Structural model of silicene-like nanoribbons on a Pb-reconstructed Si(111) surface

• Agnieszka Stępniak-Dybala and
• Mariusz Krawiec

Beilstein J. Nanotechnol. 2017, 8, 1836–1843, doi:10.3762/bjnano.8.185

• additional argument for the Si nature of nanoribbons can be provided by measurements of the local work function (Φ). In a first approximation Φ is proportional to the derivative of the tunneling current (I) with respect to the STM tip–sample distance (z) [55]. Thus, changes of Φ should be reflected in

• recorded dI/dz maps. Figure 1c,d shows topography and dI/dz maps simultaneously measured in the same area of the sample. A clear correlation between these quantities is observed. It is evident that the nanostructures feature a higher work function than the substrate, which suggests the NRs are composed of

• protrusion had substantially spoiled the agreement between theoretical and experimental STM topography images. As a result of Pb passivation an STM topography with two protrusions is now obtained. To further check the validity of the model, we have calculated the work function Φ for Si NRs and for Si–Pb NRs

α-Silicene as oxidation-resistant ultra-thin coating material

• Ali Kandemir,
• Fadil Iyikanat,
• Cihan Bacaksiz and
• Hasan Sahin

Beilstein J. Nanotechnol. 2017, 8, 1808–1814, doi:10.3762/bjnano.8.182

• electronics. Although the oxidation of silver forms thin layer of Ag2O, which protects from more oxygen diffusion into silver surface, it is an undesirable reaction. Previous studies have shown that oxidation of silver surfaces leads to increase in work function, color change and significant deterioration of

Group-13 and group-15 doping of germanane

• Nicholas D. Cultrara,
• Maxx Q. Arguilla,
• Shishi Jiang,
• Chuanchuan Sun,
• Michael R. Scudder,
• R. Dominic Ross and
• Joshua E. Goldberger

Beilstein J. Nanotechnol. 2017, 8, 1642–1648, doi:10.3762/bjnano.8.164

• observed using 100 nm Au as a contact metal. Furthermore, the highest ambient and vacuum conductivities in As:GeH were achieved when contacting with Ag (80 nm)/Au (20 nm). The fact that Au with its higher work function is needed to make ohmic contacts for Ga:GeH, compared to Ag for As:GeH, suggests that Ga

Charge transfer from and to manganese phthalocyanine: bulk materials and interfaces

• Florian Rückerl,
• Daniel Waas,
• Bernd Büchner,
• Martin Knupfer,
• Dietrich R. T. Zahn,
• Francisc Haidu,
• Torsten Hahn and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 1601–1615, doi:10.3762/bjnano.8.160

• the evolution of the high binding energy cutoff (a) and the energy region close to the Fermi energy (b). The data in panel (a) show the evolution of the work function of the layer system as a function of increasing F6TCNNQ layer thickness. With the exception of the thinnest F6TCNNQ layer on top of

• represents the changes of the work function. Panel (b) focusses on the energy region close to the Fermi level. N 1s excitation spectra as obtained using X-ray absorption spectroscopy (adapted from [127]). Corresponding data for (c) a 2.0 nm thick MnPc film on Au(100), (b) an additional 0.6 nm thick F16CoPc

Two-dimensional carbon-based nanocomposites for photocatalytic energy generation and environmental remediation applications

• Suneel Kumar,
• Ashish Kumar,
• Ashish Bahuguna,
• Vipul Sharma and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2017, 8, 1571–1600, doi:10.3762/bjnano.8.159

• photocatalysts to produce more reactive sites and to reduce the activation energy for H2 and O2 gas evolution. Cocatalysts also enhances the charge separation in photocatalytic materials because of their high work function. This high work function of noble metals and some metal oxides accelerates the transfer of

• alternatives for noble metals. Graphene acts as a promising cocatalyst in H2 evolution reactions due to its high work function (4.42 eV) [117], and the reduction potential of graphene/graphene− is reported to be −0.08 eV, which is more negative than reduction potential of H+ → H2 [52]. It is noteworthy to

• mention here that the work function of any material is an important parameter for many technical applications, mainly device fabrication as it decides contact properties with foreign material and charge transfer direction in nanocomposites. The work function of carbon-based materials, graphene, GO, carbon

Adsorption and electronic properties of pentacene on thin dielectric decoupling layers

• Sebastian Koslowski,
• Daniel Rosenblatt,
• Alexander Kabakchiev,
• Klaus Kuhnke,
• Klaus Kern and
• Uta Schlickum

Beilstein J. Nanotechnol. 2017, 8, 1388–1395, doi:10.3762/bjnano.8.140

• values are well known from photoemission and inverse photoemission experiments [15]. In a first approximation, the physical quantity connecting Ea and Ei with the measured energetic positions of the HOMO and LUMO, respectively, is the work function Φ of the underlying h-BN/Rh(111) substrate, namely the

• insulating layer to electronically decouple an adsorbate from the metal substrate. The ratios between the on-surface Ei − Ea gaps and the unperturbed gas-phase gaps are listed in Table 1. For a similar decoupling layer (KCl), but various substrates, the decoupling strength decreases with the work function of

• perturbs the molecular states less than the more reactive Cu(110) substrate. The values for Ea and Ei were calculated for all the investigated material systems according to the scheme shown in Figure 6 (Table 1). Plotting Ea and Ei versus the work function of the respective substrate yields the graph

Charge transport in organic nanocrystal diodes based on rolled-up robust nanomembrane contacts

• Vineeth Kumar Bandari,
• Lakshmi Varadharajan,
• Longqian Xu,
• Abdur Rehman Jalil,
• Mirunalini Devarajulu,
• Pablo F. Siles,
• Feng Zhu and
• Oliver G. Schmidt

Beilstein J. Nanotechnol. 2017, 8, 1277–1282, doi:10.3762/bjnano.8.129

• . Furthermore, the candidate materials for rolled-up nanomembranes are metals, ferromagnetic layers, oxides, and complex materials, of which the various properties of thin solid films, e.g., work function and magnetic properties, can be utilized to develop novel functional organic devices [30][31]. In our

Adsorption characteristics of Er₃N@C₈₀on W(110) and Au(111) studied via scanning tunneling microscopy and spectroscopy

• Sebastian Schimmel,
• Zhixiang Sun,
• Danny Baumann,
• Denis Krylov,
• Nataliya Samoylova,
• Alexey Popov,
• Bernd Büchner and
• Christian Hess

Beilstein J. Nanotechnol. 2017, 8, 1127–1134, doi:10.3762/bjnano.8.114

• (blue). The rigid downward shift of the molecular derived states at the fcc adsorption sites could be assigned to a more pronounced pillow effect [24][25][26]. The influence of the interface dipole which appears stronger in the fcc regions led to a further reduction of the Au(111)-work-function

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

• -micrometers. Metal contacts can interact with graphene in different ways [52], as shown in Figure 6. Metals physisorbed on graphene cause charge-transfer-induced doping of the graphene sheet because of the difference in work function values [53]. Metals chemisorbed on graphene are open a band gap in graphene

• -metal work function (WF) and increasing metal reactivity. A clear trend can be observed correlating the high measured Rc values with the most reactive metals (Ni, Ti). Reprinted with permission from [52], copyright 2015 AIP Publishing. Schematic of the edge-contact fabrication process. Reprinted with

Energy-level alignment at interfaces between manganese phthalocyanine and C₆₀

• Daniel Waas,
• Florian Rückerl,
• Martin Knupfer and
• Bernd Büchner

Beilstein J. Nanotechnol. 2017, 8, 927–932, doi:10.3762/bjnano.8.94

• , which represents the work function of the actual sample (see Supporting Information File 1). In Figure 2 we summarize all the energy shifts that are observed in valence-band, core-level and secondary-cutoff data for both deposition series in a relative manner. Inspection of this figure makes clear that

• -level alignment has been demonstrated. For instance, at the interface between CuPc and F16CuPc a significant change in the ionization potential and work function due to the molecular orientation was observed [54]. Also, the orientation of phthalocyanine molecules has been used to influence the C60

• ) surface. N1s core-level data of MnPc as a function of c) MnPc deposition onto C60 and d) C60 deposition onto MnPc. The corresponding layer thicknesses are indicated. Comparison of the energy shifts of core levels, valence-band features and the secondary-electron cutoff (work function) of a) the C60/MnPc

Analysis and modification of defective surface aggregates on PCDTBT:PCBM solar cell blends using combined Kelvin probe, conductive and bimodal atomic force microscopy

• Hanaul Noh,
• Alfredo J. Diaz and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 579–589, doi:10.3762/bjnano.8.62

• typical energy levels of PCDTBT, PCBM and PEDOT:PSS were used to draw the energy diagrams in Figure 5b–d. Since the tip is exposed to air, we used 4.25 eV for the work function of platinum [30]. Because the tip diameter is several times smaller than the thickness of the active layer, the electric field is

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

• , 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

• the use of low work function contacts (such as Sc or Ti) to minimize the effect of contact resistance in n-type MoS2 FETs [5], we focused on a high work function metal such as Ni in this paper in order to evaluate the impact of Ni/MoS2 contact resistance on the device field effect mobility μ and

• at the interface, it is worth comparing the experimental value with the one deduced from theoretical expression of the flat band voltage (VFB,id) of an ideal metal-oxide-semiconductor field effect transistor (i.e., without fixed or interface charges). VFB,id is expressed as [15]: where WM is the work

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

• ) calculations we gain insight into the nature of the interaction of cadmium, mercury and lead with graphene as well as estimate the work function and the Schottky barrier height of the graphene/SiC structure before and after applying heavy metals to the sensing material. A shift of the I–V characteristics of

• determines the graphene thickness. It is obvious that increasing the graphene thickness from 1 ML to multilayered graphene causes a change of the electronic properties of the carbonaceous material (energy gap, work function) and, as a consequence, the Schottky barrier height. In this case, it is not easy to

• properties, such as Fermi level, work function, density of states, C–С bond lengths. Once we know the influence of heavy metals on the work function of graphene, we can predict the values of the Schottky barrier height and output characteristics of the devices (for example current–voltage characteristics

Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

• Suneel Kumar,
• Rahul Sharma,
• Vipul Sharma,
• Gurunarayanan Harith,
• Vaidyanathan Sivakumar and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2016, 7, 1684–1697, doi:10.3762/bjnano.7.161

• from CB of CdS to the CB of ZnO [22]. The charge transfer dynamics in the CdS–ZnO composite material have been investigated before and it has been reported that this transfer occurs very rapidly in less than 18 ps [64]. The work function of ZnO is 5.2–5.3 eV and that of graphene is 4.5 eV [65]. Thus

Scanning probe microscopy studies on the adsorption of selected molecular dyes on titania

• Jakub S. Prauzner-Bechcicki,
• Lukasz Zajac,
• Piotr Olszowski,
• Res Jöhr,
• Antoine Hinaut,
• Thilo Glatzel,
• Bartosz Such,
• Ernst Meyer and
• Marek Szymonski

Beilstein J. Nanotechnol. 2016, 7, 1642–1653, doi:10.3762/bjnano.7.156

• molecules on the (110) face of rutile titania using spectroscopic techniques. For a few nanometre thick overlayers, the formation of an interfacial potential barrier due to band bending in the substrate, the molecular polarization in the organic film, and an increase in the work function have been reported

• )[44], FePc/TiO2(110) [45], and metal-free Pc/TiO2(110) [47] systems. Let us first take a look at the results published for a CuPc/TiO2 system. For CuPc overlayers that were a few nanometres thick on TiO2(110), a decrease in the work function values was reported [27]. Wang, Ye and Wu studied the

• microscopies, it is indispensable to use other techniques such as Kelvin probe force microscopy, which allows measuring the local work function with high resolution. Such a measurement may shed some light on fundamental processes taking place in an organic DSSC upon photon absorption. Quite often, in

Filled and empty states of Zn-TPP films deposited on Fe(001)-p(1×1)O

• Gianlorenzo Bussetti,
• Alberto Calloni,
• Rossella Yivlialin,
• Andrea Picone,
• Federico Bottegoni and
• Marco Finazzi

Beilstein J. Nanotechnol. 2016, 7, 1527–1531, doi:10.3762/bjnano.7.146

• between the vacuum level, Evac, and the leading edge of the HOMO) and the electron affinity (the difference between Evac and the LUMO) of the condensed organic film can be deduced. For this purpose, we have measured the sample work function from the energy position of the low-energy secondary electron

• cutoff edge that, compared with the work function (WF) of the pristine Fe(001)-p(1×1)O (4.50 eV [13]), allows the determination of the interface dipole, as reported in Figure 3. The results obtained for the 20 ML film are in good agreement with those reported for Zn-Pc [14] deposited on a gold substrate

• in tuning the barrier height [16]. With these interfaces, the sign of the dipole is deduced from the decreasing substrate work function and interpreted in terms of a (partial) electron transfer from the organic material to the Fe(001)-p(1×1)O surface [14]. In this picture, the direction of the dipole

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

• discussed only very recently [11][12][13][14][15][16][17][18][19][20][21][22]. The most obvious impact may be the change of the work function, because the tunnelling does not take place through vacuum states but through an electrolyte that alters the work function of the electrode and thereby affects the

• stretching curves for Mes, Tol and EtOH. Obviously, for Mes the conductance decays on a much shorter distance than for Tol. This hints at a solvent-dependent variation of the work function of Au [9][10]. The fluctuations of the conductance show a larger amplitude for Tol than for EtOH and Mes despite the

• the distance of the counter supports, and ξ is a correction factor which has a value varying from 2 to 4 depending on details of the sample [47]. r can be determined experimentally from conductance–distance curves in vacuum, when the work function of the electrode is known. By using the value Φ0 = 5.1

A terahertz-vibration to terahertz-radiation converter based on gold nanoobjects: a feasibility study

• Kamil Moldosanov and
• Andrei Postnikov

Beilstein J. Nanotechnol. 2016, 7, 983–989, doi:10.3762/bjnano.7.90

• stands at a large angle γ to that of the longitudinal phonon. However, the electron cannot leave the GNB because of substantial work function of gold (approx. 4.3 eV) [5]. By creating conditions to prevent the scattering of the excited electron at the GNB boundaries and its relaxation via emission of a

• absorbed radiation into heat; (iv) releasing the surplus energy into a transversal surface phonon; (v) emitting the surplus energy in form of a THz photon. We emphasize that the electron with the given excitation energy will not exit the sample because the work function of gold is too high to overcome. Let

Optical absorption signature of a self-assembled dye monolayer on graphene

• Tessnim Sghaier,
• Sylvain Le Liepvre,
• Céline Fiorini,
• Ludovic Douillard and
• Fabrice Charra

Beilstein J. Nanotechnol. 2016, 7, 862–868, doi:10.3762/bjnano.7.78

• “surface only” nature [22][23] and has been applied to tailor its band structure [24] or its work function [25][26] with a monolayer of PTCDI and similar molecules, which can be laterally patterned [27] or even manipulated at the single-molecule level [28]. Beyond H-bond-steered organizations [29], a high

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

• approximately 2.90 meV for the ZnO-NR and 2.10 meV for the ZnO-TF hybrid structure (measured from the work function equation), thus contributing to the overall increase in resistance [76]. One of the possible explanations can be the dipole–dipole interactions between the extracellular site of the protein and

Synthesis and applications of carbon nanomaterials for energy generation and storage

• Marco Notarianni,
• Jinzhang Liu,
• Kristy Vernon and
• Nunzio Motta

Beilstein J. Nanotechnol. 2016, 7, 149–196, doi:10.3762/bjnano.7.17

Charge injection and transport properties of an organic light-emitting diode

• Peter Juhasz,
• Juraj Nevrela,
• Michal Micjan,
• Miroslav Novota,
• Jan Uhrik,
• Lubica Stuchlikova,
• Jan Jakabovic,
• Ladislav Harmatha and
• Martin Weis

Beilstein J. Nanotechnol. 2016, 7, 47–52, doi:10.3762/bjnano.7.5

• dominates in the high-voltage region. The energy band diagram reconstruction is required for further identification of the energy barrier origin. The work function of cleaned ITO electrodes is at a level of 4.9 eV [18][19], while the Al electrode reaches only 4.2 eV [20]. The energies of the highest

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

• shows the effect schematically, starting with two separated G9 planes and an AB molecule with its HOMO at −6.16 eV for the free molecule. The −4.7 eV work function observed experimentally is close to the −4.68 eV HOMO calculated for G9, and both G9s have identical HOMO levels. When the G9–AB–G9 system

• is formed, DFT predicts that 0.032 e− are transferred to the AB molecules, as shown in Figure 8B. The local electrostatic potential associated with these electrons shifts all of the orbitals in AB to higher energy, and decreases the transport barrier predicted from the work function and HOMO energy

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

• detection of electrostatic forces and the determination of local work function values was intensively discussed and models combining large scale influences with atomistic simulations have been developed [1][2][3][4]. As early as in the late 1980s H. Wickramasinghe proposed several SPM based methods for the

• . Firstly, we discuss KPFM results from a contact surface of a copper alloy utilized in a power switch. The presence and shape of chromium grains embedded in the copper alloy are clearly visible. The contrast in the measured work function is strongly enhanced by sputtering the sample with argon ions to

• . The grain seems to be covered by a residual layer partly smearing out the CPD contrast. The PtIr-coated tip is most probably contaminated by a metal oxide cluster (CuO or CrO) due to slight tip–sample contacts before the measurements, such that the work function is around Φtip = 5 eV [40]. Also in

Self-organization of gold nanoparticles on silanated surfaces

• Htet H. Kyaw,
• Salim H. Al-Harthi,
• Azzouz Sellai and
• Joydeep Dutta

Beilstein J. Nanotechnol. 2015, 6, 2345–2353, doi:10.3762/bjnano.6.242

• electron emission after APTES was deposited on the glass substrate and AuNPs were deposited on the APTES-functionalized glass substrate. The work function (Φ) can be calculated from the difference in the photon energy of He(I) (21.2 eV) and the energy difference ΔE between the secondary cut-off energy

• (Ecut-off) and the Fermi edge (EF) (as shown in Figure 5a) [28] as The work function is obtained as 4.5 eV for glass and 4.65 eV for the APTES-functionalized glass substrate as well as the substrate with AuNPs deposited on APTES-functionalized glass. The valance band maximum (VBM) of bare glass, APTES

• substrates. The work function also changed from 4.55 eV for sample 1 to 4.62 eV for sample 2 and 4.65 eV for sample 3, respectively. Due to different coverage of AuNPs on APTES-functionalized glass substrates, energy shift in VBM is observed (see Figure 6b). Effects of annealing of AuNPs deposited APTES