Characterization and influence of hydroxyapatite nanopowders on living cells

• Przemyslaw Oberbek,
• Tomasz Bolek,
• Adrian Chlanda,
• Seishiro Hirano,
• Sylwia Kusnieruk,
• Julia Rogowska-Tylman,
• Ganna Nechyporenko,
• Viktor Zinchenko,
• Wojciech Swieszkowski and
• Tomasz Puzyn

Beilstein J. Nanotechnol. 2018, 9, 3079–3094, doi:10.3762/bjnano.9.286

• , interactions between nanoparticles (NPs) and the biological environment are not yet fully understood. Structures such as human skin or lungs are in constant contact with the environment and are thus exposed to nanoobjects. Lack of knowledge about nanoparticle effects on cell viability is a significant barrier

A novel polyhedral oligomeric silsesquioxane-modified layered double hydroxide: preparation, characterization and properties

• Xianwei Zhang,
• Zhongzhu Ma,
• Hong Fan,
• Carla Bittencourt,
• Jintao Wan and
• Philippe Dubois

Beilstein J. Nanotechnol. 2018, 9, 3053–3068, doi:10.3762/bjnano.9.284

• reacts with the metal oxides to form a continuous and compact condensed phase. This mixed carbonized protecting layer provides a good barrier to the transfer of heat and mass, preventing the inner layer against further decomposition and accelerating the formation of char. Evidence in favor of this

Apparent tunneling barrier height and local work function of atomic arrays

• Neda Noei,
• Alexander Weismann and
• Richard Berndt

Beilstein J. Nanotechnol. 2018, 9, 3048–3052, doi:10.3762/bjnano.9.283

• Neda Noei Alexander Weismann Richard Berndt Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany 10.3762/bjnano.9.283 Abstract Spatially resolved measurements of the apparent tunneling barrier height Φapp in scanning tunneling microscopy

• filament and, consequently, on the local surface structure. Keywords: scanning tunneling microscopy; tunneling barrier height; work function; Findings The work function of a metal surface [1], the work required at temperature T = 0 K to move an electron from the metal to infinity, is relevant for, e.g

• apparent barrier height Φapp [27]. Although there is no simple expression connecting Φapp and the local work function of the sample Φ (partially because the tip structure is usually unknown), it is common practice to assume that measured variations of Φapp represent those of Φ [28][29][30][31]. Here we

Investigation of CVD graphene as-grown on Cu foil using simultaneous scanning tunneling/atomic force microscopy

• Majid Fazeli Jadidi,
• Umut Kamber,
• Oğuzhan Gürlü and
• H. Özgür Özer

Beilstein J. Nanotechnol. 2018, 9, 2953–2959, doi:10.3762/bjnano.9.274

• conduct simultaneous STM/AFM measurements. This system with a sensitivity of 2·10−4 Å/√Hz is capable of measuring tunnel current, force, force gradient, tunnel barrier height and energy loss [32]. The UHV chamber is equipped with an argon sputtering gun and a resistive heater that could be used for sample

Layered calcium phenylphosphonate: a hybrid material for a new generation of nanofillers

• Kateřina Kopecká,
• Ludvík Beneš,
• Klára Melánová,
• Vítězslav Zima,
• Petr Knotek and
• Kateřina Zetková

Beilstein J. Nanotechnol. 2018, 9, 2906–2915, doi:10.3762/bjnano.9.269

• higher values compared to the pristine film. While the value of the loss modulus of the composite with unexfoliated CaPhP is roughly the same as for the pristine epoxy film, the loss modulus of the composite with exfoliated CaPhP is higher. Barrier properties The addition of thin but large particles can

• influence the barrier properties of polymer films. In the case of CaPhP, the permeability of the epoxy film with 5% CaPhP (CaPhP_ a_5) as a filler for H2, CO2, He and CH4 was measured and the results were 21.02, 4.28, 13.55 and 4.85 Barrer, respectively (Table 2). This implies that the highest permeability

• acceleration voltage of 20 kV. Powder X-ray diffraction data were obtained with a D8-Advance diffractometer, Bruker, Germany, with a Bragg–Brentano θ–θ geometry and with an EMPYREAN diffractometer, PANalytical, Netherlands (in both cases using Cu Kα radiation). The barrier properties for gas permeation were

Charged particle single nanometre manufacturing

• Philip D. Prewett,
• Cornelis W. Hagen,
• Claudia Lenk,
• Steve Lenk,
• Marcus Kaestner,
• Tzvetan Ivanov,
• Ahmad Ahmad,
• Ivo W. Rangelow,
• Xiaoqing Shi,
• Stuart A. Boden,
• Alex P. G. Robinson,
• Dongxu Yang,
• Sangeetha Hari,
• Marijke Scotuzzi and
• Ejaz Huq

Beilstein J. Nanotechnol. 2018, 9, 2855–2882, doi:10.3762/bjnano.9.266

• physical process of emission is quantum mechanical tunneling of the electrons through the potential barrier, which is tilted due to the electric field (see Figure 14b for a schematic description of the tunneling process). The theory of electron field emission from metals was developed by Ralph H. Fowler

Graphene-enhanced metal oxide gas sensors at room temperature: a review

• Dongjin Sun,
• Yifan Luo,
• Marc Debliquy and
• Chao Zhang

Beilstein J. Nanotechnol. 2018, 9, 2832–2844, doi:10.3762/bjnano.9.264

• barrier and achieve the required electron mobility, the operating temperature of MOS sensors is above 200 °C in general. The excessive operating temperature leads to high power consumption and difficulty of integration, which is contrary to our concept of energy conservation and emission reduction

• , meaning that electrons transfer from rGO to SnO2 in the heterojunctions. The Schottky barrier is only 0.2 eV due to the changed Fermi level of the composite structure after achieving a dynamic balance of the electron flow, indicating that the electrons are able to pass through the energy barrier. In

• summary, the SnO2–rGO sensor allow for the transition of electrons even at room temperature because of its low Schottky barrier. When exposed to air at room temperature, oxygen molecules obtain electrons from n-type SnO2–rGO hybrids to form O2−. The electron depletion layers generated on the interfaces of

Variation of the photoluminescence spectrum of InAs/GaAs heterostructures grown by ion-beam deposition

• Alexander S. Pashchenko,
• Leonid S. Lunin,
• Eleonora M. Danilina and
• Sergei N. Chebotarev

Beilstein J. Nanotechnol. 2018, 9, 2794–2801, doi:10.3762/bjnano.9.261

• their isovalent doping with bismuth on the photoluminescence properties of InAs/GaAs heterostructures. The experimental samples were grown by ion-beam deposition. We showed that using three vertically stacked layers of InAs quantum dots separated by thin GaAs barrier layers was accompanied by a red

• -shift of the photoluminescence peak of InAs/GaAs heterostructures. An increase in the thickness of the GaAs barrier layers was accompanied by a blue shift of the photoluminescence peak. The effect of isovalent Bi doping of the GaAs barrier layers on the structural and optical properties of the InAs/GaAs

• follows from the above that it is possible to manipulate the photosensitivity spectrum of heterostructures through three methods: 1) the size, shape and density of the quantum dot; 2) the vertical stacking of quantum dot arrays; 3) the material of the barrier layers surrounding the quantum dots. We and

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

• adhesion of Mo to the substrates [22][23][24]. The Mo/Cr back contact has been already proposed in flexible thin-film solar cells on metallic foils and stainless steel [25][26][27][28]. However, in these reports Cr was used as a barrier layer to reduce/prevent impurity out-diffusion from the metallic

Au–Si plasmonic platforms: synthesis, structure and FDTD simulations

• Anna Gapska,
• Marcin Łapiński,
• Paweł Syty,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2018, 9, 2599–2608, doi:10.3762/bjnano.9.241

• efficient diffusion barrier against metal atoms [24], so Au–Si monoatomic layer could be present on the surface of the support. Exemplary absorbance spectra recorded for the 2.8 nm Au film after annealing at 550 °C for 15 min is presented in Figure 10. A strong maximum corresponding to plasmon resonance is

Improved catalytic combustion of methane using CuO nanobelts with predominantly (001) surfaces

• Qingquan Kong,
• Yichun Yin,
• Bing Xue,
• Yonggang Jin,
• Wei Feng,
• Zhi-Gang Chen,
• Shi Su and
• Chenghua Sun

Beilstein J. Nanotechnol. 2018, 9, 2526–2532, doi:10.3762/bjnano.9.235

• release atomic oxygen after exceeding the small barrier of 0.47 eV, which can oxidize adsorbed CO to form CO2, as outlined in Figure 4i–l. The energy profile for the above full process is given in Figure 5 in units of eV, using the total energy of a clean (001) surface and free gas-phase CH4 and O2 as the

• reference. According to the results, the early oxidation to release the first H2O (oxygen is from the surface) is exothermic and generates an OV (see Figure 4c). This is followed by O2 dissociation which occurs over the vacancy with a maximum energy barrier of 0.91 eV. This is informative because it

• indicates that the key role of OV is to activate O2 and release a highly active oxygen atom, although a barrier of 0.91 eV is found for O2 dissociation in the case of CuO(001), but the dehydrogenation from CHx becomes exothermic, confirming the importance of surface oxygen and oxygen vacancies, as suggested

High-temperature magnetism and microstructure of a semiconducting ferromagnetic (GaSb)_1−x(MnSb)_x alloy

• Leonid N. Oveshnikov,
• Elena I. Nekhaeva,
• Alexey V. Kochura,
• Alexander B. Davydov,
• Mikhail A. Shakhov,
• Sergey F. Marenkin,
• Oleg A. Novodvorskii,
• Alexander P. Kuzmenko,
• Alexander L. Vasiliev,
• Boris A. Aronzon and
• Erkki Lahderanta

Beilstein J. Nanotechnol. 2018, 9, 2457–2465, doi:10.3762/bjnano.9.230

• interaction is affected by the appearance of Schottky barriers at the MnSb/GaSb boundaries. Basically, these type of barriers appear on the semiconductor/metal interfaces providing a tunneling charge transfer across the boundary, if the barrier is high enough. In the present case, Schottky barriers may appear

• with the effective penetration depth of the carrier (hole) wave function, lp, under triangular barrier. Taking into account that the energy gap in GaSb is Eg = 0.7 eV and the Schottky barrier height is about (1/3)Eg[21], the value of dbarrier can be estimated as 2 nm at Np = 1020 cm−3 while lp is of

• temperature (due to the triangular shape of the barrier). Below 50 K another contribution becomes significant, the interaction with isolated Mn moments. From our data we cannot define the corresponding Tc value accurately because this interaction can be significant even above the ordering temperature [24][25

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

• -underlap. Schottky-potential barriers build up although the same Schottky-barrier-height at the metal–Si interface at drain and source were chosen in both devices to examine the effectiveness of “doping” (Si3N4-coating) of underlap areas. A shift of the Schottky-barrier for device II due to workfunction

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

• states at VZ≈ 3 meV is provided in Figure 6 where we plot the wave-function probability profiles (in the Majorana basis) of the low-energy states around the QD–Majorana levels anticrossing. For simplicity, we consider only the case of the potential barrier model. At the anticrossing, the Majorana and dot

• increasing values of the Zeeman splitting. The same wire parameters as in Figure 2 were used. Note that the main effect of the bulk normal leads is to create confining potential wells at the wire edges. (b) Barrier-like potential energy profile used to mimic the self-consistent solution. Spectra of the

• behavior as before, while blue color indicates QD-like behavior due to the metallic contacts. Evolution with Zeeman field of the spectrum (a) and the absolute value of the Majorana charge QM (b) for the barrier-like potential model of Figure 5b. Panels (c) and (e) show the wave-function probability profile

Localized photodeposition of catalysts using nanophotonic resonances in silicon photocathodes

• Evgenia Kontoleta,
• Sven H. C. Askes,
• Lai-Hung Lai and
• Erik C. Garnett

Beilstein J. Nanotechnol. 2018, 9, 2097–2105, doi:10.3762/bjnano.9.198

• nanoparticles act as electron-trapping centers on the surface of TiO2 [45][46]. After the formation of the very first platinum nanoparticles, photogenerated electrons from the silicon nanostructures are transferred to TiO2 and in sequence to the already formed platinum. The Schottky barrier between TiO2 and

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

• barrier of O2 molecules on CNTs depends on their curvature and whether the nanotubes are metallic or semiconducting [21]. However, in most of the examples reported in this review concerning CNTs, the CNTs are mostly multiwalled and the theory used in the cited works is usually based on graphene as model

• had a poor ORR activity with 0.3 V difference in the onset potential compared to a Pt disk. The low performance was associated to the mutual repulsion between the lone-pair electrons in both pyridinic nitrogen and O2, which causes a higher energy barrier for the activation of molecular oxygen. The

• catalyst (Figure 9b). Different groups calculated by using DFT the energy barriers for oxygen molecule adsorption and dissociation on pristine and N-doped graphene depending on the nitrogen configuration [21][60][110][111][112]. Ni and co-workers [111], in particular, found that the energy barrier

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

• of most nanomanipulation experiments, but recent theoretical studies have pointed out its significance, especially with respect to its influence of the relative orientation between particle and substrate. It was shown that, e.g., the succession of orientational maxima of the potential energy barrier

• mechanisms of structural lubricity. This crucial importance of the edge was also demonstrated by molecular dynamics (MD) simulations for Kr islands adsorbed on Pb(111). Here, depending on size and shape of the islands, the edge generates a barrier for the unpinning and successive advancement of the edge

• result of a modulation of the effective lateral energy barrier height by changing the distance between the contacting bodies. Since the resonance frequency of small nanometer-sized contacts is in the range from megahertz to gigahertz, the contact may move fast enough to cross the barrier during the short

Electromigrated electrical optical antennas for transducing electrons and photons at the nanoscale

• Arindam Dasgupta,
• Mickaël Buret,
• Nicolas Cazier,
• Marie-Maxime Mennemanteuil,
• Reinaldo Chacon,
• Kamal Hammani,
• Jean-Claude Weeber,
• Juan Arocas,
• Laurent Markey,
• Gérard Colas des Francs,
• Alexander Uskov,
• Igor Smetanin and
• Alexandre Bouhelier

Beilstein J. Nanotechnol. 2018, 9, 1964–1976, doi:10.3762/bjnano.9.187

• optical antenna primarily consists of measuring the current-to-voltage characteristics IT(Vdc). An example is illustrated in Figure 3a. In this graph, the current density (JT = IT/A) is displayed for an arbitrary tunneling junction area A, chosen at 100 nm2. For a tunneling barrier subject to a small

• applied bias, the transport may be described by Simmons’ equation of tunneling electrons [40]: where , A and d are the effective area and width of the junction, m is the electron mass, and h is Planck’s constant. The average barrier height includes the presence of an image potential that reduces the

• barrier height. Considering that the work function of gold is ca. 5.4 eV, Equation 1 is usually valid for applied bias voltages up to a few volts. The shape of the tunneling characteristics of IT(Vdc) essentially depends on the parameters d and with minor corrections from the effective area A [41]. These

Nonlinear effect of carrier drift on the performance of an n-type ZnO nanowire nanogenerator by coupling piezoelectric effect and semiconduction

• Yuxing Liang,
• Shuaiqi Fan,
• Xuedong Chen and
• Yuantai Hu

Beilstein J. Nanotechnol. 2018, 9, 1917–1925, doi:10.3762/bjnano.9.183

• being negatively charged. At the same time, a Schottky barrier formed between the AFM tip and the nanowire and the piezoelectric potential will not disappear as long as the mechanical stress is maintained. This potential can be made use of to generate an electrical current [30]. Recently, Fan et al

Electrical characterization of single nanometer-wide Si fins in dense arrays

• Steven Folkersma,
• Janusz Bogdanowicz,
• Andreas Schulze,
• Paola Favia,
• Dirch H. Petersen,
• Ole Hansen,
• Henrik H. Henrichsen,
• Peter F. Nielsen,
• Lior Shiv and
• Wilfried Vandervorst

Beilstein J. Nanotechnol. 2018, 9, 1863–1867, doi:10.3762/bjnano.9.178

• technique uses the so-called punch-through current, i.e., a short current pulse of magnitude Ipulse applied between two electrodes, which causes the breakdown of the native oxide barrier [12][13][14] and hence creates the conductive path required to inject Iin into the investigated material. Empirically, it

The role of the Ge mole fraction in improving the performance of a nanoscale junctionless tunneling FET: concept and scaling capability

• Hichem Ferhati,
• Fayçal Djeffal and
• Toufik Bentrcia

Beilstein J. Nanotechnol. 2018, 9, 1856–1862, doi:10.3762/bjnano.9.177

• exhibits better electrostatic behavior and less parasitic ambipolar conduction than the other designs. In fact, this behavior can be attributed to two essential effects: Firstly, the enhanced tunneling current resulting from the low tunneling barrier giving rise to a higher probability of electron transfer

• at the source/channel interface. Secondly, the heterostructure at the channel/drain interface can be beneficial for sufficiently enlarging the tunneling barrier under reverse-bias conditions in order to effectively suppress the undesired ambipolar conduction. Moreover, we can notice that the

• tunneling barrier width at the source/channel junction by varying the Ge concentration. Figure 3a shows the transfer characteristics associated of the proposed Si1−xGex/Si/Ge DG-HJ-JL TFET design with different Ge mole fractions. Increasing the Ge content leads to an increase of the drain current. This is

Toward the use of CVD-grown MoS₂ nanosheets as field-emission source

• Geetanjali Deokar,
• Nitul S. Rajput,
• Junjie Li,
• Francis Leonard Deepak,
• Wei Ou-Yang,
• Nicolas Reckinger,
• Carla Bittencourt,
• Jean-Francois Colomer and
• Mustapha Jouiad

Beilstein J. Nanotechnol. 2018, 9, 1686–1694, doi:10.3762/bjnano.9.160

• factor) is a particular value of the principal Schottky–Nordheim barrier function U. β is the local electrical field enhancement factor. is the work function of the emitter (considered to be 4.04 eV here [29]). In Figure 6a, the current density versus electric field (J–E) curve of the transferred MoS2

Light extraction efficiency enhancement of flip-chip blue light-emitting diodes by anodic aluminum oxide

• Yi-Ru Huang,
• Yao-Ching Chiu,
• Kuan-Chieh Huang,
• Shao-Ying Ting,
• Po-Jui Chiang,
• Chih-Ming Lai,
• Chun-Ping Jen,
• Snow H. Tseng and
• Hsiang-Chen Wang

Beilstein J. Nanotechnol. 2018, 9, 1602–1612, doi:10.3762/bjnano.9.152

• process (45 min) were carried out. The second pore-widening process was conducted to eliminate possible residues in the barrier layer (Al2O3) of the AAO [47][48][49]. The second pore widening process was performed with durations of 60, 70, or 80 min, and the resulting samples were denoted as AAO60, AAO70

Spatial Rabi oscillations between Majorana bound states and quantum dots

• Jun-Hui Zheng,
• Dao-Xin Yao and
• Zhi Wang

Beilstein J. Nanotechnol. 2018, 9, 1527–1535, doi:10.3762/bjnano.9.143

• Majorana bound states that have an exponentially protected small splitting energy. As shown in Figure 1a, one of the Majorana bound states is coupled to the quantum dot with a single electron tunneling through a potential barrier. The barrier is produced by a voltage gate, which is implemented between the

• quantum dot is coupled to one of the Majorana bound states by electron tunneling through a potential barrier between the dot and the Majorana island. This coupling can be described by a tunneling Hamiltonian, where T is the tunneling strength that is taken as a real number for simplicity. Here we consider

• an oscillating tunneling strength T = T0 + 2T1cosωt, with T0 being the static tunneling strength, T1 the oscillating tunneling strength, and ω the oscillating frequency for the tunneling strength. It can be produced by an ac gate voltage controlling the tunneling barrier [39]. When the driving

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

• SRO, or respectively, SRON were deposited on Si and quartz glass substrates by PECVD using processes described in [16][17]. Small amounts of 1% PH3/Ar, or respectively, 10% B2H6/SiH4 were added to the Si-rich layers (both SRO and SRON) whereas in all cases the SiO2 barrier layers remained undoped. All