Blue and white light emission from zinc oxide nanoforests

• Nafisa Noor,
• Luca Lucera,
• Thomas Capuano,
• Venkata Manthina,
• Alexander G. Agrios,
• Helena Silva and
• Ali Gokirmak

Beilstein J. Nanotechnol. 2015, 6, 2463–2469, doi:10.3762/bjnano.6.255

• 2.15 µm). The resulting I–V characteristics showed breakdown voltages at around 35 and 49 V at vacuum and atmospheric pressure, respectively. At lower pressure, lower temperature and hence, smaller applied electrical energy lead to sufficient vapor pressure to initiate the sublimation process [26]. The

• during the electrical test suggests local temperatures above the melting point of tungsten (3422 °C). (a) I–V characteristics for two DC voltage sweep measurements from 0–60 V performed in vacuum (red) and at atmospheric pressure (black). These measurements were performed on ZnO nanorods grown on two

High electronic couplings of single mesitylene molecular junctions

• Yuki Komoto,
• Shintaro Fujii,
• Tomoaki Nishino and
• Manabu Kiguchi

Beilstein J. Nanotechnol. 2015, 6, 2431–2437, doi:10.3762/bjnano.6.251

• -binding to the electrodes. However, there are little direct experimental results revealing strong metal–molecule couplings. The electronic structure of molecular junctions including metal–molecule couplings can be characterized by current-voltage (I–V) characteristics of molecular junctions. Transition

• voltage spectroscopy [27][28] is one of the methods to characterize energy level of conduction orbitals in junctions by analysing I–V characteristics. Energy level alignment of conduction orbitals with respect to Fermi level of metal electrodes has been examined for the molecular junctions of

• experimentally obtained I–V characteristics to the Breit-Wigner model, the metal–molecule coupling Γ, and energy difference between Fermi level and conduction orbital ε0 are obtained. This I–V analysis has been applied for molecular junctions with a variety of anchoring groups. For example Γ = 60 meV and ε0

Electrical properties and mechanical stability of anchoring groups for single-molecule electronics

• Riccardo Frisenda,
• Simge Tarkuç,
• Elena Galán,
• Mickael L. Perrin,
• Rienk Eelkema,
• Ferdinand C. Grozema and
• Herre S. J. van der Zant

Beilstein J. Nanotechnol. 2015, 6, 1558–1567, doi:10.3762/bjnano.6.159

• conductance at low bias in accordance with the observations made for Figure 3 [45]. We have measured hundreds of different junction breaking traces to perform a statistical analysis of the I–V characteristics. Figure 5 shows two-dimensional histograms, plotted in semi-logarithmic scale, built from all the I

Nano-contact microscopy of supracrystals

• Adam Sweetman,
• Nicolas Goubet,
• Ioannis Lekkas,
• Marie Paule Pileni and
• Philip Moriarty

Beilstein J. Nanotechnol. 2015, 6, 1229–1236, doi:10.3762/bjnano.6.126

• Middleton and Wingreen in the early 1990s [6], a number of groups [7][8][9][10][11] have shown that the current–voltage (I(V)) characteristics of nanocrystal superlattices follow a power law dependence above a voltage threshold (which is related to the Coulomb gap for the system). The power law exponent

• , mesoscopic, and microscopic scales [12]. Although a similar power law behaviour has been observed for the I(V) characteristics of both interfacial and precipitated supracrystals, Yang et al. [11][13] point out that it is somewhat counter-intuitive and surprising that supracrystals that are of order 5 μm

• height mode over the same region provides additional supporting evidence (inset to Figure 3B), showing a comparable tunnel current image to the previous STM imaging at a tip height −0.5 nm closer to the sample than the constant height DFM imaging shown in Figure 2C. We note that the I(V) characteristics

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

• desired position close to the disc center rather than at the contacts is shown in Figure 5c. We measured four patterned discs and all of them showed a similar behavior. Measuring the I–V-characteristics of such an electroburned device can verify the actual presence of a gap. Typically a bias voltage of 1

Chains of carbon atoms: A vision or a new nanomaterial?

• Florian Banhart

Beilstein J. Nanotechnol. 2015, 6, 559–569, doi:10.3762/bjnano.6.58

• the Fermi level leads to a high conductance. Song et al. [48] have calculated the influence of even/odd number of atoms on the I–V characteristics of chains. Plateaus are found where the current becomes independent of bias for even chains whereas in odd chains the current increases monotonically with

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

• between the nanowire and the electrodes. The contacts were not pure platinum, but rather a mixture of platinum and carbon, which was the residual phase from the organic component of the gaseous precursor used. The electrical characteristics were measured and nonlinear I–V characteristics were observed. A

Characterization of 10,12-pentacosadiynoic acid Langmuir–Blodgett monolayers and their use in metal–insulator–metal tunnel devices

• Saumya Sharma,
• Mohamad Khawaja,
• Manoj K. Ram,
• D. Yogi Goswami and
• Elias Stefanakos

Beilstein J. Nanotechnol. 2014, 5, 2240–2247, doi:10.3762/bjnano.5.233

• probe tip positioning outside of the active area of the device without the need for a liquid top contact. After such optimization, the I–V characteristics of the Ni–PDA–Ni MIM configuration could be successfully measured using the 4145B Semiconductor Parameter Analyzer and micromanipulator setup to

• layer. A confined Ni top contact was sputtered through a shadow mask at low RF power over the underlying Langmuir–Blodgett film assembly and the I–V characteristics of the MIM diode were successfully measured. A rectification ratio of ≈110 at ±200 mV was obtained for a bias voltage of 200 mV. Chemical

• control the probe tips. The rectification ratio, RR, calculated at a bias voltage of 200 mV was as high as ≈110 at ±200 mV. This was calculated as a ratio of currents for an equal voltage deviation around the bias voltage (Vb) as RR = If (at Vb +200 mV)/Ir (at Vb −200 mV). Figure 8 shows the I–V

Low cost, p-ZnO/n-Si, rectifying, nano heterojunction diode: Fabrication and electrical characterization

• Vinay Kabra,
• Lubna Aamir and
• M. M. Malik

Beilstein J. Nanotechnol. 2014, 5, 2216–2221, doi:10.3762/bjnano.5.230

• an n-Si substrate using a dip coating technique. The device was then characterized by current–voltage (I–V) and capacitance–voltage (C–V) measurements. The effect of UV illumination on the I–V characteristics was also explored and indicated the formation of a highly rectifying, nano heterojunction

• heterojunction diode. Furthermore, work is in progress to achieve a carrier concentration for the p-ZnO nanoparticles on the order of 1018 cm−3. Current–voltage (I–V) characteristics Figure 2a shows the I–V characteristics of the p-ZnO/n-Si nano heterojunction diode (area: 0.25 cm2) under dark and UV

• illumination (λ = 220 nm, intensity: 233 lux). It is clear from the I–V characteristics that the nano heterojunction possesses good rectification with a forward to reverse current ratio (IF/IR) of 101 under dark conditions, which increases to 232 under UV illumination at 3 V. These characteristics indicate a

Optical properties and electrical transport of thin films of terbium(III) bis(phthalocyanine) on cobalt

• Peter Robaschik,
• Pablo F. Siles,
• Daniel Bülz,
• Peter Richter,
• Manuel Monecke,
• Michael Fronk,
• Svetlana Klyatskaya,
• Daniel Grimm,
• Oliver G. Schmidt,
• Mario Ruben,
• Dietrich R. T. Zahn and
• Georgeta Salvan

Beilstein J. Nanotechnol. 2014, 5, 2070–2078, doi:10.3762/bjnano.5.215

• locations and with different voltages, we are able to reconstruct the I–V characteristics. Figure 6a shows a schematic diagram of the set up for local electrical measurements. A conductive AFM probe placed directly in contact with the TbPc2 surface plays the role of the top electrode, while the Co bottom

• . In order to verify the reproducibility of the I–V spectroscopy results, a series of current maps were also obtained at different applied voltages for both organic films. I–V characteristics were then reconstructed by obtaining the average current corresponding to 512 × 512 data points from current

• maps as the ones shown in Figure 6c–e. Solid dots in Figure 7a correspond to the I–V characteristics reconstructed with current maps and indicate the high reproducibility of the transport measurements for TbPc2 organic films performed via cs-AFM. The current values measured for the TbPc2 thin films are

Photodetectors based on carbon nanotubes deposited by using a spray technique on semi-insulating gallium arsenide

• Domenico Melisi,
• Maria Angela Nitti,
• Marco Valentini,
• Antonio Valentini,
• Teresa Ligonzo,
• Giuseppe De Pascali and
• Marianna Ambrico

Beilstein J. Nanotechnol. 2014, 5, 1999–2006, doi:10.3762/bjnano.5.208

• the dark-current–voltage (I–V) characteristics for the SFS, DFS and ITO/GaAs/Ti/Au photodetector configurations are reported. The inset reports the negative part of the I–V, showing the same trend for SFS and DFS samples. From the positive part a different behaviour of the SFS and DSF, due to the

The influence of molecular mobility on the properties of networks of gold nanoparticles and organic ligands

• Edwin J. Devid,
• Paulo N. Martinho,
• M. Venkata Kamalakar,
• Úna Prendergast,
• Christian Kübel,
• Tibebe Lemma,
• Jean-François Dayen,
• Tia. E. Keyes,
• Bernard Doudin,
• Mario Ruben and
• Sense Jan van der Molen

Beilstein J. Nanotechnol. 2014, 5, 1664–1674, doi:10.3762/bjnano.5.177

• estimated typical Coulomb-blockade charging energies of around 14–17 meV [5], in correspondence with temperature- and voltage-dependent transport measurements. Hence, in alkanethiol and OPE-based networks Coulomb blockade dominates below 200–250 K, whereas around room temperature, the current–voltage (I–V

• ) characteristics are linear and practically independent of temperature. The same method as in [5] is used to investigate the charge transport through Au-NP–S-BPP networks. We fabricate nanotrench devices with a high width-to-length aspect ratio (ca. 200) by electron beam lithography and metal lift-off. Through

An analytical approach to evaluate the performance of graphene and carbon nanotubes for NH₃ gas sensor applications

• Elnaz Akbari,
• Vijay K. Arora,
• Aria Enzevaee,
• Mohamad. T. Ahmadi,
• Mehdi Saeidmanesh,
• Mohsen Khaledian,
• Hediyeh Karimi and
• Rubiyah Yusof

Beilstein J. Nanotechnol. 2014, 5, 726–734, doi:10.3762/bjnano.5.85

• surface molecules is emphasized. NH3 has been used as the prototype gas to be detected by the nanosensor and the corresponding current–voltage (I–V) characteristics of the FET-based sensor are studied. A graphene-based gas sensor model is also developed. The results from graphene and CNT models are

• in the I–V characteristics of graphene/CNT. Operational amplifiers amplify these signals that can be converted to digital format for digital signal processing. FET-based structure As presented in Figure 2, the structure of the proposed gas sensors that use CNT/graphene as the conducting channel looks

• modified through this interaction. The phenomenon is likely to occur as a result of the interaction of NH3 molecules with the carbon on the surface of graphene/CNT. Thus, electrons move from NH3 molecules to these materials. Figure 4 illustrates the I–V characteristics of the graphene/CNT gas sensors

Photovoltaic properties of ZnO nanorods/p-type Si heterojunction structures

• Rafal Pietruszka,
• Bartlomiej S. Witkowski,
• Grzegorz Luka,
• Lukasz Wachnicki,
• Sylwia Gieraltowska,
• Krzysztof Kopalko,
• Eunika Zielony,
• Piotr Bieganski,
• Ewa Placzek-Popko and
• Marek Godlewski

Beilstein J. Nanotechnol. 2014, 5, 173–179, doi:10.3762/bjnano.5.17

• sizes of nanorods enable us to study the influence of ZnONR on the electrical and optical properties of the ZnONR/Si PV structures. Dark I–V characteristics of the structures are shown in Figure 3a. From the dark I–V measurements we see that the size and density of the nanorods affect the diode

• . The fill factor can be expressed by the following equation: where Vm is the value of the voltage for the maximum power from a solar cell, and Jm is the value of the current for the maximum power from a solar cell. Figure 3b shows I–V characteristics for the samples A, B and C measured under an

Kelvin probe force microscopy of nanocrystalline TiO₂ photoelectrodes

• Alex Henning,
• Gino Günzburger,
• Res Jöhr,
• Yossi Rosenwaks,
• Biljana Bozic-Weber,
• Catherine E. Housecroft,
• Edwin C. Constable,
• Ernst Meyer and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2013, 4, 418–428, doi:10.3762/bjnano.4.49

• calculations for N719 [38] and N3 [42][63] adsorbed on anatase plane-surface. However, for a complete DSC device the surface dipole may change due to screening by the surrounding electrolyte [64]. Figure 9a depicts the I–V characteristics for three different DSCs, a bare TiO2 solar cell with electrolyte and

Micro- and nanoscale electrical characterization of large-area graphene transferred to functional substrates

• Gabriele Fisichella,
• Salvatore Di Franco,
• Patrick Fiorenza,
• Raffaella Lo Nigro,
• Fabrizio Roccaforte,
• Cristina Tudisco,
• Guido G. Condorelli,
• Nicolò Piluso,
• Noemi Spartà,
• Stella Lo Verso,
• Corrado Accardi,
• Cristina Tringali,
• Sebastiano Ravesi and
• Filippo Giannazzo

Beilstein J. Nanotechnol. 2013, 4, 234–242, doi:10.3762/bjnano.4.24

• rectangular graphene area. The current–voltage (I–V) characteristics for different distances between adjacent contacts are reported in Figure 4b, showing an Ohmic behaviour for all the contact distances. In Figure 4c the resistance R, obtained from the slope of each curve, is plotted versus the contact

• method. The contacts had identical geometry (200 µm width and 100 µm length) and the distance between the pairs of adjacent contacts were 20, 20, 40, 60, 80, 100 and 100 µm, respectively. The current–voltage (I–V) characteristics were measured in a Karl-Süss probe station by using a HP 4156B parameter

• ) magnifications. Line scans on a peculiar corrugation of the graphene membrane (d) and across a microscopic crack (e). Tapping-mode AFM images of the bare PEN surface (a) and of graphene transferred onto PEN (b). (a) Optical Image of a TLM structure, (b) I–V characteristics measured between pairs of contacts at

Photoresponse from single upright-standing ZnO nanorods explored by photoconductive AFM

• Igor Beinik,
• Markus Kratzer,
• Astrid Wachauer,
• Lin Wang,
• Yuri P. Piryatinski,
• Gerhard Brauer,
• Xin Yi Chen,
• Yuk Fan Hsu,
• Aleksandra B. Djurišić and
• Christian Teichert

Beilstein J. Nanotechnol. 2013, 4, 208–217, doi:10.3762/bjnano.4.21

• were carried out under ambient conditions on as-grown samples. The current–voltage (I–V) characteristics were recorded at the sample surface, which was under illumination directly from the optical fiber placed at an angle of about 15 to 20° with respect to the surface. For these measurements, we used a

• . The blue curve represents a TR-PL spectrum where each point was measured in a time frame from 0 to 0.7 ns from the moment of excitation. Figure 3 shows the influence of illumination on the I–V characteristics of a single upright-standing ZnO NR. The dark and illuminated I–V characteristics were both

• attributed to the photoexcitation of charge carriers from the valence band to a defect-perturbed host state (PHS, depicted as transition (3) in Figure 6, see below). The I–V characteristics recorded from ZnO NRs under illumination are degenerated with high currents at reverse (positive) sample bias, which

Sub-10 nm colloidal lithography for circuit-integrated spin-photo-electronic devices

• Adrian Iovan,
• Marco Fischer,
• Roberto Lo Conte and
• Vladislav Korenivski

Beilstein J. Nanotechnol. 2012, 3, 884–892, doi:10.3762/bjnano.3.98

• 40 nm thick SiO2 layer for insulation, rotating the sample holder during deposition. Finally, the resist was lifted off, and the last step of lithography was the use of negative resist and deposition of a 200 nm thick Al top electrode. Transport measurements: The current–voltage (I–V) characteristics

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

• several thousands of traces are used. A more detailed discussion about the histograms and the stability of individual junctions is given in Supporting Information File 1. For recording the current–voltage (I–V) characteristics the breaking procedure can be stopped at any position of the stretching or

• ) forms of photochromic molecules (difurylethene); R indicates the extended side-arms and end-groups. (c) Structures of three different molecules, 4Py (black), TSC (red), MN (green) investigated in this study. Examples of I–V characteristics of open and closed isomers. (a) Open form of TSC, (b) closed

The memory effect of nanoscale memristors investigated by conducting scanning probe microscopy methods

• César Moreno,
• Carmen Munuera,
• Xavier Obradors and
• Carmen Ocal

Beilstein J. Nanotechnol. 2012, 3, 722–730, doi:10.3762/bjnano.3.82

• ) and high-resistive (OFF) states was locally achieved by applying voltages within the range of a few volts. Retention times of several months were tested for both ON and OFF states. Spectroscopy modes were used to investigate the I–V characteristics of the different resistive states. This permitted the

• , interpretation of colour-coded current maps depends on the voltage sign as well as the absolute current magnitude. Thus higher currents appear darker in C-SFM images taken at negative Vtip, while brighter for positive Vtip. The current–voltage (I–V) characteristics of the contact were measured as a function of

• are performed (writing and erasing) and followed (reading) in a noninvasive way. Analytical simulation of the memristor I–V behaviour Typical I–V characteristics conducted by application of a voltage cycle at a fixed location on the virgin (preswitched) 10 nm thick LSMO thin film surface presented a

Low-temperature synthesis of carbon nanotubes on indium tin oxide electrodes for organic solar cells

• Andrea Capasso,
• Luigi Salamandra,
• Aldo Di Carlo,
• John M. Bell and
• Nunzio Motta

Beilstein J. Nanotechnol. 2012, 3, 524–532, doi:10.3762/bjnano.3.60

• with bare ITO-coated glass were also made for comparison with the same procedure. The current–voltage (I–V) characteristics under 1 sun (AM1.5G) were measured with an Agilent E5262A source meter. SEM images of MWCNTs grown on ITO-coated glass by CVD at: (a) 550 °C, (b) 525 °C, (c) 500 °C. Transmittance

Conducting composite materials from the biopolymer kappa-carrageenan and carbon nanotubes

• Ali Aldalbahi,
• Jin Chu,
• Peter Feng and
• Marc in het Panhuis

Beilstein J. Nanotechnol. 2012, 3, 415–427, doi:10.3762/bjnano.3.48

• conductivity of films Free-standing films were prepared by evaporative casting and vacuum filtration of KC–CNT dispersions. All films exhibited linear I–V characteristics, i.e., ohmic behaviour (Figure 5a). The total resistance (RT) increased with channel length (Figure 5b), and was found to scale linearly

• waveform generator (Agilent 33220A). I–V measurements were conducted under controlled ambient conditions (21 °C, RH = 45%) as a function of film length, by repeatedly cutting the end of the strip, contacting with the electrodes and remeasuring the I–V characteristics. Film thickness was determined with a

• dispersions. The lines in (c) and (d) are fits to Equation 1 and Equation 2, respectively. (a) I–V characteristics for KC–CNT (channel length 2 cm) and (b) resistance as a function of length for KC–CNT composite films prepared by evaporative casting and vacuum filtration of KC–CNT dispersions. Numbers 1 and 2

Surface functionalization of aluminosilicate nanotubes with organic molecules

• Wei Ma,
• Weng On Yah,
• Hideyuki Otsuka and
• Atsushi Takahara

Beilstein J. Nanotechnol. 2012, 3, 82–100, doi:10.3762/bjnano.3.10

• . studied the I–V characteristics of imogolite and proposed that bound water molecules contribute to the surface conductivity [69][70]. The current flow observed was attributed to the ability of OH groups on the imogolite surface to lose or gain positive charge (a proton) from water molecules resulting in a

Charge transport in a zinc–porphyrin single-molecule junction

• Mickael L. Perrin,
• Christian A. Martin,
• Ferry Prins,
• Ahson J. Shaikh,
• Rienk Eelkema,
• Jan H. van Esch,
• Jan M. van Ruitenbeek,
• Herre S. J. van der Zant and
• Diana Dulić

Beilstein J. Nanotechnol. 2011, 2, 714–719, doi:10.3762/bjnano.2.77

• )porphyrin) molecular junctions using the lithographic mechanically controllable break-junction (MCBJ) technique at room temperature and cryogenic temperature (6 K). We combined low-bias statistical measurements with spectroscopy of the molecular levels in the form of I(V) characteristics. This combination

• electrode spacing. In contrast, I(V) characteristics on the ZnTPPdT–Pyr junction show a sharper current onset, marked by arrows in Figure 2d. This observation may be viewed as a molecular fingerprint as the marked points correspond to the onset of resonant transport through an energy level of the molecule

• molecular junction are not always reflected in the low-bias trace histograms, supporting high-bias I(V) characteristics are essential for the interpretation of such histograms. Conclusion In summary, we investigated charge transport in ZnTPPdT–Pyr molecular junctions using the lithographic MCBJ technique

An MCBJ case study: The influence of π-conjugation on the single-molecule conductance at a solid/liquid interface

• Wenjing Hong,
• Hennie Valkenier,
• Gábor Mészáros,
• David Zsolt Manrique,
• Artem Mishchenko,
• Alexander Putz,
• Pavel Moreno García,
• Colin J. Lambert,
• Jan C. Hummelen and
• Thomas Wandlowski

Beilstein J. Nanotechnol. 2011, 2, 699–713, doi:10.3762/bjnano.2.76

• conductance states in a molecular junction require a careful statistical analysis of several thousands of individual traces to extract the “most probable” I–V characteristics of a certain molecule under a given set of experimental conditions. This approach is particularly important for single-molecule

• nature of the transport process. In a first approximation, we considered a single-level model in the low-bias limit and with the molecules coupled equally to the leads. We thus evaluated the experimentally observed I–V characteristics based on the following expression ([1] page 366, and [18]): where Δε0