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

• design reported in the literature with a coupling efficiency of only 8.7%, we propose an optimized photonic platform with efficiency reaching 65.5%. Keywords: FDTD modeling; nanowire LED; nitride nanowires; photonic integrated circuit; photonic platform; SiN/InGaN co-integration; visible light

• tunable bandgap [14] and reduced dislocation density [15][16], nitride nanowires (NWs) have become important materials for optical components in the visible to ultraviolet (UV) spectral range [17][18]. Despite their small size, single NW light emitting diodes (LEDs) can produce bright electroluminescence

Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

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

• from exposure to air/moisture was suggested via the growth of HP nanowires in the pores of anodized alumina membranes [122]. The effective blockage of the diffusion of water and oxygen molecules to the alumina-incorporated MASnI3 nanowires resulted in a three order of magnitude slower degradation of

• min ripening at 220 °C (Figure 7c) [133]. The Cs2SnI6 nanorods gradually transform into nanowires (Figure 7d) with the aspect ratio increasing from 3 to 28 after a 10 min reaction. At longer reaction times (30 min) nanowires transform into nanobelts (Figure 7e) that assemble into nanoplatelets with a

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

• , Universidad Autónoma de Madrid, E-28049 Madrid, Spain 10.3762/bjnano.9.203 Abstract Majorana modes emerge in non-trivial topological phases at the edges of specific materials such as proximitized semiconducting nanowires under an external magnetic field. Ideally, they are non-local states that are charge

• -neutral superpositions of electrons and holes. However, in nanowires of realistic length their wave functions overlap and acquire a finite charge that makes them susceptible to interactions, specifically with the image charges that arise in the electrostatic environment. Considering a realistic three

• features are observed in recent experiments on the detection of Majoranas and could thus help to properly characterize them. Keywords: hybrid superconductor–semiconductor nanowires; interactions; Majorana bound states; quantum dots; Introduction Semiconducting nanowires with strong spin–orbit interaction

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

• , and larger surface-to-volume ratio [34]. The large surface-area-to-volume ratio of nanofibers (NFs), hollow nanofibers (HNFs), nanotubes (NTs) and nanowires (NWs) with micro/mesoporous surfaces results in improved adsorption and better reaction kinetics of gas-sensitive materials. Nanofibers can be

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

• spots”. These areas can be used for localized extraction of the photogenerated charges, which in turn could drive chemical reactions for synthesis of catalytic materials. In this work, we use these nanophotonic hot spots in vertical silicon nanowires to locally deposit platinum nanoparticles in a photo

• -electrochemical system. The tapering angle of the silicon nanowires as well as the excitation wavelength are used to control the location of the hot spots together with the deposition sites of the platinum catalyst. A combination of finite difference time domain (FDTD) simulations with scanning electron

• appearance of localized “hot spots”. In particular, semiconducting nanostructures can sustain Mie-like leaky modes due to their high refractive index and the occurrence of multiple internal light reflections from the boundaries of the structure [9][13]. However, in vertical nanowires under normal-incidence

A scanning probe microscopy study of nanostructured TiO₂/poly(3-hexylthiophene) hybrid heterojunctions for photovoltaic applications

• Laurie Letertre,
• Roland Roche,
• Olivier Douhéret,
• Hailu G. Kassa,
• Denis Mariolle,
• Nicolas Chevalier,
• Łukasz Borowik,
• Philippe Dumas,
• Benjamin Grévin,
• Roberto Lazzaroni and
• Philippe Leclère

Beilstein J. Nanotechnol. 2018, 9, 2087–2096, doi:10.3762/bjnano.9.197

• can easily form nanostructures, such as nanoporous layers, nanowires or nanocolumns [5][11][12]. Because of its large band gap (3.2 eV [13]), light absorption is carried out by an organic or inorganic dye. The nanostructuration of the acceptor material is crucial for the cell performance [11], as it

High-throughput synthesis of modified Fresnel zone plate arrays via ion beam lithography

• Kahraman Keskinbora,
• Umut Tunca Sanli,
• Margarita Baluktsian,
• Corinne Grévent,
• Markus Weigand and
• Gisela Schütz

Beilstein J. Nanotechnol. 2018, 9, 2049–2056, doi:10.3762/bjnano.9.194

• . This can be attributed to the shifting plasmon resonances of the gold nanowires that make up the zones of the FZPs. A scanning transmission electron microscope (STEM) dark-field overview image of the completed array is shown in Figure 4b. The FZPs mostly exhibited high quality with zones free from

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

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

• this work will have a minimum thickness of about 6 nm, so that the quantum-confinement effect can be neglected. An additional low-dimension effect is the dielectric confinement, which has been investigated in silicon nanowires surrounded by a dielectric material (such as its native oxide) [37][38]. For

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

• vertically aligned ZnO nanowires [18][19][20][21][22][23][24][25][26][27]. The principle of nanogenerators is that the piezoelectric potential produced by the piezoelectric effect can produce a current in an external circuit when the ZNW is deformed. Specifically, a transversely applied force makes the

• -workers [35]. In particular, Henneghien et al. have pointed out that circular and hexagonal nanowires exhibit the same behavior if the ZnO nanowire sections of each structure have the same area. Linear solutions were obtained for small fluctuations of carrier concentration in a bent n-type ZnO nanowire

Toward the use of CVD-grown MoS₂ nanosheets as field-emission source

• Geetanjali Deokar,
• Nitul S. Rajput,
• Junjie Li,
• Francis Leonard Deepak,
• Wei Ou-Yang,
• Nicolas Reckinger,
• Carla Bittencourt,
• Jean-Francois Colomer and
• Mustapha Jouiad

Beilstein J. Nanotechnol. 2018, 9, 1686–1694, doi:10.3762/bjnano.9.160

• displays, X-ray sources and cold-cathode electron sources [2]. 1D and 2D materials such as carbon nanotubes [3], ZnO nanorods [1], LaB6 nanowires [2], SnS2 nanosheets (NSs) [4], vertically aligned graphene [5], WS2 nanotubes [6], MoSe2 nanosheets [7], and MoS2 NSs [8][9][10] are potential field-emitter

• ][12], and comparable with the vertically aligned MoS2 NSs with ultrathin edges in [9] (Table 1). It has been shown previously that vertically grown 1D nanowires/nanotubes and 2D NSs with atomically thin edges may considerably improve the FE properties, so that vertically standing materials are

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

• ] 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

• matrices σx,y,z and σ0 refer to spin. In the figures shown below, we choose the model parameters in Equation 34 as discussed in [43]. The lattice spacing is set to a = 10 nm, which results in a nearest-neighbor hopping t = 2/(2m*a2) = 20 meV and the spin–orbit coupling strength α = 4 meV for InAs nanowires

Sheet-on-belt branched TiO₂(B)/rGO powders with enhanced photocatalytic activity

• Huan Xing,
• Wei Wen and
• Jin-Ming Wu

Beilstein J. Nanotechnol. 2018, 9, 1550–1557, doi:10.3762/bjnano.9.146

• common but still draws much attention. Many types of TiO2(B) nanostructures have been synthesized, such as nanowires [9][10], nanotubes [11], nanobelts [12][13][14], nanofibers [15] and nanosheets [16]. TiO2(B) is mostly used in lithium-ion batteries due to its relatively open crystal structure, superior

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

• Science and Engineering, Reykjavik University, Menntavegur 1, IS-101 Reykjavik, Iceland 10.3762/bjnano.9.142 Abstract We consider core–shell nanowires with prismatic geometry contacted with two or more superconductors in the presence of a magnetic field applied parallel to the wire. In this geometry, the

• the value of the critical field associated with the topological quantum phase transition. Keywords: core–shell nanowires; Majorana states; multiple 1D chains; prismatic geometry; topological superconducting phase; Introduction The intense ongoing search for Majorana zero modes (MZMs) in solid states

• . However, the experimental realization and detection of these modes involve 3D nanowires [26]. The most common materials are InSb and InAs due to their large g-factor and strong SOC. The wires are grown by bottom-up methods and have usually a prismatic shape with a hexagonal cross section, as determined by

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

• deactivate P-donors and B-acceptors in heavily doped Si nanowires [47] and in the bulk [48][49][50]. However, this type of dopant passivation solely relies on very reactive atomic hydrogen (rather than molecular H2 gas) and requires much lower temperatures of 100–150 °C to be efficient. When considering H2

• offsets created by locally Si3N4 and SiO2 embedded Si-nanowires [61]). P- and B-concentrations as measured by MCs+-SIMS as function of PH3 to SiH4 gas flow ratio, or respectively, as function of B2H6 to SiH4 gas flow ratio for both SRO and SRON PECVD-recipes. The lines are just a guide to the eye to

Cathodoluminescence as a probe of the optical properties of resonant apertures in a metallic film

• Kalpana Singh,
• Evgeniy Panchenko,
• Babak Nasr,
• Amelia Liu,
• Lukas Wesemann,
• Timothy J. Davis and
• Ann Roberts

Beilstein J. Nanotechnol. 2018, 9, 1491–1500, doi:10.3762/bjnano.9.140

• GaAs nanowires [46], modes of single and pairs of AlGaAs disks [47], the optical properties of quantum discs of GaN/AlN in GaN nanowires [48] and various modes of gold nanodecahedra [49]. The potential of CL used in transmission to observe various colour centres in nanodiamonds has also been

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

• –orbit coupling (usually meaningful at boundaries, e.g., surfaces) [20][21][22]. Such interaction in one-dimensional magnetic nanowires can induce the topologically nontrivial superconducting phase, in which the YSR states undergo mutation to Majorana (zero-energy) quasiparticles. Coulomb repulsion

• unit vector shows the direction of the spin–orbit field, which can be arbitrary. Here we restrict our considerations to the in-plane = (1, 0, 0) polarization, which will be important for nontrivial superconductivity in nanowires discussed in the subsection ’Magnetically polarized Majorana

• attempting to braid the Majorana end modes, e.g., in T-shape nanowires upon turning on and off the topological superconducting phase in its segments. We briefly analyse here the polarized zero-energy Majorana modes leaking into the multi-site quantum dot (comprising ten lattice sites) side-attached to the

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

• -Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China 10.3762/bjnano.9.128 Abstract We investigate the effect of three types of intrinsic disorder, including that in pairing energy, chemical potential, and hopping amplitude, on the transport properties through the superconducting nanowires

• several experiments since 2012 [23][24][25][26][27][28][29][30]. As an important signature of MBSs in the semiconductor nanowires which are proximity-coupled to s-wave superconductors, the zero-bias conductance peak has been observed in the tunneling spectra in the presence of a finite magnetic field [23

• direct evidence for the presence of MBSs, and its emergence is often associated with the resonant Andreev reflection [41]. However, for realistic Majorana nanowires, the observed conductance peaks are often much smaller than 2e2/h. In Figure 6, we show the disorder-induced effects on the zero-bias

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

• Madrid, E-28049 Madrid, Spain Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Cantoblanco, 28049 Madrid, Spain 10.3762/bjnano.9.127 Abstract Hybrid superconductor–semiconductor nanowires with Rashba spin–orbit coupling are arguably becoming the leading platform for the search of Majorana bound

• states (MBSs) in engineered topological superconductors. We perform a systematic numerical study of the low-energy Andreev spectrum and supercurrents in short and long superconductor–normal–superconductor junctions made of nanowires with strong Rashba spin–orbit coupling, where an external Zeeman field

• –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

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

• advances of the past few years was the successful epitaxial growth of thin layers of superconducting Al on InAs and InSb nanowires [38][39][40][41][42]. The intimate contact between the semiconductor and superconductor in these devices ensures a hard induced superconducting gap. Recently, this epitaxial

• phase. However, for most devices, the large band shift makes it very challenging to realize a topological phase. Increasing thickness of superconducting layer The self-energy appearing most frequently in the literature to describe proximitized nanowires and 2DEGs [55][56][57][58][59][60], which also has

Circular dichroism of chiral Majorana states

• Javier Osca and
• Llorenç Serra

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

• condensed matter devices may be of a localized nature, such as in hybrid semiconductor/superconductor nanowires, or chirally propagating along the edges such as in hybrid 2D quantum-anomalous Hall/superconductor structures. Results: We calculate the circular dichroism due to chiral Majorana states in a

• states in condensed matter devices is attracting strong interest for a few years now [1][2][3][4][5][6][7][8]. The measured zero-bias conductance peaks in hybrid semiconductor/superconductor nanowires have been attributed to the presence of localized Majorana modes on the two ends of the nanowires [9][10

• them from other normal states lying at finite energies. Besides the zero energy of the Majorana state, also the conductance peak height was recently seen to coincide with the expected value 2e2/h [15]. Majorana end states in (quasi) 1D nanowires are inherently localized, i.e., their wave function

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

• Novgorod, 23 Gagarina, 603950 Nizhny Novgorod, Russia 10.3762/bjnano.9.109 Abstract We study the influence of the inverse proximity effect on the superconductivity nucleation in hybrid structures consisting of semiconducting nanowires placed in contact with a thin superconducting film and discuss the

• ; semiconducting nanowires; Introduction The transport phenomena in semiconducting wires with induced superconducting ordering and strong spin–orbit interaction are in the focus of current experimental and theoretical research in field of nanophysics and quantum computing [1][2][3][4][5][6][7][8][9][10]. The

• ratio of mode numbers as Nw/Ns ≈ 10−5–10−4 for typical Majorana nanowires [11][12][13][14][15][16]. Taking into account the decrease of the υ0 value close to the van Hove singularity (/υ0 ≈ 102–103), we get Γw/Γs ≈ 10−3–10−1. Assuming strong coupling between the nanowire and superconducting shell with

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

• impurity concentration the sign reversal persists. Keywords: topological insulators, nanowires, thermoelectric current; Introduction It has been known for quite some time now that the efficiency of thermoelectric devices can be increased by reducing the system size. The size reduction can improve

• properties is not always straightforward [3]. Even though few experimental studies exist on thermoelectric properties in topological insulator nanowires (TIN), many studies have reported magnetoresistance oscillations, both in longitudinal and transversal fields for TINs [4][5][6][7][8][9][10]. In its

Field-controlled ultrafast magnetization dynamics in two-dimensional nanoscale ferromagnetic antidot arrays

• Anulekha De,
• Sucheta Mondal,
• Sourav Sahoo,
• Saswati Barman,
• Yoshichika Otani,
• Rajib Kumar Mitra and
• Anjan Barman

Beilstein J. Nanotechnol. 2018, 9, 1123–1134, doi:10.3762/bjnano.9.104

• magnetic metamaterials, known as magnonic crystals (MCs), which have great potential for technological applications and fundamental research [1][2]. Investigation and tailoring of the magnetization dynamics in ferromagnetic nanodots [3][4], nanowires [5] and antidots [6][7][8] have fuelled considerable

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

• external nanoscale dimension or having internal nanoscale surface structure” [4]. Nanofibers, nanoplates, nanowires, quantum dots and other related terms have been defined based on this ISO definition [5]. Likewise, the term nanomaterial is described as “a manufactured or natural material that possesses