Dependence of lattice strain relaxation, absorbance, and sheet resistance on thickness in textured ZnO@B transparent conductive oxide for thin-film solar cell applications

• Kuang-Yang Kou,
• Yu-En Huang,
• Chien-Hsun Chen and
• Shih-Wei Feng

Beilstein J. Nanotechnol. 2016, 7, 75–80, doi:10.3762/bjnano.7.9

• oxide; textured ZnO; Introduction Thin-film solar cells require a transparent conductive oxide (TCO) to allow light to reach the absorber layers and create the electrical current. Due to its superior characteristics, including a wide band gap, high dielectric constant, high exciton binding energy (60

• ]. The variation in the physical properties of nanostructures drastically influences the optoelectronic properties of ZnO [11][12][13]. X-ray-excited optical luminescence of ZnO nanoneedles shows a sharp band gap emission and a broad red emission related to surface defects, while that of ZnO

• size and weaker quantum size effect. The band gap energy, Eg, of a semiconductor can be estimated by extrapolating the linear portion of the absorbance square to zero. As shown in Table 1, as the thickness increases, the red-shifted Eg is consistent with the weaker quantum size effect. The lower Eg of

Current-induced runaway vibrations in dehydrogenated graphene nanoribbons

• Rasmus Bjerregaard Christensen,
• Jing-Tao Lü,
• Per Hedegård and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2016, 7, 68–74, doi:10.3762/bjnano.7.8

• band gap, giving rise to the gap in the electronic transmission for the perfect ribbon as shown in Figure 1b. We have introduced a broadening of the electronic states as in Christensen et al. [6] to mimic coupling to metallic electrodes. This in effect smoothens the transmission curves Figure 1b

Evaluation of gas-sensing properties of ZnO nanostructures electrochemically doped with Au nanophases

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2016, 7, 22–31, doi:10.3762/bjnano.7.3

• used as a gas-sensing material because of its remarkable properties, such as high chemical and thermal stability, wide direct band gap, chemical sensitivity to different adsorbed gases, highly mobile conduction carriers, non-toxicity and low cost [18][19][20]. Moreover, since gas-sensing mechanism is a

Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

• Urs Gysin,
• Thilo Glatzel,
• Thomas Schmölzer,
• Adolf Schöner,
• Sergey Reshanov,
• Holger Bartolf and
• Ernst Meyer

Beilstein J. Nanotechnol. 2015, 6, 2485–2497, doi:10.3762/bjnano.6.258

• and ND the doping concentrations for the p- and n-type materials, respectively. The intrinsic charge carrier concentration can be calculated to be ni = 9.65 × 10−9 cm−3 by using the temperature-corrected values (T = 300 K) for the band gap Eg = Eg,0 − 6.5 × 10−4·T2/(T + 1300) = 3.25 eV and the

• effective density of states in the conduction (NC = 3.25 × 1015·T3/2 = 1.69 × 1019 cm−3) and valence band (NV = 4.8 × 1015·T3/2 = 2.49 × 1019 cm−3) [46]. This leads to Vb = 3.0 eV, which is a reasonable value taking into account the band gap of 4H-SiC. With a theoretically determined electron affinity of χ

• pinning at the surface at an energy around mid band gap (Ei = 4.6 eV). For SiC it was already observed before, that the measured work function seems to be largely independent of the doping concentration indicating a well defined Fermi-level pinning at approx. 4.6 eV due to intrinsic surface-state bands

Blue and white light emission from zinc oxide nanoforests

• Nafisa Noor,
• Luca Lucera,
• Thomas Capuano,
• Venkata Manthina,
• Alexander G. Agrios,
• Helena Silva and
• Ali Gokirmak

Beilstein J. Nanotechnol. 2015, 6, 2463–2469, doi:10.3762/bjnano.6.255

• nanostructures [2], nanoscale electronic devices and large area electronics has led to significant research efforts in metal-oxide semiconductors such as ZnO. ZnO is a common, low-cost, antibacterial [3] material that forms various nanostructures depending on the process conditions. It is a direct and wide band

• gap semiconductor (≈3.4 eV) with large exciton binding energy (60 meV). ZnO nanowires have been shown to yield stimulated emission with optical pumping (e.g., nanowire laser) [4] and have been demonstrated as photodetectors [5]. ZnO films have also been used in transparent thin film transistors [6

Influence of wide band gap oxide substrates on the photoelectrochemical properties and structural disorder of CdS nanoparticles grown by the successive ionic layer adsorption and reaction (SILAR) method

• Mikalai V. Malashchonak,
• Alexander V. Mazanik,
• Olga V. Korolik,
• Еugene А. Streltsov and
• Anatoly I. Kulak

Beilstein J. Nanotechnol. 2015, 6, 2252–2262, doi:10.3762/bjnano.6.231

• General and Inorganic Chemistry, National Academy of Sciences of Belarus, Surganov St. 9/1, 220072 Minsk, Belarus 10.3762/bjnano.6.231 Abstract The photoelectrochemical properties of nanoheterostructures based on the wide band gap oxide substrates (ZnO, TiO2, In2O3) and CdS nanoparticles deposited by the

• ; semiconductor photoelectrochemistry; wide band gap oxide; Introduction Quantum dot sensitized solar cells (QDSSCs) utilize light absorbed by semiconductor nanoparticles (CdS, CdSe, CdTe, PbS, etc.) deposited on wide band gap oxide (WBGO) scaffolds (TiO2, ZnO, In2O3) which act as a photoanode [1][2][3][4][5][6

• with a systematic comparison of Raman spectra for the SILAR-grown NPs illustrating their dependence on the number of SILAR cycles and the wide band gap oxide substrate used. Results and Discussion SEM, BET, and XRD studies of ZnO, TiO2, and In2O3 electrodes Top and cross-sectional scanning electron

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

• information about some electronic properties of semiconductor compounds. Absorption spectra were acquired in diffuse reflection mode (Rdiff) and are shown in Figure 4a for ZnO1−xClx samples. It can be seen that chlorine doping leads to a shift of the band gap energy, Egap, to higher energies, and there is a

• carriers one knows the so-called Burstein–Moss effect [69][70]: Valence-band electrons need to be excited into vacant states at higher energies due to a substantial population of Bloch functions near the lower edge of the conduction band. As a consequence the band gap gets overestimated. It should also be

• HRTEM (scalebar 10 nm) of the ZnO1−xClx material. See also Figure S4 (Supporting Information File 1). (a) Absorption spectra in diffuse reflection modus, room temperature photoluminescence spectra; overview (b) and band gap region (c). (d) PL spectra recorded at T = 7 K. Hashes (blue): ZnO (Dcryst = 22

Nonconservative current-driven dynamics: beyond the nanoscale

• Brian Cunningham,
• Tchavdar N. Todorov and
• Daniel Dundas

Beilstein J. Nanotechnol. 2015, 6, 2140–2147, doi:10.3762/bjnano.6.219

• = 0.36361. Noninteracting electrons are considered throughout. As in [13], we compress the chain to a lattice spacing of R = 2.373 Å to suppress a Peierls distortion and resultant band gap that form after geometry relaxation. Landauer steady state In the adiabatic steady-state method for the electronic

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

• carrier mobility and velocity of graphene is utilized in ballistic and high switching speeds devices [3][4]. However, the very large off-current of graphene at room temperature, which is associated with the small band gap, renders it incapable of being integrated as a building block for pure carbon-based

• defect reduces the paths of conducting channels, making larger effective transport gaps. However, with the reduction of paths, the mobility and carrier density at higher energies is extremely reduced. Figure 1c shows the band structure of ideal and defect AGNR. Compared to the ideal AGNR, the band gap of

• of the effective band gap (Figure 1c) is considerable. Figure 2b shows the transfer characteristics of the transistors. As shown in the figure, compared to the ideal GNRFET, ELD-GNRFET has a lower current value in various gate voltages. Thanks to a significant increase of the effective band gap, off

Simulation of thermal stress and buckling instability in Si/Ge and Ge/Si core/shell nanowires

• Suvankar Das,
• Amitava Moitra,
• Mishreyee Bhattacharya and
• Amlan Dutta

Beilstein J. Nanotechnol. 2015, 6, 1970–1977, doi:10.3762/bjnano.6.201

• for next generation transistor devices. The radial heterostructure offers the advantage of control of the band gap and charge carrier mobility by tuning their size [5] and selecting suitable impurity doping scheme [3][6]. In addition, they exhibit significantly suppressed phonon thermal conductivity

Paramagnetism of cobalt-doped ZnO nanoparticles obtained by microwave solvothermal synthesis

• Jacek Wojnarowicz,
• Sylwia Kusnieruk,
• Tadeusz Chudoba,
• Stanislaw Gierlotka,
• Witold Lojkowski,
• Wojciech Knoff,
• Malgorzata I. Lukasiewicz,
• Bartlomiej S. Witkowski,
• Anna Wolska,
• Marcin T. Klepka,
• Tomasz Story and
• Marek Godlewski

Beilstein J. Nanotechnol. 2015, 6, 1957–1969, doi:10.3762/bjnano.6.200

• attractive material with a wide range of applications such as: transparent transistors based on semiconducting transparent oxides [4], ultraviolet (UV) light blockers [5], photocatalysts [6] or antibacterial uses [7]. The energy band gap of ZnO is ≈3.3 eV at room temperature, corresponding to a wavelength of

Temperature-dependent breakdown of hydrogen peroxide-treated ZnO and TiO₂ nanoparticle agglomerates

• Sinan Sabuncu and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2015, 6, 1897–1903, doi:10.3762/bjnano.6.193

• ]. These studies indicate that hydrogen peroxide treatment not only influences the surface properties of NPs but also changes the band gap of ZnO and TiO2 NPs and shifts the emission wavelength to blue wavelengths. Another study showed that the hydrogen peroxide treatment of TiO2 NPs increases the

Metal hydrides: an innovative and challenging conversion reaction anode for lithium-ion batteries

• Luc Aymard,
• Yassine Oumellal and
• Jean-Pierre Bonnet

Beilstein J. Nanotechnol. 2015, 6, 1821–1839, doi:10.3762/bjnano.6.186

• hydride MgH2 exist as α, β and γ, with the space groups P42/mnm (tetragonal, a = b = 4.516 Å, c = 3.020 Å) Pa−3 (cubic) and Pbcn (orthorhombic, a = 4.526 Å, b = 5.448 Å, c = 4.936 Å), respectively. The tetragonal phase is the more stable phase. These hydrides exhibit band gap energies of 5.3, 5.6 and 4.2

Nonlinear optical properties of near-infrared region Ag₂S quantum dots pumped by nanosecond laser pulses

• Li-wei Liu,
• Si-yi Hu,
• Yin-ping Dou,
• Tian-hang Liu,
• Jing-quan Lin and
• Yue Wang

Beilstein J. Nanotechnol. 2015, 6, 1781–1787, doi:10.3762/bjnano.6.182

• use as NIR emitters [12][13][14][15][16][17][18][19]. Ag2S QDs have a band gap of 1.1 eV, the appropriate narrow band gap for NIR emission, and a relatively large absorption coefficient, which may enhance the emission intensity. Therefore, Ag2S QDs provide a powerful route for improving the optical

• surrounding the QDs will be changed. Ag2S has a narrow band gap, which leads to the strong absorption characteristics of Ag2S and which makes Ag2S particularly suitable for use in optical detectors and solar cells. Conclusion In summary, we have demonstrated, using NIR Ag2S QDs pumped by 532 nm nanosecond

A facile method for the preparation of bifunctional Mn:ZnS/ZnS/Fe₃O₄ magnetic and fluorescent nanocrystals

• Houcine Labiadh,
• Tahar Ben Chaabane,
• Romain Sibille,
• Lavinia Balan and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2015, 6, 1743–1751, doi:10.3762/bjnano.6.178

• diodes [6][7] or solar cells [8]. Conventional QDs systems have a core/shell architecture. The shell, generally constituted of a wide band gap material such as ZnS, prevents degradation and preserves the optical properties [3][4]. Magnetic nanoparticles have many advantages, especially for biological

The eNanoMapper database for nanomaterial safety information

• Nina Jeliazkova,
• Charalampos Chomenidis,
• Philip Doganis,
• Bengt Fadeel,
• Roland Grafström,
• Barry Hardy,
• Janna Hastings,
• Markus Hegi,
• Vedrin Jeliazkov,
• Nikolay Kochev,
• Pekka Kohonen,
• Cristian R. Munteanu,
• Haralambos Sarimveis,
• Bart Smeets,
• Pantelis Sopasakis,
• Georgia Tsiliki,
• David Vorgrimmler and
• Egon Willighagen

Beilstein J. Nanotechnol. 2015, 6, 1609–1634, doi:10.3762/bjnano.6.165

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

• therefore is able to probe the optical properties, e.g., to measure the local band gap through a monochromated STEM [98][99]. Before the introduction of a monochromator and/or cold FEG, the energy resolution was limited to approximately 1 eV, which hinders the low-loss part of the EELS spectrum to be

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

• 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

Current–voltage characteristics of manganite–titanite perovskite junctions

• Benedikt Ifland,
• Patrick Peretzki,
• Birte Kressdorf,
• Philipp Saring,
• Andreas Kelling,
• Michael Seibt and
• Christian Jooss

Beilstein J. Nanotechnol. 2015, 6, 1467–1484, doi:10.3762/bjnano.6.152

• evaluation for photovoltaic systems reveal vastly different properties ranging from narrow band gap manganite oxides perovskites with hopping transport to broad band gap lead halide perovskites [9][12][13][14]. For the lead halide perovskites the constituents are: A = CH3NH3+, B = Pb, and X = I, Br, Cl

• colossal electro-resistance (CER). For the perovskite heterojunction La0.32Pr0.33Ca0.33MnO3 with 0.5 wt % Nb-doped SrTiO3, the influence of a magnetic field on the temperature-dependent photovoltaic effect was reported [5]. In contrast, STNO has a band gap of around Eg = 3.2 eV [25] and the reported type

• then applied to the analysis of data sets collected from PCMO/STNO p–n heterojunctions. Despite the absence of a band gap above the charge ordering temperature of TCO ≈ 240 K, photocarrier lifetimes in PCMO are of the order of ns [41]. The diffusion length of electron–hole-type excitations at room

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

• ]. Although a promising photocatalytic candidate, the catalytic activity of SrTiO3 is still heavily influenced by its considerably large band gap of ≈3.25 eV and high dielectric permittivity [14]. The calculated band structure of SrTiO3 shows that the top of the valence band (VB) and the bottom of the

• of SrTiO3. Previous works showed that doping with 3d (V, Fe, Ni) and 4f (Nd, Sm, Er) ions can significantly decrease the band gap through the hybridization of the Ti-3d and dopant-d states [16][17]. Additionally, the doped SrTiO3 also has an improved conductivity. Several groups have reported the

• light. This means that V5+ ion doping improves the impurity level and narrows the band gap of SrTiO3, leading to the enhanced light absorption. Additionally, based on earlier research regarding 3d ion doping for SrTiO3, V5+ doping may also improve the conductivity of SrTiO3. Hence, the higher

Addition of Zn during the phosphine-based synthesis of indium phospide quantum dots: doping and surface passivation

• Natalia E. Mordvinova,
• Alexander A. Vinokurov,
• Oleg I. Lebedev,
• Tatiana A. Kuznetsova and
• Sergey G. Dorofeev

Beilstein J. Nanotechnol. 2015, 6, 1237–1246, doi:10.3762/bjnano.6.127

• and the distance between them is constant could be explained through the doping scheme in Figure 12. This scheme solely depends on the assumption that the Zn levels are pinned in the band gap when the size of the QDs changes. The valence band energy of bulk InP is set to zero. The quantum confinement

• of particles decreases the band gap increases on the account of moving electron levels. The Zn-based PL originates from an electron in the electron levels and a hole in the Zn level, which skips by excitation from the QDs hole levels. In this case Zn-based PL should be size dependent, differ from the

• of a Zn level in the InP band gap and to a red shifted tail in the PL spectra. By using photochemical etching with HF, we have confirmed that the Zn dopant atoms are situated inside the InP nanoparticles. Experimental Synthesis Colloidal InP QDs with an average diameter of 1.5–6.5 nm were prepared

Electronic interaction in composites of a conjugated polymer and carbon nanotubes: first-principles calculation and photophysical approaches

• Florian Massuyeau,
• Jany Wéry,
• Jean-Luc Duvail,
• Serge Lefrant,
• Abu Yaya,
• Chris Ewels and
• Eric Faulques

Beilstein J. Nanotechnol. 2015, 6, 1138–1144, doi:10.3762/bjnano.6.115

• required to produce mobile charge carriers in the tubes. This assumption is valid assuming that the Fermi level of the semiconducting tubes remains within their band gap, i.e., that there is no charge-transfer doping from the surrounding environment. Through density functional calculations we explore below

• to LDA to some extent counteracts what would otherwise be an overestimation in the modelling of the band gap of the experimental tubes. Specifically, we note that our calculated bandgap for the (7,0) nanotube of 0.08 eV is considerably underestimated compared to experiments, due to the well-known

• limitations of the LDA approximation. It is nonetheless in agreement with previous LDA calculations [25][26][27], notably with studies [27] showing that full structural and lattice optimization drops the calculated LDA band gap from around 0.5 eV [27][28] to around 0.2 eV. The main results of our DFT model

Superluminescence from an optically pumped molecular tunneling junction by injection of plasmon induced hot electrons

• Kai Braun,
• Xiao Wang,
• Andreas M. Kern,
• Hilmar Adler,
• Heiko Peisert,
• Thomas Chassé,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2015, 6, 1100–1106, doi:10.3762/bjnano.6.111

• photons with an energy equivalent to the band gap. The quantum efficiency of 10−5 shown in panel (iii) of Figure 2b is comparable to the state of the art [2][10]. Comparing the data in Figure 2a and Figure 2b we note a dramatic effect of the incident radiation: For a positive bias the voltage-dependent

From lithium to sodium: cell chemistry of room temperature sodium–air and sodium–sulfur batteries

• Philipp Adelhelm,
• Pascal Hartmann,
• Conrad L. Bender,
• Martin Busche,
• Christine Eufinger and
• Juergen Janek

Beilstein J. Nanotechnol. 2015, 6, 1016–1055, doi:10.3762/bjnano.6.105

• ) and look for electric transport in Li2O2. Since Li2O2 is an intrinsic wide band gap insulator, additional transport mechanisms such as transport along metal-type surfaces or hole polaron transport are proposed [88][89][90][91]. The assumption of a soluble redox-active species (e.g., soluble O2−), as

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

• nanodevices and nanosystems [1][2]. It has a wide band gap (3.37 eV), and a high exciton binding energy (60 meV) at room temperature, which allows for an efficient UV emission from the exciton, making it suitable for UV-emitting devices [3]. Depending on the form and the shape of the deposited thin films

• appears in this spectrum is attributed to the porosity of this material and the spaces between the nanostructures; this is confirmed by the HRSEM images. Estimation of the optical band gap Ignoring the reflectivity, which is expected to be low, the coefficient α may be determined from the results of the

• transmittance by using Equation 1: where d is the thickness of the thin film, and T is measured transmission. In consequence, the relation between the coefficient and the photon energy for direct transition is , where A is a constant, Eg is the optical band gap, the plot of this relation has a linear region