Effects of post-lithography cleaning on the yield and performance of CVD graphene-based devices

• Eduardo Nery Duarte de Araujo,
• Thiago Alonso Stephan Lacerda de Sousa,
• Luciano de Moura Guimarães and
• Flavio Plentz

Beilstein J. Nanotechnol. 2019, 10, 349–355, doi:10.3762/bjnano.10.34

• polymer are still present. Structural disorder in graphene can be quantified through the ID/IG intensity ratio. For laser excitation with wavelength λL, the characteristic size of well-ordered domains in graphene can be estimated as: which properly applies to La > 4 nm [19][20][21]. According to Figure 4

• graphene. Furthermore, the value of La showed no expressive decrease as the devices fabricated by procedure P2 are cleaned by method C1. However, when the cleaning is performed by methods C2 and C3, the size of well-ordered domains shows a further decrease, which suggests an increase of structural disorder

• holes. Figure 5 shows that graphene conductivity, σ, behaves as a sublinear function of the gate voltage, Vg. This sublinear behavior is associated to a weak-point disorder in graphene, which emerges as a carrier density independent residual resistivity, ρs. The strong disorder and the charged-impurity

Raman study of flash-lamp annealed aqueous Cu₂ZnSnS₄ nanocrystals

• Yevhenii Havryliuk,
• Oleksandr Selyshchev,
• Mykhailo Valakh,
• Alexandra Raevskaya,
• Oleksandr Stroyuk,
• Constance Schmidt,
• Volodymyr Dzhagan and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2019, 10, 222–227, doi:10.3762/bjnano.10.20

• lower frequency values can be cation disorder [10][39], the formation of other polytypes, particularly so-called disordered KS [10][39], stannite [39][41], and wurtzite (WZ) [42][43][44]. Based on the XRD data of our samples [21], we can exclude the WZ phase. Furthermore, the Raman spectra of freshly

• bulk CZTS [10][11]. The discussed “disorder” does not mean, however, the absence of crystallinity, as can be concluded from the sharp phonon spectra (Figure 1). It is rather a certain rearrangement of the cations (and probably anions) in the sublattice that does not deteriorate the overall

Nanoporous water oxidation electrodes with a low loading of laser-deposited Ru/C exhibit enhanced corrosion stability

• Sandra Haschke,
• Dmitrii Pankin,
• Vladimir Mikhailovskii,
• Maïssa K. S. Barr,
• Adriana Both-Engel,
• Alina Manshina and
• Julien Bachmann

Beilstein J. Nanotechnol. 2019, 10, 157–167, doi:10.3762/bjnano.10.15

• -frequency region, the conspicuous maximum at ≈1600 cm−1 is due the stretching vibration of C=C bonds in aromatic or graphitic carbon. The peak at 1224 cm−1 corresponds to stretching vibrations of C–C and C–O single bonds (the ‘disorder’ peak usually found for graphitic material) [56][57][58][59][60][61

Threshold voltage decrease in a thermotropic nematic liquid crystal doped with graphene oxide flakes

• Mateusz Mrukiewicz,
• Krystian Kowiorski,
• Paweł Perkowski,
• Rafał Mazur and
• Małgorzata Djas

Beilstein J. Nanotechnol. 2019, 10, 71–78, doi:10.3762/bjnano.10.7

• aggregates is much more visible for the higher concentration (Figure 3e) than for the lower concentration (Figure 3b). The large aggregates disorder the long-range orientational order and disturb the liquid crystal alignment. According to the classical Michel–Levy interference color chart [38], we observe a

Zn/F-doped tin oxide nanoparticles synthesized by laser pyrolysis: structural and optical properties

• Florian Dumitrache,
• Iuliana P. Morjan,
• Elena Dutu,
• Ion Morjan,
• Claudiu Teodor Fleaca,
• Monica Scarisoreanu,
• Alina Ilie,
• Marius Dumitru,
• Cristian Mihailescu,
• Adriana Smarandache and
• Gabriel Prodan

Beilstein J. Nanotechnol. 2019, 10, 9–21, doi:10.3762/bjnano.10.2

• qualitative information via phononic behavior regarding the crystalline nature of materials, is a useful tool for investigating disorder in oxide materials. Figure 4a presents a typical room temperature Raman spectra of as-synthesized F or Zn/F-doped SnO2 nanopowders. The Raman spectra analyzed in this work

• (Figure 4b) a direct dependence of the mode frequency with XPS Zn content detected on the nanoparticle surface. This shifting correlated with the B2g Raman mode area increase indicates nanoparticle surface disorder induced by F attachment. S1 and S2 bands appear as a disorder activation consequence [25

• ] inferred by F, Zn and nanocrystallite size. When the F concentration is high (without Zn doping) the disorder is considered to be surface induced, while for a sample with a high Zn concentration (EDX – 3.74 atom %), ZTO0.44, the disorder is volume generated, along with a depreciation in the crystalline

Disorder in H⁺-irradiated HOPG: effect of impinging energy and dose on Raman D-band splitting and surface topography

• Lisandro Venosta,
• Noelia Bajales,
• Sergio Suárez and
• Paula G. Bercoff

Beilstein J. Nanotechnol. 2018, 9, 2708–2717, doi:10.3762/bjnano.9.253

• . 8400 San Carlos de Bariloche, Argentina 10.3762/bjnano.9.253 Abstract Disorder was induced in pristine highly oriented pyrolytic graphite (HOPG) by irradiation with H+ ions with energies of 0.4 MeV and 1 MeV, and doses of 1014 ions/cm2 and 1016 ions/cm2. Raman spectroscopy was used as the main

• engineering in carbon-based materials. Keywords: disorder; highly oriented pyrolytic graphite (HOPG); ion–solid interactions; Raman spectroscopy; topography; Introduction The development of novel methods to control the properties of carbon-based materials by introducing disorder is currently a subject of

• interest for many nanotechnological applications [1][2][3]. The identification of particle-induced disorder in the sp2 carbon network [3][4][5][6][7], such as the creation and aggregation of defects and/or impurities, has been mainly conducted by using Raman spectroscopy as a fast and non-destructive tool

Block copolymers for designing nanostructured porous coatings

• Roberto Nisticò

Beilstein J. Nanotechnol. 2018, 9, 2332–2344, doi:10.3762/bjnano.9.218

• –disorder transition at a certain value of χN [43]. In detail, the Flory–Huggins model relies on the thermodynamics of polymer solutions by considering the Gibbs free energy for mixing polymer with solvents. According to the Flory–Huggins theory, to calculate the Flory–Huggins interaction parameter, it must

• polymeric systems enhances the disorder degree within the polymeric chains since it mediates also nonfavorable interactions within the polymeric chains, working as plasticizers (affecting also the glass transition temperature value). When the evaporation phenomenon takes place at the film surface

Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

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

• suppressed lattice disorder of this HP results in a low density of traps and sub-bandgap states reflecting in a relatively small Eg–Voc loss of 0.45 eV [70]. The bandgap of alloyed FASnxPb1−xI3 HPs was found to vary in an unexpected way, that is, decreasing upon the introduction of Sn from ≈1.5 eV for MAPI

• characteristic Urbach energy of ≈60 meV, indicating a substantial level of structural and energetic disorder. Due to the disorder, planar inverted solar cells based on amorphous MA3Sb2I9 showed low photocurrent densities, however, with a relatively high open-circuit voltage (≈890 meV) and a decent fill factor

Influence of the thickness of an antiferromagnetic IrMn layer on the static and dynamic magnetization of weakly coupled CoFeB/IrMn/CoFeB trilayers

• Deepika Jhajhria,
• Dinesh K. Pandya and
• Sujeet Chaudhary

Beilstein J. Nanotechnol. 2018, 9, 2198–2208, doi:10.3762/bjnano.9.206

• in the magnitude and direction of both magnetization and magnetic anisotropy. It could be associated with the magnetic disorder created due to the large interfacial roughness of IrMn at higher tIrMn, which is also supported well by the XRR fitting results. On the other hand, the extrinsic

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

• -based quantum computing devices [6][7][8][9]. Progress in fabrication techniques has allowed to induce a hard superconducting gap in InAs [10] or InSb [11] nanowires with epitaxially deposited Al layer. Moreover, last-generation devices exhibit a very low degree of disorder, which allows them to almost

• and the unavoidable presence of disorder [38]. If this is the case, it is then characterized by a finite effective dielectric permittivity which depends on the SC shell width as well as its composition, as we show in Section 1 of Supporting Information File 1. Some experiments [39] have reported that

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

• -bandgap region [53][54][55][56] including band tails that yield the Urbach energy as a measure of disorder as well as the detection of (optically active) defects in the band gap which can act as recombination centers in a solar cell. The Sb-TU process shows a slight increase in uncovered substrate area

Defect formation in multiwalled carbon nanotubes under low-energy He and Ne ion irradiation

• Santhana Eswara,
• Jean-Nicolas Audinot,
• Brahime El Adib,
• Maël Guennou,
• Tom Wirtz and
• Patrick Philipp

Beilstein J. Nanotechnol. 2018, 9, 1951–1963, doi:10.3762/bjnano.9.186

• show that ion irradiation with incidence angles closer to the surface normal favours the formation of double and multiple vacancies and in-plane disorder while more grazing incidence leads mainly to single vacancies and substitution, the latter being limited to chemical species reacting with carbon [9

• in the sample. Depending on the sample a fourth peak due to intercalated graphite compounds and increasing disorder produced by functionalization and strain can appear in the region of 1617–1625 cm−1 [1]. Further information on defects can be obtained by the intensity of optical absorbance which is

• quite a large amount of disorder is present in our initial samples. For He+ irradiation at 1017 ions/cm2 two different spectra have been obtained. The spectra with D and G band has been obtained on suspended nanotubes while the spectra with only a broad G band has been recorded on a part of the sample

Synthesis of carbon nanowalls from a single-source metal-organic precursor

• André Giese,
• Sebastian Schipporeit,
• Volker Buck and
• Nicolas Wöhrl

Beilstein J. Nanotechnol. 2018, 9, 1895–1905, doi:10.3762/bjnano.9.181

• to measure the structure of the carbon bonds in the materials. In this work the method is used to determine the sp2/sp3 ratio, the disorder of the carbon structures [29][30] and to get spectroscopic fingerprints for the different structures described before. The Raman spectra in this paper are

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

• -graphene layers [18]. With this morphology it represents a typological carbon adsorbent with extended structural disorder. Graphene oxide (GO) has a 2D layered structure as shown schematically in Figure 1b. The starting material for the synthesis of GO is graphite, the oxidation of which introduces oxygen

• proportional to the presence of defects or disorder in the material and is strongly dependent on the laser excitation energy [32]. The 2D band for sp2-hybridized carbon materials is found between 2500 and 2800 cm−1 and is a double-resonance two-phonon process [33]. The 2D band intensity is found to be

• indicating maximum disorder in the structure. The N2 adsorption isotherms at 77 K of the six adsorbents are plotted in Figure 4a. The predominantly microporous nature of Norit R1 Extra is evident from the Langmuir-type adsorption isotherm (type I). The observed steep adsorption at low relative pressures is

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

• Pasquale Marra,
• Alessandro Braggio and
• Roberta Citro

Beilstein J. Nanotechnol. 2018, 9, 1705–1714, doi:10.3762/bjnano.9.162

• topological invariant. These signatures are topologically robust against small perturbations, such as disorder. This means that these discontinuities and the associated zero-energy modes cannot be removed by the presence of, e.g., disorder or interactions, if these perturbations are small compared to the

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

• reported below also apply to those settings. Available materials are often of sufficiently high quality to meet the conditions for ballistic transport, and we will therefore neglect disorder effects. In view of the large amount of published theoretical works on the Josephson effect in such systems, let us

Interaction-tailored organization of large-area colloidal assemblies

• Silvia Rizzato,
• Elisabetta Primiceri,
• Anna Grazia Monteduro,
• Adriano Colombelli,
• Angelo Leo,
• Maria Grazia Manera,
• Roberto Rella and
• Giuseppe Maruccio

Beilstein J. Nanotechnol. 2018, 9, 1582–1593, doi:10.3762/bjnano.9.150

• lateral capillary forces tend to induce aggregation and disorder. Nevertheless, we were able to control the surface coverage by tuning the absorption time in order to achieve a long range order. Notably, we showed how this method can be easily transferred for use with different materials to produce large

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

• topological character of these modes endows them with robustness against perturbations that do not close the superconductor gap, e.g., weak interactions, wire bending, a certain amount of disorder, etc. The most straightforward experimental signature of a Majorana mode is a zero-bias conductance peak that is

• satisfying this condition is manifest in regimes characterized by small topological gaps, as δE and ΔE become comparable in the gapless superconductor limit. Effects of disorder Another element that can compromise the topological protection of the Majorana subspace is the presence of disorder. Generically

• , disorder induces low-energy sub-gap states, thus reducing ΔE[46][47][48][49][50]. The effect of potential disorder on a topological phase realized in a triangular wire is illustrated in Figure 12. Panel (A) shows the position dependence (along the wire) of a typical disorder potential Vdis(x) considered in

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

• with Majorana bound states (MBSs). The conductance and the noise Fano factor are calculated based on a tight-binding model by adopting a non-equilibrium Green’s function method. It is found that the disorder can effectively lead to a reduction in the conductance peak spacings and significantly suppress

• 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

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

• exhibits a clear sawtooth profile at a phase difference of π when the energy splitting is negligible, signalling a strong dependence of current–phase curves on the length of the superconducting regions. Effects of temperature, scalar disorder and reduction of normal transmission on supercurrents are also

• , therefore signalling the presence of weakly overlapping MBSs. We find that while this sawtooth profile is robust against variations in the normal transmission and scalar disorder, it smooths out when temperature effects are included, making it a fragile, yet useful, signature of MBSs. We identify that in

• of the maximum supercurrent. In particular, well-localized MBSs are revealed in the sawtooth profile of I() at = π. In what follows we analyze the effect of temperature, variation of normal transmission and random disorder on the sawtooth profile at = π of the supercurrent. Temperature effects In

Induced smectic phase in binary mixtures of twist-bend nematogens

• Anamarija Knežević,
• Irena Dokli,
• Marin Sapunar,
• Suzana Šegota,
• Ute Baumeister and
• Andreja Lesac

Beilstein J. Nanotechnol. 2018, 9, 1297–1307, doi:10.3762/bjnano.9.122

• intercalated smectic phase was unravelled by combined spectroscopic and computational methods and can be traced to conformational disorder of the terminal chains. These results show the importance of understanding the phase behaviour of binary mixtures, not only in targeting a wide temperature range but also

• considered to be mostly trans-planar [44]. The increase in hydrocarbon chain conformational disorder has also been intensively studied by FTIR on phospholipid bilayers and is used for monitoring of lipid hydrocarbon chain melting phase transitions [39][45][46][47]. The temperature dependent IR spectra of

• accordance with the increase of the motional rate of the molecule [37][39][41]. Considering the chemical structure of both pure compounds, it is reasonable to assume that shifting of CH2 vibrations rises from conformational disorder of terminal chains present only in the structure of BB. In order to

Electrodeposition of reduced graphene oxide with chitosan based on the coordination deposition method

• Mingyang Liu,
• Yanjun Chen,
• Chaoran Qin,
• Zheng Zhang,
• Shuai Ma,
• Xiuru Cai,
• Xueqian Li and
• Yifeng Wang

Beilstein J. Nanotechnol. 2018, 9, 1200–1210, doi:10.3762/bjnano.9.111

• intensity ratio of the D to G-band can be employed to evaluate the structure disorder of carbon materials [30][31]. Thus, the Raman spectroscopy analysis of HACC-rGO suggests that there exist some structural defects in HACC-rGO. Particularly, the resulting HACC-rGO disperses well in aqueous solutions, and

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

• disorder at the interface. Thus, the ensemble average of the tunneling amplitudes has the form: where is the length of the order of the atomic scale. The tunneling is also assumed to be independent of energy and spin and occurs locally in time and in space, i.e., from a point r on the superconducting

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

• = 4.0 T, for a nanowire of length L = 1000 nm. The disorder strength is set to W = 4.8 and the density of impurities is varied: ni = 3.0 nm−1, 6.0 nm−1 and 12 nm−1. For comparison, we consider two types of impurities: scalar impurities described by Equation 3 (red traces), and magnetic impurities

Theoretical study of strain-dependent optical absorption in a doped self-assembled InAs/InGaAs/GaAs/AlGaAs quantum dot

• Tarek A. Ameen,
• Hesameddin Ilatikhameneh,
• Archana Tankasala,
• Yuling Hsueh,
• James Charles,
• Jim Fonseca,
• Michael Povolotskyi,
• Jun Oh Kim,
• Sanjay Krishna,
• Monica S. Allen,
• Jeffery W. Allen,
• Rajib Rahman and
• Gerhard Klimeck

Beilstein J. Nanotechnol. 2018, 9, 1075–1084, doi:10.3762/bjnano.9.99

• electrons and holes. It is worth noting that the hole ground state has an s-orbital-like shape. QDs have a complicated band profile since multiple effects such as geometric confinement, strain and alloy disorder, can cause major changes in the band edges of the bulk material. It is important to know where

• to longer absorption wavelengths. In conclusion, the method presented here provides a way to incorporate the inhomogeneous environment of QDs in simulations by taking into account device geometry and quantum confinement, alloy disorder, electrostatics, many-particle interactions, and spatially