Reconstruction of a 2D layer of KBr on Ir(111) and electromechanical alteration by graphene

• Zhao Liu,
• Antoine Hinaut,
• Stefan Peeters,
• Sebastian Scherb,
• Ernst Meyer,
• Maria Clelia Righi and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2021, 12, 432–439, doi:10.3762/bjnano.12.35

• ]. Compared to the adsorption energy, the ionic interaction within the layer is typically stronger such that structural deformations are weak [25]. However, it was demonstrated that a NaCl adlayer on Ag(100), besides strongly reducing the overall work function, can create clearly modulated dipole moment

• to the expected cubic configuration of bulk KBr and the work function of the system is strongly altered. Results and Discussion The thermal deposition of less than a monolayer of KBr on an atomically clean Ir(111) surface under ultrahigh vacuum (UHV) conditions results in the formation of islands on

• modulated by the distance to the Ir(111) substrate, inducing an overall reduction of the work function to ΦDFT(KBr/Ir(111)) = 4.16 eV. Taking bare Ir(111) as a reference with a calculated work function of ΦDFT(Ir(111)) = 5.76 eV, experimentally a work function of ΦEXP(KBr/Ir(111)) = 4.06 eV was measured by

Nickel nanoparticle-decorated reduced graphene oxide/WO₃ nanocomposite – a promising candidate for gas sensing

• Ilka Simon,
• Alexandr Savitsky,
• Rolf Mülhaupt,
• Vladimir Pankov and
• Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

• the conduction band toward the valence band. Processes on the WO3 surface make it possible for the work function of WO3 to lower to a point close to that of rGO [37]. The latter facilitates transfer of electrons at the rGO/WO3 interface. The continuous capture of electrons by chemisorption of NO2

Bio-imaging with the helium-ion microscope: A review

• Matthias Schmidt,
• James M. Byrne and
• Ilari J. Maasilta

Beilstein J. Nanotechnol. 2021, 12, 1–23, doi:10.3762/bjnano.12.1

• the secondary electron. In SEM, the acceleration voltage of the electron beam needs to be lowered to yield low-energy secondary electrons. This increases surface sensitivity since only secondary electrons produced directly under the surface will be able to overcome the work function of the sample and

Free and partially encapsulated manganese ferrite nanoparticles in multiwall carbon nanotubes

• Saja Al-Khabouri,
• Salim Al-Harthi,
• Toru Maekawa,
• Mohamed E. Elzain,
• Ashraf Al-Hinai,
• Ahmed D. Al-Rawas,
• Abbsher M. Gismelseed,
• Ali A. Yousif and
• Myo Tay Zar Myint

Beilstein J. Nanotechnol. 2020, 11, 1891–1904, doi:10.3762/bjnano.11.170

• applied during work function measurements to separate the sample and analyzer spectral cutoffs. Hysteresis loops at 300, 77, and 4 K and zero-field cooling curves were recorded using a superconducting quantum interference device (SQUID). Mössbauer spectra were obtained for the powdered samples at 300 and

• semiconducting structures [31][32]. The valence edge of the CNTs correspond to the work function [33]. The well-known features of three-fold coordination of C atoms are the deep-lying σ band, corresponding to a strong in-plane bonding located at 8.1 eV, and delocalized π bands, representing the weak bonding

• perpendicular to the graphene plane positioned at 3.1 eV (sp2-hybridized carbon network) [34]. These features can be clearly seen in Figure 6. A work function identification of MnFe2O4/MWCNTs is needed to better understand the electronic structure and the interaction between MWCNTs and MnFe2O4 at the interface

Absorption and photoconductivity spectra of amorphous multilayer structures

• Oxana Iaseniuc and
• Mihail Iovu

Beilstein J. Nanotechnol. 2020, 11, 1757–1763, doi:10.3762/bjnano.11.158

• applied field becomes higher than the internal electrical field. For amorphous semiconductors the barrier height of an Al–semiconductor contact, with a work function of φm = 4.18 eV, is φb = 0.40–0.75 eV [14][17]. This is very important from a practical point of view, because there is the possibility to

Adsorption and self-assembly of porphyrins on ultrathin CoO films on Ir(100)

• Feifei Xiang,
• Tobias Schmitt,
• Marco Raschmann and
• M. Alexander Schneider

Beilstein J. Nanotechnol. 2020, 11, 1516–1524, doi:10.3762/bjnano.11.134

• in the calculations, the true PDOS will deviate and conclusions have to be drawn with care. However, the work function of CoO is, with 5.85 eV (1BL) and 6.01 eV (2BL) [47], significantly higher than that of most metals. Following the arguments of Yang et al. [48], a charge transfer into unoccupied

Controlling the electronic and physical coupling on dielectric thin films

• Philipp Hurdax,
• Michael Hollerer,
• Larissa Egger,
• Georg Koller,
• Xiaosheng Yang,
• Anja Haags,
• Serguei Soubatch,
• Frank Stefan Tautz,
• Mathias Richter,
• Alexander Gottwald,
• Peter Puschnig,
• Martin Sterrer and
• Michael G. Ramsey

Beilstein J. Nanotechnol. 2020, 11, 1492–1503, doi:10.3762/bjnano.11.132

• of such decoupling layers may effectively change the electron donating properties of the substrate, for example, by lowering its work function and thus enhancing the charging of the molecular adsorbate layer through electron tunneling. Here, an experimental study of the charging of para-sexiphenyl

• (6P) on ultrathin MgO(100) films supported on Ag(100) is reported. By deliberately changing the work function of the MgO(100)/Ag(100) system, it is shown that the charge transfer (electronic coupling) into the 6P molecules can be controlled, and 6P monolayers with uncharged molecules (Schottky–Mott

• underlying metal [2][3]. As dielectric films can significantly reduce the work function, principally due to Pauli repulsion (pushback) at the metal interface, adsorbates of sufficiently high electron affinity (EA) will become negatively charged via tunneling from the underlying metal. This was predicted by

Self-assembly and spectroscopic fingerprints of photoactive pyrenyl tectons on hBN/Cu(111)

• Domenik M. Zimmermann,
• Knud Seufert,
• Luka Ðorđević,
• Tobias Hoh,
• Sushobhan Joshi,
• Tomas Marangoni,
• Davide Bonifazi and
• Willi Auwärter

Beilstein J. Nanotechnol. 2020, 11, 1470–1483, doi:10.3762/bjnano.11.130

• as such spacer layers [18] and can promote site-dependent decoupling and adsorption [19][20], yielding access to optical transitions [21] as well as allowing for orbital-resolved STM imaging [19][21][22][23]. For instance, hBN/Cu(111) [24][25][26][27] features a work function template with a moiré

• superstructure: Depending on the registry of the layer and substrate atoms, the surface is divided in areas of low and high local work function, denoted as “pores” and “wires”, respectively [28][29][30][31]. In recent years, our group and others used hBN/Cu(111) to guide the self-assembly of porphyrins [28][32

• underlying hBN/Cu(111) support. This template featured a moiré pattern with areas of low local work function (pores, P) and high local work function (wires, W) [25][29][30], which was reflected by the molecular level alignment, as measured by dI/dV spectroscopy [28][35][36][37]. On pore areas, the MOs were

Impact of fluorination on interface energetics and growth of pentacene on Ag(111)

• Qi Wang,
• Meng-Ting Chen,
• Antoni Franco-Cañellas,
• Bin Shen,
• Thomas Geiger,
• Holger F. Bettinger,
• Frank Schreiber,
• Ingo Salzmann,
• Alexander Gerlach and
• Steffen Duhm

Beilstein J. Nanotechnol. 2020, 11, 1361–1370, doi:10.3762/bjnano.11.120

• ) spectra (Figure 2b) allowed to determine the VL position above the Fermi level (EF), which was reduced from an initial value of 4.62 eV [i.e., the work function of clean Ag(111)] to 4.05 eV for a nominal F4PEN thickness of 4 Å and stayed essentially constant when increasing the coverage. The VL decrease

• of 0.57 eV was rather similar to that of PEN or PFP thin films on the same substrate [28][50] and could be mainly attributed to the so-called push-back effect, i.e., the reduction of the surface dipole part of the metal work function [78] by the mere presence of the molecular adsorbate [73][79][80

• analyzer work function. Thus, the position of the SECO corresponds to the vacuum level (VL) with respect to EF. All organic thin film preparation steps and all measurements were performed at room temperature (295 K). (a) C 1s and (b) F 1s core levels of F4PEN in monolayers on Ag(111) measured at DLS. (c

Hybridization vs decoupling: influence of an h-BN interlayer on the physical properties of a lander-type molecule on Ni(111)

• Maximilian Schaal,
• Takumi Aihara,
• Marco Gruenewald,
• Felix Otto,
• Jari Domke,
• Roman Forker,
• Hiroyuki Yoshida and
• Torsten Fritz

Beilstein J. Nanotechnol. 2020, 11, 1168–1177, doi:10.3762/bjnano.11.101

• -temperature scanning tunneling microscopy. Finally, the investigation of the valence band structure by ultraviolet photoelectron spectroscopy shows that the low work function of h-BN/Ni(111) further decreases after the DBP deposition. For this reason, the h-BN-passivated Ni(111) surface may serve as potential

• as clusters of molecules on top of the first DBP layer. The fast Fourier transform (FFT) of that STM image resembles the LEED simulation of the molecular lattice (considering eight symmetry equivalent domains only), which supports our structural model. Valence band structure and work function change

• , as well as by a decrease in hybridization. Probable reasons for the shift of the molecular orbitals to higher binding energies are the work function change as well as the less efficient photo hole screening compared to DBP on bare Ni(111). The adsorption of DBP molecules on the bare Ni(111) surface

Scanning tunneling microscopy and spectroscopy of rubrene on clean and graphene-covered metal surfaces

• Karl Rothe,
• Alexander Mehler,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2020, 11, 1157–1167, doi:10.3762/bjnano.11.100

• energy since the HOMO resonance essentially retains its energy at approx. −0.87 eV. Assuming that C42H28 is weakly coupled to the substrate, its orbital energies are expected to be aligned with the vacuum level [46] and, thus, susceptible to local changes in the work function. Site-specific work

• functions are indeed present on the moiré lattice of graphene. For instance, graphene-covered Ir(111), which may serve as a reference for graphene on Pt(111) owing to the comparably low hybridization of graphene with the two metal surfaces, exhibits work function changes of the order of 0.1 eV [47]. In the

• could in principle reduce or compensate the work-function-induced shift of the HOMO. A similar behavior was previously reported for C64H36 adsorbed on h-BN-covered Ru(0001) [48]. Intermolecular couplings [49] that were previously shown to induce strong orbital energy shifts due to different local

Monolayers of MoS₂ on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

• Asieh Yousofnejad,
• Gaël Reecht,
• Nils Krane,
• Christian Lotze and
• Katharina J. Franke

Beilstein J. Nanotechnol. 2020, 11, 1062–1071, doi:10.3762/bjnano.11.91

• conduction bands between the MoS2 bands on Ag and Au. In a very simple interpretation, this agrees with the lower work function of Ag than that of Au. A down-shift of the conduction band structure by approx. 280 meV has been observed by photoemission of WS2 on Au(111) and Ag(111) [33]. Angle-resolved

• ][54] is consistent with the LUMO alignment just above EF when considering the work function of MoS2/Ag(111) of 4.7 eV [55]. We found small shifts of the LUMO onsets by at most 50 mV between the spectra of TCNQ molecules lying at the top or hollow sites of the moiré structure of MoS2. These shifts

• used to calculate the tunneling matrix element Mts with an s-wave tip at a tip–molecule distance of 7.5 Å, work function of 5 eV. The map of the spatial distribution of is shown in the middle panel. a) STM topography image of a TCNQ island recorded at V = 1 V, I = 10 pA. b) Simulated (top panel) and

Measurement of electrostatic tip–sample interactions by time-domain Kelvin probe force microscopy

• Christian Ritz,
• Tino Wagner and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2020, 11, 911–921, doi:10.3762/bjnano.11.76

• Kalman filter; Kelvin probe force microscopy (KFM); time domain; Introduction Electrostatic forces are important interactions in non-contact atomic force microscopy (NC-AFM). They arise from differences in the work function of the tip and the sample, from trapped charges, or from potentials applied to

• active nanoelectronic devices. Kelvin probe force microscopy (KFM) is a technique used to quantitatively characterize such electrical properties [1][2][3]. It is applied to map material compositions via changes in the work function, to localize charge distributions in dielectric samples [4][5], and to

Implementation of data-cube pump–probe KPFM on organic solar cells

• Benjamin Grévin,
• Olivier Bardagot and
• Renaud Demadrille

Beilstein J. Nanotechnol. 2020, 11, 323–337, doi:10.3762/bjnano.11.24

• to ease the comparison with the experimental results. This y-shift with respect to the zero baseline results from the difference of the tip–substrate work function. (a) Plot of the KPFM compensation potential measured at the solar cell cathode as a function of time (spectroscopic sequence of 320

Stationary beam full-field transmission helium ion microscopy using sub-50 keV He⁺: Projected images and intensity patterns

• Michael Mousley,
• Santhana Eswara,
• Olivier De Castro,
• Olivier Bouton,
• Nico Klingner,
• Christoph T. Koch,
• Gregor Hlawacek and
• Tom Wirtz

Beilstein J. Nanotechnol. 2019, 10, 1648–1657, doi:10.3762/bjnano.10.160

• local work function of the material, similar to studies using mirror electron microscopy [37]. There may be many solutions satisfying the intensity distribution, so, to get an approximation closer to the true surface, constraints on the solution may be required. This could be achieved by using

Kelvin probe force microscopy work function characterization of transition metal oxide crystals under ongoing reduction and oxidation

• Dominik Wrana,
• Karol Cieślik,
• Wojciech Belza,
• Christian Rodenbücher,
• Krzysztof Szot and
• Franciszek Krok

Beilstein J. Nanotechnol. 2019, 10, 1596–1607, doi:10.3762/bjnano.10.155

• , Germany Peter Grünberg Institute (PGI-7), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany August Chelkowski Institute of Physics, University of Silesia, 40–007 Katowice, Poland 10.3762/bjnano.10.155 Abstract Controlling the work function of transition metal oxides is of key importance with regard to

• characterization of the work function using the example of artificially formed crystalline titanium monoxide (TiO) nanowires on strontium titanate (SrTiO3) surfaces, providing a sharp atomic interface. The measured value of 3.31(21) eV is the first experimental work function evidence for a cubic TiO phase, where

• obtaining work function and conductivity maps on the same area by combining noncontact and contact modes of atomic force microscopy (AFM). As most of the real applications require ambient operating conditions, we have additionally checked the impact of air venting on the work function of the TiO/SrTiO3(100

Synthesis of P- and N-doped carbon catalysts for the oxygen reduction reaction via controlled phosphoric acid treatment of folic acid

• Rieko Kobayashi,
• Takafumi Ishii,
• Yasuo Imashiro and
• Jun-ichi Ozaki

Beilstein J. Nanotechnol. 2019, 10, 1497–1510, doi:10.3762/bjnano.10.148

• decreases the work function and thus raises the Fermi level above the standard O2/H2O reduction potential, which resulted in enhanced ORR activity. Finally, CPAT was concluded to be applicable to the synthesis of PN-doped carbon materials from N-containing organic compounds other than FA. Keywords: folic

• such as changes in the chemical states of N and the amount of P were retained. The work function of PH-series carbon materials was determined by the vibration capacitance (Kelvin) method and fluctuated in the range of 5.4–5.6 eV (Figure 6a), decreasing with increasing CPAT temperature in the range of

• 400–700 °C and increasing with increasing CPAT temperature above 700 °C. As a result, the smallest work function was observed for PH-700. Figure 6b shows the relationship between the ORR activity and the work function. These two values exhibited a good correlation with r = −0.853. ORR activity of the

Kelvin probe force microscopy of the nanoscale electrical surface potential barrier of metal/semiconductor interfaces in ambient atmosphere

• Petr Knotek,
• Tomáš Plecháček,
• Jan Smolík,
• Petr Kutálek,
• Filip Dvořák,
• Milan Vlček,
• Jiří Navrátil and
• Čestmír Drašar

Beilstein J. Nanotechnol. 2019, 10, 1401–1411, doi:10.3762/bjnano.10.138

• ; work function; Introduction Increasing energy demand and the negative effects of current energy technologies on the environment lead to increased interest in alternative energy technologies. Thermoelectric (TE) devices, utilizing TE phenomena, i.e., the Seebeck and the Peltier effect, can be

• voltage of 20 kV (which results in a penetration depth of the electrons of 1 µm into Bi2Se3) for a period of maximally 360 s. The work function (WF) was determined by utraviolet photoelectron spectroscopy (UPS) using a helium gas discharge source with He I radiation (hν = 21.22 eV). All UPS measurements

• generated in the analyzer. The work function of the sample was calculated as WF = hν Ecut-off, where Ecut-off was determined from the intersection of the linear extrapolation of the secondary-electron cut-off (SECO) with the background. All samples were sputtered with argon ions using a scanning focused ion

Imaging the surface potential at the steps on the rutile TiO₂(110) surface by Kelvin probe force microscopy

• Masato Miyazaki,
• Huan Fei Wen,
• Quanzhen Zhang,
• Yuuki Adachi,
• Jan Brndiar,
• Ivan Štich,
• Yan Jun Li and
• Yasuhiro Sugawara

Beilstein J. Nanotechnol. 2019, 10, 1228–1236, doi:10.3762/bjnano.10.122

• ) surface with O2 exposure using Kelvin probe force microscopy. A drop in contact potential difference was observed at the steps, indicating that the work function locally decreased. Moreover, for the first time, we found that the drop in contact potential difference at a <1−11> step was larger than that at

• ]. Concerning the charge properties of steps on TiO2, it has been measured with using ultraviolet photoelectron spectroscopy (UPS) that surfaces with a high step density have a lower work function than surfaces with a low step density [28]. The local change in the surface potential at steps on TiO2 has been

• on rutile TiO2(110) surfaces with O2 exposure using KPFM and observed the drop in CPD at the steps, indicating that the work function locally decreased. Moreover, we found, for the first time, that the drop in CPD at a step was larger than that at a step. We discuss a possible origin of the change

Synthesis and characterization of quaternary La(Sr)S–TaS₂ misfit-layered nanotubes

• Marco Serra,
• Erumpukuthickal Ashokkumar Anumol,
• Dalit Stolovas,
• Iddo Pinkas,
• Ernesto Joselevich,
• Reshef Tenne,
• Andrey Enyashin and
• Francis Leonard Deepak

Beilstein J. Nanotechnol. 2019, 10, 1112–1124, doi:10.3762/bjnano.10.111

• van der Waals forces. Frequently, the difference in the work function between the MX and TX2 slabs leads to a partial charge transfer from the MX slab to that of TX2. This charge transfer induces polar interactions between the layers juxtaposing on the van der Waals forces [29]. As the constituting

• been discussed in the past [32][35][38]. It was argued that the low work function of the rare earth atom forces it to transfer a charge to the half-filled 4dz2 orbital of the Ta atom. Thus, the MLC gains extra stability by this charge transfer as discussed also in [39]. The question then arises: how

Influence of dielectric layer thickness and roughness on topographic effects in magnetic force microscopy

• Alexander Krivcov,
• Jasmin Ehrler,
• Marc Fuhrmann,
• Tanja Junkers and
• Hildegard Möbius

Beilstein J. Nanotechnol. 2019, 10, 1056–1064, doi:10.3762/bjnano.10.106

• electrostatic interactions. Origin of these artifacts is the work-function difference between tip and sample material. Yu et al. [10] demonstrated that topographic features can be avoided by combining MFM with electrostatic force microscopy (EFM) compensating the contact potential difference by an appropriate

• substrates with a minimized work-function difference between tip and substrate or the usage of a tip with smaller radius. In [20] we demonstrated that capacitive coupling effects vanish investigating nanoparticles embedded in a polymer matrix. In this work we show that capacitive coupling effects can be

• SPIONs are often hidden by repulsive electrostatic interactions due to the changes in capacitive coupling. In [14] possibilities are discussed to minimize the capacitive coupling, e.g., by using a substrate with minimized work-function difference between tip and substrate or by using a sharper tip

Comparing a porphyrin- and a coumarin-based dye adsorbed on NiO(001)

• Sara Freund,
• Antoine Hinaut,
• Nathalie Marinakis,
• Edwin C. Constable,
• Ernst Meyer,
• Catherine E. Housecroft and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2019, 10, 874–881, doi:10.3762/bjnano.10.88

• to the experimental results in Table 2. The data demonstrate that the parameters correspond nicely, highlighting the accuracy of the model. Charge-transfer direction studied by KPFM KPFM is an analytical method that can be applied to examine the change of the work function induced by the adsorption

• KPFM images were acquired simultaneously with the topographic images presented in Figure 3a and Figure 4a, respectively. In Figure 5a, as well as in the profile recorded along the red line present in this image and displayed in Figure 5c, it can be seen that the CPD, and hence the work function, is

• recorded along the green line and displayed in Figure 5d, show that the CPD, and therefore also the work function, is locally increased above the molecular layer compared to the surface of NiO. Thus, in contrast to Cu-TCPP, the electron transfer occurs from the substrate towards the molecules (see

Review of time-resolved non-contact electrostatic force microscopy techniques with applications to ionic transport measurements

• Aaron Mascaro,
• Yoichi Miyahara,
• Tyler Enright,
• Omur E. Dagdeviren and
• Peter Grütter

Beilstein J. Nanotechnol. 2019, 10, 617–633, doi:10.3762/bjnano.10.62

• difference (which can be used to extract the local work function) [1] and local piezoelectric response [2], and dynamic properties such as the charging and decay times of photoexcited carriers [3][4][5][6], and local activation energies for ionic transport [7][8]. These measurements play a crucial role in

Integration of LaMnO_3+δ films on platinized silicon substrates for resistive switching applications by PI-MOCVD

• Raquel Rodriguez-Lamas,
• Dolors Pla,
• Odette Chaix-Pluchery,
• Benjamin Meunier,
• Fabrice Wilhelm,
• Andrei Rogalev,
• Laetitia Rapenne,
• Xavier Mescot,
• Quentin Rafhay,
• Hervé Roussel,
• Michel Boudard,
• Carmen Jiménez and
• Mónica Burriel

Beilstein J. Nanotechnol. 2019, 10, 389–398, doi:10.3762/bjnano.10.38

• an inert and ohmic contact, as the work function of LMO is 4.5–5.1 eV [23] and the one of Pt is 5.9–6.2 eV [24]. In order to integrate crystalline LMO memristive films in silicon-based devices, we used commercial platinized silicon as the bottom electrode/substrate heterostructure. Nevertheless

Scanning probe microscopy for energy-related materials

• Rüdiger Berger,
• Benjamin Grévin,
• Philippe Leclère and
• Yi Zhang

Beilstein J. Nanotechnol. 2019, 10, 132–134, doi:10.3762/bjnano.10.12

• interfaces is therefore essential. Furthermore, these interface phenomena are strongly linked to material properties such as grain size, roughness, mechanical properties and work function. In an attempt to address the diversity of phenomena on the nanoscale, scanning probe microscopy (SPM) methods play an