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

• characterization showed a distribution of surface defects, which were ascribed to the burst of hydrogen blisters formed as a consequence of the irradiation process. The results presented in this work contribute to the current trend in nanotechnology in areas devoted to the control of properties by defect

• clear explanation of the dependence of the D-band components on the irradiation parameters together with the type of defect is still a challenge. Hydrogen-irradiated carbon allotropes have received special attention as promising materials to develop hydrogen storage devices [16][17][18][19][20][21], as

• 2D-band relative to G-band intensity, in addition to a band located around 2950 cm−1, assigned to a combination mode (D + D′) [18]. It was also found that multilayer graphene with the same top-layer defect density as single-layer graphene exhibits a lower ID/IG ratio because intact sub-layers with π

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

• is beneficial and can enhance the electro-optical properties of the absorber layer [41][42][43][44][45]. On the other side, Cr incorporation in CIGS absorber layer reduces the cell performance due to creation of deep defect levels in the CIGS layer [46]. In order to investigate the diffusion

Silencing the second harmonic generation from plasmonic nanodimers: A comprehensive discussion

• Jérémy Butet,
• Gabriel D. Bernasconi and
• Olivier J. F. Martin

Beilstein J. Nanotechnol. 2018, 9, 2674–2683, doi:10.3762/bjnano.9.250

• from a practical point of view, since the second harmonic light is often collected in these two directions. Note that the case of a single defect located in the gap has been considered in a previous publication, showing the same behavior [36]. Gold dimers made of rectangular arms In this last section

Nanoantenna structures for the detection of phonons in nanocrystals

• Alexander G. Milekhin,
• Sergei A. Kuznetsov,
• Ilya A. Milekhin,
• Larisa L. Sveshnikova,
• Tatyana A. Duda,
• Ekaterina E. Rodyakina,
• Alexander V. Latyshev,
• Volodymyr M. Dzhagan and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2018, 9, 2646–2656, doi:10.3762/bjnano.9.246

• current’s symmetry. The simplest way to the symmetry breakdown is to deform the nanoantenna shape. Such a defect-induced activation of the 2nd-order LSPR mode was observed for non-ideal nanoantennas at normal incidence [37]. The second way to the symmetry breakdown condition is off-normal illumination [38

Exploring the photoleakage current and photoinduced negative bias instability in amorphous InGaZnO thin-film transistors with various active layer thicknesses

• Dapeng Wang and
• Mamoru Furuta

Beilstein J. Nanotechnol. 2018, 9, 2573–2580, doi:10.3762/bjnano.9.239

• are exactly identical, except the deposition duration, the results suggest that the variation in the SS value mainly originates from the density of defect states in the active layer. Correspondingly, the obtained results indicate that the increase in the Nt majorly stems from the increase of the IGZO

• channel layer is totally depleted under the negative VGS bias since the TIGZO is less than the Debye length. Therefore, the photoexcited electrons and holes will be respectively accumulated and trapped at the IGZO/etch-stopper and the GI/IGZO interfaces. Meanwhile, the defect states are generated, which

• originate from the photoexcited VO+/VO2+. In the forward measurement, the transfer curves exhibit a positive shift in the VGS direction with a hump at the turn-on voltage region when the NBIS duration exceeds 1000 s, which is attributed to the synergistic effects of the generated defect states and the

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

• improvements in nanotube adsorption rates compared to similar diameter nanorods and nanoneedles are associated with both the increase in surface area (via the formation of a cavity) and the adsorption bonds due to surface defect sites. A large number of defects can be explained by the fact that, unlike

• ZnO nanoplates, the measured CV curve shows even better results in the reduction component than in the case of nanotubes, thereby proving the effectiveness of porous structures: adsorption bonds, which are located on surface defect sites or on metastable polar planes, have a better ability to form

• higher sensitivity than nanorods and nanoneedles. This confirms that adsorption bonds associated with defect states contribute more to the process than the adsorption bonds, which are located on the nonpolar, side surfaces. This fact was also confirmed by an additional experiment on ZnO nanoplates. The

Pinning of a ferroelectric Bloch wall at a paraelectric layer

• Vilgelmina Stepkova and
• Jiří Hlinka

Beilstein J. Nanotechnol. 2018, 9, 2356–2360, doi:10.3762/bjnano.9.220

• placed 1–7 nm away from the defect layer always spontaneously moved back to it. These simulations suggest that an approximately 1 nm thin SrTiO3 layer incorporated in ferroelectric BaTiO3 crystal is capable of considerably influencing the structure and properties of the 180-degree Bloch domain walls

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

• [7][8] and dopant-associated defect states [8][9]. Modulation doping – i.e., doping of materials adjacent to semiconductors which then provide free carriers to the unperturbed semiconductor – was first used for group III–V semiconductor combinations such as GaAs/AlAs in the late 1970s [10]. Recently

Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

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

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

• 10 ppm H2S compared with pure ZnO NFs with a response of 1.57 at 230 °C and response and recovery times of 18 s and 20 s, respectively [196]. Doping with multivalent ions (In3+, Al3+, Sn4+, etc.) may change the defect density and carrier concentration of a ZnO matrix [201][202][203][204]. A common

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

• the absorption strength of the substrate becomes comparable to that of the Sb2S3 film which is evident from the characteristic H2O absorption peak of Corning glass below 1 eV. While the layer crystallized at 265 °C and 300 °C behave almost identical, the defect absorption of the layer crystallized at

• °C sample does not coincide with the other samples that match very well for energies above the band gap. The increased defect absorption for the crystallization at 350 °C or higher hints towards a lower cell performance because a higher defect density would cause increased recombination and

• drastically which is consistent with the increased defect absorption observed with PDS (Figure 3c). When the film morphology degenerates at 400 °C the cell performance decays further. Next, a similar study was conducted for the Sb-BDC process with a focus on crystallization at 265 °C and 300 °C. The SEM image

Metal-free catalysis based on nitrogen-doped carbon nanomaterials: a photoelectron spectroscopy point of view

• Mattia Scardamaglia and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2018, 9, 2015–2031, doi:10.3762/bjnano.9.191

• molecular dynamics combined with analytical potential and density functional theory methods, Lehtinen et al. reported on the influence of the ion kinetic energy and mass on the probability of defect formation during irradiation of suspended graphene sheets and single-walled CNTs [86]. Being proportional to

• higher kinetic energies, the cross section for vacancy creation decreases and more complex defect configurations are created, such as di-vacancies and distortions (Figure 5) [83][86][87]. The effect of different ion kinetic energies on supported graphene has been highlighted in the case of CF4 plasma

• vacancies, a higher substitution-to-defect ratio can be reached [87]. Other advantages of the post-synthesis functionalization methods include the possibility to perform the doping after the integration of the nanostructures in a device and the possibility to create different nanopatterns using appropriate

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

• annealing, dehalogenation as well as cyclodehydrogenation can be achieved, which leads to clean, defect-free GNRs. Therefore, ideal contacts, free of contaminants, can be grown on the gold surface. The GNRs are observed to move preferentially in the [−101] direction, where the moiré pattern forming with Au

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

• ]. For He+ irradiation of graphene, Stone–Thrower–Wales defects form preferentially [10]. For graphene, 1000 eV proved also to be the optimum energy for defect and nanopore formation at an incidence angle of 60° with respect to the surface normal and of 400–500 eV for angles closer to the surface normal

• defect production in SWCNTs [26], the characterisation of composite materials containing MWCNTs [27], the implantation of Si and C ions into DWCNTs [28], and to differentiate between carbon materials with different sp2 environment [29]. The latter study focused on graphene, highly oriented pyrolytic

• scattering processes around the K point of the Brillouin zone and, like the D band, is sensitive to the defect density [1]. It gets significantly broadened with increasing fluence, indicating that the defect density is increasing, but significant difference between He+ and Ne+ irradiation is not observed. A

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

• between the nanorods and the straight CNWs. Chemical characterization Raman spectroscopy can give information about the hybridization and the defect density of the carbon material. All samples were measured at three different positions and the measured values were averaged for the interpretation. In

• ratio) is higher for shorter mean wall lengths. A high intensity of the D-peak can be interpreted as high defect density in the carbon material. Since shorter walls mean more edges and smaller graphitic crystals, the defect density is higher with more carbon atoms at grain boundaries. Furthermore, the

Improving the catalytic activity for hydrogen evolution of monolayered SnSe_2(1−x)S_2x by mechanical strain

• Sha Dong and
• Zhiguo Wang

Beilstein J. Nanotechnol. 2018, 9, 1820–1827, doi:10.3762/bjnano.9.173

• trace amounts of Pt nanoparticles interacting with defect-rich SnS2; the results demonstrated that SnS2 may offer new perspectives regarding a utilization in HER. The catalytic activity for HER shows great dependence on the electronic structure of the catalyst. As alloying and strain can be used to tune

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

• all sp2-hybridized carbon materials and arises from the in-plane stretching mode of the C–C bond [32]. The D-band (ca. 1350 cm−1) is a defect-activated vibrational mode where the defects act as an elastic scattering center to assist the intervalley double-resonance process. Its intensity is

• inversely proportional to the concentration of defects in the structure [34]. The D′-band (ca. 1620 cm−1) is also another defect-induced band which is assigned to the in-plane vibrations of the outer parts of the graphite domains [35][36]. It is typically observed for MWCNTs and intercalated graphite

Magnetic properties of Fe₃O₄ antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction

• Juan L. Palma,
• Alejandro Pereira,
• Raquel Álvaro,
• José Miguel García-Martín and
• Juan Escrig

Beilstein J. Nanotechnol. 2018, 9, 1728–1734, doi:10.3762/bjnano.9.164

• tendency changes. It is important to point out that the coercivities obtained by the AFIR technique are almost twice as high as those obtained with other techniques, considering similar geometrical and magnetic parameters [39]. From a magnetic viewpoint each nanohole may be considered as a defect since

• they act as pinning centers for the domain wall motion during magnetization reversal. If a is the lattice constant (nearest neighbor center-to-center distance) and d is the hole diameter, the defect volume density (DVD), which is the ratio of the surface covered by holes to the total surface, is given

• applying the external magnetic field along the first and second neighbors directions. (b) Coercivity as a function of the defect volume density (DVD). Coercivity (red squares) and normalized remanence (blue dots) as a function of the angle θ at which the external magnetic field is applied for a square

Multimodal noncontact atomic force microscopy and Kelvin probe force microscopy investigations of organolead tribromide perovskite single crystals

• Yann Almadori,
• David Moerman,
• Jaume Llacer Martinez,
• Philippe Leclère and
• Benjamin Grévin

Beilstein J. Nanotechnol. 2018, 9, 1695–1704, doi:10.3762/bjnano.9.161

• (enabling discrimination between extrinsic surface contamination and intrinsic defect formation). Here, our primary goal is to check if the surface photovoltage and crystal photostriction can be simultaneously and reliably probed by nc-AFM/KPFM. The discussion will be thus focused on the analysis of the

Evaluation of replicas manufactured in a 3D-printed nanoimprint unit

• Manuel Caño-García,
• Morten A. Geday,
• Manuel Gil-Valverde,
• Xabier Quintana and
• José M. Otón

Beilstein J. Nanotechnol. 2018, 9, 1573–1581, doi:10.3762/bjnano.9.149

• features below 10 nm, but increases significantly the defect rate from contaminating particles and air bubbles. Soft NIL employs molds of elastomeric materials such as polydimethylsiloxanes (PDMS) or polyimides at the expense of lower resolution [5]. Hybrid NIL adopts an intermediate position by utilizing

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

• context, it is also likely that for samples with >1 atom % P the P-concentration peak found at the Si/SiO2 interface (cf. Figure 2b) reaches a level where a highly enriched P-shell forms on the NC-surface that enables efficient formation of non-radiative defect states. For boron, strong PL-quenching is

• doping, i.e., the generation of free carriers from dopants on substitutional lattice sites, requires thermal ionization, typically provided by the thermal energy at room temperature. Ignoring all the evidence of a defect-related PL-quenching of Si NCs containing P- or B-atoms, we would anticipate from

• temperature. Hence, a freeze-out effect of dopant-induced free carriers that quench the PL is not observed in accordance with dopant-induced defect states deep within the fundamental gap of the NCs. Figure 4b plots the PL peak shift with reference to 300 K, i.e., where a maximum of dopant-induced free

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

• place by the sulfate redox couple attached to nitrogen-doped TiO2 [63]. Hydrogenated defect-promoted black titania exhibits much higher absorption and photocatalytic activity [94][95]. The recombination and charge transfer efficiency can be understood from PL spectra. The PL emission intensity is

Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane

• Nor Fazila Khairudin,
• Mohd Farid Fahmi Sukri,
• Mehrnoush Khavarian and
• Abdul Rahman Mohamed

Beilstein J. Nanotechnol. 2018, 9, 1162–1183, doi:10.3762/bjnano.9.108

• , Yan et al. [101] confirmed that plasma treated catalysts can improve the interaction between Ni and the SiO2 support and produces less defect sites on the Ni particles. The authors further remarked that this plasma treatment could suppress inactive carbon deposition and enhance catalyst performance

• for Ni catalysts were treated via thermal decomposition recorded with a great number of defect sites, which consist of Ni (100) and Ni (101) surfaces. These surfaces could increase carbon deposition rate. Table 3 summarizes the development and process conditions of Mg-containing oxide catalysts used

Semi-automatic spray pyrolysis deposition of thin, transparent, titania films as blocking layers for dye-sensitized and perovskite solar cells

• Hana Krýsová,
• Josef Krýsa and
• Ladislav Kavan

Beilstein J. Nanotechnol. 2018, 9, 1135–1145, doi:10.3762/bjnano.9.105

• ,FTO is the current density peak measured at a bare FTO electrode. The actual values are listed in Table 2. As suggested in a previous work [3], there are two types of defects in the barrier film: (i) “defect A” – the partially blocked electrode behaves like a “clean” FTO but with a relatively smaller

• effective area. The relative increase of voltammetric peaks separation (ΔEpp) on the BL normalized to that for pure FTO is smaller than 3. (ΔEpp is defined as the difference between the peak potentials for the Fe(CN)64− oxidation and Fe(CN)63− reduction). (ii) “defect B” – a more complex situation, where

• the defect causes not only the delamination of the titania film from FTO, but also the slowdown of charge transfer kinetics (accompanied by a strong increase in ΔEpp). The barrier properties after post calcination were fairly good for the 0.05 M TAA precursor and the largest layer thickness (200 SCs

Room-temperature single-photon emitters in titanium dioxide optical defects

• Kelvin Chung,
• Yu H. Leung,
• Chap H. To,
• Aleksandra B. Djurišić and
• Snjezana Tomljenovic-Hanic

Beilstein J. Nanotechnol. 2018, 9, 1085–1094, doi:10.3762/bjnano.9.100

• observing its photon statistics. Once a single-photon emitter was identified, the defect was characterised by obtaining its PL spectrum and recording the photodynamics of its count trace. Fluorescence was observed in all the morphologies. However, single-photon emission was only observed in two morphologies

• acquired and can be seen in Figure 4a. The PL spectrum of the defect shows red fluorescence between 600 and 700 nm. There were three resolvable peaks at 610, 619 and 630 nm. Red fluorescence has been attributed to under-coordinated Ti3+ ions in atomic layer deposited films [41], electrons trapped at

• surface defect sites [59] and surface oxygen vacancies on anatase nanocrystal films [60]. Similar photoluminescence in the red was also observed from ZnO defects [7][8][9]. The photodynamics of D1 was also recorded and can be seen for a pump power of 82 μW in Figure 4b. The time trace shows photostability