Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallo)tetraphenylporphyrins

• Rasha K. Al-Shewiki,
• Carola Mende,
• Roy Buschbeck,
• Pablo F. Siles,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1191–1204, doi:10.3762/bjnano.8.121

• which symmetry-related molecules with planar porphyrin cores interact with each other by, for example, formation of intermolecular ZnII…O contacts. Further intermolecular interactions refer to those that were described in detail by, for example, Goldberg et al. [14] or by us [15]. In contrast, saddle

Growth, structure and stability of sputter-deposited MoS₂ thin films

• Reinhard Kaindl,
• Bernhard C. Bayer,
• Roland Resel,
• Thomas Müller,
• Viera Skakalova,
• Gerlinde Habler,
• Rainer Abart,
• Alexey S. Cherevan,
• Dominik Eder,
• Maxime Blatter,
• Fabian Fischer,
• Jannik C. Meyer,
• Dmitry K. Polyushkin and
• Wolfgang Waldhauser

Beilstein J. Nanotechnol. 2017, 8, 1115–1126, doi:10.3762/bjnano.8.113

• exposed to visible light radiation and local temperature increase. Electrical properties of MoS2 thin films In order to investigate the electrical properties of our PVD MoS2 films on the SiO2-covered Si substrates two types of FET devices with rectangular and circular source and drain contacts were

• (with some devices showing higher resistances, which might however be related to non-continuous film regions under the contacts), in all our measurements we find no response to the applied gate bias. Since bulk MoS2 in its most stable 2H form is a semiconductor [8] the observation of such metallic-like

• (FET) devices with rectangular and circular contacts have been made. The drain/source contacts were defined by means of optical lithography. The Ti/Au (5/50 nm) contact pads have been fabricated by means of thermal evaporation. As the global back gate to the FET devices the highly doped Si wafer under

Stable Au–C bonds to the substrate for fullerene-based nanostructures

• Taras Chutora,
• Jesús Redondo,
• Bruno de la Torre,
• Martin Švec,
• Pavel Jelínek and
• Héctor Vázquez

Beilstein J. Nanotechnol. 2017, 8, 1073–1079, doi:10.3762/bjnano.8.109

• Au is very fast at room temperature, individual molecules cannot be stabilized and contacted outside islands. This has important consequences for single-molecule transport, where it would be desirable to have reliable and stable metal–molecule contacts. In the case of molecular spintronics, the

The integration of graphene into microelectronic devices

• Guenther Ruhl,
• Sebastian Wittmann,
• Matthias Koenig and
• Daniel Neumaier

Beilstein J. Nanotechnol. 2017, 8, 1056–1064, doi:10.3762/bjnano.8.107

• devices. Generally speaking the crucial issues for graphene integration are identified today and the corresponding research tasks can be clearly defined. Keywords: contacts; deposition; encapsulation; graphene; process integration; Introduction Since the discovery of the electronic properties of

• should be manageable with respect to device manufacturing. 5 Contacts Because the performance of an electronic device, e.g., a transistor, is strongly affected by parasitic effects such as contact resistances (the contact resistance should not exceed 10% of the channel resistance), this issue is of

• enormous importance, especially for short-channel devices. Numerous studies have been published during the last few years on the understanding and improvement of graphene–metal contacts, reporting contact resistivity values in a wide range from several ohm-micrometers to several hundred thousand ohm

CVD transfer-free graphene for sensing applications

• Chiara Schiattarella,
• Sten Vollebregt,
• Tiziana Polichetti,
• Brigida Alfano,
• Ettore Massera,
• Maria Lucia Miglietta,
• Girolamo Di Francia and
• Pasqualina Maria Sarro

Beilstein J. Nanotechnol. 2017, 8, 1015–1022, doi:10.3762/bjnano.8.102

• gold contacts with wire-bonds are clearly visible. As can be seen, accurately defined multilayer graphene patterns down to micrometre-size can be obtained using this method. From an electrical point of view, the fabrication technique has proven to be quite repeatable and uniform, since devices with the

• SiO2. Cr/Au metal contacts have finally been patterned by a lift-off process to design a four-point probe structure. The final chemiresistive devices consist of a material strip 206 µm long and 5 µm wide, placed between two couples of metal electrodes (Figure 1). Raman analyses have been performed at

Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins

• Gheorghe Stan,
• Richard S. Gates,
• Qichi Hu,
• Kevin Kjoller,
• Craig Prater,
• Kanwal Jit Singh,
• Ebony Mays and
• Sean W. King

Beilstein J. Nanotechnol. 2017, 8, 863–871, doi:10.3762/bjnano.8.88

• measurements, the tip–sample contact is mechanically vibrated at various frequencies to detect the so called “contact resonance frequencies”. These CR-frequencies are characteristic of the tip–sample contact stiffness (higher frequencies for stiffer contacts) and depend on the mechanical properties of the tip

• considering the blanket film as a reference with a modulus of 3.5 GPa and reporting all the measured values of contact stiffness to the contact stiffness measured on the blanket film. The tip–sample contacts were treated as Hertz contacts [33]. Results and Discussion To monitor changes in the chemical

Measuring adhesion on rough surfaces using atomic force microscopy with a liquid probe

• Juan V. Escobar,
• Cristina Garza and
• Rolando Castillo

Beilstein J. Nanotechnol. 2017, 8, 813–825, doi:10.3762/bjnano.8.84

• widely varying heights, shapes and relative distances (Figure 2). In summary, larger contact lengths lead to larger deformations of the solid or liquid probe, and possibly of the substrate, which results in a larger pull-off force due to the increase of contacts. We point out that the pull-off forces for

• number of contacts between the glass sphere and the peaks for each run. The number of contacts we find in this system ranges between 1 and 5 as shown in Figure 10a. The low number of contacts in this case, the relative insensibility of the pull-off force to the contact length, and the high stiffness of

• measured for a contact line pinned on a strong defect on a carbon nanotube dipped in a liquid, also measured by AFM [35]. Just as before, dividing each measured pull-off force by 14.9 pN, we obtain numbers that are statistically close to integers. In this way, we get the approximate number of contacts

3D Nanoprinting via laser-assisted electron beam induced deposition: growth kinetics, enhanced purity, and electrical resistivity

• Brett B. Lewis,
• Robert Winkler,
• Xiahan Sang,
• Pushpa R. Pudasaini,
• Michael G. Stanford,
• Harald Plank,
• Raymond R. Unocic,
• Jason D. Fowlkes and
• Philip D. Rack

Beilstein J. Nanotechnol. 2017, 8, 801–812, doi:10.3762/bjnano.8.83

• combination of photolithography and electron beam lithography (EBL) were used to produce the two-contact pads with a spacing of 500 nm. An initial set of gold electrical contacts were patterned using photolithography and deposited with a thickness of 100 nm. A 3 nm titanium adhesion layer was deposited, prior

• to gold sputtering, to promote adhesion between the gold contacts and the underlying, insulating SiO2 film (290 nm). The original photolithographically defined spacing between electrical contacts was 20 µm. EBL was performed using a Raith ELPHY Quantum patterning engine equipped on the FEI NovaLab

Copper atomic-scale transistors

• Fangqing Xie,
• Maryna N. Kavalenka,
• Moritz Röger,
• Daniel Albrecht,
• Hendrik Hölscher,
• Jürgen Leuthold and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2017, 8, 530–538, doi:10.3762/bjnano.8.57

• atomic-scale transistor with a copper quantum point contact as switching block. The fabrication and electron-transport properties of metallic point contacts have been investigated both experimentally and theoretically [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. The

• copper atomic-scale point contacts have been fabricated as mechanically controllable break junctions (MCBJ) [42][43][44][45], by using scanning probe microscopy (SPM) with a conductive tip [46][47], or electrochemical techniques [24][25][26][48][49]. Copper is an interconnection material in ultra-large

• for copper deposition on the three microelectrodes source, drain and gate. After the gap between the source and drain electrodes was closed with the deposited copper the deposition process continued for about 20 min to stabilize the contact. The copper point contacts were trained as atomic-scale

Advances in the fabrication of graphene transistors on flexible substrates

• Gabriele Fisichella,
• Stella Lo Verso,
• Silvestra Di Marco,
• Vincenzo Vinciguerra,
• Emanuela Schilirò,
• Salvatore Di Franco,
• Raffaella Lo Nigro,
• Fabrizio Roccaforte,
• Amaia Zurutuza,
• Alba Centeno,
• Sebastiano Ravesi and
• Filippo Giannazzo

Beilstein J. Nanotechnol. 2017, 8, 467–474, doi:10.3762/bjnano.8.50

• smoother substrates. However, it is still possible to identify wrinkles, as indicated by the dashed green circle in Figure 4a. A schematic illustration of the graphene channel fabricated over the FET gate contact is reported in Figure 4b. After patterning the graphene channel, the source and drain contacts

• determine the total electrical resistance, RTOT, between source and drain contacts are also illustrated in Figure 4d. Here, the gate-bias-dependent graphene channel resistance, Rch(Vg), the source and drain contact resistance, Rc, and the access resistance, Racc, associated with the ungated graphene access

• regions between the channel and the source and drain contacts (Lacc = 20 µm length per access region) are shown. The total resistance resulting from the series combination of these contributions can be expressed as: The capacitance of the Al2O3 dielectric deposited by ALD on the flexible substrate was

Study of the surface properties of ZnO nanocolumns used for thin-film solar cells

• Neda Neykova,
• Jiri Stuchlik,
• Karel Hruska,
• Ales Poruba,
• Zdenek Remes and
• Ognen Pop-Georgievski

Beilstein J. Nanotechnol. 2017, 8, 446–451, doi:10.3762/bjnano.8.48

• vertical geometry of these textures, the optical thickness is dictated by the height of the NCs, such that most of the light traversing the cell sees an absorber-layer thickness approximately equal to the NC height. In contrast, as the front and back TCO contacts are interpenetrating, the inter-electrode

Impact of contact resistance on the electrical properties of MoS₂ transistors at practical operating temperatures

• Filippo Giannazzo,
• Gabriele Fisichella,
• Aurora Piazza,
• Salvatore Di Franco,
• Giuseppe Greco,
• Simonpietro Agnello and
• Fabrizio Roccaforte

Beilstein J. Nanotechnol. 2017, 8, 254–263, doi:10.3762/bjnano.8.28

• voltage (Vth). This paper reports a detailed electrical characterization of back-gated multilayer MoS2 transistors with Ni source/drain contacts at temperatures from T = 298 to 373 K, i.e., the expected range for transistor operation in circuits/systems, considering heating effects due to inefficient

• demonstrated using single [3] and multilayers of MoS2 [4]. MoS2 thin films, obtained either by cleavage from the bulk material or by chemical vapor deposition, are typically unintentionally n-type doped. Since well-assessed methods for doping enrichment of MoS2 under source/drain contacts are still lacking

• , MoS2 transistors are mostly fabricated by deposition of metals directly on the unintentionally doped material, resulting in the formation of Schottky contacts. Experimental investigations showed that both low work function (e.g., Sc, Ti) and high work function (e.g., Ni, Pt) metals mostly exhibit a

Influence of hydrofluoric acid treatment on electroless deposition of Au clusters

• Rachela G. Milazzo,
• Antonio M. Mio,
• Giuseppe D’Arrigo,
• Emanuele Smecca,
• Alessandra Alberti,
• Gabriele Fisichella,
• Filippo Giannazzo,
• Corrado Spinella and
• Emanuele Rimini

Beilstein J. Nanotechnol. 2017, 8, 183–189, doi:10.3762/bjnano.8.19

• shown quite interesting applications in the fields of Si nanowire (SiNW) catalysis [1][2][3], metal-assisted etching (MAE) [4] or even as electrical contacts in standard miniaturized devices [5]. Their ability to display enhanced surface plasmon resonance (SPR) at optical frequencies makes them

Studying friction while playing the violin: exploring the stick–slip phenomenon

• Santiago Casado

Beilstein J. Nanotechnol. 2017, 8, 159–166, doi:10.3762/bjnano.8.16

• generally understood to be the resistance to the sliding motion of objects. It is an everyday life phenomenon that originates from the atomic-scale asperities found at the interfacial contacts [1]. However, substantially different physical descriptions apply when friction is studied at the nanoscale

Sensitive detection of hydrocarbon gases using electrochemically Pd-modified ZnO chemiresistors

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Gennaro Cassano,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2017, 8, 82–90, doi:10.3762/bjnano.8.9

• -like ZnO-based chemiresistive gas sensor. After the annealing at 550 °C, pristine and Pd-modified ZnO were redispersed in ACN and drop-cast on alumina substrates to obtain sensing layers between gold contacts. These assemblies were subsequently thermally stabilized at 300 °C for 2 h. The description of

Structural and tribometric characterization of biomimetically inspired synthetic "insect adhesives"

• Matthias W. Speidel,
• Malte Kleemeier,
• Andreas Hartwig,
• Klaus Rischka,
• Angelika Ellermann,
• Rolf Daniels and
• Oliver Betz

Beilstein J. Nanotechnol. 2017, 8, 45–63, doi:10.3762/bjnano.8.6

• viscosity of the liquid, in thin films, friction can be enhanced by processes such as (1) the formation of dry contacts by dewetting, (2) the solid-like behaviour of the liquid attributable to non-Newtonian properties, (3) the molecular ordering of the liquid at zones at which the film becomes thinner than

• a few monolayers and (4) the penetration of surface irregularities through the liquid film resulting in solid–solid contacts (cf. discussion in [55]). The influence of film thickness can also be seen in our experiments. Although we assume that in all of our experiments, we measured in the regimes of

Sub-nanosecond light-pulse generation with waveguide-coupled carbon nanotube transducers

• Felix Pyatkov,
• Svetlana Khasminskaya,
• Vadim Kovalyuk,
• Frank Hennrich,
• Manfred M. Kappes,
• Gregory N. Goltsman,
• Wolfram H. P. Pernice and
• Ralph Krupke

Beilstein J. Nanotechnol. 2017, 8, 38–44, doi:10.3762/bjnano.8.5

• -coupled CNT transducers to electrical signals and analyze the optical pulses propagating in the waveguide. Results and Discussion Fabrication of waveguide-integrated CNT emitters Our waveguide-coupled CNT (WG-CNT) transducers consist of three components: a rib waveguide, metallic contacts next to the

• waveguide, and metallic single-walled carbon nanotubes (SWCNTs) placed on top of the waveguide, bridging the contacts (Figure 1a). We use the design and fabrication approach for our samples that has been described in detail elsewhere [4]. Both electrodes and waveguides were defined using several steps of

• electron beam lithography on top of Si3N4/SiO2/Si substrate. Au/Cr contacts were produced by physical vapor deposition, and 600 nm wide, half-etched Si3N4-waveguides were formed with reactive ion etching. A typical sample contains tens of contact pairs and CNTs that were placed in between using

Solvent-mediated conductance increase of dodecanethiol-stabilized gold nanoparticle monolayers

• Patrick A. Reissner,
• Jean-Nicolas Tisserant,
• Antoni Sánchez-Ferrer,
• Raffaele Mezzenga and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2016, 7, 2057–2064, doi:10.3762/bjnano.7.196

• 0.76 Å−1 for alkane chains with one and two chemisorbed contacts [30]. Since Δa = 0.5 nm for immersion in EtOH, the conductance would increase by a factor between 190 and 45. On average, the conductance of our monolayers increased by 36 during EtOH immersion, which is slightly lower than the calculated

• samples were rinsed with THF or EtOH and dried under nitrogen flow [3]. Contact deposition Electric contacts were applied by shadow mask evaporation. We aligned a 400 mesh TEM grid with the printed lines on the substrate and deposited 3 nm titanium and 65 nm gold by electron-beam evaporation at a pressure

Zigzag phosphorene nanoribbons: one-dimensional resonant channels in two-dimensional atomic crystals

• Carlos. J. Páez,
• Dario. A. Bahamon,
• Ana L. C. Pereira and
• Peter. A. Schulz

Beilstein J. Nanotechnol. 2016, 7, 1983–1990, doi:10.3762/bjnano.7.189

• = 57 nanoribbon, as a function of the energy. In order to avoid any coupling between the edge states the width of the nanoribbon in the contacts is also NZ = 60. Transmission plateaus above and below the edge states band are shown, for the sake of completeness, since these structures are of entirely

• ). When mZ is further diminished, the barriers to the upper-edge contacts become too large, but now the coupling to the lower edge becomes relevant. For mZ ≤ 15 transmission shows asymmetric Fano-like resonances at the low-energy side and sharp anti-resonances at higher energies within the central band

• (keeping the central band of the contacts unaltered). In our constriction the role of both channels (discrete states and continuum at the upper and lower edges) can be made explicit by picturing the local density of states (LDOS) in Figure 4, at the energy values indicated by arrows 1, 2, 3 and 4 in Figure

Monolayer graphene/SiC Schottky barrier diodes with improved barrier height uniformity as a sensing platform for the detection of heavy metals

• Ivan Shtepliuk,
• Jens Eriksson,
• Volodymyr Khranovskyy,
• Tihomir Iakimov,
• Anita Lloyd Spetz and
• Rositsa Yakimova

Beilstein J. Nanotechnol. 2016, 7, 1800–1814, doi:10.3762/bjnano.7.173

• behaviour and a good quality of ohmic palladium–graphene contacts. Keeping in mind the strong sensitivity of graphene to analytes we propose the possibility to use the graphene/SiC Schottky diode as a sensing platform for the recognition of toxic heavy metals. Using density functional theory (DFT

• characterization provides evidence for the formation of monolayered graphene [51]. The 1 ML coverage is found to be about 99%, thereby implying the high uniformity of the graphene thickness. To avoid the necessity to etch parts of the graphene coverage in order to form the ohmic contacts to SiC, we did not utilize

• the lateral Schottky diode structure and mainly focused on designing vertical devices. It might be expected that the vertical structure has some advantages over the lateral device, since it offers a simpler design and a higher breakdown voltage (because of larger area efficiency). Palladium contacts

Active and fast charge-state switching of single NV centres in diamond by in-plane Al-Schottky junctions

• Christoph Schreyvogel,
• Vladimir Polyakov,
• Sina Burk,
• Helmut Fedder,
• Andrej Denisenko,
• Felipe Fávaro de Oliveira,
• Ralf Wunderlich,
• Jan Meijer,
• Verena Zuerbig,
• Jörg Wrachtrup and
• Christoph E. Nebel

Beilstein J. Nanotechnol. 2016, 7, 1727–1735, doi:10.3762/bjnano.7.165

• channel, NV centres are quenched, i.e., switched to the nonfluorescent state NV+ as proved by PL-intensity mappings which show no bright spots (Figure 1d). For fabricating a two-dimensional Schottky diode structure, aluminium (Al) and gold (Au) contacts with a thickness of 200 nm each were deposited onto

• the diamond surface using photolithography with subsequent thermal evaporation of the metals. Al is a Schottky contact showing a barrier height of 570 meV and Au is an Ohmic contact [18]. The contacts exhibit dimensions of 1 mm × 300 µm and were separated from each other by 400 µm. In order to have a

• defined conductive channel between the Al and Au contacts, the channel region including the contacts were protected with a photoresist and then the whole diamond surface surrounding the channel area were O-terminated via exposition to oxygen plasma. After lift-off process of the photoresist, the

Thickness-modulated tungsten–carbon superconducting nanostructures grown by focused ion beam induced deposition for vortex pinning up to high magnetic fields

• Ismael García Serrano,
• Javier Sesé,
• Isabel Guillamón,
• Hermann Suderow,
• Sebastián Vieira,
• Manuel Ricardo Ibarra and
• José María De Teresa

Beilstein J. Nanotechnol. 2016, 7, 1698–1708, doi:10.3762/bjnano.7.162

• , one sample with 120 nm pitch and two samples with 140 nm pitch. The area of the W–C films is 20 × 5 μm2 and the distance between the voltage probes is 5 μm. The Pt contacts under the superconducting film have been designed to allow for the growth of the W–C film to be started on a flat surface. For

• that, first, substrate FIB milling (200 nm deep and 1 μm wide) is performed in order to dig trenches to be subsequently filled with Pt contacts grown by FIBID using a (CH3)3PtCpCH3 precursor. As the surface of the Pt contacts is at the same height as the substrate’s top surface, the superconducting

• film starts the growth on a flat surface. In the final step, the linear Pt contacts are soldered to the Ti pads by the addition of thick, square, Pt deposits by FIBID. (a) Scheme of the experiment performed to measure the electrical resistance under perpendicular magnetic field. Due to the Lorentz

Analysis of self-heating of thermally assisted spin-transfer torque magnetic random access memory

• Austin Deschenes,
• Sadid Muneer,
• Mustafa Akbulut,
• Ali Gokirmak and
• Helena Silva

Beilstein J. Nanotechnol. 2016, 7, 1676–1683, doi:10.3762/bjnano.7.160

• different heat paths through metal and passivation layers, the configurations with passivation–Cu contacts (I, III) are simulated with and without thermal boundary resistances (TBR) applied on the passivation–Cu interfaces. This TBR is modeled as a 1 nm thick virtual layer with a thermal conductivity of

Sb₂S₃ grown by ultrasonic spray pyrolysis and its application in a hybrid solar cell

• Erki Kärber,
• Atanas Katerski,
• Ilona Oja Acik,
• Arvo Mere,
• Valdek Mikli and
• Malle Krunks

Beilstein J. Nanotechnol. 2016, 7, 1662–1673, doi:10.3762/bjnano.7.158

• P3HT layer remained below 400 nm, as estimated from SEM images. The Au layer was deposited onto the P3HT by thermal evaporation of metallic Au for 10 min under a pressure of 2·10−6 Torr through a metal mask with a number of holes that had an area of 1.7 mm2 each. Alternatively, larger contacts of 1 cm2

Nanostructured germanium deposited on heated substrates with enhanced photoelectric properties

• Ionel Stavarache,
• Valentin Adrian Maraloiu,
• Petronela Prepelita and
• Gheorghe Iordache

Beilstein J. Nanotechnol. 2016, 7, 1492–1500, doi:10.3762/bjnano.7.142

• ) observed in the absence of light can be the result of the serial combination of these interface junctions that can act as rectifying diode-like contacts. It is known that the chemical reduction of GeOx plays an important role and represents the major mechanism to produce size-controlled Ge-nps, embedded