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Gallium-doped zinc oxide thin films were prepared on glass substrates by dc magnetron sputtering under various hydrogen contents in sputtering ambient. The carrier concentration of the films deposited at low-temperatures (80 and 160 °C) was increased due to the incorporation of hydrogen atoms, acting as shallow donors. A low resistivity of 4.0×10-4 Ω cm was obtained for the film grown at 160 °C with H2 10%, which has a carrier concentration of 8.2×1020/cm3. The beneficial effect of hydrogen doping was not observed for the films deposited at 270 °C. Both carrier concentration and mobility were decreased by the addition of hydrogen gas in the sputtering ambient. Variations in the electrical transport properties upon vacuum annealing showed that the difference is attributed to the thermal stability of interstitial hydrogen atoms in the films. The hydrogen incorporation was found to induce the lattice expansion and the free carrier absorption in near infrared range. The investigation of the structural and optical properties of the films upon annealing also revealed that the incorporated hydrogen atoms are unstable at high temperature, which is consistent with the results obtained in the electrical properties. [ABSTRACT FROM AUTHOR]

BiFeO3 (BFO) films were processed on BaTiO3 (BTO) buffered (111) Pt/Ti/SiO2/Si substrate by pulsed laser deposition. Improved ferroelectric properties, as well as induced ferromagnetism, were observed by the insertion of a BTO layer for rather thick BFO films (450 nm) deposited at an oxygen pressure of 40 mTorr. Reduced leakage current, coercive field, and increased ferroelectric saturation of BFO/BTO bilayer films were obtained and compared with those of BFO films. In order to better understand the buffer layer effect on the magnetic properties, two thinner (140 and 220 nm) BFO films were also deposited and investigated. Both films showed ferromagnetic hysteresis loops and larger in-plane magnetization than out-of-plane magnetization. By introducing the BTO barrier layer, the remnant and saturated magnetizations were also increased. These results demonstrated not only the interface constraint effect but also a coupling between ferroelectric BTO and magnetic BFO, which deserve further investigation. [ABSTRACT FROM AUTHOR]

an important step towards the realisation of silicon-based tandem solar cells using silicon quantum dots embedded in a silicon dioxide (SiO) matrix, single-junction silicon quantum dot (Si QD) solar cells on quartz substrates have been fabricated. The total thickness of the solar cell material is 420 nm. The cells contain 4 nm diameter Si quantum dots. The impacts of post-metallisation treatments such as phosphoric acid (HPO) etching, nitrogen (N) gas anneal and forming gas (Ar: H) anneal on the cells' electrical and photovoltaic properties are investigated. The Si QD solar cells studied in this work have achieved an open circuit voltage of 410 mV after various processes. Parameters extracted from dark I- V, light I- V and circular transfer length measurement (CTLM) suggest limiting mechanism in the Si QD solar cell operation and possible approaches for further improvement. [ABSTRACT FROM AUTHOR]

Abstract: Thermoelectric bismuth telluride thin films were prepared on SiO2/Si substrates by radio-frequency (RF) magnetron sputtering. Co-sputtering method with Bi and Te targets was adopted to control films'' composition. Bi x Te y thin films were elaborated at various deposition temperatures with fixed RF powers, which yielded the stoichiometric Bi2Te3 film deposition without intentional substrate heating. The effects of deposition temperature on surface morphology, crystallinity and electrical transport properties were investigated. Hexagonal crystallites were clearly visible at the surface of films deposited above 290 °C. Change of dominant phase from rhombohedral Bi2Te3 to hexagonal BiTe was confirmed with X-ray diffraction analyses. Seebeck coefficients of all samples have negative value, indicating the prepared Bi x Te y films are n-type conduction. Optimum of Seebeck coefficient and power factor were obtained at the deposition temperature of 225 °C (about −55 μV/K and 3×10−4 W/K2·m, respectively). Deterioration of thermoelectric properties at higher temperature could be explained with Te deficiency and resultant BiTe phase evolution due to the evaporation of Te elements from the film surface. [Copyright &y& Elsevier]

Abstract: Bismuth thin films were prepared on glass substrates with RF magnetron sputtering and the effects of deposition temperature on surface morphology and their electrical transport properties were investigated. Grain growth of bismuth and the coalescence of grains were observed above 393K with field emission secondary electron microscopy. Continuous thin films could not be obtained above 448K because of the segregation of grains. Hall effect measurements showed that substrate heating yields the decrease of carrier density and the increase of mobility in exponential ways until 403K. Resistivity of sputter deposited bismuth films has its minimum (about 0.7×10−3 Ωcm) in range of 403–433K. Annealing of bismuth films deposited at room temperature was carried out in a radiation furnace with flowing hydrogen gas. The change of resistivity was not significant due to the cancellation of the decrease of carrier density and the increase of mobility. However, the abrupt change of electrical properties of film annealed above 523K was observed, which is caused by the oxidation of bismuth layer. [Copyright &y& Elsevier]

Abstract: Molecular dynamics simulations of energetic ion bombardments were carried out to investigate physical sputtering process. Bombardments of several ion species (He+, Ne+, Ar+, Kr+, Xe+) on a modeled amorphous silicon oxide substrate were simulated to find out the effect of plasma ion species on sputtering. Reflection characteristics of ions, fraction of energy deposited on substrate, and sputtering yield were obtained for each species, which collide on the surface at incident angle (φ i) of 60° and with incident energy (E i) of 100eV. Simulations of Ar+ bombardments on SiO2 and Si3N4 substrates were carried out to compare the sputtering yield of two substrates at various incident angles (, 30°, 45°, 60°, 75°, 85°) and with incident energies (E i=100 and 200eV). The sputtering yield of silicon nitride was more than twice of that of silicon oxide in this range of incident energy. The preferential sputtering of O or N atoms rather than Si atoms was also observed in the physical sputtering of these multi-component substrates (SiO2 and Si3N4). [Copyright &y& Elsevier]

Abstract: Indium tin oxide (ITO) films with various thicknesses in range of 40–280nm were prepared onto a plastic substrate (PMMA). Deposition was carried out with RF magnetron sputtering method and the substrate temperature was held at ∼70°C, in lack of the thermal damage to the polymer substrate. Changes in microstructure and electrical properties of ITO films according to their thicknesses were investigated. It was found that amorphous layer with thickness of 80nm was formed at the interface on the polymer substrate and polycrystalline ITO could be obtained above the thickness. Conductivity of ITO films was found to be strongly dependent on the crystallinity. Consequently, it is suggested that crystallinity of the deposited films should be enhanced at the initial stage of deposition and the thickness of amorphous region be reduced in order to prepare high quality ITO thin films on polymer substrates. [Copyright &y& Elsevier]

A simple fabrication of gate-controlled nanodevices made of the Co nanodots on tungsten (W)-nanowire templates by using conventional photolithography and a thin film technique is reported. The combined multiple grain nanobridge allows the observation of the Coulomb gap up to a temperature as high as 200 K and shows nonlinear current-voltage characteristics up to 250 K. The combination of Co dots with straight W-nanowire templates opens possibilities of reproducible blockade devices. [ABSTRACT FROM AUTHOR]

Transfer printing of inorganic amorphous thin film semiconductors remains a challenge because no suitable sacrificial layer is available. In article number 1601269, Dong‐Ho Kim, Sungjin Jo, and co‐workers demonstrate a versatile transfer printing method using a water‐soluble germanium oxide sacrificial layer for fabricating stretchable a‐Si thin film solar cells. This first attempt to fabricate stretchable solar cells with thin film semiconductors will significantly broaden the scope of solar cell applications. [ABSTRACT FROM AUTHOR]

Abstract: The nucleation and coalescence of silver islands on coated glass was investigated by in situ measurements of the sheet resistance. Sub-monolayer amounts of niobium and other transition metals were deposited prior to the deposition of silver. It was found that in some cases, the transition metals lead to coalescence of silver at nominally thinner films with smoother topology. The smoothing or roughening effects by the presence of the transition metal can be explained by kinetically limited transition metal islands growth and oxidation, followed by defect-dominated nucleation of silver. [Copyright &y& Elsevier]

MgO films have been suggested as the protective layer for alternating current plasma display panels, which play significant roles in preventing the failure of the dielectric layer from sputtering by ions, in lowering the firing and sustain voltages due to a higher secondary electron emission coefficient (γ), and in allowing higher optical transmittance. To investigate the structural and optical properties of the MgO protective films, MgO thin films were deposited on glass substrates by vacuum arc deposition with a magnesium metal target at various oxygen gas flows. To measure the erosion rate of the MgO protective layers, an acceleration test method was used, namely, the Ar+ ion beam-induced erosion test. The effect of moisture on the optical transmittance of the MgO protective layers was also examined. It was found that the optical transmittance decreased with the relative humidity. X-Ray diffraction and AFM have also been used to study the behaviors of the structure and surface morphology. [Copyright &y& Elsevier]

Highlights: [•] We fabricated TiNi thin films using advanced multi-target sputtering system. [•] We examine martensitic transformation of TiNi thin films by heat-treatment. [•] Composition effect on martensitic transformation of TiNi films was also examined. [•] Ideal heat-treatment condition of TiNi thin films for application was reported. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the effects of hydrogen plasma treatment on the physical and electrical properties of fluorine-doped tin oxide (FTO) films used for amorphous silicon (a-Si) thin film solar cells. A slight increase in carrier concentration by the hydrogen doping effect was observed for the FTO film exposed to the hydrogen plasma for 5 min. For further exposure to the plasma, the chemical reduction became prominent and resulted in deterioration of the electrical and optical properties of the film. XPS analysis revealed that the chemical reduction of SnO2 to Sn metallic state occurs on the surface region. It was found that the defects formed by hydrogen plasma act as recombination centers at the interface between FTO electrode and p-layer of a-Si solar cells. This phenomenon resulted in the deterioration of the cell performance. The averaged conversion efficiency (6.82%) of the cells on pristine FTO hydrogen substrate was decreased to 5.81% for the cells on FTO treated for 5 min, which is mainly attributed to the decrease in short-circuit current density. [Copyright &y& Elsevier]

Abstract: This paper reports the effects of p-type NiO thin films deposited by magnetron sputtering on performance of organic solar cells (OSCs). The effects of a p-type NiO interfacial layer between indium tin oxide (ITO) and active layer were examined systematically to increase the efficiency and stability of OSCs. Characterization of the sputter-deposited NiO film revealed it to be a p-type semiconductor with a resistivity of 2.7×10−2 Ωcm. Its conduction type was demonstrated by measuring the Seebeck coefficient (+70μV/K). The insertion of a 5nm-thick NiO layer resulted in a power conversion efficiency and a fill factor as high as 2.8±0.1% and 0.62±0.02, respectively, which are comparable to OSCs adopting the conventional conducting polymer, PEDOT:PSS. Furthermore, lifetime of the OSCs adopting the NiO layer was 3 times higher than that of the conventional PEDOT:PSS. [ABSTRACT FROM AUTHOR]

Abstract: ZnO films were deposited by the PEALD using oxygen and hydrogen plasmas at 100 °C. As the oxygen plasma increased by 200 W, the growth rate saturated to 1.78 Å/cycle over 150 W. The film resistivity increased to 4.95 × 103 Ω cm without a significant change of film crystallinity but the carrier concentration drastically decreased to 4.87 × 1013 cm−3 as the oxygen plasma power increased to 200 W. Interestingly, as the hydrogen plasma power increased during ZnO PEALD (DEZ + O2 plasma + H2 plasma), the growth rate, film crystallinity and resistivity drastically decreased. Although the crystallinity of z-axis ZnO film decreased, the ZnO film exhibited the conducting property. Based on x-ray photoelectron spectroscopy and auger electron spectroscopy analysis, the higher oxygen plasma power may help to decrease oxygen vacancies but the higher hydrogen plasma power can induce in generation oxygen vacancies and hydroxyl groups in ZnO films, strongly relating with the changes of carrier concentrations. The hydrogen and oxygen plasma exhibited conflicting behaviors in terms of ZnO electrical property. Thus, the electrical properties on ZnO film PEALD are easily manipulated even on very low deposition temperature, with only selecting oxygen and hydrogen plasma conditions. [Copyright &y& Elsevier]