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EN
Dye sensitized solar cells were fabricated using ZnO nanostructured photoelectrodes sensitized with N-719 or Rose Bengal dyes. We assessed the device performance as a function of the sensitization time and found a dependence on time for the N-719 and no significant changes for the Rose Bengal. Furthermore, we observe that the structure of the N-719 molecule beneficial for sensitization of TiO₂ may lead to the degradation of the ZnO crystals and a growth of an amorphous shell limiting dye performance in the cells.
EN
Zn-O-N thin films fabricated by reactive radio frequency magnetron sputtering have been investigated for their compositional, structural, transport and optical properties. In contrast to processes in which the reaction for either the oxide or the nitride is dominant, the multireaction process yields a substantially amorphous films with the Hall mobility within the range from 15 to 80 cm²/(V s). In addition, it has been observed that the Hall mobility increases for Zn-O-N. Since it has a narrower bandgap than ZnO, it is put forward that the high mobility is due to the valence band maximum in this material lying above the trap states in the gap commonly observable in ZnO. These traps originate from oxygen vacancies and are localized at the bottom of the band gap influencing the carrier mobility.
EN
Ar-O-Zn plasma discharges created during DC reactive magnetron sputtering of a Zn target and RF reactive magnetron sputtering of a ceramic ZnO target were investigated and compared by means of the Langmuir probe measurements in order to determine the mechanism of growth of porous Zn films during DC-mode Zn reactive sputtering. The power supplied to the magnetrons during the sputtering was kept at 125 W and the plasma was characterised as a function of oxygen content in the sputtering gas mixture, ranging from 0 to 60% for two gas pressures related to porous Zn film deposition, namely 3 mTorr and 5 mTorr. Based on the correlation of plasma properties measurements with scanning electron microscope imaging and X-ray diffraction of the films deposited under selected conditions it was found that the growth of porous, polycrystalline Zn films was governed by high electron density in the plasma combined with a high electron temperature and an increased energy of the ions impinging on the substrate.
EN
Transparent supercapacitors were fabricated using nanostructures ZnO electrodes deposited using reactive magnetron sputtering. By fine tuning the deposition process parameters the electrodes with different morphologies were obtained, from hierarchical through sponge-like to nanocolumnar. The device performance related to the electrode morphology was assessed. It was found that the nanocolumnar electrodes provided best performance both in terms of effective device capacitance (18.3 μF/cm²) and transparency ( ≈ 100% in the visible range). The worst performance, with 80% lower effective capacitance, was obtained in the devices with the sponge-like morphology.
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Gas Sensors Based on ZnO Structures

88%
EN
The paper presents the results of investigations concerning sensor structures based on porous layers of zinc oxide (ZnO) sensitive to a selected gaseous environment. The investigations comprised analyses of the influence of the gaseous environment on the optical properties of a sensor structure, in particularly on the change of the spectral characteristics of optical transmission within the range of ultraviolet light and in the visible range. These presented investigations were carried out in such a gaseous environment as nitrogen dioxide NO_2 in synthetic air.
EN
The capacitance-voltage measurements were applied for characterization of the semiconductor/dielectric interface of GaN MOS capacitors with SiO_2 and HfO_2/SiO_2 gate stacks. From the Terman method low density of interface traps (D_{it} ≈ 10^{11} eV^{-1} cm^{-2}) at SiO_2/GaN interface was calculated for as-deposited samples. Samples with HfO_2/SiO_2 gate stacks have higher density of interface traps as well as higher density of mobile charge and effective charge in the dielectric layers. High quality of SiO_2/GaN interface shows applicability of SiO_2 as a gate dielectric in GaN MOSFET transistors.
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76%
EN
Fabrication of a Ti₂AlN MAX phase for contact applications to GaN-based devices is reported. Sample characterisation was done by means of X-ray diffraction and secondary ion mass spectroscopy. Successful Ti₂AlN monocrystalline growth was observed on GaN and Al₂O₃ substrates by annealing sputter-deposited Ti, Al and TiN layers in Ar flow at 600°C. The phase was not seen to grow when the layers were deposited on Si (111) or when the first layer on the substrate was TiN. N-type GaN samples with Ti₂AlN layers showed ohmic behaviour with contact resistivities in the range 10¯⁴ Ωcm².
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64%
EN
The paper presents investigations concerning the analysis of photonic structures with grating couplers. In the paper basic theoretically information on photonic structures with grating couplers is presented. The results of numerical investigations on photonic structures with grating couplers are discussed, too. Investigations show an essential influence of the geometrical parameters of grating couplers on the effectiveness of the input and output of optic power into and out of this photonic structure. In the paper the selected results of experimental realizations of photonic structures with grating couplers based on zinc oxide ZnO are presented.
EN
ZnO (0001) layers on sapphire (0001) substrates were fabricated by means of high temperature high vacuum magnetron sputtering. The layers were deposited onto a thin MgO buffer and a low temperature ZnO nucleation layer, which is a technology commonly used in MBE ZnO growth. This paper reports on using this technology in the sputtering regime.
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Response of ZnO/GaN Heterostructure to Ion Irradiation

64%
EN
In this paper we report on the analysis of Al⁺-implanted ZnO/GaN bilayers in search for the damage production mechanism and possible ion mixing. 100 nm or 200 nm thick ZnO epitaxial layers were grown on GaN substrates by either sputter deposition or atomic layer deposition technique followed by adequate annealing. Ion irradiations of ZnO/GaN were carried out at room temperature using 200 keV Al⁺ ions with fluences of 2×10¹⁵ and 10¹⁶ at./cm². Unprocessed and irradiated samples were characterized by the Rutherford backscattering spectrometry in channeling geometry (RBS\c), X-ray diffraction and transmission electron microscopy. Additionally, secondary ion mass spectrometry was employed for the aforementioned samples as well as for the implanted samples subjected to further annealing. It was found that the damage distributions in ZnO/GaN differ considerably from the corresponding defect profiles in the bulk ZnO and GaN crystals, most probably due to an additional strain originating from the lattice mismatch. Amount of intermixing appears to be relatively small; apparently, efficient recombination prevents foreign atoms to relocate to large distances.
EN
We report fabrication and characterization of ultrathin NbN and NbTiN films designed for superconducting photodetectors. Our NbN and NbTiN films were deposited on Al_2O_3 and Si single-crystal wafers by a high-temperature, reactive magnetron sputtering method and, subsequently, annealed at 1000°C. The best, 18 nm thick NbN films deposited on sapphire exhibited the critical temperature of 15.0 K and the critical current density as high as ≈ 8 × 10^6 A/cm^2 at 4.8 K.
EN
Electrical properties of RF magnetron sputtered p-NiO films were characterized after fabrication and after gamma irradiations using ^{137}Cs and ^{60}Co sources. Electrical parameters are obtained from the Hall measurements, impedance spectroscopy and C-V measurement of n-Si/p-NiO junction diodes. The results show that resistivity of the NiO film is gradually increased following after sequential irradiation processes because of the decrease in holes' concentration. Hole concentration of a NiO film decreases from the original value of 4.36 × 10^{16} cm^{-3} to 2.86 × 10^{16} cm^{-3} after ^{137}Cs γ irradiation with doses of 10 Gy. In the case of γ irradiation from ^{60}Co source, hole concentration of the film decreases from 6.3 × 10^{16}/cm^3 to 4.1 × 10^{16}/cm^3 and to 2.9 × 10^{16}/cm^3 after successive expositions with a dose of 20 Gy.
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52%
EN
We present our research on fabrication and structural and transport characterization of ultrathin superconducting NbN layers deposited on both single-crystal Al_2O_3 and Si wafers, and SiO_2 and Si_3N_4 buffer layers grown directly on Si wafers. The thicknesses of our films varied from 6 nm to 50 nm and they were grown using reactive RF magnetron sputtering on substrates maintained at the temperature 850°C. We have performed extensive morphology characterization of our films using the X-ray diffraction method and atomic force microscopy, and related the results to the type of the substrate used for the film deposition. Our transport measurements showed that even the thinnest, 6 nm thick NbN films had the superconducting critical temperature of 10-12 K, which was increased to 14 K for thicker films.
EN
In the paper, the results of technological investigations on planar optical waveguides based on high band gap oxide semiconductors were presented. Investigations concerned the technologies of depositing very thin layers of: zinc oxide ZnO, titanium dioxide TiO_2 and tin dioxide SnO_2 on substrates of quartz glass plates. There were investigated both morphological structures of the produced layers and their optical properties. The paper also presents investigations on the technology of input-output light systems in the Bragg grating structures.
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