Zigzag phosphorene nanoribbons: one-dimensional resonant channels in two-dimensional atomic crystals

• Carlos. J. Páez,
• Dario. A. Bahamon,
• Ana L. C. Pereira and
• Peter. A. Schulz

Beilstein J. Nanotechnol. 2016, 7, 1983–1990, doi:10.3762/bjnano.7.189

• present work, edge-confined states are supported only by zigzag edges and are absent in armchair or bearded edges [11][12]. Therefore, introducing perturbations to a zigzag edge, such as edge vacancies, would locally destroy these 1D states. The consequences of these perturbations are very relevant in the

• transmission probability as a function of the energy as well as the LDOS associated to selected resonances in the presence of vacancies. Defects are normally seen as mechanisms that hinder the observation of transport properties associated to shape modulation of nanoscopic low-dimensional systems. Indeed, the

• resonance spectra are also dramatically modified in the present case. However, the issue can be seen from an entirely different point of view. The vacancies change locally the character of the edge. Thus, they actually introduce small barriers and further divide the system into smaller segments. The system

Nanostructured TiO₂-based gas sensors with enhanced sensitivity to reducing gases

• Wojciech Maziarz,
• Anna Kusior and
• Anita Trenczek-Zajac

Beilstein J. Nanotechnol. 2016, 7, 1718–1726, doi:10.3762/bjnano.7.164

• ], there are several possible explanations for this phenomenon. The first is related to formation of titanium vacancies, VTi, in the flower-like structure during synthesis. Upon Ti foil oxidation by H2O2, a mesoporous hierarchical structure is formed. The three-step process includes, inter alia

Scanning probe microscopy studies on the adsorption of selected molecular dyes on titania

• Jakub S. Prauzner-Bechcicki,
• Lukasz Zajac,
• Piotr Olszowski,
• Res Jöhr,
• Antoine Hinaut,
• Thilo Glatzel,
• Bartosz Such,
• Ernst Meyer and
• Marek Szymonski

Beilstein J. Nanotechnol. 2016, 7, 1642–1653, doi:10.3762/bjnano.7.156

• either by the formation of oxygen vacancies [36], which are point defects commonly found in TiO2(110) surfaces, or by doping [37], and are redistributed among multiple Ti lattice sites in the subsurface layers [36][37][38][39][40][41]. Thus, a defect state in the band gap is formed. Such delocalized

• to the oxide takes place, and an interface dipole is formed. To further understand the energy level alignment between a semiconducting substrate and an organic adsorbate, Lackinger, Janson and Ho [59] studied interactions between zinc(II) etioporphyrin (ZnEP) and oxygen vacancies, which are point

• defects commonly found in TiO2(110) surfaces. The energy level alignment is of crucial importance for DSSC applications of titania. The authors took special care to prepare a sample with unsaturated oxygen vacancies [59] because it is known that they can be easily passivated even at very low partial

Influence of hydrothermal synthesis parameters on the properties of hydroxyapatite nanoparticles

• Sylwia Kuśnieruk,
• Jacek Wojnarowicz,
• Agnieszka Chodara,
• Tadeusz Chudoba,
• Stanislaw Gierlotka and
• Witold Lojkowski

Beilstein J. Nanotechnol. 2016, 7, 1586–1601, doi:10.3762/bjnano.7.153

• of crystalline structure defects, caused by calcium ion vacancies, increases, diminishing material stability, and as a result, enhancing its solubility [20][21]. A range of various methods have been developed in order to produce HAp powder, among others, combustion preparation [22], and numerous wet

Three-gradient regular solution model for simple liquids wetting complex surface topologies

• Sabine Akerboom,
• Marleen Kamperman and
• Frans A. M. Leermakers

Beilstein J. Nanotechnol. 2016, 7, 1377–1396, doi:10.3762/bjnano.7.129

• approximation) we can evaluate the mixing interaction energy in the system by Umix = NχφV, where we ignored boundary effects and φV = NV/M is the volume fraction of vacancies. The entropy of mixing can be evaluated when we assume once more that the sites are randomly filled by solvent. The total number of ways

• to arrange the fluid and the vacancies is given by and the mixing entropy is found by Smix = −kB·lnΩ = −kB(N·ln φ + NV·ln φV) with φ = N/M and kB the Boltzmann constant. The free energy of mixing is given by Fmix = Umix – T·Smix. Introducing the dimensionless free energy density f = Fmix/(Mb3kBT

• obey scaling relations with respect to the difference to the critical point Δχ = χ − 2. Interestingly, near the critical point there is an analytical route to optimise the free energy F [40]. In short, near the critical point the density of the liquid (and thus also for the vacancies) is never far from

Influence of synthesis conditions on microstructure and phase transformations of annealed Sr₂FeMoO_6−x nanopowders formed by the citrate–gel method

• Marta Yarmolich,
• Nikolai Kalanda,
• Sergey Demyanov,
• Herman Terryn,
• Jon Ustarroz,
• Maksim Silibin and
• Gennadii Gorokh

Beilstein J. Nanotechnol. 2016, 7, 1202–1207, doi:10.3762/bjnano.7.111

• atmosphere with predetermined anionic and cationic defectiveness, is problematic [9]. This is due to several factors: the phase purity within the sample, cation and anion vacancies, sample microstructure, chemical composition and thickness of the grain boundaries [10][11][12][13]. Sol–gel technology is a

Reasons and remedies for the agglomeration of multilayered graphene and carbon nanotubes in polymers

• Rasheed Atif and
• Fawad Inam

Beilstein J. Nanotechnol. 2016, 7, 1174–1196, doi:10.3762/bjnano.7.109

• into vacancies thereby self-repairing holes in the graphene sheet. Faber and Evans, using crack deflection modeling, showed that, among all other nano-reinforcements, maximum enhancement in fracture toughness can be attained by employing graphene as reinforcement. This improvement in fracture toughness

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• surface-located intrinsic and extrinsic defects arising from Hf3+ and O2− vacancies. The small diameter of the nanoparticles in the present study, 2.6 nm on average, implies a very high surface-to-volume ratio, and consequently, enhanced surface-defect-related luminescence. Furthermore, for the cubic

• -phase HfO2 nanoparticles, oxygen vacancies acting as luminescence trap states are present in large amounts [22]. In the variety of different techniques used to decorate CNTs, the first step is usually the dispersion of the CNTs in a liquid solution as they exist in the form of bundled ropes [23]. Acid

• nanoparticles in the process of CNT decoration. In fact, acid treatment creates defects (vacancies and holes in the side walls) on the CNT surfaces along with carboxyl groups in the case of carboxylic acid treatment [24]. The bond with these carboxyl groups is then created via hydroxyl groups present on the

NO gas sensing at room temperature using single titanium oxide nanodot sensors created by atomic force microscopy nanolithography

• Li-Yang Hong and
• Heh-Nan Lin

Beilstein J. Nanotechnol. 2016, 7, 1044–1051, doi:10.3762/bjnano.7.97

• Figure S1 in Supporting Information File 1.) We discussed the electrical properties of the sensors in our previous report [32]. A TiOx ND behaves like an n-type semiconductor due to oxygen vacancies. When NO molecules (or O2 molecules under ambient environment) adsorb on the ND surface, they become

Microscopic characterization of Fe nanoparticles formed on SrTiO₃(001) and SrTiO₃(110) surfaces

• Miyoko Tanaka

Beilstein J. Nanotechnol. 2016, 7, 817–824, doi:10.3762/bjnano.7.73

• surface is sputter-cleaned, it becomes severely disordered, forming oxygen vacancies in the uppermost layers [28]. Subsequent annealing induces oxygen diffusion and surface recrystallization at the same time, making various superstructures possible to appear. In our experiments, TEM STO(001) substrates

• , especially the presence of oxygen vacancies formed during UHV annealing. Our previous studies found that surfaces of both STO(001) and STO(110) have oxygen-depleted (1 × 1) structures [25]. Surface energies for these may differ from those of fully oxidized ones and may alter above values. Still, the present

Microwave solvothermal synthesis and characterization of manganese-doped ZnO nanoparticles

• Jacek Wojnarowicz,
• Roman Mukhovskyi,
• Elzbieta Pietrzykowska,
• Sylwia Kusnieruk,
• Jan Mizeracki and
• Witold Lojkowski

Beilstein J. Nanotechnol. 2016, 7, 721–732, doi:10.3762/bjnano.7.64

• ., formation of clusters [31]), the precipitation of foreign phases [33][34], the stoichiometry; the presence of oxygen vacancies [35][36], and defects of the crystalline lattice. When the synthesis or calcination of Zn1−xMnxO was carried out in an oxidising environment and the absence of foreign phases was

• ]. But when a reducing environment was selected for sample calcination, also precipitations of ZnMnO3 and ZnMn2O4 phase emerged in Zn1−xMnxO and the material displayed only ferromagnetic properties [36]. Ferromagnetic properties of Zn1−xMnxO are explained by the presence of oxygen vacancies, manganese in

• properties in the case of Zn1−xMnxO is the lack of control over the doping impact on the formation of oxygen vacancies, crystalline lattice defects and dopant clusters [48]. It is presumed that there are several competitive chemical reactions in the reaction of Zn1−xMnxO synthesis, such as the oxidisation of

Orientation of FePt nanoparticles on top of a-SiO₂/Si(001), MgO(001) and sapphire(0001): effect of thermal treatments and influence of substrate and particle size

• Martin Schilling,
• Paul Ziemann,
• Zaoli Zhang,
• Johannes Biskupek,
• Ute Kaiser and
• Ulf Wiedwald

Beilstein J. Nanotechnol. 2016, 7, 591–604, doi:10.3762/bjnano.7.52

• leading to an atomically smooth surface for nanoparticle and film deposition. Since charging of the MgO substrate turned out to deteriorate the RHEED pattern, we further annealed the bare substrate under hydrogen atmosphere at 5·10−6 mbar to create oxygen vacancies, leading to a sufficient surface

Bacteriorhodopsin–ZnO hybrid as a potential sensing element for low-temperature detection of ethanol vapour

• Saurav Kumar,
• Sudeshna Bagchi,
• Senthil Prasad,
• Anupma Sharma,
• Ritesh Kumar,
• Rishemjit Kaur,
• Jagvir Singh and
• Amol P. Bhondekar

Beilstein J. Nanotechnol. 2016, 7, 501–510, doi:10.3762/bjnano.7.44

• crystallization and less oxygen vacancies [53]. As observed from Figure 4, the PL intensity increases with increasing excitation wavelength (i.e., 280 nm and 320 nm), which may be attributed to electron–hole plasma recombination shift by band renormalization [54]. Figure 5 shows the Raman spectra for all the

Plasticity-mediated collapse and recrystallization in hollow copper nanowires: a molecular dynamics simulation

• Amlan Dutta,
• Arup Kumar Raychaudhuri and
• Tanusri Saha-Dasgupta

Beilstein J. Nanotechnol. 2016, 7, 228–235, doi:10.3762/bjnano.7.21

• scales associated with different stages of the evolution process. Our findings suggest a plasticity-mediated mechanism of collapse and recrystallization. This contradicts the prevailing notion of diffusion driven transport of vacancies from the interior to outer surface being responsible for collapse

• with hollow core is thermodynamically unstable due to the internal free surface, and shows the tendency to collapse. The kinetics of the collapse has been assumed to proceed through the slow diffusive route, where the migration of vacancies from the hollow core to the outer surface is considered to be

• the dominating mechanism. Accordingly, analytical theories and Monte Carlo simulations based on the process of thermally activated diffusion process have been developed and carried out [12]. However, the proposed mechanism of collapse via migration of vacancies from the inner core to the outer surface

Fabrication of hybrid graphene oxide/polyelectrolyte capsules by means of layer-by-layer assembly on erythrocyte cell templates

• Joseba Irigoyen,
• Nikolaos Politakos,
• Eleftheria Diamanti,
• Elena Rojas,
• Marco Marradi,
• Raquel Ledezma,
• Layza Arizmendi,
• J. Alberto Rodríguez,
• Ronald F. Ziolo and
• Sergio E. Moya

Beilstein J. Nanotechnol. 2015, 6, 2310–2318, doi:10.3762/bjnano.6.237

• ratio of 0.8. The D resonance corresponds to the vibration of sp2 carbon while G corresponds to sp3 carbon and defects associated with vacancies and grain boundaries [28]. The peaks at higher wavenumbers are also characteristic of graphene oxide. XRD results (Figure 1d) indicate the absence of graphite

Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability

• Claudia Struzzi,
• Mattia Scardamaglia,
• Axel Hemberg,
• Luca Petaccia,
• Jean-François Colomer,
• Rony Snyders and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2015, 6, 2263–2271, doi:10.3762/bjnano.6.232

• on the surface attracts water adsorption, in contrast to the case of pure fluorinated carbon systems that show strong hydrophobicity [20]. In addition to the presence of oxygen atoms grafted during plasma treatment, we must consider that defects such as vacancies created during the process are

• associated to the A1g-mode breathing vibrations of six-membered sp2 carbon rings. It becomes Raman active after neighboring sp2 carbons are converted to sp3 hybridization in graphitic materials. This can be due to the presence of in-plane substitutional heteroatom vacancies, grain boundaries, or other

A single-source precursor route to anisotropic halogen-doped zinc oxide particles as a promising candidate for new transparent conducting oxide materials

• Daniela Lehr,
• Markus R. Wagner,
• Johanna Flock,
• Julian S. Reparaz,
• Clivia M. Sotomayor Torres,
• Alexander Klaiber,
• Thomas Dekorsy and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2015, 6, 2161–2172, doi:10.3762/bjnano.6.222

• recorded at room temperature (Figure 4c). Furthermore, Cl doping strongly affects the so-called green luminescence, which is associated with electrons trapped at oxygen vacancies (VO•• in Kröger–Vink notation) present in many different types of ZnO materials [63]. It can be seen that the intensity of the

High I_on/I_off current ratio graphene field effect transistor: the role of line defect

• Mohammad Hadi Tajarrod and
• Hassan Rasooli Saghai

Beilstein J. Nanotechnol. 2015, 6, 2062–2068, doi:10.3762/bjnano.6.210

• transistor devices [5][6]. The electronic properties of graphene are the result of its particular structure. In order to modify the transport behavior, the physical structure of graphene needs to be changed. Consequently, topological defects such as vacancies, impurities, adatoms and Stone–Wales defects are

Nitrogen-doped graphene films from chemical vapor deposition of pyridine: influence of process parameters on the electrical and optical properties

• Andrea Capasso,
• Theodoros Dikonimos,
• Francesca Sarto,
• Alessio Tamburrano,
• Giovanni De Bellis,
• Maria Sabrina Sarto,
• Giuliana Faggio,
• Angela Malara,
• Giacomo Messina and
• Nicola Lisi

Beilstein J. Nanotechnol. 2015, 6, 2028–2038, doi:10.3762/bjnano.6.206

• [17]. Besides, the electron mobility itself can be greatly affected by the presence of substitutional atoms (which are a kind of lattice defects, such as vacancies, and grain boundaries) [18]. Graphene can be doped through surface proximity by layering it with other materials (such as metals [19

Distribution of Pd clusters on ultrathin, epitaxial TiO_x films on Pt₃Ti(111)

• Christian Breinlich,
• Maria Buchholz,
• Marco Moors,
• Tobias Pertram,
• Conrad Becker and
• Klaus Wandelt

Beilstein J. Nanotechnol. 2015, 6, 2007–2014, doi:10.3762/bjnano.6.204

• (i.e., oxygen vacancies) in this structure are confined to these trenches and act as nucleation sites. Therefore, the Pd clusters are mostly arranged in unidirectional rows along the trenches, creating a template effect. The second phase, w'-TiOx, exhibits a hexagonal, long range, (7 × 7)R21.8°, Moiré

• ) standard surface science techniques can be applied due to the high conductivity of these films compared to the respective bulk oxides, (b) the films can be prepared with a very high degree of structural preciseness, and (c) the influence of bulk effects such as subsurface oxygen vacancies is excluded. In

Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials

• Xiaoxing Ke,
• Carla Bittencourt and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2015, 6, 1541–1557, doi:10.3762/bjnano.6.158

• subsequent reconstruction of large even-number vacancies takes place, as discussed in detail in [43]. One example is shown in Figure 4a,b. When carbon atoms in CNTs are displaced by electron irradiation, single vacancies (SV), divacancies (DV), and even tetravacancies can be created; a schematic illustration

• is presented in Figure 4a,b. Displaced carbon atoms may form adatoms (A) on the lattice. Atomistic computer simulations predict that the reconstruction of the atomic network near vacancies and adatoms is very likely to happen, resulting in an agglomeration of 5- to 8-membered rings [44][45]. As shown

• thus provide a HRTEM image with an acceptable signal to noise ratio with only limited damage to the sample. The introduction of a high-speed detector may also have an impact on increasing the time resolution. In a molecular dynamics simulations on the reconstruction of vacancies, the time scale is

Transformations of PTCDA structures on rutile TiO₂ induced by thermal annealing and intermolecular forces

• Szymon Godlewski,
• Jakub S. Prauzner-Bechcicki,
• Thilo Glatzel,
• Ernst Meyer and
• Marek Szymoński

Beilstein J. Nanotechnol. 2015, 6, 1498–1507, doi:10.3762/bjnano.6.155

• located in between. The overall STM appearance is much different from the surface topography. Additional bright spots recorded within dark oxygen rows are attributed to oxygen vacancies (fainter spots) or single and double surface hydroxy groups (brighter spots). The oxygen vacancies are created during

• the preparation procedure, leading to a slight reduction of the sample and decreasing the intrinsic band gap from approximately 3.0 eV to 1.5–2.5 eV. Hydroxy groups are created as a result of atomic hydrogen adsorption and dissociative adsorption of water at oxygen vacancies. The surface is very

• sensitive to the presence of water among residual gases and therefore the maintenance of the high vacuum level during sample preparation plays a crucial role. The adopted experimental procedure enables us to obtain clean surfaces with several oxygen vacancies and some hydroxy groups after final annealing

Enhanced fullerene–Au(111) coupling in (2√3 × 2√3)R30° superstructures with intermolecular interactions

• Michael Paßens,
• Rainer Waser and
• Silvia Karthäuser

Beilstein J. Nanotechnol. 2015, 6, 1421–1431, doi:10.3762/bjnano.6.147

• ” C60 [8][16], are observed in different structural domains. In a systematic study Gardener et al. [16] proposed, that the reason for the dim C60 are nanopits, also called vacancies, which are formed at the C60–Au interface. Dim C60 molecules adsorbed at vacancies are lower in height than the bright C60

• reconstruction [16] or the forming of a new surface arrangement at the C60–Au interface depending on the thermal treatment [24][25]. The number and the distribution of dim C60 molecules adsorbed on vacancies differ in the respective superstructures on Au(111). While very few dim C60 molecules are randomly

• is commonly called “disordered”. Interestingly, this (2√3 × 2√3)R30° superstructure shows a dynamic bright–dim flipping near room temperature, which points to highly mobile vacancies at the C60–Au(111) interface [16][26]. Recently, also a uniform (2√3 × 2√3)R30° structure with all C60 molecules

The Kirkendall effect and nanoscience: hollow nanospheres and nanotubes

• Abdel-Aziz El Mel,
• Ryusuke Nakamura and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2015, 6, 1348–1361, doi:10.3762/bjnano.6.139

• , the position of the initial interface changes during the annealing process since the atomic diffusion coefficients of atom A in metal B and of atom B in metal A are different. As a consequence of the unbalanced diffusion rates between the two stacked metals, vacancies will be injected at the interface

• region will be more extended within metal B and vacancies will be injected at the interface region within metal A (Figure 2b). The coalescence of excess of vacancies leads to the formation of small voids distributed all along the interface. As the annealing process progresses in time, vacancies will be

• , vacancies are created and injected at the Co(core)/CoSe(shell) interface. The migration and agglomeration of vacancies result in the formation and merging of the initial voids located at the interface and extended along the Co core (Figure 4a). The increase in size of these voids was found to lead to the

High photocatalytic activity of V-doped SrTiO₃ porous nanofibers produced from a combined electrospinning and thermal diffusion process

• Panpan Jing,
• Wei Lan,
• Qing Su and
• Erqing Xie

Beilstein J. Nanotechnol. 2015, 6, 1281–1286, doi:10.3762/bjnano.6.132

• above room temperature in air, generally, the oxygen vacancy is one of the most important defects that can be easily introduced [31]. The crystal cell is then distorted and the cell volume or lattice constant is reduced. However, if a few Ti4+ ions are substituted by V5+ ions, some oxygen vacancies will