Search for charged-particle emission from deuterated palladium foils

Results are presented from the search for energetic charged particles possibly emitted from a deuterium loaded palladium electrode in an electrolysis cell. Within the sensitivity of our experimental set-up, we could not find events originating from ‘cold nuclear fusion’ processes. Based on this outcome, an upper limit for the non-observation of CNF of 2.0×10^?2s^?1 emitted charged particles per cm³(Pd) resp. 1.6×10^?24s^?1 emitted charged particles per D pair has been deduced.     

Die Diffusionskoeffizienten und mittleren freien Weglängen der geladenen und neutralen Radon-Folgeprodukte in Luft

The knowledge of the diffusion coefficients of radioactive atoms and ions in air is very important in a number of investigations on and computations of the attachment of radon decay products to aerosol particles. In this work measurements of the diffusion coefficients of neutral and charged²¹²Pb atoms are reported. The values found areD ₀=(7.6±0.4)·10^?2cm²s^?1 for neutral atomsD=(5.0±0.3)·10^?2cm²s^?1 for charged atoms The used method of measurement allowed to determine these constants 1–5 seconds after the formation aged²¹²Pb atoms, so that a “cluster” formation was improbable. The mean free path for neutral (λ₀=(4.9±0.3)·10^?6cm) and charged (λ=(3.2±0.2)· 10^?6cm) lead 212 atoms in air were computed from the measured diffusion coefficients. All obtained results were compared with values, calculated from theory.     

Anisotropic charge transport properties of chrysene derivatives as organic semiconductor: A computational study

We used density functional theory to calculate the angular resolution anisotropic charge mobility of the substituted chrysene molecules, viz, 4,10‐diphenoxychrysene (DPC), 4,10‐bis(phenylsulfanyl)chrysene (BPSC), and ethyl 8,9,12‐trimethoxychrysene‐6‐carboxylate (ETCC). The highest occupied molecular orbital–lowest unoccupied molecular orbital gap for DPC, BPSC, and ETCC was calculated to be 3.92, 3.83, and 3.81 eV, respectively, which inferred the compounds to be wide‐band‐gap semiconductors indicating that the compounds should have high stability in atmospheric conditions. The fact is also supported by electronic band‐structure calculation. In addition, higher electron affinity of studied compounds as compared with the bare chrysene molecule imparts enhancement of n‐type character in the compounds. The maximum hole ( ) and electron mobilities ( ) for DPC compound were found to be 0.739 cm²V^?1s^?1 and 0.319 cm²V^?1s^?1, respectively, at Φ = 0°. On the other hand, in the case of BPSC crystal, comparatively larger anisotropic electron mobility (0.709 cm²V^?1s^?1 at Φ = 0° and Φ = 179.90°) than the hole mobility (0.208 cm²V^?1s^?1 at Φ = 127.19° and Φ = 307.10°) was noted. Similarly, in ETCC, the parallel dimers were found to contribute maximum and of 0.052 and 0.102 cm²V^?1s^?1, respectively, at Φ = 0°. The substitution of ‐SPh in BPSC and ‐OCH₃ and ‐CO₂CH₂CH₃ in ETCC have relatively more impact on band reduction than ‐OPh in DPC, thus facilitating electron transport in BPSC and ETCC.     

An influence of deposition temperature on structural,optical and electrical properties of sprayed ZnO thin films of identical thickness

Nanocrystalline ZnO thin films were deposited at different temperatures (T_s = 325 °C–500 °C) by intermittent spray pyrolysis technique. The thickness (300 ± 10 nm) independent effect of T_s on physical properties was explored. X-Ray diffraction analysis revealed the growth of wurtzite type polycrystalline ZnO films with dominant c-axis orientation along [002] direction. The crystallite size increased (31 nm–60 nm) and optical band-gap energy decreased (3.272 eV–3.242 eV) due to rise in T_s. Scanning electron microscopic analysis of films deposited at 450 °C confirmed uniform growth of vertically aligned ZnO nanorods. The films deposited at higher T_s demonstrated increased hydrophobic behavior. These films exhibited high transmittance (>91%), low dark resistivity (～10^?2 Ω-cm), superior figure of merit (～10^?3 Ω^?1) and low sheet resistance (～10² Ω/□). The charge carrier concentration (η -/cm³) and mobility (μ – cm²V^?1s^?1) are primarily governed by crystallinity, grain boundary passivation and oxygen desorption effects.     

Die experimentelle Bestimmung der Koeffizienten der Anlagerung der neutralen und elektrisch geladenen Radon-Folgeprodukte an Aerosole

The attachment of the neutral and charged²¹²Pb atoms to monodisperse polystyene latex aerosols with diameters 10^?5-2·10^?4 cm is measured and compared with the theoretical values. The method of measurement allowed to determine the difference between the attachment coefficients of the ions and neutral atoms. The obtained values are explained with the diffusion model by considering the electrostatic forces between the diffusing ions and the aerosol particles. The best agreement of the measured attachment coefficients with those of theory is obtained if the image forces of the²¹²Pb ions (good dried latex aerosols!) are neglected in the computations.     

Aerosol emission and collection in styrene-contaminated air remediation with a multi-stage plasma system

A multi-stage plasma reactor is developed for the remediation of styrene-contaminated air and the removal of plasma-generated aerosols. The plasma aerosol is fully positively charged and has a unimodal-like size distribution. More than 90% of the plasma aerosols are produced from styrene-related reaction processes. The use of an electrostatic precipitator not only leads to aerosol collection but also enhances styrene removal. Notably, below the onset corona voltage, an aerosol collection of up to 36% is observed. We also find that the collection of ultrafine aerosols (diameters < 100 nm) can be improved by using a bi-polar charging reactor.     

Pulsed dephotolysis in emulsion nanocrystals of silver halides: I. Recombination processes at early stages of photolysis

Early stages of formation of few-atom clusters of photolytic silver in AgBr nanocrystals are studied using the pulsed dephotolysis technique. It is shown that dephotolysis is characterized by a clearly pronounced dependence on the pulse duration of nonactinic and actinic radiations, the highest efficiency of dephotolysis being achieved for nanosecond pulses. The rate constant of recombination of free electrons with captured holes is determined (κ_p = (6 ± 1) × 10^?9 cm³ s^?1) and the dependence of the recombination rate on the level of excitation is found. The maximum recombination rate for the highest excitation level is found to be V _p ^max = 10⁹ s^?1 and the surface concentration of recombination centers is determined to be N _r = (2 ± 0.5) × 10¹¹ cm^?2.     

Lithium diffusion in Li<Subscript>3</Subscript>V<Subscript>2</Subscript>(PO<Subscript>4</Subscript>)<Subscript>3</Subscript>-based electrodes: a joint analysis of electrochemical impedance,cyclic voltammetry,pulse chronoamperometry,and chronopotentiometry data

In order to establish the mechanism and to determine the parameters of lithium transport in electrodes based on lithium-vanadium phosphate (Li₃V₂(PO₄)₃), the kinetic model was designed and experimentally tested for joint analysis of electrochemical impedance (EIS), cyclic voltammetry (CV), pulse chronoamperometry (PITT), and chronopotentiometry (GITT) data. It comprises the stages of sequential lithium-ion transfer in the surface layer and the bulk of electrode material’s particles, including accumulation of lithium in the bulk. Transfer processes at both sites are of diffusion nature and differ significantly, both by temporal (characteristic time, τ) and kinetic (diffusion coefficient, D) constants. PITT data analysis provided the following D values for the predominantly lithiated and delithiated forms of the intercalation material: 10^?9 and 3 × 10^?10 cm² s^?1, respectively, for transfer in the bulk and 10^?12 cm² s^?1 for transfer in the thin surface layer of material’s particles. D values extracted from GITT data are in consistency with those obtained from PITT: 3.5–5.8 × 10^?10 and 0.9–5 × 10^?10 cm² s^?1 (for the current and currentless mode, respectively). The D values obtained from EIS data were 5.5 × 10^?10 cm² s^?1 for lithiated (at a potential of 3.5 V) and 2.3 × 10^?9 cm² s^?1 for delithiated (at a potential 4.1 V) forms. CV evaluation gave close results: 3 × 10^?11 cm² s^?1 for anodic and 3.4 × 10^?11 cm² s^?1 for cathodic processes, respectively. The use of complex experimental measurement procedure for combined application of the EIS, PITT, and GITT methods allowed to obtain thermodynamic E,c dependence of Li₃V₂(PO₄)₃ electrode, which is not affected by polarization and heterogeneity of lithium concentration in the intercalate.     

Analysis of current–voltage and capacitance–voltage characteristics of perylene-monoimide/n-Si Schottky contacts

The electrical and interface state properties of Au/perylene-monoimide (PMI)/n-Si Schottky barrier diode have been investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements at room temperature. A good rectifying behavior was seen from the I–V characteristics. The series resistance (R_s) values were determined from I–V and C–V characteristics and were found to be 160 Ω and 53 Ω, respectively. The barrier height (Φ_b) of Au/PMI/n-Si Schottky diode was found to be 0.694 eV (I–V) and 0.826 eV (C–V). The ideality factor (n) was obtained to be 4.27 from the forward bias I–V characteristics. The energy distribution of interface state density (N_ss) of the PMI-based structure was determined, and the energy values of N_ss were found in the range from E_c ? 0.508 eV to E_c ? 0.569 eV with the exponential growth from midgap toward the bottom of the conduction band. The values of the N_ss without R_s are 2.11 × 10¹² eV^?1 cm^?2 at E_c ? 0.508 eV and 2.00 × 10¹² eV^?1 cm^?2 at E_c ? 0.569 eV. Based on the above results, it is clear that modification of the interfacial potential barrier for metal/n-Si structures has been achieved using a thin interlayer of the perylene-monomide.     

A change in the electro-physical properties of narrow-band CdHgTe solid solutions acted upon by a volume discharge induced by an avalanche electron beam in the air at atmospheric pressure

The effect of a nanosecond volume discharge forming in an inhomogeneous electrical field at atmospheric pressure on the CdHgTe (MCT) epitaxial films of the p-type conduction with the hole concentration 2·10¹⁶ cm³ and mobility 500 cm²·V^–1·s^–1 is studied. The measurement of the electrophysical parameters of the MCT specimens upon irradiation shows that a layer exhibiting the n-type conduction is formed in the near-surface region of the epitaxial films. After 600 pulses and more, the thickness and the parameters of the layer are such that the measured field dependence of the Hall coefficient corresponds to the material of the n-type conduction. Analysis of the preliminary results reveals that the foregoing nanosecond volume discharge in the air at atmospheric pressure is promising for modification of electro-physical MCT properties.     

The synthesis of organic molecules in a laser plasma similar to the plasma that emerges in hypervelocity collisions of matter at the early evolutionary stage of the Earth and in interstellar clouds

Ions of organic molecules and polymers as well as multiply ionized hydrocarbons were synthesized and detected with a time-of-flight mass analyzer in laboratory experiments simulating with a laser the plasma processes that accompany a hypervelocity micrometeorite impact on the target surface. A hypervelocity impact of micrometeorites moving at velocities of 80 km s^?1 on a inorganic target was simulated with a Q-switched laser. The laser provided a power density of 10⁹?10¹¹ W cm^?2 in a spot with an impact diameter of 30–150 μm for a pulse duration of 7–10 ns and a laser plasma electron density of 10⁵?10⁶ K. The ions of organic compounds are shown to be synthesized mostly during the free expansion of a hot laser plasma at the stage of its cooling and recombination if, initially, the plasma was completely atomized and ionized. Molecular ions have high yields only for a carbon target. The results obtained indicate that organic or other polyatomic compounds can be abiogenically synthesized in intense hypervelocity meteorite impacts on the Earth’s surface at the early stage of its formation during meteorite showers and in hypervelocity collisions of dust particles in interstellar molecular clouds.     

Synthesis,electrical and optical properties of CuNdO2 compound

CuNdO₂, a p-type transparent conducting oxide has been synthesized by conventional solid-state reaction. The XRD and TEM results show that the pure delafossite phase is obtained, furthermore, the EDX results indicate the sample is obviously oxygen-rich. The p-type conduction of CuNdO₂ was confirmed by Hall and Seebeck measurements. Carrier concentration and mobility at room temperature are around 1.38×10¹⁷ cm^?3 and 1.24 cm²V^?1s^?1, respectively. On the other hand, the optical band gap of CuNdO₂ is estimated to be around 3.14 eV, which agrees well with the theoretical result predicted by the first-principle calculation.     

Recombination measurements at low energies with Ar16+ and Ar18+ ions in a dense, cold electron target

Recombination of multiply charged ions with electrons at very low relative energies has become a major topic of interest, due to the observation of rates which are enhanced beyond the expectations for radiative recombination. We present results for Ar¹⁶⁺ and Ar¹⁸⁺ ions from systematic measurements along the argon isonuclear sequence using a high density cold electron beam target (n_e = 7 × 10⁹ cm^-3) at the UNILAC of GSI. The transverse and longitudinal temperatures of the electron beam were determined from DR resonance features observed with metastable Ar¹⁶⁺ (2³S) ions. The rate at E_rel = 0 for radiative recombination of completely stripped Ar¹⁸⁺ calculated with electron beam temperatures kT_∥ = 0.002 eV, kT_⊥ = 0.2 eV amounts to α = 10^-9 cm³ s^-1. This is exceeded by nearly a factor of 10 by the rate measured in experiments with Ar¹⁸⁺ ions. This revised version was published online in August 2006 with corrections to the Cover Date.     

A study of electrical enhancement of polycrystalline MgZnO/ZnO bi-layer thin film transistors dependence on the thickness of ZnO layer

A polycrystalline MgZnO/ZnO bi-layer was deposited by using a RF co-magnetron sputtering method and the MgZnO/ZnO bi-layer TFTs were fabricated on the thermally oxidized silicon substrate. The performances with varying the thickness of ZnO layer were investigated. In this result, the MgZnO/ZnO bi-layer TFTs which the content of Mg is about 2.5 at % have shown the enhancement characteristics of high mobility (6.77–7.56 cm² V⁻¹ s⁻¹) and low sub-threshold swing (0.57–0.69 V decade⁻¹) compare of the ZnO single layer TFT (μ_FE = 5.38 cm² V⁻¹ s⁻¹; S.S. = 0.86 V decade⁻¹). Moreover, in the results of the positive bias stress, the ΔV_on shift (4.8 V) of MgZnO/ZnO bi-layer is the 2 V lower than ZnO single layer TFT (ΔV_on = 6.1 V). It reveals that the stability of the MgZnO/ZnO bi-layer TFT enhanced compared to that of the ZnO single layer TFT.     

Vacuum ultraviolet resonance line radiation source from rare gas atoms and ions for UHV photoelectron spectroscopy

A source and differential pumping system for producing high intensity resonance line radiation from rare gas atoms and ions for ultrahigh vacuum (UHV) photoelectron spectroscopy has been developed. Photoelectron count rates from a gold sample, as measured with a double-pass cylindrical mirror analyzer at pass energy 15 eV and 0.10 eV resolution, are ～ 300,000 c s^?1 for the He(I) (21.22 eV) line and ～30000 c s^?1 for the He(II) (40.81 eV) line. The source design is based on the principle of the electrostatic charged particle oscillator and is capable of sustaining discharges over the pressure range 1 to ～ 10^?6 torr. The discharge segment consists of a cylindrical cold cathode surrounding two tungsten rod anodes which are held at high positive potential. Three stages of differential pumping are employed in order that the vacuum in the main spectrometer chamber can be maintained at 2 × 10^?10 torr during operation. The calculated helium flow reaching the main chamber under these conditions is < 101 s^?1. Details of the construction and operating characteristics of the source are presented.     

Effects of Ti addition on sol-gel derived InO and InZnO thin film transistors

In this study, we have newly developed titanium-indium oxide (TiInO) and titanium-indium zinc oxide (TiInZnO) thin films as the active channel layer in thin film transistors (TFTs) by the sol-gel process. The effects of adding Ti on TiInO and TiInZnO TFTs were investigated. The addition of Ti elements can suppress formation of oxygen vacancies because of the stronger oxidation tendency of Ti relative to that of Zn or In. TiInO and TiInZnO TFTs showed lower off currents and higher on/off current ratios than pure InO and InZnO TFTs. A TiInO TFT doped with 10.31 mol% Ti showed good performance with an on/off current ratio greater than 10⁷, and a field-effect mobility of 1.91 cm² V^?1 S^?1. A TiInZnO TFT doped with 2.92 mol % Ti showed an on/off current ratio greater than 10⁶, and a field-effect mobility of 0.45 cm² V^?1 S^?1.     

Modified structural,morphological and photoelectrochemical properties of 120 MeV Ag9+ ion irradiated BaTiO3 thin films

The effects of high electronic energy deposition on the structure, surface topography, optical property and photoelectrochemical behavior of barium titanate thin (BaTiO₃) films have been investigated by irradiating films with 120 MeV Ag⁹⁺ ions at different ion fluences in the range of 1 × 10¹¹–3 × 10¹² ions cm^?2. Barium titanate thin films were deposited on indium tin oxide-coated glass substrate by sol–gel spin coating method. The structure of the film was crystalline with tetragonal phase. Surface topography was studied by atomic force microscopy detailing the values of roughness of the films. Maximum photocurrent density of 1.78 mA cm^?2 at 0.4 V/SCE and applied bias photon-to-current efficiency (ABPE) of 0.91% was observed for BaTiO₃ film irradiated at 1 × 10¹¹ ions cm^?2.     

Development of sulphurized SnS thin film solar cells

Thin films of tin sulphide (SnS) have been grown by sulphurization of sputtered tin precursor layers in a closed chamber. The effect of sulphurization temperature (T_s) that varied in the range of 150–450 °C for a fixed sulphurization time of 120 min on SnS film was studied through various characterization techniques. X-ray photoelectron spectroscopy analysis demonstrated the transformation of metallic tin layers into SnS single phase for T_s between 300 °C and 350 °C. The X-ray diffraction measurements indicated that all the grown films had the (111) crystal plane as the preferred orientation and exhibited orthorhombic crystal structure. Raman analysis showed modes at 95 cm⁻¹, 189 cm⁻¹ and 218 cm⁻¹ are related to the A_g mode of SnS. AFM images revealed a granular change in the grain growth with the increase of T_s. The optical energy band gap values were estimated using the transmittance spectra and found to be varied from 1.2 eV to 1.6 eV with T_s. The Hall effect measurements showed that all the films were p-type conducting nature and the layers grown at 350 °C showed a low electrical resistivity of 64 Ω-cm, a net carrier concentration of 2 × 10¹⁶ cm⁻³ and mobility of 41 cm² V⁻¹ s⁻¹. With the use of sprayed Zn_0.76Mg_0.24O as a buffer layer and the sputtered ZnO:Al as window layer, the SnS based thin film solar cell was developed that showed a conversion efficiency of 2.02%.     

X-ray-line plasma satellites of ions in solid target plasmas produced by picosecond laser pulse

The X-ray lines of ions in a solid target interacting with picosecond laser pulses of moderate intensity (2×10¹⁷ W/cm²) were measured on the “Neodim” laser facility. X-ray Ly _α emission spectra of hydrogen-like fluorine ions were observed. Satellite lines were also observed, evidencing the presence of intense plasma oscillations. The positions and separation between the satellites allow their assignment to the intense electrostatic oscillations with an amplitude larger than 10⁸ V/cm and a frequency of about 7× 10¹⁴ s^?1 that is noticeably lower than the laser frequency ω_las～1.8×10¹⁵ s^?1. It is suggested that these oscillations may be due to strong plasma turbulence caused by the development of plasma oscillations of the Bernstein-mode type under the action of a strong magnetic field generated in plasma. The experimental results are compared with the calculated spectra of multicharged ions.     

Single-electron charge transfer and excitations at collisions between Bi<Superscript>4+</Superscript> ions in the kiloelectronvolt energy range

Pioneering theoretical data for single-electron charge transfer and excitations due to collisions between Bi⁴⁺ ions in the ground (6s) and metastable (6p) states are gained in the collision energy interval 5–75 keV in the center-of-mass frame. The cross sections of the processes are calculated in terms of the close-coupling method in the basis of two-electron quasi-molecular states for the Coulomb trajectory of nuclei. It is found that single-electron capture into the singlet 6s ² states of Bi³⁺ ions makes a major contribution to the charge transfer total cross section for Bi⁴⁺(6s) + Bi⁴⁺(6s) collisions (reaction 1), whereas single-electron capture into the singlet 6s6p states is the basic contributor to the total cross section in Bi⁴⁺(6s) + Bi⁴⁺(6p) collisions (reaction 2). In the collision energy interval mentioned above, the collision cross sections vary between 1.2 × 10^?17 and 1.9 × 10^?17 cm² for reaction 1 and between 3.8 × 10^?17 and 5.3 × 10^?17 cm² for reaction 2. In reaction 1, the 6s → 6p excitation cross sections vary from 0.6 × 10^?16 to 0.8 × 10^?16 cm² for the singlet channel and from 2.2 × 10^?16 to 2.8 × 10^?16 cm² for the triplet channel. The calculation results are compared with the data obtained in experiments with crossed ion beams of kiloelectronvolt energy. The fraction of metastable ions in the beams is estimated by comparing the experimental data with the weighted average theoretical results for the cross sections of reactions 1 and 2. From the data for the charge transfer cross sections, one can estimate particle losses in relativistic beams due to a change in the charge state of the ions colliding with each other in the beam because of betatron oscillations.