Effect of substitutional defects on resonant tunneling diodes based on armchair graphene and boron nitride nanoribbons lateral heterojunctions

• Majid Sanaeepur

Beilstein J. Nanotechnol. 2020, 11, 688–694, doi:10.3762/bjnano.11.56

• between graphene and hBN [3]. However, inevitable interfacial defects located at the interface of Gr/hBN heterojunctions, including point defects (single vacancies and substitutional defects) and topological defects can alter the electronic properties of Gr/hBN heterostructures and, consequently, the

DFT calculations of the structure and stability of copper clusters on MoS₂

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2020, 11, 391–406, doi:10.3762/bjnano.11.30

• are 5.4 eV for Cu, 4.2 eV for Ag and 4.5 eV for Au. The presence of a complete row of sulfur vacancies enhances the adsorption energy of the nanoparticles for all three metals, increasing it to 7.1 eV, 7.0 eV and 6.0 eV for Cu, Ag and Au, respectively. It also increases the charge transfer from the

• particular when the monolayer is defect-rich. MoS2 is known to be naturally high in defects [21][32], in particular S vacancies. It has been predicted that S vacancies in a MoS2 monolayer are most stable when they occur in a row, with a decrease in the vacancy formation energy as the number of vacancies

• increases [2]. Experimental methods for controlling the formation of sulfur vacancies in the MoS2 monolayer have also been developed [33], and this would allow for the targeted use of S vacancies to enhance desired properties such as adsorption energy. In this study we aim to fill the gap in the literature

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• Kondo screening of magnetic impurities in graphene [75]. They found an asymmetric behavior of the Kondo temperature depending on the sign of the chemical potential in the limit of U → ∞. Experimental measurements of the Kondo effect produced by lattice vacancies in graphene layers reveal high values of

• on the bias voltage is in agreement with the theoretical results of Świrkowicz et al., who considered a QD connected to metallic electrodes [31]. The zero-bias peak of the differential conductance was observed experimentally for magnetic impurities induced by vacancies on graphite surface [77]. In

Antimony deposition onto Au(111) and insertion of Mg

• Lingxing Zan,
• Da Xing,
• Abdelaziz Ali Abd-El-Latif and
• Helmut Baltruschat

Beilstein J. Nanotechnol. 2019, 10, 2541–2552, doi:10.3762/bjnano.10.245

• epitaxial 2D growth occurs to form the row structure with the width of ≈2.4 or ≈3.2 nm and the height of 0.35 nm. The angle between the two different oriented domains is around 120°, which suggests that they are probably aligned along the densely packed (111) rows of the substrate. Some vacancies appeared

Deterministic placement of ultra-bright near-infrared color centers in arrays of silicon carbide micropillars

• Stefania Castelletto,
• Abdul Salam Al Atem,
• Faraz Ahmed Inam,
• Hans Jürgen von Bardeleben,
• Sophie Hameau,
• Ahmed Fahad Almutairi,
• Gérard Guillot,
• Shin-ichiro Sato,
• Alberto Boretti and
• Jean Marie Bluet

Beilstein J. Nanotechnol. 2019, 10, 2383–2395, doi:10.3762/bjnano.10.229

• enhancement of the optical emission between 850 and 1400 nm of an ensemble of silicon mono-vacancies (VSi), silicon and carbon divacancies (VCVSi), and nitrogen vacancies (NCVSi) in an n-type 4H-SiC array of micropillars. The micropillars have a length of ca. 4.5 μm and a diameter of ca. 740 nm, and were

• ; Introduction Silicon carbide (SiC) is an established material for many electronic devices and has also been considered for photonics applications recently. After the improvement of the purity of the material and the isolation of point defects (primarily vacancies), SiC has been considered to host physical

• near-infrared color centers in SiC using hydrogen irradiation and annealing at different temperatures. We have optimized the enhancement of color centers relevant for quantum sensing applications, such as silicon monovacancies and divacancies, and nitrogen vacancies. Due to the high fluence during

Multiwalled carbon nanotube based aromatic volatile organic compound sensor: sensitivity enhancement through 1-hexadecanethiol functionalisation

• Nadra Bohli,
• Meryem Belkilani,
• Juan Casanova-Chafer,
• Eduard Llobet and
• Adnane Abdelghani

Beilstein J. Nanotechnol. 2019, 10, 2364–2373, doi:10.3762/bjnano.10.227

• decoration of MWCNTs Prior to their deposition on the interdigitated electrode surface, the MWCNTs were treated by oxygen plasma to create oxygen vacancies on the walls of the CNTs in order to enhance their surface reactivity [14][15]. The detailed description of the experimental steps undertaken is

Improved adsorption and degradation performance by S-doping of (001)-TiO₂

• Xiao-Yu Sun,
• Xian Zhang,
• Xiao Sun,
• Ni-Xian Qian,
• Min Wang and
• Yong-Qing Ma

Beilstein J. Nanotechnol. 2019, 10, 2116–2127, doi:10.3762/bjnano.10.206

• % to 68.5% due to the synergistic effects of the oxygen vacancies, increased number of surface chemical adsorption centers as a result of SO42− adsorption on the TiO2 surface and the larger pore size. (3) S-doping increases the MB degradation rate from 6.9 × 10−2 min−1 to 18.2 × 10−2 min−1 due to an

• , the XP spectrum of O 1s can be fitted by three peaks and the CSs correspond to TiO2, –OH and oxygen vacancies (Ov) [44]. As the RS/Ti increases, the ratio of Ov increases from 4.3% (2-S0) to 22.9% (2-S3) and then decreases again to 19.9% (2-S5) (Table 3). The XPS signals of the oxygen vacancies were

• the O 2p orbitals. At the same time, the ratio of the Ov increases in the order of 2-S0.5 < 2-S1 < 2-S5 < 2-S3, as given in Table 3; therefore, the decrease of the DOS mainly results from an increase of the ratio of oxygen vacancies. Figure 6 shows the UV–vis DRS of 2-S0, 2-S0.5, 2-S1, 2-S3 and 2-S5

Synthesis of highly active ETS-10-based titanosilicate for heterogeneously catalyzed transesterification of triglycerides

• Muhammad A. Zaheer,
• David Poppitz,
• Khavar Feyzullayeva,
• Marianne Wenzel,
• Jörg Matysik,
• Radomir Ljupkovic,
• Aleksandra Zarubica,
• Alexander A. Karavaev,
• Andreas Pöppl,
• Roger Gläser and
• Muslim Dvoyashkin

Beilstein J. Nanotechnol. 2019, 10, 2039–2061, doi:10.3762/bjnano.10.200

• vacancies are partially removed due to the detitanation process. This can additionally contribute to the decrease in the observed intensities of NH3 desorption below 600 K for treated samples compared to Na,K-ETS-10. At temperatures above 600 K, highly pronounced NH3 desorption, presumably from the surface

Improvement of the thermoelectric properties of a MoO₃ monolayer through oxygen vacancies

• Wenwen Zheng,
• Wei Cao,
• Ziyu Wang,
• Huixiong Deng,
• Jing Shi and
• Rui Xiong

Beilstein J. Nanotechnol. 2019, 10, 2031–2038, doi:10.3762/bjnano.10.199

• , China 10.3762/bjnano.10.199 Abstract We have investigated the thermoelectric properties of a pristine MoO3 monolayer and its defective structures with different oxygen vacancies using first-principles methods combined with Boltzmann transport theory. Our results show that the thermoelectric properties

• oxygen vacancies leads to a sharp peak near the Fermi level in the density of states. This proves to be an effective way to enhance the ZT values of the MoO3 monolayer. The increased ZT values can reach 0.84 (x-axis) and 0.12 (y-axis) at 300 K. Keywords: Boltzmann transport theory; first-principles

• calculations; molybdenum trioxides; MoO3 monolayer; oxygen vacancies; thermoelectric properties; Introduction Thermoelectric materials that can directly convert temperature gradients to voltage gradients and vice versa provide a valid strategy to mitigate the global energy crisis. Owing to the unique ability

Magnetic properties of biofunctionalized iron oxide nanoparticles as magnetic resonance imaging contrast agents

• Natalia E. Gervits,
• Andrey A. Gippius,
• Alexey V. Tkachev,
• Evgeniy I. Demikhov,
• Sergey S. Starchikov,
• Igor S. Lyubutin,
• Alexander L. Vasiliev,
• Vladimir P. Chekhonin,
• Maxim A. Abakumov,
• Alevtina S. Semkina and
• Alexander G. Mazhuga

Beilstein J. Nanotechnol. 2019, 10, 1964–1972, doi:10.3762/bjnano.10.193

• -site) and octahedral [B-site]. The cationic distribution can be represented as: (Fe3+)A[Fe2.5+2]BO4 in the case of magnetite and (Fe3+)A[Fe3+5/3□1/3]BO4 for maghemite, where □ denotes vacancies. The fast electron exchange between the Fe3+ and Fe2+ ions in the B-sites of magnetite leads to an average

Kelvin probe force microscopy work function characterization of transition metal oxide crystals under ongoing reduction and oxidation

• Dominik Wrana,
• Karol Cieślik,
• Wojciech Belza,
• Christian Rodenbücher,
• Krzysztof Szot and
• Franciszek Krok

Beilstein J. Nanotechnol. 2019, 10, 1596–1607, doi:10.3762/bjnano.10.155

• conductivity. Here, a huge advantage over other materials is the possibility of oxides that self-dope via the introduction of oxygen vacancies [13], which is also a reason why there are not many reliable experimental studies on the work function of transition metal oxides (with one notable exception [14

• beforehand, resulting in the formation of a high concentration of oxygen vacancies. Therefore, the conductivity is much higher than that of a pristine single crystal, which has been estimated via a comparable LC-AFM study to be around 10−16 S [28]. Here the observed changes of conductivity on the surface

• comparable conductivity but notably different work functions. The reason behind this is that although undoped SrTiO3(100) is a band insulator, it could be easily self-doped with oxygen vacancies upon thermal reduction [28][30]. Reduction preferentially occurs at the surface, resulting in the reconstruction

Rapid thermal annealing for high-quality ITO thin films deposited by radio-frequency magnetron sputtering

• Petronela Prepelita,
• Ionel Stavarache,
• Doina Craciun,
• Florin Garoi,
• Catalin Negrila,
• Beatrice Gabriela Sbarcea and
• Valentin Craciun

Beilstein J. Nanotechnol. 2019, 10, 1511–1522, doi:10.3762/bjnano.10.149

• near the valence band (such as oxygen interstitials and indium vacancies) and the number of states increases with increasing oxygen flow. A poor crystalline quality with abundant structural defects leads to effective compensation of doping [33][48]. The metallic nature of the highly conductive ITO

Direct observation of oxygen-vacancy formation and structural changes in Bi₂WO₆ nanoflakes induced by electron irradiation

• Hong-long Shi,
• Bin Zou,
• Zi-an Li,
• Min-ting Luo and
• Wen-zhong Wang

Beilstein J. Nanotechnol. 2019, 10, 1434–1442, doi:10.3762/bjnano.10.141

• prominent role of oxygen vacancies in the photocatalytic performance of bismuth tungsten oxides is well recognized, while the underlying formation mechanisms remain poorly understood. Here, we use the transmission electron microscopy to investigate the formation of oxygen vacancies and the structural

• evolution of Bi2WO6 under in situ electron irradiation. Our experimental results reveal that under 200 keV electron irradiation, the breaking of relatively weak Bi–O bonds leads to the formation of oxygen vacancies in Bi2WO6. With prolonged electron irradiation, the reduced Bi cations tend to form Bi

• . Keywords: bismuth tungsten oxide; electron diffraction; electron irradiation; nanoflakes; oxygen vacancies; Introduction Bi2WO6 has drawn great interest regarding its physical properties such as the piezoelectric effect and ferroelectricity with large spontaneous polarization and high Curie temperature [1

Kelvin probe force microscopy of the nanoscale electrical surface potential barrier of metal/semiconductor interfaces in ambient atmosphere

• Petr Knotek,
• Tomáš Plecháček,
• Jan Smolík,
• Petr Kutálek,
• Filip Dvořák,
• Milan Vlček,
• Jiří Navrátil and
• Čestmír Drašar

Beilstein J. Nanotechnol. 2019, 10, 1401–1411, doi:10.3762/bjnano.10.138

• nanometers for SiO2 on Si [51][52]). In our case it is increased by the electric field and good oxygen mobility in BiOx due to the formation of charged Bi vacancies [59][60]. This assumption is in good agreement with the observed increase of the cut-in potential barrier upon thinning of the Au layer (see

Gas sensing properties of individual SnO₂ nanowires and SnO₂ sol–gel nanocomposites

• Alexey V. Shaposhnik,
• Dmitry A. Shaposhnik,
• Sergey Yu. Turishchev,
• Olga A. Chuvenkova,
• Stanislav V. Ryabtsev,
• Alexey A. Vasiliev,
• Xavier Vilanova,
• Francisco Hernandez-Ramirez and
• Joan R. Morante

Beilstein J. Nanotechnol. 2019, 10, 1380–1390, doi:10.3762/bjnano.10.136

• nanowires, which is usually connected with the presence of oxygen vacancies [35][37][38]. The decrease in the half-widths and the increase in the relative intensity of the peaks for each of the features observed around 490 eV (main absorption edge of the SnO2) provides evidence for a more ordered structure

• structure density of states is typical of native SnO2-x oxide covering the surface of pure metallic tin foils [37][38] and was confirmed for SnO2 powder samples by the presence of noticeable amounts of oxygen vacancies (Figure 7). XANES oxygen lines near K-edge spectra are presented in Figure 8. The fine

• , powder particles may contain noticeable amounts of oxygen vacancies in their volume. This assumption moves the electronic structure of SnO2 powder particles close to the bulk (core) of natural SnO2-x oxides as confirmed by the XANES Sn M4,5 results (see Figure 7). After calcination, followed by

Imaging the surface potential at the steps on the rutile TiO₂(110) surface by Kelvin probe force microscopy

• Masato Miyazaki,
• Huan Fei Wen,
• Quanzhen Zhang,
• Yuuki Adachi,
• Jan Brndiar,
• Ivan Štich,
• Yan Jun Li and
• Yasuhiro Sugawara

Beilstein J. Nanotechnol. 2019, 10, 1228–1236, doi:10.3762/bjnano.10.122

• [1][2][3][4][5][6][7]. The catalytic activity can be enhanced by the presence of defects, such as oxygen vacancies (Ov), Ti interstitials (Tiint) [8], and crystal steps. TiO2 is an n-type semiconductor because of these defects. In addition, reactive oxygen species, such as OH and H2O2 (compounds with

Pure and mixed ordered monolayers of tetracyano-2,6-naphthoquinodimethane and hexathiapentacene on the Ag(100) surface

• Robert Harbers,
• Timo Heepenstrick,
• Dmitrii F. Perepichka and
• Moritz Sokolowski

Beilstein J. Nanotechnol. 2019, 10, 1188–1199, doi:10.3762/bjnano.10.118

• example. The four symmetry-equivalent domains are marked by A to D. The molecular rows are well visible. The domains exhibit local defects, mostly vacancies, where single molecules are missing. For this structure, STM images of good quality with a low level of noise were obtained easily. We interpret this

Photoactive nanoarchitectures based on clays incorporating TiO₂ and ZnO nanoparticles

• Eduardo Ruiz-Hitzky,
• Pilar Aranda,
• Marwa Akkari,
• Nithima Khaorapapong and
• Makoto Ogawa

Beilstein J. Nanotechnol. 2019, 10, 1140–1156, doi:10.3762/bjnano.10.114

• visible wavelengths (blue and green emission at around 436–438 nm and 544–548 nm) of ZnO hybridized with CTA-smectites varies depending on the ZnO loading. This was attributed to defects, such as oxygen vacancies in ZnO, and trapped surface charges. The photoluminescence intensity of ZnO in saponite and

Quantitative analysis of annealing-induced instabilities of photo-leakage current and negative-bias-illumination-stress in a-InGaZnO thin-film transistors

• Dapeng Wang and
• Mamoru Furuta

Beilstein J. Nanotechnol. 2019, 10, 1125–1130, doi:10.3762/bjnano.10.112

• higher-energy light irradiation, demonstrating that the generated ionized oxygen vacancies (VO+/VO2+) are neutralized by capturing electrons [8]. However, SS degradation still can be observed in the 300 °C-annealed TFT under the irradiation with short-wavelength light (below 430 nm), indicating that

Synthesis and characterization of quaternary La(Sr)S–TaS₂ misfit-layered nanotubes

• Marco Serra,
• Erumpukuthickal Ashokkumar Anumol,
• Dalit Stolovas,
• Iddo Pinkas,
• Ernesto Joselevich,
• Reshef Tenne,
• Andrey Enyashin and
• Francis Leonard Deepak

Beilstein J. Nanotechnol. 2019, 10, 1112–1124, doi:10.3762/bjnano.10.111

• vacancies in the parent MLC compound. For smaller amounts of lanthanum atoms (i.e., larger Sr content in the MS sublattice), the charge transfer to the CrS2 slab becomes smaller. Therefore, the hexagonal (layered) phase of CrS2 becomes unstable beyond 20 atom % Sr and the MLC vanishes. While the parent

Electronic and magnetic properties of doped black phosphorene with concentration dependence

• Ke Wang,
• Hai Wang,
• Min Zhang,
• Yan Liu and
• Wei Zhao

Beilstein J. Nanotechnol. 2019, 10, 993–1001, doi:10.3762/bjnano.10.100

• experimentally demonstrated that substitutional doping of TMDs could be achieved by filling the vacancies observed in CVD-grown monolayer TMDs [18]. Liu et al. [19] prepared epitaxial copper-doped ZnO films and observed that the substitution of Cu for Zn and the presence of strong Cu–Zn–O bonds are necessary for

Rapid, ultraviolet-induced, reversibly switchable wettability of superhydrophobic/superhydrophilic surfaces

• Yunlu Pan,
• Wenting Kong,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2019, 10, 866–873, doi:10.3762/bjnano.10.87

• are generated on the TiO2 surfaces under UV illumination. The holes lead to the production of oxygen vacancies to enhance the adsorption of hydroxy groups, while the hydroxy groups are replaced by oxygen atoms that have a stronger bond on the defect sites during heating process. However, the change in

On the transformation of “zincone”-like into porous ZnO thin films from sub-saturated plasma enhanced atomic layer deposition

• Alberto Perrotta,
• Julian Pilz,
• Stefan Pachmajer,
• Antonella Milella and
• Anna Maria Coclite

Beilstein J. Nanotechnol. 2019, 10, 746–759, doi:10.3762/bjnano.10.74

• (vacancies). The latter peak is also attributed to the formation of metal carbonates, in line with the FTIR results and the literature values [60]. Finally, the peak at 529.8 eV was attributed to lattice O–Zn bonds [56]. Increasing the plasma time led to the decrease and eventual disappearance of the pure

• spectra confirm the removal of the carbon functionalities and the calcined layers showed an O/Zn ratio of 1.0 ± 0.1 (Table 1). The oxygen peaks were decomposed into two contributions, assigned to the oxygen–zinc bonds in the oxide lattice (O–Zn, 529.8 eV), and zinc hydroxides and/or oxygen vacancies (Zn

Review of time-resolved non-contact electrostatic force microscopy techniques with applications to ionic transport measurements

• Aaron Mascaro,
• Yoichi Miyahara,
• Tyler Enright,
• Omur E. Dagdeviren and
• Peter Grütter

Beilstein J. Nanotechnol. 2019, 10, 617–633, doi:10.3762/bjnano.10.62

• a phase-locked loop (PLL). This was first performed by Bennewitz et al. to measure the mobility of F− vacancies in a CaF2 crystal [27]. Schirmeisen et al. later improved the technique by performing the measurements at various temperatures to extract the activation energy for ionic transport in Li

Choosing a substrate for the ion irradiation of two-dimensional materials

• Egor A. Kolesov

Beilstein J. Nanotechnol. 2019, 10, 531–539, doi:10.3762/bjnano.10.54

• vacancy generation event involves chalcogen atom removal) [23]. If the fluence is enough, multiple generated vacancies can subsequently merge through the migration processes [15][24], leading to a creation of more complex defects. Additionally, the incident ion can become embedded into the 2D material