Fabrication of high-resolution nanostructures of complex geometry by the single-spot nanolithography method

• Alexander Samardak,
• Margarita Anisimova,
• Aleksei Samardak and
• Alexey Ognev

Beilstein J. Nanotechnol. 2015, 6, 976–986, doi:10.3762/bjnano.6.101

• lithography; exposure dose; high-resolution lithography; nanomagnets; nanostructure; overexposure; PMMA; polymer; resist carbonization; Introduction The continuous growth of the nanotechnology and microelectronic industries requires the development of new approaches and methods for the formation of nanoscale

• of complex shape. The effect of high-dose electron irradiation on the chemical properties of polymers (resulting in hardening or overexposure) was observed in different types of positive resists: DQN [7], AZ-PF514 [8], and PMMA [9][10]. Poly(methyl methacrylate) (PMMA) is the most prevalent EBL

• resist employed due to its high-resolution capability, good lift-off performance, stability, excellent adhesion to substrates and compatibility with the other processing steps. PMMA consists of long polymer chains that are broken into smaller, more soluble fragments by scission with the electron beam

Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

• Jana Vlachová,
• Rebekka König and
• Diethelm Johannsmann

Beilstein J. Nanotechnol. 2015, 6, 845–856, doi:10.3762/bjnano.6.87

• frequency, tangential excitation of variable amplitude (0–20 nm). The contacts were established between glass spheres and the surface of a quartz crystal microbalance (QCM), where the resonator surface had been coated with either sputtered SiO2 or a spin-cast layer of poly(methyl methacrylate) (PMMA). The

• , PMMA, gold) and use the same values on both sides. For the sake of quantitative modeling (see Figure 5 below) we keep the Poisson number fixed at v1 = v2 = 0.17 and express the shear modulus as where E is the Young’s modulus and E is a fit parameter. The contact radius, a, is assumed to obey the JKR

• of the amplitudes, in particular) see [10]. Experiments were carried out with either SiO2-coated resonators (purchased from Inficon) or PMMA-coated resonators. The thickness of the spin-cast PMMA layer was 250 nm. Previous experiments did not find evidence of an influence of the thickness of a glassy

Mapping of elasticity and damping in an α + β titanium alloy through atomic force acoustic microscopy

• M. Kalyan Phani,
• Anish Kumar,
• T. Jayakumar,
• Walter Arnold and
• Konrad Samwer

Beilstein J. Nanotechnol. 2015, 6, 767–776, doi:10.3762/bjnano.6.79

• micrometer resolution. An improved UAFM technique was used for mapping the resonance frequency and the quality factor, Q, in carbon reinforced plastics composites [7]. In recent years, AFAM has been extensively used to determine elastic stiffness or damping properties in nano-crystalline nickel [2], PMMA

Electroburning of few-layer graphene flakes, epitaxial graphene, and turbostratic graphene discs in air and under vacuum

• Andrea Candini,
• Nils Richter,
• Domenica Convertino,
• Camilla Coletti,
• Franck Balestro,
• Wolfgang Wernsdorfer,
• Mathias Kläui and
• Marco Affronte

Beilstein J. Nanotechnol. 2015, 6, 711–719, doi:10.3762/bjnano.6.72

• plasma (2–3 min depending on the discs thickness, for such a long etching time we had to use a 800 nm thick PMMA layer) and finally electrically contacted with thermally evaporated 10 nm Cr/100 nm Au by electron beam lithography and lift-off. After the PMMA development and immediately before the metal

Synergic combination of the sol–gel method with dip coating for plasmonic devices

• Cristiana Figus,
• Maddalena Patrini,
• Francesco Floris,
• Lucia Fornasari,
• Paola Pellacani,
• Gerardo Marchesini,
• Andrea Valsesia,
• Flavia Artizzu,
• Daniela Marongiu,
• Michele Saba,
• Franco Marabelli,
• Andrea Mura,
• Giovanni Bongiovanni and
• Francesco Quochi

Beilstein J. Nanotechnol. 2015, 6, 500–507, doi:10.3762/bjnano.6.52

• conical poly(methyl methacrylate) (PMMA) pillars [32][33][34]. Such a plasmonic platform has been shown to work efficiently as an SPR-sensitive surface for biosensing applications in medical diagnostics [35]. A sketch of the pillar profile along a normal cross section is provided in Figure 4, where the

• consisted of a 2D array of truncated, conical poly(methyl methacrylate) (PMMA) pillars (with a height of about 150 nm and a diameter of 350 nm) embedded into a gold layer that was used to fill the space between the pillars, resulting in a perforated-like film [32][33][34][35] . An ND-R rotatory coater

Electrical properties of single CdTe nanowires

• Elena Matei,
• Camelia Florica,
• Andreea Costas,
• María Eugenia Toimil-Molares and
• Ionut Enculescu

Beilstein J. Nanotechnol. 2015, 6, 444–450, doi:10.3762/bjnano.6.45

• similar behavior for CdTe, as would be expected for objects with similar geometries. In Figure 5 current–voltage characteristics are presented for a nanowire contacted by this approach before and after poly(methyl methacrylate) (PMMA) passivation. A difference of almost an order of magnitude between the

• sample before and after PMMA covering was observed. This increase in current observed when adding the polymer layer has a potential source: the passivation of surface states, which may be responsible for a decrease in the number of the free charge carriers available in the nanowire. Conclusion CdTe

• transport through the nanowire, a third electrical contact was made to the n++ Si substrate. A comparison of the transport properties of the nanowires with and without a passivated thin layer of PMMA was performed. This polymer passivation layer was deposited onto the wire by means of spin coating. SEM

Exploring plasmonic coupling in hole-cap arrays

• Thomas M. Schmidt,
• Maj Frederiksen,
• Vladimir Bochenkov and
• Duncan S. Sutherland

Beilstein J. Nanotechnol. 2015, 6, 1–10, doi:10.3762/bjnano.6.1

• sulfate latex polystyrene particles with diameter of 0.11 µm were obtained from Invitrogen Denmark. Deionized water with 18.2 MΩ resistivity from a Millipore Milli-Q water system. Poly(methyl methacrylate) (PMMA) (Mw 120,000), Polystyrene (Mw 280,000), PDDA (poly(diallydimethylammonium chloride)) (Mw

High-frequency multimodal atomic force microscopy

• Adrian P. Nievergelt,
• Jonathan D. Adams,
• Pascal D. Odermatt and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2014, 5, 2459–2467, doi:10.3762/bjnano.5.255

• squeeze-film damping of the cantilever, the latter of which is roughly constant while in feedback. We used a thin-film blend of polystyrene (PS) and poly(methyl methacrylate) (PMMA) as a sample (PS–PMMA–15M, Bruker AFM probes); its separation into soft and hard domains makes it a widely used standard for

• /. d) Thermal noise peak of the second flexural mode of a FastScan A at 6.6 MHz. Bimodal AFM imaging of a PS/PMMA polymer blend with small, high-frequency cantilevers in both air (panels a–c) and water (panels d–f). Panels a and c show topography based on amplitude modulation of the fundamental

Inorganic Janus particles for biomedical applications

• Isabel Schick,
• Steffen Lorenz,
• Dominik Gehrig,
• Stefan Tenzer,
• Wiebke Storck,
• Karl Fischer,
• Dennis Strand,
• Frédéric Laquai and
• Wolfgang Tremel

Beilstein J. Nanotechnol. 2014, 5, 2346–2362, doi:10.3762/bjnano.5.244

• d) embedding of the final hybrid particle at the interface in a PS-PMMA blend. Reprinted with permission from [34]. Copyright 2013 Elsevier. a) Proposed photocatalytic process for efficient hydrogen generation using the Janus Au@TiO2 nanostructures, based on excitation of the LSPR under visible

Anticancer efficacy of a supramolecular complex of a 2-diethylaminoethyl–dextran–MMA graft copolymer and paclitaxel used as an artificial enzyme

• Yasuhiko Onishi,
• Yuki Eshita,
• Rui-Cheng Ji,
• Masayasu Onishi,
• Takashi Kobayashi,
• Masaaki Mizuno,
• Jun Yoshida and
• Naoji Kubota

Beilstein J. Nanotechnol. 2014, 5, 2293–2307, doi:10.3762/bjnano.5.238

• through grafting MMA onto DEAE–dextran as the backbone polymer by using a tetravalent ceric salt [14]. It generates a polymer micelle that forms a microphase-separated structure with a hydrophilic domain for the DEAE–dextran part and a hydrophobic domain for the graft polymer PMMA. When the transfection

• (DEAE-dextran) and a hydrophobic domain (PMMA) [21]. Thus, it is difficult for this complex to be decomposed by foreign substance recognition. As the drug interaction of the DDMC/PTX complex is in accordance with a Michaelis–Menten-style multi-enzyme reaction model of a 1:1 ratio of a substrate and

Electrical contacts to individual SWCNTs: A review

• Wei Liu,
• Christofer Hierold and
• Miroslav Haluska

Beilstein J. Nanotechnol. 2014, 5, 2202–2215, doi:10.3762/bjnano.5.229

• reported in [85], where 92% of the devices did not function after 8 days. Even for the contact-passivated (by 1 µm PMMA) devices, 69% of them were not functional after a few days [85]. Without the passivation layer, the lifetime of devices using the same contact metals varies from a few months [41][83] to

• annealing treatment. Figure reprinted with permission from (a) [57] copyright 2000 American Institute of Physics and (b) [64] copyright IEEE Electron Devices Society. Inspection of the cleanliness of SWCNTs. a) AFM image obtained after developing a PMMA resist from the SiO2-supported SWCNTs. b) AFM image

• obtained after PMMA and following alumina removal from the contact area. c) SEM image of a Pd contact on a suspended SWCNT using a shadow mask process. d) The cumulative distribution function of on-resistance for n-type CNFETs. Red circles and blue triangles represent the experimental results with and

Influence of stabilising agents and pH on the size of SnO₂ nanoparticles

• Olga Rac,
• Patrycja Suchorska-Woźniak,
• Marta Fiedot and
• Helena Teterycz

Beilstein J. Nanotechnol. 2014, 5, 2192–2201, doi:10.3762/bjnano.5.228

• each measurement was performed for 3 min. A poly(methyl methacrylate) (PMMA) cuvette with dimensions of 40 × 10 × 10 mm was used for the measurements. The calculation of the hydrodynamic diameter was performed on the basis of the Stokes–Einstein equation, assuming a measurement temperature of 298 K and

Carbon nano-onions (multi-layer fullerenes): chemistry and applications

• Juergen Bartelmess and
• Silvia Giordani

Beilstein J. Nanotechnol. 2014, 5, 1980–1998, doi:10.3762/bjnano.5.207

• properties of CNO and CNO composites in a wide range of frequencies [68][69][70], the authors prepared CNO–poly(methyl methacrylate) (PMMA) composite films and studied the terahertz shielding properties in a frequency range of 0.1–3 THz and found a shielding of up to 14 dB [67][71]. Catalysis One of the most

High speed e-beam lithography for gold nanoarray fabrication and use in nanotechnology

• Jorge Trasobares,
• François Vaurette,
• Marc François,
• Hans Romijn,
• Jean-Louis Codron,
• Dominique Vuillaume,
• Didier Théron and
• Nicolas Clément

Beilstein J. Nanotechnol. 2014, 5, 1918–1925, doi:10.3762/bjnano.5.202

• use an EBPG 5000 Plus from Vistec Lithography. The (100) Si substrate (resistivity = 10−3 Ω·cm) is cleaned with UV/ozone and native oxide etched before resist deposition. The e-beam lithography has been optimized by using a 45 nm-thick diluted (3:5 with anisole) PMMA (950 K). For the writing, we use

Review of nanostructured devices for thermoelectric applications

• Giovanni Pennelli

Beilstein J. Nanotechnol. 2014, 5, 1268–1284, doi:10.3762/bjnano.5.141

• standard poly(methyl methacrylate) (PMMA) resist. An etching with well calibrated buffered HF (BHF) allows for the transferring of the pattern from the PMMA to the SiO2 layer (reactive ion etching can be used as alternative). Once the SiO2 mask is defined, the top silicon layer is etched anisotropically

Hole-mask colloidal nanolithography combined with tilted-angle-rotation evaporation: A versatile method for fabrication of low-cost and large-area complex plasmonic nanostructures and metamaterials

• Jun Zhao,
• Bettina Frank,
• Frank Neubrech,
• Chunjie Zhang,
• Paul V. Braun and
• Harald Giessen

Beilstein J. Nanotechnol. 2014, 5, 577–586, doi:10.3762/bjnano.5.68

• , glass substrates are functionalized directly after the cleaning process with 20 µL isobutyl(trimethoxy)silane (Sigma Aldrich) in 10 mL toluene solution for about 8 h to improve the adhesion of a polymer layer. Afterwards, a layer of poly(methylmethacrylate) (PMMA) is spin coated onto the substrate (see

• Figure 1a). We use different PMMA from Allresist (AR-P 661.04 and AR-P 661.06) and rotation speeds of about 4000 rpm to create 230 nm and 480 nm thick polymer layers, respectively. Varying the rotation speed enables us to tune the thickness of the PMMA layer within ±50 nm. After that, the sample is hard

• baked at 165 °C for 2 min to fix the PMMA layer on the substrates. For the following drop coating of the solution on the polymer film surface, we treat the sample in an oxygen plasma for about 18 seconds (Diener Pico, 0.5 mbar O2, power level 50% of 200 W, HF power at 2.45 GHz) to decrease the

Fabrication of carbon nanomembranes by helium ion beam lithography

• Xianghui Zhang,
• Henning Vieker,
• André Beyer and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2014, 5, 188–194, doi:10.3762/bjnano.5.20

• is formed on a gold substrate; secondly, the SAM is irradiated locally with He+ ions; thirdly, the transfer is assisted by a layer of poly(methyl methacrylate) (PMMA) for mechanical stabilization, which allows the dissolution of underlying Au layer; lastly, the PMMA layer is dissolved and only the

• were transferred onto another substrate for further investigations again with the HIM. For the transfer of NBPT CNMs onto a SiO2/Si substrate the samples were spin-coated with a layer of poly(methyl methacrylate) (PMMA) for stabilization and baked on a hotplate at 90 °C for 5 min. The separation of the

• PMMA/CNM/Au layer from the mica substrate was achieved by carefully dipping the sample into water. Subsequently, the Au layer was completely etched by a gold etchant (5 wt % I2 and 10 wt % KI in water). Afterwards, the PMMA/CNM layer was transferred to a Si substrate with an oxide layer with the

Cyclic photochemical re-growth of gold nanoparticles: Overcoming the mask-erosion limit during reactive ion etching on the nanoscale

• Burcin Özdemir,
• Axel Seidenstücker,
• Alfred Plettl and
• Paul Ziemann

Beilstein J. Nanotechnol. 2013, 4, 886–894, doi:10.3762/bjnano.4.100

• SiO2 layer had to be pre-patterned first to obtain a more resistant mask for the subsequent transfer of the pattern into the subjacent substrate. The self-organization of PS-b-PMMA (polymethylmethacrylate) diblock-copolymers forms hexagonally arranged cylindrical PMMA nanodomains that are surrounded by

• PS. Selective removal of the PMMA nanodomains by an oxygen plasma process delivers the mask for subsequent SiO2 etching. In this way, densely packed silica nanopillars with a diameter of 20 nm and a height of 150 nm could be fabricated [11]. Still another variant of exploiting the self-assembly of

Dynamic nanoindentation by instrumented nanoindentation and force microscopy: a comparative review

• Sidney R. Cohen and
• Estelle Kalfon-Cohen

Beilstein J. Nanotechnol. 2013, 4, 815–833, doi:10.3762/bjnano.4.93

• values obtained in dynamic INI vs AFM and the change of E″ and tan δ with the frequency are favorable. The differences will be discussed below. Creep measurements Creep tests were performed on 1-mm thick polymethyl methacrylate (PMMA, Mw = 350,000 ) films. The tests were performed by using an AFM (NTEGRA

• was not significantly better than the double exponential fit. The following values are obtained: Asymptotic storage modulus, E∞ = 6.25 GPa; E1 = 1.53 GPa, η1 = 42 MPa·s, τ1 = 0.027 s; E2 = 2.08 GPa, η2 = 71 MPa·s, τ2 = 1.01 s. As a comparison, the dynamic nanoindentation of PMMA gives E′ = 3.89 GPa

3D nano-structures for laser nano-manipulation

• Gediminas Seniutinas,
• Lorenzo Rosa,
• Gediminas Gervinskas,
• Etienne Brasselet and
• Saulius Juodkazis

Beilstein J. Nanotechnol. 2013, 4, 534–541, doi:10.3762/bjnano.4.62

• films from nano-holes defined in a sacrificial PMMA mask, which was made by electron beam lithography, was carried out with a dry plasma etching tool in order to form well-like structures with a high aspect ratio (height/width ≈ 3–4) at the rims of the nano-holes. The extraordinary transmission through

• . Patterns on a sacrificial 300-nm thick PMMA mask were defined by electron beam lithography (EBL; Raith 150TWO). The mask was spin coated on a cover glass which was magnetron sputter-coated (AXXIS, JKLesker) with a 100 nm thick gold film. Figure 1a and Figure 1b show a sketch of the sample structure before

• and after the re-sputtering step, with conical well structures formed at the rim of holes in the Au film. The plasma etching rate of PMMA was approximately 2.0–2.5 times higher than that of Au. The opening of the holes in the Au-film and the structural quality of samples were characterized by scanning

Polynomial force approximations and multifrequency atomic force microscopy

• Daniel Platz,
• Daniel Forchheimer,
• Erik A. Tholén and
• David B. Haviland

Beilstein J. Nanotechnol. 2013, 4, 352–360, doi:10.3762/bjnano.4.41

• reconstruction allows for the extraction of properties such as surface adhesion, sample stiffness or interaction geometry. We demonstrate this extraction of surface properties with high-resolution stiffness maps on a blend of polystyrene (PS) and poly(methyl methacrylate) (PMMA). Polynomial reconstruction, and

• reconstruction at every point of an AFM image. A specific force model can then be fitted to the complete force curve or parts thereof, generating a map of the model parameters over the complete surface. To demonstrate this we scanned the surface of a PS/PMMA blend with ImAFM. To the repulsive part of the

• Figure 4 a map of the DMT stiffness factor is shown. Even though the two polymers are very similar in stiffness at room temperature [28], two domains of different stiffness are clearly visible in the stiffness-factor map. The stiffer domains are PMMA-rich and 10 nm higher than the surrounding matrix

Selective surface modification of lithographic silicon oxide nanostructures by organofunctional silanes

• Thomas Baumgärtel,
• Christian von Borczyskowski and
• Harald Graaf

Beilstein J. Nanotechnol. 2013, 4, 218–226, doi:10.3762/bjnano.4.22

• the ambient atmosphere the microscope was placed under a closed PMMA dome, which can be purged with dry nitrogen or water-vapor-saturated nitrogen. The humidity was measured by using a “SHT15” digital humidity sensor (Sensirion AG, Switzerland). Lithography of diverse patterns was performed by

Functionalization of vertically aligned carbon nanotubes

• Eloise Van Hooijdonk,
• Carla Bittencourt,
• Rony Snyders and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2013, 4, 129–152, doi:10.3762/bjnano.4.14

• also mention the work of Raravikar et al. [142] who embedded VA-CNTs into a poly(methyl methacrylate) (PMMA) matrix with a two-step strategy. The first step is the fabrication of a VA-CNTs array followed by a MMA monomer infiltration while the subsequent step is in situ polymerization. Finally, we

Current–voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution

• Bernd M. Briechle,
• Youngsang Kim,
• Philipp Ehrenreich,
• Artur Erbe,
• Dmytro Sysoiev,
• Thomas Huhn,
• Ulrich Groth and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 798–808, doi:10.3762/bjnano.3.89

• was annealed for 6 h at 430 °C in vacuum (10−5 mbar). The polyimide layer serves as an electrical insulator and a sacrificial layer in the subsequent etching process. Prior to performing the electron beam lithography process, a double layer of electron-beam resists, MMA-MAA/PMMA, was deposited by spin

Revealing thermal effects in the electronic transport through irradiated atomic metal point contacts

• Bastian Kopp,
• Zhiwei Yi,
• Daniel Benner,
• Fang-Qing Xie,
• Christian Obermair,
• Thomas Schimmel,
• Johannes Boneberg,
• Paul Leiderer and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 703–711, doi:10.3762/bjnano.3.80

• Prior to the electron-beam lithography process, a thin polyimide layer and a double layer of electron-beam resists, MMA-MAA/PMMA, were deposited by spincoating on the wafer and soft-baked in an oven at 170 °C. The polyimide layer served for both planarization of the commercial glass substrate and for