Characterization of nanostructured ZnO thin films deposited through vacuum evaporation

• Jose Alberto Alvarado,
• Arturo Maldonado,
• Héctor Juarez,
• Mauricio Pacio and
• Rene Perez

Beilstein J. Nanotechnol. 2015, 6, 971–975, doi:10.3762/bjnano.6.100

• . There are a lot of emission lines related to the characteristics of the deposited thin films, as the annealing temperature and the intrinsic defects (VZn, VO). One of the emissions is in the blue region, which is close to 2.6 and 2.5 eV, and refers to the Zn vacancies. The emission close to 1.6 eV (red

• region) corresponds to oxygen vacancies (VO). The emission intensities are similar intensity for the thin films annealed at 400 and 25 °C. They change drastically when we have the nanostructures deposited as thin film where the main emission line attributed to VZn is related to the form of the

Graphene on SiC(0001) inspected by dynamic atomic force microscopy at room temperature

• Mykola Telychko,
• Jan Berger,
• Zsolt Majzik,
• Pavel Jelínek and
• Martin Švec

Beilstein J. Nanotechnol. 2015, 6, 901–906, doi:10.3762/bjnano.6.93

• SLG and BLG graphene, (e) 6.4 × 6.4 nm2, Vbias = −0.2 V, I = 0.16 nA; × near to vacancies created by ion etching. (Color online) (a) Spectroscopy curves of average tunneling current , Δf and force F vs the tip–sample distance on graphene/SiC(0001), taken with a bias voltage of 100 mV, just before

Transformation of hydrogen titanate nanoribbons to TiO₂ nanoribbons and the influence of the transformation strategies on the photocatalytic performance

• Melita Rutar,
• Nejc Rozman,
• Matej Pregelj,
• Carla Bittencourt,
• Romana Cerc Korošec,
• Andrijana Sever Škapin,
• Aleš Mrzel,
• Srečo D. Škapin and
• Polona Umek

Beilstein J. Nanotechnol. 2015, 6, 831–844, doi:10.3762/bjnano.6.86

• vacancies [35][41]. In addition to this resonance, in the samples that were treated in reductive atmosphere, i.e., in TN-400, TN-580 and TN-650, exhibit another intense line at g ≈ 1.988, which is assigned to the Ti3+ centers in the bulk. Moreover, as the reaction temperature increases the intensity of this

• ., TO-580, TN-400 and TN-580, both resonances that were observed at room temperature (Figure 8) increase, i.e., the number of oxygen vacancies and the Ti3+ ions increases. Moreover, the former are most likely responsible also for the resonances appearing at g values [35][41] of approx. 2.012, and approx

• within the band-gap states created by substitutional and interstitional N-doping [23][36] and to creation of an additional localized state due to oxygen vacancies below the conduction band [36]. Assessment of the photocatalytic performance of the TiO2 NRs The photocatalytic performance (PP) of the

Tm-doped TiO₂ and Tm₂Ti₂O₇ pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

• Desiré M. De los Santos,
• Javier Navas,
• Teresa Aguilar,
• Antonio Sánchez-Coronilla,
• Concha Fernández-Lorenzo,
• Rodrigo Alcántara,
• Jose Carlos Piñero,
• Ginesa Blanco and
• Joaquín Martín-Calleja

Beilstein J. Nanotechnol. 2015, 6, 605–616, doi:10.3762/bjnano.6.62

• , respectively, confirming the presence of Tm(III) in an oxide matrix. Thus, considering that the predominant cations in the TiO2 lattice of the doped samples are Ti4+ and Tm3+, and that the doping is substitutional, oxygen vacancies are generated to maintain the local neutrality of the lattice. The presence of

• oxygen vacancies is interesting for photocatalytic applications because, for example, an increase in oxygen vacancies generates more surface defects on the synthesized nanoparticles. This can be studied from the O 1s XPS spectra. Figure 2c (bottom) shows the different contributions in the O 1s spectrum

• demonstrates how the amount of O in the adsorbed species increases with the Tm concentration. This is due to the increase in oxygen vacancies produced, and thus in the number of adsorption centers available. The adsorption of hydroxy groups onto the surface is of interest in photocatalytic applications

Novel ZnO:Ag nanocomposites induce significant oxidative stress in human fibroblast malignant melanoma (Ht144) cells

• Syeda Arooj,
• Samina Nazir,
• Akhtar Nadhman,
• Nafees Ahmad,
• Bakhtiar Muhammad,
• Ishaq Ahmad,
• Kehkashan Mazhar and
• Rashda Abbasi

Beilstein J. Nanotechnol. 2015, 6, 570–582, doi:10.3762/bjnano.6.59

• possible presence of the ZnO2 structure. The minor variation in oxygen amount is, however, due to oxygen vacancies created by the Fermi gas we used in our annealing procedure. These oxygen vacancies gradually obtained some atmospheric oxygen when samples were stored under normal atmospheric conditions. The

Chains of carbon atoms: A vision or a new nanomaterial?

• Florian Banhart

Beilstein J. Nanotechnol. 2015, 6, 559–569, doi:10.3762/bjnano.6.58

• layers led to growing vacancies and holes. The phenomenon has been confirmed later [39][40]; in some experiments even two parallel chains were observed once a graphene ribbon has been thinned laterally to a certain minimum width. The narrowing graphene ribbons between two holes ended in atomic chains as

• is around 80 keV [75]. Undercoordinated edge atoms can be sputtered off at lower energies although the edges tend to reconstruct [76]. The same holds for atoms next to unreconstructed vacancies. As for graphene, the displacement threshold for carbon chains should be highly asymmetric, being much

Nanoporous Ge thin film production combining Ge sputtering and dopant implantation

• Jacques Perrin Toinin,
• Alain Portavoce,
• Khalid Hoummada,
• Michaël Texier,
• Maxime Bertoglio,
• Sandrine Bernardini,
• Marco Abbarchi and
• Lee Chow

Beilstein J. Nanotechnol. 2015, 6, 336–342, doi:10.3762/bjnano.6.32

• of the Ge film up to a depth of 140 nm. One can observe in Figure 1 that no dopants and no vacancies are expected to be found at a depth larger than 220 nm. Consequently, the implantation-induced defects should be confined in the Ge layer thickness. Figure 2 presents scanning electron microscopy (SEM

• straight lines on the right axis and the vacancies distributions are shown using dashed lines on the left axis. SEM plan-view images of the as-implanted Se sample: (1) low resolution view showing the different types of defects; (2) a single GeOx cluster; (3) the structure of holes; and (4) the nanoporous

Tunable white light emission by variation of composition and defects of electrospun Al₂O₃–SiO₂ nanofibers

• Jinyuan Zhou,
• Gengzhi Sun,
• Hao Zhao,
• Xiaojun Pan,
• Zhenxing Zhang,
• Yujun Fu,
• Yanzhe Mao and
• Erqing Xie

Beilstein J. Nanotechnol. 2015, 6, 313–320, doi:10.3762/bjnano.6.29

• -like heterostructure composed of SiOx particles orderly embedded in the highly crystalline α-Al2O3 nanoribbons. They observed a strong and stable blue emission centered at 467 nm under excitation at 320 nm, which was attributed to the neutral oxygen vacancies (≡Si–Si≡) in the SiOx–Al2O3 heterostructure

Morphology, structural properties and reducibility of size-selected CeO_2−x nanoparticle films

• Maria Chiara Spadaro,
• Sergio D’Addato,
• Gabriele Gasperi,
• Francesco Benedetti,
• Paola Luches,
• Vincenzo Grillo,
• Giovanni Bertoni and
• Sergio Valeri

Beilstein J. Nanotechnol. 2015, 6, 60–67, doi:10.3762/bjnano.6.7

• electrostatic force. With the assumption that the increase of the lattice parameter is also due to a higher concentration of oxygen vacancies, Tsunekawa results are complementary with the ones of Zhou et al. [7], obtained for NP diameters between 4 and 60 nm. These results led to the conclusion that the lattice

• parameter increase is related to the formation of oxygen vacancies and Ce3+ ions. Following this approach, Deshpande et al. [8] correlated the lattice parameter expansion with the concentration of Ce3+ ions (measured by X-ray photoelectron spectroscopy, XPS), ascribing it to the higher ionic radius of Ce3

• +, compared to the Ce4+, and to the introduction of oxygen vacancies, which in turn induces a distortion of the local symmetry. In the last years a ‘Madelung model’ has been proposed to describe the properties of ionic crystals as a function of their surface to volume ratio. Here, the balance between long

Manganese oxide phases and morphologies: A study on calcination temperature and atmospheric dependence

• Matthias Augustin,
• Daniela Fenske,
• Ingo Bardenhagen,
• Anne Westphal,
• Martin Knipper,
• Thorsten Plaggenborg,
• Joanna Kolny-Olesiak and
• Jürgen Parisi

Beilstein J. Nanotechnol. 2015, 6, 47–59, doi:10.3762/bjnano.6.6

• especially useful for application as molecular sieves and absorbents for the removal of toxic species from waste gases such as carbon monoxide and nitrogen oxide [6][7][8]. Additionally, manganese oxide structures exhibiting oxygen vacancies provide additional active sites for reduction and oxidation

• crystallite sizes of less than a third compared to those obtained in O2. Furthermore, the lattice constants of Mn3O4 produced in Ar are smaller at all temperatures than those obtained by calcination in O2 atmosphere. This could be due to oxygen vacancies, as the oxygen for the oxidation to Mn3O4 in pure Ar is

• only supplied by the manganese glycolate precursor and cannot be obtained from the gas atmosphere. The presence of oxygen vacancies is also supported by the less pronounced variation of the lattice constants of Mn3O4 obtained at 320 °C and 350 °C in O2 atmospheres, leading to the assumption of

Liquid-phase exfoliated graphene: functionalization, characterization, and applications

• Mildred Quintana,
• Jesús Iván Tapia and
• Maurizio Prato

Beilstein J. Nanotechnol. 2014, 5, 2328–2338, doi:10.3762/bjnano.5.242

• vacancies, adatoms or substitutional atoms might act as active chemical sites on the graphene layer [37]. These features make the organic chemistry of graphene very accessible, but only partially understood. Improvement in the chemical knowledge of the two dimensional material is expected to increase the

Patterning a hydrogen-bonded molecular monolayer with a hand-controlled scanning probe microscope

• Matthew F. B. Green,
• Taner Esat,
• Christian Wagner,
• Philipp Leinen,
• Alexander Grötsch,
• F. Stefan Tautz and
• Ruslan Temirov

Beilstein J. Nanotechnol. 2014, 5, 1926–1932, doi:10.3762/bjnano.5.203

• consisting of 47 vacancies that were created by removing individual PTCDA molecules from the PTCDA/Ag(111) monolayer. The sequence of intermediate steps recorded during writing can be downloaded from the supplement. The three insets show the “repair” of a vacancy created by mistake. The black arrow marks the

• position of the error vacancy. The white arrow marks the position of the molecule at the edge of the molecular monolayer island that was used to fill the error vacancy. The molecule from the edge was removed by using the same manipulation protocol as for all other vacancies and was then placed into the

Synthesis of Pt nanoparticles and their burrowing into Si due to synergistic effects of ion beam energy losses

• Pravin Kumar,
• Udai Bhan Singh,
• Kedar Mal,
• Sunil Ojha,
• Indra Sulania,
• Dinakar Kanjilal,
• Dinesh Singh and
• Vidya Nand Singh

Beilstein J. Nanotechnol. 2014, 5, 1864–1872, doi:10.3762/bjnano.5.197

• interface at ≈242 nm below the surface is clearly seen in Figure 5a. This is mainly attributed to the amorphization of the silicon by collision cascade which can propagate even further than the range of ions (see Si vacancies profile distribution in Figure 6). Figure 5b, which is the zoomed image of the

• . Therefore, local defects (especially vacancies) produced by elastic collisions, which are governed by Sn, are mainly responsible for the burrowing of NPs in silicon as also discussed by Hu et al. [22]. Given the irradiation parameters (50 keV energy, 1 µA beam current and 16 × 103 s to irradiate 1017 ions

• silicon is estimated to be ≈50 nm. Therefore, the presence of NPs beneath the surface and up to ≈250 nm is probably due to radiation-induced enhanced diffusion. Holm et al. [41] have reported Pt distribution into lightly damaged regions of silicon approximately congruous to the vacancies generated during

Silicon and germanium nanocrystals: properties and characterization

• Ivana Capan,
• Alexandra Carvalho and
• José Coutinho

Beilstein J. Nanotechnol. 2014, 5, 1787–1794, doi:10.3762/bjnano.5.189

• by varying the implantation conditions (implantation energy and dose) and subsequent annealing. It is a well-known fact that Si ion implantation of SiO2 is characterized by the production of a large number of oxygen vacancies and other defects in the oxide matrix. These defects enhance the QD

On the structure of grain/interphase boundaries and interfaces

• K. Anantha Padmanabhan and
• Herbert Gleiter

Beilstein J. Nanotechnol. 2014, 5, 1603–1615, doi:10.3762/bjnano.5.172

• as vacancies and extra occupancies, are due to the details of the electronic structure requirements and not just structural defects [19][20][21]. In these cases, the formation of structural/basic units will depend on the separation between the atoms and the nature (metallic, ionic or covalent) of the

Effects of palladium on the optical and hydrogen sensing characteristics of Pd-doped ZnO nanoparticles

• Anh-Thu Thi Do,
• Hong Thai Giang,
• Thu Thi Do,
• Ngan Quang Pham and
• Giang Truong Ho

Beilstein J. Nanotechnol. 2014, 5, 1261–1267, doi:10.3762/bjnano.5.140

• the gas sensing response characteristics allows us to suggest that the dissociation of hydrogen takes place at PdZn-vacancies ([Pd 2+(4d9)]). The design of this sensor allows for a continuous monitoring in the range of 0–100% LEL H2 concentration with high sensitivity and selectivity. Keywords

• interstitials, Zn anti-site vacancies, and oxygen vacancies, it is of interest to find out whether Pd incorporated in ZnO significantly improves sensitivity and specificity for hydrogen [13][14]. In this work, we have successfully synthesized Pd-doped ZnO nanoparticles for an application as gas sensors by a low

• -temperature wet-chemical process. Photoluminescence (PL) measurements at room temperature are then carried out in order to determine the role of vacancies, trapping levels, and the transition shift of the PL emission maximum in these samples. In order to study and optimize the four main factors affecting the

Sublattice asymmetry of impurity doping in graphene: A review

• James A. Lawlor and
• Mauro S. Ferreira

Beilstein J. Nanotechnol. 2014, 5, 1210–1217, doi:10.3762/bjnano.5.133

• lattice sites yields no band gap [17]. Further investigations using vacancies, where carbon atoms are removed from the lattice, found that both superlattices [18] and random distributions restricted to one of the two graphene sublattices [19] both lead to a tunable band gap, and in the latter case an

Fringe structures and tunable bandgap width of 2D boron nitride nanosheets

• Peter Feng,
• Muhammad Sajjad,
• Eric Yiming Li,
• Hongxin Zhang,
• Jin Chu,
• Ali Aldalbahi and
• Gerardo Morell

Beilstein J. Nanotechnol. 2014, 5, 1186–1192, doi:10.3762/bjnano.5.130

• images is 8 s. Also visible in the sequence is the generation of vacancies within the layer. (c,d) Topological defects are incorporated during this edge reconstruction. On the other edge of the same hole, atoms are removed by the electron beam. Scale bar, 2 nm. (a) Experimental set up for H plasma

Electron-beam induced deposition and autocatalytic decomposition of Co(CO)₃NO

• Florian Vollnhals,
• Martin Drost,
• Fan Tu,
• Esther Carrasco,
• Andreas Späth,
• Rainer H. Fink,
• Hans-Peter Steinrück and
• Hubertus Marbach

Beilstein J. Nanotechnol. 2014, 5, 1175–1185, doi:10.3762/bjnano.5.129

• subsequently exposed to Co(CO)3NO. The investigated surfaces were SiOx layers on Si(100) and Si3N4, both of which are suitable substrates for EBISA using Fe(CO)5 [7][16]. On these surfaces, electron stimulated desorption of oxygen and the thereby created oxygen vacancies were identified as the active sites for

Resonance of graphene nanoribbons doped with nitrogen and boron: a molecular dynamics study

• Ye Wei,
• Haifei Zhan,
• Kang Xia,
• Wendong Zhang,
• Shengbo Sang and
• Yuantong Gu

Beilstein J. Nanotechnol. 2014, 5, 717–725, doi:10.3762/bjnano.5.84

• different dopants. The study will be carried out by large-scale molecular dynamics (MD) simulations. Both perfect and defective (with initial vacancies) GNRs doped with boron and nitrogen will be considered. Numerical implementation Based on large-scale molecular dynamics (MD) simulations, a series of

• of dopants have been adopted to build the testing models. Three groups of samples have been tested based on three different GNRs, e.g., a perfect GNR, a defective GNR with two vacancies, and a defective GNR with four vacancies. Each group contains two subgroups, one of which is only doped with boron

• of 109 GHz. In all, although different densities of dopants influence the value of Q differently, the resonance frequency generally decreases with an increasing of the dopant density. Defective GNRs with two vacancies Experimental results show that defects normally exist in GNRs. These defects can be

Mesoporous cerium oxide nanospheres for the visible-light driven photocatalytic degradation of dyes

• Subas K. Muduli,
• Songling Wang,
• Shi Chen,
• Chin Fan Ng,
• Cheng Hon Alfred Huan,
• Tze Chien Sum and
• Han Sen Soo

Beilstein J. Nanotechnol. 2014, 5, 517–523, doi:10.3762/bjnano.5.60

• , and solar thermal dissociation of water and CO2 [14][15][16][17][18]. Cerium oxides with oxygen vacancies represent an underexplored area of nanotechnology with the potential to provide visible-light absorbing photocatalysts [13][19][20][21]. Cerium is relatively earth-abundant and the oxides

• Polycrystalline Ce7O12 samples have been previously synthesized, but harsh conditions (up to 1030 °C) by reduction of CeO2 with CO were employed [25][26]. Instead, mild, surfactant-free solvothermal conditions were used to prepare mesoporous cerium oxide with oxygen vacancies. A solution of ceric ammonium nitrate

• P25 TiO2 nanomaterials. The estimated band gap from the Tauc plot is approximately 2.7 eV (Figure 2b), which corresponds to an absorption edge in the blue region (460 nm). The reduced band gap compared to CeO2 can be attributed to the presence of oxygen vacancies, as previously reported [32]. The

Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods

• Jinzhang Liu,
• Marco Notarianni,
• Llew Rintoul and
• Nunzio Motta

Beilstein J. Nanotechnol. 2014, 5, 485–493, doi:10.3762/bjnano.5.56

• –matter interaction within those crystals, the luminescence of the cavity material has been conventionally used as a light source. Under excitation, ZnO emits UV light at about 380 nm ascribed to its wide band gap (Eg ≈ 3.4 eV). With crystal defects such as oxygen vacancies, ZnO show visible

En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays

• Slawomir Boncel,
• Sebastian W. Pattinson,
• Valérie Geiser,
• Milo S. P. Shaffer and
• Krzysztof K. K. Koziol

Beilstein J. Nanotechnol. 2014, 5, 219–233, doi:10.3762/bjnano.5.24

• most probable ways of N-incorporation into graphene walls, including substitutions and substitutions with a simultaneous formation of vacancies structures, are presented in Figure 13. The presence of nitrogen or 5- and 7-member-ring defects is crucial for the formation of the cone structure of the N

• -CNTs. The vacancies also provide geometrical degrees of freedom to the structure of N-CNTs, which allows for the fulfilment of the crystallographic matching criteria (–ABAB–) between the layers. This is geometrically impossible in the case of MWCNTs. Conclusion N-CNTs were synthesized via an injection

Fabrication of carbon nanomembranes by helium ion beam lithography

• Xianghui Zhang,
• Henning Vieker,
• André Beyer and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2014, 5, 188–194, doi:10.3762/bjnano.5.20

• encountered at the sides of 1D structures. As regards the entropic barrier, an extreme example would be that for the insurmountable entropic barriers the crosslinking does not occur and vacancies that contain isolated molecules are formed. XPS spectra showed that the maximum degree of crosslinking of the BPT

Core level binding energies of functionalized and defective graphene

• Toma Susi,
• Markus Kaukonen,
• Paula Havu,
• Mathias P. Ljungberg,
• Paola Ayala and
• Esko I. Kauppinen

Beilstein J. Nanotechnol. 2014, 5, 121–132, doi:10.3762/bjnano.5.12

• . Furthermore, we simulated the simplest atomic defects, namely single and double vacancies and the Stone–Thrower–Wales defect. Finally, we studied modifications of a reactive single vacancy with O and H functionalities, and compared the calculated values to data found in the literature. Keywords: core level

• . Several intrinsic defects are relevant for graphene. Of these, the simplest are single (SV) and double vacancies (DV), along with the Stone–Thrower–Wales (STW) bond rotation. All of these have been directly observed [8] in aberration-corrected transmission electron microscopes (TEM). More extended defects

• perfect agreement with previous studies [2]. The values for the single (7.21 eV) and double vacancies (7.01 eV) are marginally lower than previously reported, which could be attributed to the unconstrained structural relaxation allowed here. Following Banhart et al. [9], it should be noted that the