Localized photodeposition of catalysts using nanophotonic resonances in silicon photocathodes

• Evgenia Kontoleta,
• Sven H. C. Askes,
• Lai-Hung Lai and
• Erik C. Garnett

Beilstein J. Nanotechnol. 2018, 9, 2097–2105, doi:10.3762/bjnano.9.198

• adjusting the excitation wavelength from red to green to white, or (not shown) the nanostructure shape. (a) SEM images of a silicon nanocone (left), an inverted nanocone (middle) and a nanowire (right) coated with an 18 nm TiO2 layer. The tapering angle was controlled by varying the Cl2 and HBr/O2 flow

• deposited particle (100 pA beam current, 10 kV acceleration beam voltage). (a) Overlay images of backscattered electron (red) and secondary-electron (grey) SEM images after photo-electrodeposition of platinum on a silicon nanocone (left), inverted nanocone (middle), and nanowire (right). (b, c) Total amount

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

• connected tunneling optical antennas is fabricated by electron-beam lithography, Au evaporation and lift-off process. The structures consist of either a gold nanowire of 1.1 μm length and 130 nm width or a constriction as discussed above. For both types, the structures are connected to a set of electrodes

• . The thickness of the nanowire and electrodes is 50 nm, including a 5 nm Ti adhesion layer. The third step is the dry etching of the TiO2 layer. For that, we first create an etching mask by electron-beam lithography, thermal deposition of a 30 nm thick nickel layer and lift-off. Reactive ion etching is

• electromigrating in situ the nanowire to create the optical tunneling gap antenna. Figure 6a,c,e illustrates the experiment with different waveguide geometries and gap orientations. In Figure 6a, the TiO2 waveguide is 85 nm thick and 1.5 μm wide, and the SEM image was taken before the electromigration of the

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

• nanowire diameters of about 10 nm, a dopant deactivation is observed due to the dielectrical mismatch between the silicon and its surroundings. However, our previous investigations on 5 nm thick SiGeOI layers doped by ion implantation and activated by conventional rapid thermal annealing (RTA) [39][40

Nonlinear effect of carrier drift on the performance of an n-type ZnO nanowire nanogenerator by coupling piezoelectric effect and semiconduction

• Yuxing Liang,
• Shuaiqi Fan,
• Xuedong Chen and
• Yuantai Hu

Beilstein J. Nanotechnol. 2018, 9, 1917–1925, doi:10.3762/bjnano.9.183

• effect on the performance of a ZnO nanogenerator was investigated in detail and it was elucidated that carrier motion/redistribution occurs in the ZnO nanowire (ZNW) cross section while there is no carrier motion in the axial direction. At the same time, we noted that the amplitude of boundary electric

• power was analyzed in detail. The electrode size for the optimal performance of a ZnO nanowire generator was proposed. This analysis that couples electromechanical fields and carrier concentration as a whole has some referential significance to piezotronics. Keywords: carrier drift; crystallogrpahic c

• nanowire bent when an atomic force microscopy tip scans over the top of the nanowire. The electromechanical coupling converts mechanical energy into electric energy [28][29]. A piezoelectric potential is built inside the nanowire with the stretched side being positively charged and the compressed side

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

• end states. Using Green’s function techniques, the topological superconductor is alternatively described by the low-energy continuum limit of a Kitaev chain or by a more microscopic spinful nanowire model. We show that for the simplest S–TS tunnel junction, only the s-wave pairing correlations in a

• spinful TS nanowire model can generate a Josephson effect. The critical current is much smaller in the topological regime and exhibits a kink-like dependence on the Zeeman field along the wire. When a correlated quantum dot (QD) in the magnetic regime is present in the junction region, however, the

• ] have pointed out that the physics of the Kitaev chain could be realized in spin–orbit coupled nanowires with a magnetic Zeeman field and in the proximity to a nearby s-wave superconductor. The spinful nanowire model of references [2][3] indeed features p-wave pairing correlations for appropriately

Spatial Rabi oscillations between Majorana bound states and quantum dots

• Jun-Hui Zheng,
• Dao-Xin Yao and
• Zhi Wang

Beilstein J. Nanotechnol. 2018, 9, 1527–1535, doi:10.3762/bjnano.9.143

• candidate is the hybrid system of a spin–orbit-coupling nanowire and a conventional superconductor. Robust zero-bias conductance peak was first reported in this system, which originates from the self-conjugate nature of Majorana bound states and therefore was wildly recognized as a signature. An exotic

• fractional Josephson effect was also studied in the nanowire Josephson junctions, where novel Shapiro steps and Josephson radiations have been reported. Recently, the Coulomb blockade spectroscopy was exploited on finite-size nanowire segments that form nanowire islands with two Majorana bound states

• oscillation between the quantum dots and the Majorana bound states [29] and to investigate the self-conjugateness and exponential protection of Majorana bound states. In recent experiments, a hybrid structure of a quantum dot and a one-dimensional topological superconductor nanowire has been realized [36

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

• promising involving semiconductor-superconductor hybrid systems [5][6][7][8][9]. The basic idea [10][11][12][13] is to proximity-couple a semiconductor nanowire with strong Rashba-type spin-orbit coupling (e.g., InSb or InAs) to a standard s-type superconductor (e.g., NbTiN or Al) in the presence of a

• longitudinal magnetic field. The system is predicted to host zero-energy Majorana modes localized at the two ends of the nanowire [5][7][8]. These zero-energy states combine equal proportions of electrons and holes and are created by second quantized operators satisfying the “Majorana condition” γ† = γ. The

• the crystal structure [27]. The finite cross section of the wires used in the experiments may generate additional phenomena, which are not captured by ideal 1D models. In particular, the orbital effects of the magnetic field, which is oriented parallel to the nanowire, may reduce or even destroy the

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

• the bottom end of the nanoscale requires different doping approaches that either relocate the dopants in the surrounding matrix (e.g., Si modulation doping by SiO2:Al) [59] or do not require impurities at all (e.g., electrically reconfigurable nanowire-FETs [60] or p/n-behaviour induced by energy

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

• Rashmi Acharya,
• Brundabana Naik and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 1448–1470, doi:10.3762/bjnano.9.137

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• square lattice of a superconducting host, (ii) a nanoscopic chain of magnetic impurities on the classical superconductor (i.e., proximitized Rashba nanowire) in its topologically trivial/nontrivial superconducting phase, and (iii) a strongly correlated quantum dot side-attached to the Rashba chain, where

• μN↑ − μN↓. Individual atoms of the nanochain are coupled with such STM tip through For simplicity, we assume constant couplings The low-energy physics of such proximitized Rashba nanowire can be described by [44] where annihilates (creates) an electron of spin σ at site i with energy εi, and tij

• proposals for such nanodevices have been recently discussed by several authors [52][53]. In summary of this section, we emphasize that the Majorana modes coalescing from the YSR states in the proximitized Rashba nanowire are characterized by their magnetic polarization. Indeed, such a feature has been

Disorder-induced suppression of the zero-bias conductance peak splitting in topological superconducting nanowires

• Jun-Tong Ren,
• Hai-Feng Lü,
• Sha-Sha Ke,
• Yong Guo and
• Huai-Wu Zhang

Beilstein J. Nanotechnol. 2018, 9, 1358–1369, doi:10.3762/bjnano.9.128

• the peak height. Remarkably, for a longer nanowire, the zero-bias peak could be reproduced by weak disorder for a finite Majorana energy splitting. It is interesting that the shot noise provides a signature to discriminate whether the zero-bias peak is induced by Majorana zero mode or disorder. For

• -matter systems, including p-wave superconductors [10][11], topological insulator-superconductor hybrid structures [12][13], artificially engineered Kitaev chains [14][15], semiconductor-superconductor hybrid nanowire systems [16][17][18][19][20][21]. Very recently, the one-dimensional Majorana mode

• produces a finite Majorana energy splitting and zero-bias peak splitting [36][37][38] due to the finite size effects. In a recent experiment [39], the energy splitting of Majorana zero mode has been observed in InAs nanowire segments with epitaxial aluminium, which forms a proximity-induced superconducting

Andreev spectrum and supercurrents in nanowire-based SNS junctions containing Majorana bound states

• Jorge Cayao,
• Annica M. Black-Schaffer,
• Elsa Prada and
• Ramón Aguado

Beilstein J. Nanotechnol. 2018, 9, 1339–1357, doi:10.3762/bjnano.9.127

• discussed. Further, we identify the individual contribution of MBSs. In short junctions the MBSs determine the current–phase curves, while in long junctions the spectrum above the gap (quasi-continuum) introduces an important contribution. Keywords: hybrid superconductor–semiconductor nanowire

• –superconductor junctions; Josephson effect; Majorana bound states; nanowires; spin–orbit coupling; Zeeman interaction; Introduction A semiconducting nanowire with strong Rashba spin–orbit coupling (SOC) with proximity-induced s-wave superconducting correlations can be tuned into a topological superconductor by

• means of an external Zeeman field [1][2][3]. This topological phase is characterized by the emergence of zero-energy quasiparticles with Majorana character localized at the nanowire ends. These Majorana bound states (MBSs) are attracting a great deal of attention owing to their potential for topological

Proximity effect in a two-dimensional electron gas coupled to a thin superconducting layer

• Christopher Reeg,
• Daniel Loss and
• Jelena Klinovaja

Beilstein J. Nanotechnol. 2018, 9, 1263–1271, doi:10.3762/bjnano.9.118

• 2DEG, while δμk,ω corresponds to a tunneling-induced shift in the effective chemical potential of the 2DEG. Quite surprisingly, the self-energy in Equation 14 and Equation 15 coincides with that of a nanowire coupled to a two-dimensional superconductor with finite width as found in [48], with the

Circular dichroism of chiral Majorana states

• Javier Osca and
• Llorenç Serra

Beilstein J. Nanotechnol. 2018, 9, 1194–1199, doi:10.3762/bjnano.9.110

• ][11][12][13][14]. A Majorana mode enhances the zero-bias conductance by allowing a perfect Andreev backscattering at zero excitation energy when the nanowire is attached to a normal lead. These peculiar pairs of states may be seen as nonlocal split fermions, protected by an energy gap that separates

• decays exponentially with the distance to the nanowire end. By contrast, propagating Majorana states with sustained spatial oscillations can be present at the edges and along the perimeter of 2D-like hybrid structures. This is the situation in presence of p + ip superconductivity for spinless

Inverse proximity effect in semiconductor Majorana nanowires

• Alexander A. Kopasov,
• Ivan M. Khaymovich and
• Alexander S. Mel'nikov

Beilstein J. Nanotechnol. 2018, 9, 1184–1193, doi:10.3762/bjnano.9.109

• nanowire resulting in its non-trivial energy dependence. Indeed, considering, e.g., a single-channel nanowire we get the DOS diverging as a square root function of the energy relative to the bottom of the conduction band. This van Hove singularity in the DOS should cause a strong energy dependence of the

• Figure 1. Hereafter we use the units with kB = = 1, where kB is the Boltzmann constant, and is the Planck constant. The Hamiltonian of the system reads: with the first term describing the s-wave superconducting shell. corresponds to the Hamiltonian of the nanowire, and the tunnel Hamiltonian takes the

• generalization [17] of the expression for Γw for the case of an arbitrary number of transverse modes in the nanowire assuming also the value 1/υ0 to be averaged over these modes. The resulting ratio of the tunneling rates takes the form: Due to the growth of Ns with the shell thinkness ds in the multi-mode

Thermoelectric current in topological insulator nanowires with impurities

• Sigurdur I. Erlingsson,
• Jens H. Bardarson and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1156–1161, doi:10.3762/bjnano.9.107

• charge current generated by maintaining a temperature difference over a nanowire at zero voltage bias. For topological insulator nanowires in a perpendicular magnetic field the current can change sign as the temperature of one end is increased. Here we study how this thermoelectric current sign reversal

• insulator material, such as BiSe, is formed into a nanowire, topological states can appear on its surface. Recently, such wires in a magnetic field have been studied extensively both theoretically [20][21][22][23][24] and experimentally [5][6][7][8][9][10][25]. When the nanowires are of circular cross

• method [39]. Experiments on normal (not topological) nanowires show a conductance that can be complicated, but reproducible trace for a given nanowire. This means that the measurement can be repeated on the same nanowire and it will give the same conductance trace as long as the sample is kept under

Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations

• Jaison Jeevanandam,
• Ahmed Barhoum,
• Yen S. Chan,
• Alain Dufresne and
• Michael K. Danquah

Beilstein J. Nanotechnol. 2018, 9, 1050–1074, doi:10.3762/bjnano.9.98

Magnetic characterization of cobalt nanowires and square nanorings fabricated by focused electron beam induced deposition

• Federico Venturi,
• Gian Carlo Gazzadi,
• Amir H. Tavabi,
• Alberto Rota,
• Rafal E. Dunin-Borkowski and
• Stefano Frabboni

Beilstein J. Nanotechnol. 2018, 9, 1040–1049, doi:10.3762/bjnano.9.97

• magnetic sensing [5]. A new concept of fast memory, which is referred to as racetrack memory, has been proposed, based on the motion of domain walls along a nanowire (NW) subject to current pulses or external magnetic fields [6]. The strong research interest in such new types of memories is based on their

Facile synthesis of a ZnO–BiOI p–n nano-heterojunction with excellent visible-light photocatalytic activity

• Mengyuan Zhang,
• Jiaqian Qin,
• Pengfei Yu,
• Bing Zhang,
• Mingzhen Ma,
• Xinyu Zhang and
• Riping Liu

Beilstein J. Nanotechnol. 2018, 9, 789–800, doi:10.3762/bjnano.9.72

• properties [33]. In 2014, spin-coating was utilized to prepare ZnO nanowire arrays with tunable band gap, layered BiOBr–BiOI composites onto them. It showed that the BiOBr/BiOI composites played the role of sensitizer in the heterojunctions and were tunable by varying the BiOBr/BiOI ratio [34]. Kuang et al

Revealing the interference effect of Majorana fermions in a topological Josephson junction

• Jie Liu,
• Tiantian Yu and
• Juntao Song

Beilstein J. Nanotechnol. 2018, 9, 520–529, doi:10.3762/bjnano.9.50

• with Rashba spin–orbit coupling and proximity-induced superconductivity appear to be the most promising method [4]. Indeed, a semiconductor–superconductor nanowire was manufactured to confirm the prediction of the theory [12][13][14]. The second topological superconducting system that was realized

• experiments. These advances accelerate the development of nanotechnology [20][21][22][23][24][25][26][27]. Recently, a breakthrough was achieved in research groups led by Kouwenhoven and Marcus. Both groups observed the integer ZBPs in a nanowire system [28]. These are the most persuading results so far

Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

• Liga Jasulaneca,
• Jelena Kosmaca,
• Raimonds Meija,
• Jana Andzane and
• Donats Erts

Beilstein J. Nanotechnol. 2018, 9, 271–300, doi:10.3762/bjnano.9.29

• a moving element (Ge nanowire) between two drain electrodes located symmetrically (Figure 1e,f drains 1 and 2) [14] and asymmetrically (Figure 1e,f drains 1 and 3) [11] relative to the switching element in 2T configuration was demonstrated. While switching between symmetrically located drain

• ] (Table 1). Thus, the contact area experiences higher current density than that inside the nanowire. This should be taken into account during analysis performed on NEM switch operation. The nanocontact area and stiffness of the switching element determine the on–off hysteresis width of a NEM switch. With

• width for a Mo6S3I6 nanowire bundle-based 2T NEM switch, when the Mo6S3I6 –Au contact area was reduced from 100 nm2 down to 45 nm2 while maintaining the same Von voltage. However, such reduction of the contact area results in an increase of the electrical current density flowing through it, which may

Dopant-stimulated growth of GaN nanotube-like nanostructures on Si(111) by molecular beam epitaxy

• Alexey D. Bolshakov,
• Alexey M. Mozharov,
• Georgiy A. Sapunov,
• Igor V. Shtrom,
• Nickolay V. Sibirev,
• Vladimir V. Fedorov,
• Evgeniy V. Ubyivovk,
• Maria Tchernycheva,
• George E. Cirlin and
• Ivan S. Mukhin

Beilstein J. Nanotechnol. 2018, 9, 146–154, doi:10.3762/bjnano.9.17

• atomic nitrogen flux. Nanowire formation The analysis of the SEM images (Figure 1a–f) and experimental data allows us to make several important conclusions. First, the cross-section of the synthesized NWs is hexagonal (see Figure 1f). Second, we registered the highest NW elongation rate value of 35.9 nm

• electron microscope (SEM) images of the nanowire (NW) arrays: a) image of the array grown on the substrate that underwent low temperature annealing (850 °C, sample 2); b) images of the array grown on the substrate that underwent high temperature annealing (1000 °C, sample 7); c) top view image of the

Combined scanning probe electronic and thermal characterization of an indium arsenide nanowire

• Tino Wagner,
• Fabian Menges,
• Heike Riel,
• Bernd Gotsmann and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2018, 9, 129–136, doi:10.3762/bjnano.9.15

• spots may put limits on device integration. Therefore, being able to observe profiles of both electronic and thermal device properties at the nanoscale is important. Here, we show measurements by scanning thermal and Kelvin probe force microscopy of the same 60 nm diameter indium arsenide nanowire in

• operation. The observed temperature along the wire is substantially elevated near the contacts and deviates from the bell-shaped temperature profile one would expect from homogeneous heating. Voltage profiles acquired by Kelvin probe force microscopy not only allow us to determine the electrical nanowire

• conductivity, but also to identify and quantify sizable and non-linear contact resistances at the buried nanowire–electrode interfaces. Complementing these data with thermal measurements, we obtain a device model further permitting separate extraction of the local thermal nanowire and interface conductivities

Nematic topological defects positionally controlled by geometry and external fields

• Pavlo Kurioz,
• Marko Kralj,
• Bryce S. Murray,
• Charles Rosenblatt and
• Samo Kralj

Beilstein J. Nanotechnol. 2018, 9, 109–118, doi:10.3762/bjnano.9.13

• be exploited to form nanowire-type structures [9][13] consisting of NPs. In this contribution we study numerically the effects of geometry and an external electric field on the positions of nematic TDs using the Landau–de Gennes mesoscopic approach. Theoretical Background Of interest is the impact of

Beyond Moore’s technologies: operation principles of a superconductor alternative

• Igor I. Soloviev,
• Nikolay V. Klenov,
• Sergey V. Bakurskiy,
• Mikhail Yu. Kupriyanov,
• Alexander L. Gudkov and
• Anatoli S. Sidorenko

Beilstein J. Nanotechnol. 2017, 8, 2689–2710, doi:10.3762/bjnano.8.269

• in the middle to which the third terminal tip is connected. A current pulse from the third terminal switches off the superconductivity of the nanowire, that is similar to SFT operation to some extent. Unlike a Josephson junction, the nanowire in the resistive state possesses several kiloohms of