Optimization of Mo/Cr bilayer back contacts for thin-film solar cells

• Nima Khoshsirat,
• Fawad Ali,
• Vincent Tiing Tiong,
• Mojtaba Amjadipour,
• Hongxia Wang,
• Mahnaz Shafiei and
• Nunzio Motta

Beilstein J. Nanotechnol. 2018, 9, 2700–2707, doi:10.3762/bjnano.9.252

• , the back contact material should have a higher work function than the neighboring light-absorbing semiconductor layer [3]. Accordingly, different metal contacts (such as Al, Au, Cr, Mn, Mo, Pt, Ti, V and W) have been used as back contact layer in thin-film solar cells [4][5][6][7]. Among these

• substrate to the absorber layer and its effect on the adhesion of the back contact was not studied. In spite of the importance of this topic for the development of thin-film solar cells, there are very few reports regarding the application of Cr as an adhesion layer in back contacts [29][30]. Notably, the

• bilayer and the adhesion of the film to the substrate while we could reduce the required thickness to 600 nm. That is at most two thirds of reported thickness for Mo back contacts for thin-film solar cells. Experimental Film deposition A 10–15 nm thick layer of Cr was deposited on a 2.5 × 2.5 cm SLG

Characterization of the microscopic tribological properties of sandfish (Scincus scincus) scales by atomic force microscopy

• Weibin Wu,
• Christian Lutz,
• Simon Mersch,
• Richard Thelen,
• Christian Greiner,
• Guillaume Gomard and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2018, 9, 2618–2627, doi:10.3762/bjnano.9.243

• (µ = Ffric/Fload) of two bodies in contact. For a sandfish swimming in sand, however, there are numerous microscale contacts inducing friction without a defined load. The friction angle measurement introduced by Rechenberg [7] provides a simplified method to estimate a granular frictional coefficient

Pattern generation for direct-write three-dimensional nanoscale structures via focused electron beam induced deposition

• Lukas Keller and
• Michael Huth

Beilstein J. Nanotechnol. 2018, 9, 2581–2598, doi:10.3762/bjnano.9.240

• the centered beam position for both Me3CpMePt(IV) and HCo3Fe(CO)12. The polar/azimuthal angles were −60°/45° and −60°/−39°, respectively. All depositions were done on p-doped Si wafers with thermally grown SiO2 of 200 nm thickness. Au/Cr contacts, as used for some deposition experiments, were grown by

Friction reduction through biologically inspired scale-like laser surface textures

• Johannes Schneider,
• Vergil Djamiykov and
• Christian Greiner

Beilstein J. Nanotechnol. 2018, 9, 2561–2572, doi:10.3762/bjnano.9.238

• biologically inspired surface morphology has the potential to reduce friction forces by more than 80%. However, under certain conditions, especially for slow-moving lubricated steel-on-steel and steel-on-ceramic contacts, these surface morphologies may increase friction as well. Similar to classical laser

• the potential to yield significant reduction in friction forces and are expected to spark future research in the field of biologically inspired surface morphologies applied to tribological contacts. Keywords: bioinspiration; friction; laser surface texturing; scales; tribology; Introduction Friction

• achieved for mixed lubrication contacts [15][16]. While these traditional texturing elements have been studied for decades and by numerous research groups worldwide, in recent years, a new paradigm has emerged. Researchers have started to look to biology in search for morphological textures that would

Evidence of friction reduction in laterally graded materials

• Roberto Guarino,
• Gianluca Costagliola,
• Federico Bosia and
• Nicola Maria Pugno

Beilstein J. Nanotechnol. 2018, 9, 2443–2456, doi:10.3762/bjnano.9.229

• , display setae with a graded stiffness that optimises the adhesive performance on rough surfaces [1]. Hardness and stiffness gradients are of fundamental importance in the biomechanics of contacts, since they allow increased resistance against wear, impact, penetration and crack propagation [2][3][4][5][6

ZnO-nanostructure-based electrochemical sensor: Effect of nanostructure morphology on the sensing of heavy metal ions

• Marina Krasovska,
• Vjaceslavs Gerbreders,
• Irena Mihailova,
• Andrejs Ogurcovs,
• Eriks Sledevskis,
• Andrejs Gerbreders and
• Pavels Sarajevs

Beilstein J. Nanotechnol. 2018, 9, 2421–2431, doi:10.3762/bjnano.9.227

• push-in contacts (3) and a sealing system, which consists of chemically inert rubber seals (4) with holes of the same size as the electrode diameter and replaceable plastic cylinders (5). The sealing system prevents the solution from leaking, and allows for the application of the required amount of

• effective adsorbent of these ions on the other. Structure diagrams of the electrical measurement cell and electrodes. Measurement cell consists of the following parts: a corps (1), an interlayer (2) with push-in contacts (3) and a sealing rubber mask (4) with replaceable plastic cylinders (5). The complete

Adhesive contact of rough brushes

• Qiang Li and
• Valentin L. Popov

Beilstein J. Nanotechnol. 2018, 9, 2405–2412, doi:10.3762/bjnano.9.225

• modification due to finite size effect of the brush. Keywords: adhesion; brushes; contact splitting; pressure sensitive adhesion; roughness; Introduction The study of adhesive contacts has been largely enhanced by studies of the extremely effective adhesion pads of geckos [1]. For example, the adhesion can

• heights (simulating the relative roughness of surfaces in contact). We will show that the adhesion of statistical brushes can be described by a small number of simple analytical dependencies based both on Kendall’s theory of flat-ended stamps [20] and the Fuller and Tabor theory of adhesive contacts [15

• heights (see the side of the contact) one can see the “negative spikes” which stem from the not-yet-destroyed adhesive contacts of individual pillars loaded in tension. The scheme of indenting and pull-off stages of an adhesive contact of exponentially distributed pillars. An example of a pillar structure

Magnetism and magnetoresistance of single Ni–Cu alloy nanowires

• Andreea Costas,
• Camelia Florica,
• Elena Matei,
• Maria Eugenia Toimil-Molares,
• Ionel Stavarache,
• Andrei Kuncser,
• Victor Kuncser and
• Ionut Enculescu

Beilstein J. Nanotechnol. 2018, 9, 2345–2355, doi:10.3762/bjnano.9.219

• , the deposition of Ti and Au contacts (100/200 nm) by RF magnetron sputtering and thermal vacuum evaporation, respectively, was performed. Individual contacted Ni–Cu alloy nanowires are thus obtained. The main steps of the EBL process are shown in Figure 8. The morphological and compositional

Intrinsic ultrasmall nanoscale silicon turns n-/p-type with SiO₂/Si₃N₄-coating

• Dirk König,
• Daniel Hiller,
• Noël Wilck,
• Birger Berghoff,
• Merlin Müller,
• Sangeeta Thakur,
• Giovanni Di Santo,
• Luca Petaccia,
• Joachim Mayer,
• Sean Smith and
• Joachim Knoch

Beilstein J. Nanotechnol. 2018, 9, 2255–2264, doi:10.3762/bjnano.9.210

• [27]. Buettiker probes, i.e., virtual contacts, are attached to each finite difference site in order to mimic inelastic scattering [28]. To this end, an additional self-consistent calculation of the quasi-Fermi level throughout the device is computed, ensuring that the net current flow into/out of

• the electrostatic integrity of the devices causes conventional doping to fail. Metal–Si contacts formed by, e.g., silicide formation [36] result in rather high Schottky-barriers at the source/drain-channel interfaces that deteriorate the switching behaviour and on-state performance. h-DFT calculations

• on NEGF device simulations are presented. NEGF device simulations NEGF simulations were realized considering a 1.7 nm thick undoped Si-NWire MISFET with a channel length of L = 5 nm in a wrap-gate architecture placed between two metallic contacts (Figure 8a). The channel is insulated by a SiO2 layer

Optimization of the optical coupling in nanowire-based integrated photonic platforms by FDTD simulation

• Nan Guan,
• Andrey Babichev,
• Martin Foldyna,
• Dmitry Denisov,
• François H. Julien and
• Maria Tchernycheva

Beilstein J. Nanotechnol. 2018, 9, 2248–2254, doi:10.3762/bjnano.9.209

• photonic-crystal waveguide [28]. The authors integrated LEDs on top of a SiNx membrane photonic crystal and deposited electrical contacts. The photonic crystal waveguide was shown to efficiently guide the electroluminescence over a distance of about 20 µm. Brubaker et al. realized on-chip optical coupling

• encapsulating spin-on-glass layer partially covering the NW is considered (used as a mechanical support for the contacts). The NW LED is buried to one half of its diameter into this spin-on-glass (SiOx) layer, and the SiNx waveguide is positioned on top of the spin-on glass. In the optimization, calculations

Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

Beilstein J. Nanotechnol. 2018, 9, 2209–2235, doi:10.3762/bjnano.9.207

• the cell design without organic HTL and back contacts, both roles played by a carbon layer. Panels (c) and (d) in Figure 2 show CB/VB levels of selected lead-free perovskites based on Sn2+/Sn4+ (Figure 2c) and Sb3+/Bi3+ (Figure 2d) with respect to the acceptor/donor levels of a series of typical ETL

Interaction-induced zero-energy pinning and quantum dot formation in Majorana nanowires

• Samuel D. Escribano,
• Alfredo Levy Yeyati and
• Elsa Prada

Beilstein J. Nanotechnol. 2018, 9, 2171–2180, doi:10.3762/bjnano.9.203

• of parameters as in the previous section but including the normal contacts. While in the central region of the wire a similar repulsive step-like evolution with VZ is found (corresponding to compressible/incompressible electron fluid behavior), significant attractive regions appear at the wire ends

• magnetic field (or the chemical potential of the wire). However, if the electrostatic screening is smaller inside the wire than at the contacts, a repulsive interaction arises that leads to zero-energy pinning around parity crossings in the spectrum of the wire. While the screening due to the parent SC

• central region but, due to the screening from the left/right metallic contacts, it becomes strongly negative at the edges. This creates potential wells that confine QD-like states at the ends of the wire, which appear in the spectrum as discrete states within the induced gap that disperse with Zeeman

Spin-coated planar Sb₂S₃ hybrid solar cells approaching 5% efficiency

• Pascal Kaienburg,
• Benjamin Klingebiel and
• Thomas Kirchartz

Beilstein J. Nanotechnol. 2018, 9, 2114–2124, doi:10.3762/bjnano.9.200

• transport between the contacts. A beneficial effect was demonstrated for the structurally identical Sb2Se3 [9]. A proper substrate choice or embedding a seed layer might be the key to directed growth in Sb2S3. Experimental Chemicals: All chemicals were purchased from Sigma-Aldrich except for KP115 which was

Phosphorus monolayer doping (MLD) of silicon on insulator (SOI) substrates

• Noel Kennedy,
• Ray Duffy,
• Luke Eaton,
• Dan O’Connell,
• Scott Monaghan,
• Shane Garvey,
• James Connolly,
• Chris Hatem,
• Justin D. Holmes and
• Brenda Long

Beilstein J. Nanotechnol. 2018, 9, 2106–2113, doi:10.3762/bjnano.9.199

• methods and averaging between all geometries to remove most major error components and obtain an accurate Hall voltage assessed against the signal-to-noise (SNR) accuracy obtained [21]. For all samples assessed in this work, the coupon size is ca. 1 cm × 1 cm with four pressure probe metal contacts placed

Recent highlights in nanoscale and mesoscale friction

• Andrea Vanossi,
• Dirk Dietzel,
• Andre Schirmeisen,
• Ernst Meyer,
• Rémy Pawlak,
• Thilo Glatzel,
• Marcin Kisiel,
• Shigeki Kawai and
• Nicola Manini

Beilstein J. Nanotechnol. 2018, 9, 1995–2014, doi:10.3762/bjnano.9.190

• of the field foreseeable in the near future. Review Controlled nanomovements Friction force microscopy (FFM) is a well-defined AFM operation mode in which tiny lateral forces acting on the tip, as it scans across the surface, are recorded [9]. Atomic forces involving few-atom contacts can provide

• patterns on a lattice-mismatched crystal overlayer [10][11][12]. One of the most frequent motivations to utilize FFM as a tool in nanotribology is its ability to mimic a single-asperity contact by the junction between a sharp AFM tip and the substrate. Such single-asperity contacts are widely considered as

• the most fundamental building blocks of friction, as pointed out in well-established interface models, where interfaces are considered as a complex system of single-asperity contacts [13][14]. Consequently, FFM has received tremendous attention since its invention 30 years ago. To date an ever growing

Electromigrated electrical optical antennas for transducing electrons and photons at the nanoscale

• Arindam Dasgupta,
• Mickaël Buret,
• Nicolas Cazier,
• Marie-Maxime Mennemanteuil,
• Reinaldo Chacon,
• Kamal Hammani,
• Jean-Claude Weeber,
• Juan Arocas,
• Laurent Markey,
• Gérard Colas des Francs,
• Alexander Uskov,
• Igor Smetanin and
• Alexandre Bouhelier

Beilstein J. Nanotechnol. 2018, 9, 1964–1976, doi:10.3762/bjnano.9.187

• devices before electromigration is in the range of 1 to 4 mS, and includes the contribution from leads and contacts. Vdc is then incremented by steps of 100 mV. We monitor G(t) during each step and the entire electromigration process may be divided into phases. During the first few Vdc steps, G(t) is

• in agreement with this picture [19][20][21][27][54]. However, some authors reported an over-bias emission from atomic contacts where the emitted spectra are no longer limited by the kinetic energy of the electrons given by the applied bias [18][55][56]. In these devices, the emission is described by

A differential Hall effect measurement method with sub-nanometre resolution for active dopant concentration profiling in ultrathin doped Si_1−xGe_x and Si layers

• Richard Daubriac,
• Emmanuel Scheid,
• Hiba Rizk,
• Richard Monflier,
• Sylvain Joblot,
• Rémi Beneyton,
• Pablo Acosta Alba,
• Sébastien Kerdilès and
• Filadelfo Cristiano

Beilstein J. Nanotechnol. 2018, 9, 1926–1939, doi:10.3762/bjnano.9.184

• use an encapsulation cell to protect metallic contacts of the electric test structures during etch (Figure S3, Supporting Information File 1). Due to the funnel-shaped cell designed for this study, the reaction zone is confined, which results in a reduction of the etch rate. By optimising the

• symmetrical shape with peripheral contacts separated from the centre region, in which the current lines converge allowing precise characterization. For this last reason, we were able to design an encapsulation cell (Figure S3, Supporting Information File 1) defining a reaction region in the centre part of the

• Greek-cross structure while protecting the metallic contacts with the lowest impact on structure symmetry and measurement reproducibility. Electrical measurements were carried out with a HL5500PC Nanometrics Hall bench equipped with a 0.3 T magnet. For each investigated sample, the sheet resistance and

Electrical characterization of single nanometer-wide Si fins in dense arrays

• Steven Folkersma,
• Janusz Bogdanowicz,
• Andreas Schulze,
• Paola Favia,
• Dirch H. Petersen,
• Ole Hansen,
• Henrik H. Henrichsen,
• Peter F. Nielsen,
• Lior Shiv and
• Wilfried Vandervorst

Beilstein J. Nanotechnol. 2018, 9, 1863–1867, doi:10.3762/bjnano.9.178

• ) larger than dcontact, the procedure is identical to the previously described case of blanket materials. The electrical contact is indeed created, i.e., contacts j = 1, 2, 3, 4 are activated, when Ipulse ≥ Ithreshold and the electrical resistance Rfin of the region of the fin included between the two

• inner contacts is readily obtained from the ratio Rfin = V/Iin [6]. Secondly, in the more complex case of dense fins, i.e., fin pitch < dcontact, the μ4pp electrodes can physically contact multiple fins at the same time. For simplicity, this paper only considers the case of two fins physically contacted

• by the electrodes (Figure 1b). In this situation, electrical contact is formed on both fins, i.e., contacts j = 1, 2, …, 8 are activated, when the magnitude of Ipulse is similar as used on blanket materials. The measured resistance is then determined by the ratio between the two currents Iin1 and

SO₂ gas adsorption on carbon nanomaterials: a comparative study

• Deepu J. Babu,
• Divya Puthusseri,
• Frank G. Kühl,
• Sherif Okeil,
• Michael Bruns,
• Manfred Hampe and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2018, 9, 1782–1792, doi:10.3762/bjnano.9.169

• supramolecular contacts surrounding the pore [2]. The beneficial role of hydroxy groups on SO2 adsorption was also observed in the case of flue gas adsorption on MOFs [8]. All these studies point to the fact that the presence of oxygen functionalities can certainly influence the SO2 adsorption characteristics of

Josephson effect in junctions of conventional and topological superconductors

• Alex Zazunov,
• Albert Iks,
• Miguel Alvarado,
• Alfredo Levy Yeyati and
• Reinhold Egger

Beilstein J. Nanotechnol. 2018, 9, 1659–1676, doi:10.3762/bjnano.9.158

• describe the semi-infinite S/TS leads and the isolated dot in between, respectively, and Htun refers to the tunnel contacts. We often use units with e = = kB = 1, and β = 1/T denotes inverse temperature. The QD is modeled as an Anderson impurity [36], i.e., a single spin-degenerate level of energy ε0 with

• devices allow for a Majorana-induced parity switch between Andreev state sectors with different parity in a superconducting atomic contact. This observation could be useful for future microwave spectroscopy experiments of Andreev qubits in such contacts. Schematic setups studied in this paper. a) S–QD–TS

Friction force microscopy of tribochemistry and interfacial ageing for the SiO_x/Si/Au system

• Christiane Petzold,
• Marcus Koch and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2018, 9, 1647–1658, doi:10.3762/bjnano.9.157

• ; tribochemistry; wear; Introduction Contact ageing, the strengthening of contacts after formation, is an important phenomenon in tribology, with impact ranging from the nano-scale (NEMS and MEMS) [1][2] to the macro-scale (sliding of rock in earthquakes) [3][4]. Different microscopic mechanisms for contact

• structure [10], for which friction maxima have been predicted [11]. Friction force microscopy (FFM) is a key method to investigate the microscopic mechanisms underlying friction, wear, and lubrication as it allows for measurements of static and kinetic friction of single nanometer-scale contacts. In FFM, an

• atmosphere by FFM [8]. It has been explained by an increase in the number of covalent bonds across the contact facilitated by the presence of water [12][13]. Ageing of well-defined contacts between metallic nanoparticles and surfaces has also been quantified by displacement of the particles in a FFM

Robust topological phase in proximitized core–shell nanowires coupled to multiple superconductors

• Tudor D. Stanescu,
• Anna Sitek and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1512–1526, doi:10.3762/bjnano.9.142

• in Figure 14. This field is equivalent with the chain dependent potential Veff() introduced before. First, a perfectly symmetric shell is experimentally unrealistic from fabrication. Second, as already mentioned, in a regular experimental setup external gates and other contacts may affect the wire

Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

• Daniel Hiller,
• Julian López-Vidrier,
• Keita Nomoto,
• Michael Wahl,
• Wolfgang Bock,
• Tomáš Chlouba,
• František Trojánek,
• Sebastian Gutsch,
• Margit Zacharias,
• Dirk König,
• Petr Malý and
• Michael Kopnarski

Beilstein J. Nanotechnol. 2018, 9, 1501–1511, doi:10.3762/bjnano.9.141

• measurements were post-annealed in the same furnace in pure H2 gas at 450 °C for 1 h to enable the passivation of dangling bond defects [18]. For electrical measurements, MOS capacitors were processed by thermal evaporation of Al-contacts. Molecular Cs+ secondary ion mass spectrometry (MCs+-SIMS [19]; Cameca

Electrostatically actuated encased cantilevers

• Benoit X. E. Desbiolles,
• Gabriela Furlan,
• Adam M. Schwartzberg,
• Paul D. Ashby and
• Dominik Ziegler

Beilstein J. Nanotechnol. 2018, 9, 1381–1389, doi:10.3762/bjnano.9.130

• establish the two separate electrical contacts required for electrostatic actuation. To make an electrical connection to the tip we removed the polymer layers on the back side of the chip and inserted a thin sheet of gold foil between the chip and the cantilever holder. By contacting the gold foil and the

• metallic spring clip of the holder, we can provide reliable electrical contacts to the cantilever (Utip) and excitation electrode on the encasement (Udrive). Results Experimental results Electrostatic vs piezoacoustic excitation Figure 2 compares piezoacoustic and electrostatic excitation in air. In both

• encasement could potentially reduce this effect, but establishing reliable electrical contacts would be more difficult. As shown in the following section, this effect can be eliminated using sub-harmonic excitation, which is independent of static electric potentials. Sub-harmonic electrostatic excitation In

Atomistic modeling of tribological properties of Pd and Al nanoparticles on a graphene surface

• Alexei Khomenko,
• Miroslav Zakharov,
• Denis Boyko and
• Bo N. J. Persson

Beilstein J. Nanotechnol. 2018, 9, 1239–1246, doi:10.3762/bjnano.9.115

• interface between the slider and the substrate, which usually lead to an increase in friction with time. Modern rate-and-state models for rough contacts predict that aging does not only influence the transition from static contact to sliding, but affects the overall sliding dynamics. The complex nature of