra Szkudlarek,
• Artur Rydosz,
• Carlos Guerra-Nuñez,
• Fanny Béron,
• Kleber R. Pirota,
• Stanislav Moshkalev,
• José Alexandre Diniz and
• Ivo Utke

Beilstein J. Nanotechnol. 2018, 9, 91–101, doi:10.3762/bjnano.9.11

• characterisation Raman spectra were examined in the carbon range in order to elucidate the composition of the carbonaceous matrix during post-growth annealing. Raman spectroscopy was performed using an upright confocal Raman spectrometer (NT-MDT NTEGRA) featuring a laser source with a wavelength of 532 nm and a

Gas-sensing behaviour of ZnO/diamond nanostructures

• Marina Davydova,
• Alexandr Laposa,
• Jiri Smarhak,
• Alexander Kromka,
• Neda Neykova,
• Josef Nahlik,
• Jiri Kroutil,
• Jan Drahokoupil and
• Jan Voves

Beilstein J. Nanotechnol. 2018, 9, 22–29, doi:10.3762/bjnano.9.4

• electron microscopy, X-ray diffraction measurements and Raman spectroscopy. The gas sensing properties of the sensors based on i) NCD films, ii) ZnO nanorods, and iii) hybrid ZnO NRs/NCD structures were evaluated with respect to oxidizing (i.e., NO2, CO2) and reducing (i.e., NH3) gases at 150 °C. The

• [30]. The resulting morphologies of structured NCD films and ZnO NRs were characterized by field-emission scanning electron microscopy (FE-SEM, Merlin, ZEISS). Raman spectroscopy measurements were carried out at room temperature using a Renishaw InVia Raman Microscope with the following conditions

CdSe nanorod/TiO₂ nanoparticle heterojunctions with enhanced solar- and visible-light photocatalytic activity

• Fakher Laatar,
• Hatem Moussa,
• Halima Alem,
• Lavinia Balan,
• Emilien Girot,
• Ghouti Medjahdi,
• Hatem Ezzaouia and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 2741–2752, doi:10.3762/bjnano.8.273

• varied from 0.5 to 5 wt %. The CdSe/TiO2 heterostructured materials were characterized by XRD, TEM, SEM, XPS, UV–visible spectroscopy and Raman spectroscopy. TEM images and XRD patterns show that CdSe NRs with wurtzite structure are associated to TiO2 particles. The UV–visible spectra demonstrate that

• their dispersion in TiO2 particles. Raman spectroscopy was further used to confirm the structures of CdSe/TiO2 composites. Two peaks located at 206 and 414 cm−1 corresponding to the longitudinal optical (LO) phonon and its overtone (2LO) can be observed for CdSe NRs (Figure S2, Supporting Information

Dry adhesives from carbon nanofibers grown in an open ethanol flame

• Christian Lutz,
• Julia Syurik,
• C. N. Shyam Kumar,
• Christian Kübel,
• Michael Bruns and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2017, 8, 2719–2728, doi:10.3762/bjnano.8.271

• substrate directly on carbon-coated copper grids (Quantifoil). Raman spectroscopy was performed with an excitation wavelength of 532 nm (Renishaw inVia Raman microscope). X-ray photoelectron spectroscopy (XPS) measurements were performed using a K-Alpha+ XPS instrument (Thermo Fisher Scientific, East

Inelastic electron tunneling spectroscopy of difurylethene-based photochromic single-molecule junctions

• Youngsang Kim,
• Safa G. Bahoosh,
• Dmytro Sysoiev,
• Thomas Huhn,
• Fabian Pauly and
• Elke Scheer

Beilstein J. Nanotechnol. 2017, 8, 2606–2614, doi:10.3762/bjnano.8.261

• experimental findings with theoretical predictions for the IET spectra. The reason is that IET spectroscopy is not subject to rigorous selection rules [21] in contrast for instance to optical vibrational spectroscopy methods such as infrared or Raman spectroscopy. In this study, we investigate both elastic and

Refractive index sensing and surface-enhanced Raman spectroscopy using silver–gold layered bimetallic plasmonic crystals

• Somi Kang,
• Sean E. Lehman,
• Matthew V. Schulmerich,
• An-Phong Le,
• Tae-woo Lee,
• Stephen K. Gray,
• Rohit Bhargava and
• Ralph G. Nuzzo

Beilstein J. Nanotechnol. 2017, 8, 2492–2503, doi:10.3762/bjnano.8.249

• /bjnano.8.249 Abstract Herein we describe the fabrication and characterization of Ag and Au bimetallic plasmonic crystals as a system that exhibits improved capabilities for quantitative, bulk refractive index (RI) sensing and surface-enhanced Raman spectroscopy (SERS) as compared to monometallic

• promising as an analytical technique for real-time, fully label-free detection of molecules, both quantitatively and qualitatively, as well as for monitoring surface interactions [5][10][11]. Surface-enhanced Raman spectroscopy, better known as SERS, is another important analytical application that utilizes

• spectra collected in each PEG solution and a spectrum recorded in pure water. These values were integrated to account for wavelength dependence of both negative and positive changes in spectroscopic intensity using Equation 1, a value having units of Δ%T·nm. Surface-enhanced Raman spectroscopy (SERS

Optical contrast and refractive index of natural van der Waals heterostructure nanosheets of franckeite

• Patricia Gant,
• Foad Ghasemi,
• David Maeso,
• Carmen Munuera,
• Elena López-Elvira,
• Riccardo Frisenda,
• David Pérez De Lara,
• Gabino Rubio-Bollinger,
• Mar Garcia-Hernandez and
• Andres Castellanos-Gomez

Beilstein J. Nanotechnol. 2017, 8, 2357–2362, doi:10.3762/bjnano.8.235

• /spectroscopy, transmission electron microscopy, X-ray diffraction, X-ray photoemission, UV–vis–IR absorption spectroscopy and Raman spectroscopy. More details about this characterization can be found in [15]. The flakes are firstly exfoliated onto a polydimethylsiloxane (Gelfilm, with 150 µm of thickness, by