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

• improve the fitting [31]. Due to the generality of the model, usually approximate functions are used for low bias, intermediate bias, and high bias. In this context, low, intermediate and high refer to voltage ranges compared to the tunnel barrier height. Here we test the SM up to the intermediate voltage

• , where we plot two I–V curves calculated with the SLM and the SM with the level alignment equalling the barrier height. We have chosen here the typical value |E0| = Φ = 0.8 eV. The other parameters, Γ, d and A were adapted such that the linear conductance of both models is the same and lies in the order

• MCBJ contacts. This further reduces the number of I–V curves that can be described by the SM. As a result only four I–Vs for EtOH and only one for Tol/THF could be fitted. For Tol/THF the value obtained for the tunnel barrier height Φ lies in the range around 0.1 eV. Since the validity of the

Bacteriorhodopsin–ZnO hybrid as a potential sensing element for low-temperature detection of ethanol vapour

• Saurav Kumar,
• Sudeshna Bagchi,
• Senthil Prasad,
• Anupma Sharma,
• Ritesh Kumar,
• Rishemjit Kaur,
• Jagvir Singh and
• Amol P. Bhondekar

Beilstein J. Nanotechnol. 2016, 7, 501–510, doi:10.3762/bjnano.7.44

• ZnO at very high temperature (≥300 °C) is accompanied by the dehydration/dehydrogenation reaction of ethanol, releasing CO2 and H2O [75]. However, contrary to this, both the hybrid structures in our study showed p-type behaviour. This observed inconsistency is due to the increase in barrier height of

Molecular machines operating on the nanoscale: from classical to quantum

• Igor Goychuk

Beilstein J. Nanotechnol. 2016, 7, 328–350, doi:10.3762/bjnano.7.31

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

• predicts that the transport is proportional to t2(N − 1), where N is the number of “sites” between the contacts [48]. For transport in conducting polymers, Hab is related to charge propagation between polarons both along the chain and between different chains [49][50]. These theories include a barrier

• height as well as a coupling term, both of which affect the overall electron transfer rate. A case relevant to the current discussion is coupling between two orbitals in separate but identical molecules, for example the HOMO orbitals of G9. By definition, these orbitals have identical energies when the

Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

• Urs Gysin,
• Thilo Glatzel,
• Thomas Schmölzer,
• Adolf Schöner,
• Sergey Reshanov,
• Holger Bartolf and
• Ernst Meyer

Beilstein J. Nanotechnol. 2015, 6, 2485–2497, doi:10.3762/bjnano.6.258

• architectures for power electronic switches and rectifiers [58]. However, the reduction of the Schottky barrier height as well as tunneling processes are still limiting the voltage and efficiency of SiC Schottky barrier diodes. An alternative approach for such devices is the so-called junction barrier Schottky

Evidence for non-conservative current-induced forces in the breaking of Au and Pt atomic chains

• Carlos Sabater,
• Carlos Untiedt and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2015, 6, 2338–2344, doi:10.3762/bjnano.6.241

• length of the chain. The parameters influencing the barrier height were taken from experiments, but the tensile stress will vary depending on the atomic arrangements at the end points of the chain and is not easily obtained from the experimental data. Therefore, this was assumed to be the main factor

Current–voltage characteristics of manganite–titanite perovskite junctions

• Benedikt Ifland,
• Patrick Peretzki,
• Birte Kressdorf,
• Philipp Saring,
• Andreas Kelling,
• Michael Seibt and
• Christian Jooss

Beilstein J. Nanotechnol. 2015, 6, 1467–1484, doi:10.3762/bjnano.6.152

• semiconductor 2. This leads to a J–V curve of similar form to the ideal Shockley equation curve. Up to this point, no other transport mechanisms such as tunneling through the interface barrier, recombination at the interface, or a voltage-dependent barrier height have been taken into account. If these processes

• value of the band offset can be approximately calculated by the difference of the work functions of the p- and n-doped material. For the materials used, these are W = 4.9 eV for PCMO [57] and W = 4.13 eV for STNO [58]. Therefore, the expected barrier height is ΔW = 770 meV. The slightly smaller value of

• mobility, and thus also may influence the barrier height of the band discontinuity at the interface. Since a finite current density in the reverse direction can only be due to electron–hole polaron pair generation at the interface, we interpret the rate r as being limited by the generation rate of polaron

Electrical characterization of single molecule and Langmuir–Blodgett monomolecular films of a pyridine-terminated oligo(phenylene-ethynylene) derivative

• Henrry M. Osorio,
• Santiago Martín,
• María Carmen López,
• Santiago Marqués-González,
• Simon J. Higgins,
• Richard J. Nichols,
• Paul J. Low and
• Pilar Cea

Beilstein J. Nanotechnol. 2015, 6, 1145–1157, doi:10.3762/bjnano.6.116

• tunneling barrier, which has been taken as 1.64 nm (value obtained from the geometric N…N distance determined with the molecular modeling program Spartan®08 V 1.0.0); φ represents the effective barrier height of the tunneling junction (relative to the Fermi level of Au); α is a fitting parameter related to

Closed-loop conductance scanning tunneling spectroscopy: demonstrating the equivalence to the open-loop alternative

• Chris Hellenthal,
• Kai Sotthewes,
• Martin H. Siekman,
• E. Stefan Kooij and
• Harold J. W. Zandvliet

Beilstein J. Nanotechnol. 2015, 6, 1116–1124, doi:10.3762/bjnano.6.113

• effective barrier height. If one simply assumes that the effective barrier height is equal to the work function, the presence of image charges will lead to values for that are significantly lower than one would expect. Determining the tunnel behavior in molecular junctions can give an indication of the

• electrons has also been determined through the use of tunneling measurements [26]. Another active area of research deals with the interfaces between the molecule and the metal contacts making up the junction [27]. In this article, the effective tunneling barrier height is determined through the use of

• constant of the system. An important limitation to the use of z(V) measurements for the determination of the effective barrier height arises due to the density of states (DOS) of the studied sample. For samples with a featureless or weakly varying DOS, measured at limited bias voltages, the (dρ/dV)(s/ρ

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

• fitting according to the Simmons model by using the following parameters: gap size d = 1.83 nm; junction area A = 5 nm2; barrier height Φ = 0.6 eV; c) and d) corresponding SEM images showing the opening of a gap that is a few nanometers wide (scale bars: 300 nm). top) Number of measured devices displaying

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

• connected to electrical circuitry, which is typically achieved by contacting the SWCNTs with metal. Due to possible low channel resistance (or even ballistic conduction), the metal–nanotube contact resistance can dominate the performance of these transistors. Devices with a low Schottky barrier height (SBH

• the metal–semiconductor interface and lead to the so-called Fermi level pinning effect, that is, when the Fermi level tends to be fixed at a constant position in the band gap of the semiconductor [13]. The net result is that the Schottky barrier height is less sensitive to the work function difference

• results [17] are consistent with this theoretical prediction [16]. Chen et al. [15] also reported that the Schottky barrier height decreased with increasing SWCNT diameter for the metals tested (Figure 2b). Meanwhile, for SWCNTs of the same diameter, a clear difference in electrical current (and Schottky

Advances in NO₂ sensing with individual single-walled carbon nanotube transistors

• Kiran Chikkadi,
• Matthias Muoth,
• Cosmin Roman,
• Miroslav Haluska and
• Christofer Hierold

Beilstein J. Nanotechnol. 2014, 5, 2179–2191, doi:10.3762/bjnano.5.227

• increase in the Schottky barrier height for electrons), leading to a lower current in the n-branch and an increase in the p-branch [35]. On the other hand, a work function change for devices with ohmic contacts will depend on magnitude and direction of the change. For example, if the work function change

A highly pH-sensitive nanowire field-effect transistor based on silicon on insulator

• Denis E. Presnov,
• Sergey V. Amitonov,
• Pavel A. Krutitskii,
• Valentina V. Kolybasova,
• Igor A. Devyatov,
• Vladimir A. Krupenin and
• Igor I. Soloviev

Beilstein J. Nanotechnol. 2013, 4, 330–335, doi:10.3762/bjnano.4.38

• . Its height is different for electrons and holes [10]. For p-type silicon (p-Si) with a doping level of about 1015 cm−3 and Ti electrodes, the barrier height for holes is about three times higher than for electrons. Measurements of the pH sensitivity of the transistor were carried out at positive

Electronic and transport properties of kinked graphene

• Jesper Toft Rasmussen,
• Tue Gunst,
• Peter Bøggild,
• Antti-Pekka Jauho and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2013, 4, 103–110, doi:10.3762/bjnano.4.12

• comparable to results obtained by several groups using DZP or plane wave basis sets and the PW91 functional [22][29][32][33]. We find that a SZP basis set for the relaxed carbon atoms yields a reduced barrier height of 0.18 eV (both basis sets with orbital range corresponding to an energy shift of 0.01 eV

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

• behaviour such that charge injection occurs exactly at VReset = −Vwr indicating that to change the memory state of the device, carriers must overcome a barrier height equal to the switch-on voltage employed in each case. At this point, the particular HR state is reversed to the LR state. In other words

Highly efficient ZnO/Au Schottky barrier dye-sensitized solar cells: Role of gold nanoparticles on the charge-transfer process

• Tanujjal Bora,
• Htet H. Kyaw,
• Soumik Sarkar,
• Samir K. Pal and
• Joydeep Dutta

Beilstein J. Nanotechnol. 2011, 2, 681–690, doi:10.3762/bjnano.2.73

• affinity of the semiconductor (χS) and the barrier height (θSB) at the junction can be expressed as given in Equation 1. In the ZnO/Au-nanocomposite system, due to the larger work function of Au (5.1 eV) [21] compared the electron affinity of ZnO (4.2 eV) [24], a Schottky barrier exists at their interface

Deconvolution of the density of states of tip and sample through constant-current tunneling spectroscopy

• Holger Pfeifer,
• Berndt Koslowski and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 607–617, doi:10.3762/bjnano.2.64

• of characteristic DOS features change depending on parameters such as the energy position, width, barrier height, and the tip–sample separation. Then it is shown that the deconvolution scheme is capable of recovering the original DOS of tip and sample with an accuracy of better than 97% within the

• data and those based on I–V data. This points to an inconsistency between the assumed and the actual transmission probability function. Indeed, the experimentally determined differential barrier height still clearly deviates from that derived from the deconvolved DOS. Thus, the present progress in

• WKB approximation is deficient, at least in the case of Nb(110). We propose that the differential barrier height is a sensitive indicator of how to adjust the TPF to obtain a more realistic description of the tunneling probability. Results and Discussion Theory The underlying theory for z–V

Terthiophene on Au(111): A scanning tunneling microscopy and spectroscopy study

• Berndt Koslowski,
• Anna Tschetschetkin,
• Norbert Maurer,
• Elena Mena-Osteritz,
• Peter Bäuerle and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 561–568, doi:10.3762/bjnano.2.60

• differential barrier height. This not so commonly determined characteristic, describing the voltage dependent tunneling barrier, has been introduced recently in order to remove features of the tunneling tip from STS spectra, assuming the validity of the Wentzel–Kramers–Brillouin (WKB) approximation. Again, 3T

• separation of the molecules from the surface of 0.315 nm [20]. Such a considerable difference requires an explanation. Typically one would argue in STM that a change of the density of states (DOS) or the barrier height, Φ, above a molecule changes the tip–sample separation. However, the spatial distribution

• barrier height defined by Φdiff = (∂z∂VI/∂VI)2 [21] was determined. The differential barrier, Φdiff, may be thought of as similar to the commonly used apparent barrier height defined by Φapp = (∂zI/I)2, which is bias dependent. Due to differentiation, however, Φdiff is much more sensitive to changes in