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

• , setting the flow rate at 500 sccm, the temperature at 25 °C and the relative humidity (RH) at 50%. An increase of the conductance response has been recorded upon exposure towards NO2, whereas a decrease of the signal has been detected towards NH3. The material appears totally insensitive towards CO

• extent. Figure 3 displays the dynamic response of the conductance of the devices towards 1 ppm of NO2. As can be observed, the base conductance values are comparable (GA ≈ GB ≈ 22 µS). During exposure, both chemiresistors exhibit an identical percentage variation of the conductance without reaching a

• plateau. In the figures the asymptotic values of conductance are also displayed. Such quantities have been evaluated by extrapolating the final conductance value by fitting each curve, within the time window of exposure to the analyte, with the exponential function where GMIN/MAX represents the

Selective detection of Mg²⁺ ions via enhanced fluorescence emission using Au–DNA nanocomposites

• Tanushree Basu,
• Khyati Rana,
• Niranjan Das and
• Bonamali Pal

Beilstein J. Nanotechnol. 2017, 8, 762–771, doi:10.3762/bjnano.8.79

• propionic acid (MPA). The synthesized AuNSs had a CTAB coating and were positively charged in nature. The values obtained for the zeta potential, conductance and mobility are summarized in Supporting Information File 1, Table S2. In Figure 7, the zeta potential is given before binding with DNA for bare

• neutralized to some extent, as previously reported [33]. In addition, the electrostatic repulsion between positive surface charges of Au–DNA composites also imparts stability to a considerable extent. Along with changes in zeta potential, changes in mobility and conductance were also observed. This gives an

• to characterize AuNPs and DNA functionalized Au nanocomposites. The size and shape of the nanoparticles and nanocomposites were characterized by TEM analysis. The electrokinetic parameters such as zeta potential, hydrodynamic diameter and conductance were analyzed by a Brookhaven 7610 instrument

Vapor deposition routes to conformal polymer thin films

• Priya Moni,
• Ahmed Al-Obeidi and
• Karen K. Gleason

Beilstein J. Nanotechnol. 2017, 8, 723–735, doi:10.3762/bjnano.8.76

• desired liquid or gas [2][3][4]. Conformal coatings can also ensure that micro or nano-device properties (e.g., conductance, capacitance) do not vary due to large thickness variations [5][6][7]. One motivation for vapor phase synthesis of polymer thin films over traditional solution methods (e.g., spin

Graphene functionalised by laser-ablated V₂O₅ for a highly sensitive NH₃ sensor

• Margus Kodu,
• Artjom Berholts,
• Tauno Kahro,
• Mati Kook,
• Peeter Ritslaid,
• Helina Seemen,
• Tea Avarmaa,
• Harry Alles and
• Raivo Jaaniso

Beilstein J. Nanotechnol. 2017, 8, 571–578, doi:10.3762/bjnano.8.61

• functionalised sensors for 8 ppm NH3 gas were determined by fitting the time curves with the suitable functions. Either single or double exponential functions were used in the following form: In Equation 1 and Equation 2, S(t) is the relative change of conductance and t0 is the initial time when the respective

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

• electrodes directly influence the growth of the quantum point contact. Because the electrochemical current is less than 1 nA in our experiment, the use of a reference electrode is not necessary. The conductance between the source and drain electrodes is measured with a current-to-voltage converter, in which

• mV. A confocal optical microscopy image of the copper transistor is shown in Figure 1a. A schematic diagram of an atomic-scale transistor is illustrated in Figure 1b. To achieve conductance switching of copper atomic-scale transistors, the potential applied to the gate was controlled by a program

• developed in “NI LabVIEW” and the conductance was recorded simultaneously with the same program. The electrochemical potential was set using a feedback mechanism, in which the measured conductance was compared with a preset value of quantum conductance of the copper atomic-scale transistor. A transistor

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

• the transfer characteristic measurement, showing only a negligible current flow (less than nA) in the whole back gate bias range. The transfer conductance gm of the Gr-FET reported in Figure 6 was obtained considering the Id vs Vg characteristic by the formula: From the peak transfer conductance, we

• Racc) are still included. A more refined calculation of the graphene field effect mobility would include the elimination of the series resistance contributions in order to extract the intrinsic transfer conductance and the related mobility. Significant improvements in the transfer conductance and

• conductance, graphene doping and electron and hole mobility. The fabricated devices will represent the platform for the implementation of solid IS-FETs that can be part of a fully flexible, integrated system for sensing and signal processing. a) Comparison between tapping mode atomic force microscopy (tAFM

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

•  4d). Higher repetition rates are limited by the setup. In theory, the characteristic timescale of a thermal emitter τtherm solely depends on the mass density ρCNT, the specific heat capacitance cCNT, and thermal conductance g between the CNTs and the substrate, as pointed out previously [11][19

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

• .7.196 Abstract Gold nanoparticle monolayers provide convenient templates to study charge transport in organic molecules beyond single junction techniques. Conductance is reported to increase by several orders of magnitude following immersion of alkanethiol-stabilized gold nanoparticle monolayers in a

• solution containing conjugated thiol-functionalized molecules. Typically, this observation is attributed to molecular exchange. Less attention has been paid to the role of the solvent alone. Here, we report on an increase in conductance of dodecanethiol-stabilized gold nanoparticle monolayers on Si/SiO2 by

• conductance of the monolayer after molecular exchange with two different oligophenylenes to shed light on the respective contribution of the solvent-induced structural change and the molecular exchange itself on the conductance increase. Keywords: molecular electronics; molecular exchange; percolation

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

• Paulo, SP, Brazil 10.3762/bjnano.7.189 Abstract We theoretically investigate phosphorene zigzag nanoribbons as a platform for constriction engineering. In the presence of a constriction at one of the edges, quantum confinement of edge-protected states reveals conductance peaks, if the edge is uncoupled

• , revealing an effective chain-like behavior of the edges of the nanoribbons. In what follows, we initially discuss the “bulk” electronic properties of a phosphorene nanoribbon. We present the model calculation framework, as well as the effects of edge coupling on the conductance of these infinite zigzag

• -dimensional material and the conductance observed can be understood from a simple model. The resonant peaks on top of the T = 1 plateau resemble the conductance of two parallel and independent channels, as shown in Figure 6a. The lower edge provides a continuous channel of T = 1 while the upper edge presents

Layered composites of PEDOT/PSS/nanoparticles and PEDOT/PSS/phthalocyanines as electron mediators for sensors and biosensors

• Celia García-Hernández,
• Cristina García-Cabezón,
• Fernando Martín-Pedrosa,
• José Antonio De Saja and
• María Luz Rodríguez-Méndez

Beilstein J. Nanotechnol. 2016, 7, 1948–1959, doi:10.3762/bjnano.7.186

• on the material deposited on the PEDOT/PSS layer [29][30][31]. In the case of CuPc or AuNPs, the improvement in the conductance can be due to the increase in the charge carrier mobility and/or in the large effective surface provided by the metallic AuNPs. In the case of LuPc2, which is an intrinsic

Nonlinear thermoelectric effects in high-field superconductor-ferromagnet tunnel junctions

• Stefan Kolenda,
• Peter Machon,
• Detlef Beckmann and
• Wolfgang Belzig

Beilstein J. Nanotechnol. 2016, 7, 1579–1585, doi:10.3762/bjnano.7.152

• the regime of linear response of the electric and thermal currents to the difference in electric potential or temperature [12][13][14]. In that case the linear response coefficients – electrical and thermal conductance, Seebeck and Peltier coefficients – are related by the famous Onsager symmetry

• current from the measure thermally induced charge current. We consider a metal coupled to a superconductor by a tunnel contact, with normal-state tunnel conductance GT. The metal can be a normal metal or a ferromagnet, in which case the junction conductance has a finite spin polarization P. In that

• as Here G(E) is the spectral conductance and fT(E) = (exp(E/kBT) + 1)−1 is the Fermi function at energy E. The spectral conductance is given by where N0 = (N+ + N−)/2, Nz = (N+ − N−)/2, and the spin-resolved density of states in the superconductor is N±(E). We would like to point out that N0 is even

A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors

• Vardan Galstyan,
• Elisabetta Comini,
• Iskandar Kholmanov,
• Andrea Ponzoni,
• Veronica Sberveglieri,
• Nicola Poli,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2016, 7, 1421–1427, doi:10.3762/bjnano.7.133

• heater were deposited on the front and rear sides of the alumina substrate, respectively. During gas sensing tests, the conductance of the samples was monitored by means of the volt-amperometric technique and the applied voltage during the measurements was 1 V. We recorded the resistance of the

• ], where G0 is the sample conductance in air, and Gf is the sample conductance in presence of the analyte gas. Results and Discussion Morphological and structural characteristics For characterizing the GO samples with SEM, an aqueous dispersion was spin-coated onto a silicon wafer at 4000 rpm for 2 min. A

• , consequently, in an increased conductance of the structures. The proposed reactions with acetone and ethanol that lead to a sensing signal are resumed in Equations 2–4 [30][31] and Equation 5 [32], respectively. A schematic representation of the sensing mechanism between the acetone and the RGO–ZnO structure

Role of solvents in the electronic transport properties of single-molecule junctions

• Katharina Luka-Guth,
• Sebastian Hambsch,
• Andreas Bloch,
• Philipp Ehrenreich,
• Bernd Michael Briechle,
• Filip Kilibarda,
• Torsten Sendler,
• Dmytro Sysoiev,
• Thomas Huhn,
• Artur Erbe and
• Elke Scheer

Beilstein J. Nanotechnol. 2016, 7, 1055–1067, doi:10.3762/bjnano.7.99

• solvents that are commonly used in the field of molecular electronics (ethanol, toluene, mesitylene, 1,2,4-trichlorobenzene, isopropanol, toluene/tetrahydrofuran mixtures) for the study of single-molecule contacts of functional molecules. We present measurements of the conductance as a function of gap

• width, conductance histograms as well as current–voltage characteristics of narrow gaps and discuss them in terms of the Simmons model, which is the standard model for describing transport via tunnel barriers, and the resonant single-level model, often applied to single-molecule junctions. One of our

• conclusions is that stable junctions may form from solvents as well and that both conductance–distance traces and current–voltage characteristics have to be studied to distinguish between contacts of solvent molecules and of molecules under study. Keywords: electrochemical environment; mechanically

NO gas sensing at room temperature using single titanium oxide nanodot sensors created by atomic force microscopy nanolithography

• Li-Yang Hong and
• Heh-Nan Lin

Beilstein J. Nanotechnol. 2016, 7, 1044–1051, doi:10.3762/bjnano.7.97

• negatively charged by catching electrons. The conductance of the ND with NO (or O2) adsorption is thus smaller than that in the pristine state of the ND (i.e., without adsorbed molecules). Under UV illumination, the ND conductance becomes larger since the adsorbed NO (or O2) molecules are neutralized by

Reconstitution of the membrane protein OmpF into biomimetic block copolymer–phospholipid hybrid membranes

• Matthias Bieligmeyer,
• Franjo Artukovic,
• Stephan Nussberger,
• Thomas Hirth,
• Thomas Schiestel and
• Michaela Müller

Beilstein J. Nanotechnol. 2016, 7, 881–892, doi:10.3762/bjnano.7.80

• molecular weight of the block copolymers. At low voltages, the channel conductance of OmpF in 1 M KCl was around 2.3 nS. In line with these experiments, integration of OmpF was also revealed by impedance spectroscopy. Our results indicate that blending synthetic polymer membranes with phospholipids allows

• transmembrane current was observed for all lipopolymer membranes (Figure 5B). This was attributed to reversible closing and opening of individual channels of OmpF [60][61][62]. A total of 31 insertion events revealed an average conductance level of OmpF in the membranes of about 2.1 nS to 2.3 nS at low membrane

• potentials, as also demonstrated in the histograms (Figure 5D). At high membrane potentials, single-channel conductance was about 0.7 nS in 1 M KCl (Table 3), likely representing the conductance of a single pore of the OmpF trimer. These values were in line with conductance measurements of OmpF in pure DPhPC

The role of morphology and coupling of gold nanoparticles in optical breakdown during picosecond pulse exposures

• Yevgeniy R. Davletshin and
• J. Carl Kumaradas

Beilstein J. Nanotechnol. 2016, 7, 869–880, doi:10.3762/bjnano.7.79

• coupled to the TTM using the heat diffusion from the gold lattice to the surrounding medium through interface conductance, Qau|w [53]. Plasma dynamics The dynamics of plasma formation was calculated in a spherical domain surrounding the nanoparticles (Figure 1). The plasma rate equation [28], based on the

Thermo-voltage measurements of atomic contacts at low temperature

• Ayelet Ofarim,
• Bastian Kopp,
• Thomas Möller,
• León Martin,
• Johannes Boneberg,
• Paul Leiderer and
• Elke Scheer

Beilstein J. Nanotechnol. 2016, 7, 767–775, doi:10.3762/bjnano.7.68

• conductance and thermo-voltage, were using STM or MCBJs techniques. When using the STM method, results are given in a statistical manner, mostly around room temperature where the junctions are short-lived and the measurements have to be performed in a transient state [7][8][10]. Therefore correlating the

• thermopower results to the electrical conductance is not possible for the individual junctions. In most STM realizations, a temperature gradient is achieved by heating the substrate, whereas the tip remains at room temperature, or vice versa. The temperature difference is then assumed to be the difference of

• the temperature applied to the substrate and the temperature of the tip or is deferred from simulations. In the recent work by Evangeli et al. [10] simultaneous measurements of the conductance and thermo-voltage of metallic point-contacts were performed using STM. In that work pronounced deviations

Charge and heat transport in soft nanosystems in the presence of time-dependent perturbations

• Alberto Nocera,
• Carmine Antonio Perroni,
• Vincenzo Marigliano Ramaglia and
• Vittorio Cataudella

Beilstein J. Nanotechnol. 2016, 7, 439–464, doi:10.3762/bjnano.7.39

• vibrational modes and the electronic degrees of freedom affects the thermoelectric properties within the linear response regime finding out that the phonon thermal conductance provides an important contribution to the figure of merit at room temperature. Our work has been stimulated by recent experimental

• consequence, intriguing nonlinear phenomena, such as hysteresis, switching, and negative differential conductance have been observed in molecular junctions. In conducting molecules, either the center of mass oscillations [9], or thermally induced acoustic phonons [10] can be the source of coupling between

• ], where charge conductance has been obtained at zero bias voltage, by applying a small power to the antenna at a frequency close to that of the internal slow resonator. Therefore, it is of great importance to address theoretically the single-parameter charge pumping in the regime where the driving

Invariance of molecular charge transport upon changes of extended molecule size and several related issues

• Ioan Bâldea

Beilstein J. Nanotechnol. 2016, 7, 418–431, doi:10.3762/bjnano.7.37

• effect is absent or drastically suppressed within the WBL and FBL approximations. The analysis done in conjunction with the WBLs and FBLs reveals why general studies on nonequilibrium properties require a more elaborate theoretical than studies on linear response properties (e.g., ohmic conductance and

• ) electron transfer processes contributing to the current. For simplicity, it is assumed that V > 0. Taking the limit V→0 in Equation 7, one gets the well-known formula for conductance, , i.e., “conductance is transmission”: where = 2e2/h is the conductance quantum. The second-quantized Hamiltonian of the

• Equation 27 coincide with the exact one (Equation 15). Via Equation 8 and Equation 2 (see also Table 1), this implies that conductance and local density of states at equilibrium (V = 0) and zero temperature computed within the wide- or flat-band approximations are exact. Therefore, these quantities (as

Rigid multipodal platforms for metal surfaces

• Michal Valášek,
• Marcin Lindner and
• Marcel Mayor

Beilstein J. Nanotechnol. 2016, 7, 374–405, doi:10.3762/bjnano.7.34

• properties of single-molecule devices becomes possible, which is of paramount importance for molecular devices. Furthermore, not only the effect of anchoring groups, but also accurate measurements of the molecular conductance over the functional core and molecular wire is crucial to fulfill requirements for

• characteristics of junctions of symmetric molecules are not necessarily symmetric under bias voltage [18]. Furthermore, the same molecule can exhibit various conductance values [19], and its interface with the electrodes, which is usually determined by chemical anchoring groups, can have a large influence on its

• reproducible binding, sufficiently strong anchoring between a molecule and metal surfaces, and should maintain a sufficient electron density of states close to the Fermi level to pass an electron or hole through the molecule (electronically transparent nature with relatively high conductance). Finally, a well

Case studies on the formation of chalcogenide self-assembled monolayers on surfaces and dissociative processes

• Yongfeng Tong,
• Tingming Jiang,
• Azzedine Bendounan,
• Makri Nimbegondi Kotresh Harish,
• Angelo Giglia,
• Stefan Kubsky,
• Fausto Sirotti,
• Luca Pasquali,
• Srinivasan Sampath and
• Vladimir A. Esaulov

Beilstein J. Nanotechnol. 2016, 7, 263–277, doi:10.3762/bjnano.7.24

• conductance pathway than sulfur. Besides the case of self-assembly on bulk metal surfaces, the knowledge of the physics and chemistry of chalcogenide SAMs on metal nanoparticle surfaces is also very important as they are widely used in different areas. In this paper, we focus on recent work where the

• several investigations on gold [21][22][23][24][25][75] and this dithiol was used in one of the first studies of molecular conductance [70]. Many of these studies use gold electrodes. It was interesting to extend these investigations to another prototype electrode metal: copper. This prompted the work

Single pyrimidine discrimination during voltage-driven translocation of osmylated oligodeoxynucleotides via the α-hemolysin nanopore

• Yun Ding and
• Anastassia Kanavarioti

Beilstein J. Nanotechnol. 2016, 7, 91–101, doi:10.3762/bjnano.7.11

• Figure 4 and listed in Table 2. Typically current levels (I0) in unobstructed pores are about 120 ± 5 pA at 120 mV (conductance ≈ 1000 pS) at our conditions. Normalized values of residual current (Ir/I0) were obtained from the maximum value of the current histograms and are also reported in Table 2; they

Current-induced runaway vibrations in dehydrogenated graphene nanoribbons

• Rasmus Bjerregaard Christensen,
• Jing-Tao Lü,
• Per Hedegård and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2016, 7, 68–74, doi:10.3762/bjnano.7.8

• conductance through the ribbons has been investigated using STM [5], and the signals of electron vibrations in the current have been addressed by theory [6]. When cutting graphene into one-dimensional ribbons, dangling bonds emerge at the boundary carbon atoms. If there is an electrical current passing

• (dotted lines) akin to the experimental conductance [5]. The introduction of the defects results mainly in a potential shift, but besides this does not impact the transmission dramatically, as seen in Figure 1b (solid lines). In order to characterize the phonons we show the phononic transmission in Figure

Effects of electronic coupling and electrostatic potential on charge transport in carbon-based molecular electronic junctions

• Richard L. McCreery

Beilstein J. Nanotechnol. 2016, 7, 32–46, doi:10.3762/bjnano.7.4

• junction conductance [2][34][35]. A consequence of electrode/molecule interactions is that “vacuum level shifts” can change the transport barriers significantly from those based on the free molecule energy levels [14][31][36][37][38][39][40]. An unexpected result likely due to this effect is the

• and electron distributions? Second, does the calculated electronic coupling across the carbon MJ correlate with the observed junction conductance? Third, how does charge transfer between the graphene contacts and molecular layers affect the transport barriers? Fourth, can the model predict the

• electron transfer and/or the conductance relevant to the chemical system considered. These theories will not be reviewed here, but all contain a factor for electronic coupling, often denoted “t”, or “Hab”. For example, the “tight binding” model for off-resonance transport in molecular tunnel junctions

Evaluation of gas-sensing properties of ZnO nanostructures electrochemically doped with Au nanophases

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

Beilstein J. Nanotechnol. 2016, 7, 22–31, doi:10.3762/bjnano.7.3

• morphological structures of the MOs active layer and by the interface between sensing material and metal electrodes of the device [5]. In most cases, the surface conductance of MOS varies when exposed to oxidizing/reducing gases, usually exhibiting n-type behavior [6]. Therefore, the resistance increases in