To gain insight into the deposition and stability of oxygen-containing plasma polymer films, the properties of amorphous oxygenated hydrocarbon (a-C:H:O) plasma polymer coatings deposited from acetone vapors under various experimental conditions are investigated. Apart from the discharge power, the influence of the reactive carbon dioxide (CO{sub 2}) gas on the structure of the resulting films is studied. It is found by characterization using X-ray Photoelectron Spectroscopy and Fourier-Transform Infrared Spectroscopy that the experimental conditions particularly influence the amount of oxygen in the deposited a-C:H:O plasma polymer films. The O/C elemental ratio increases with increasing amount of CO{sub 2} in the working gas mixture (up to 0.2 for 24 sccm of CO{sub 2} at 30 W) and decreases with increasing RF discharge power (down to 0.17 for 50 W). Furthermore, the nature of bonds between the oxygen and carbon atoms has been examined. Only low amounts of double and triple bonded carbon are observed. This has a particular influence on the aging of the plasma polymer films which is studied both in ambient air and in distilled water for up to 4 months. Overall, stable a-C:H:O plasma polymer films are deposited comprising low amounts (up to about 5%) of ester/carboxyl groups. - Highlights: • Hydrocarbon plasma polymer films with variable oxygen content can be prepared. • Stable oxygenated hydrocarbon plasma polymers contain max 5% of ester/carboxyl groups. • Acetone-derived plasma polymer films can be used as permanent hydrophilic surfaces.  More>>

An environmentally friendly aqueous sol–gel process has been optimised to deposit indium tin oxide (ITO) thin films, aiming to improve the film properties and reduce the deposition costs. It was demonstrated how parameters such as cation concentration and viscosity could be applied to modify the physical properties of the sol and thereby reduce the need for multiple coatings to yield films with sufficient conductivity. The conductivity of the thin films was enhanced by adjusting the heat treatment temperature and atmosphere. Both increasing the heat treatment temperature of the films from 530 to 800 °C and annealing in reducing atmosphere significantly improved the electrical conductivity, and conductivities close to the state of the art sputtered ITO films were obtained. A pronounced decreased conductivity was observed after exposing the thin films to air and the thermal reduction and ageing of the film was studied by in situ conductivity measurements. - Highlights: • Spin coating of indium tin oxide using an aqueous solution was optimised. • The conductivity was enhanced by thermal annealing in reducing atmosphere. • The conductivity of is comparable to the conductivity of sputtered films. • A relaxation process in the reduced thin film was observed after exposure in air.  More>>

Orderly structured ZnO films were fabricated by electrochemical deposition combined with a templating method. The floating-transfer technique was used to assemble polystyrene sphere (PS) templates. Hierarchical structures containing two-diameter PS were easily assembled on the surface of F–SnO{sub 2} conductive glass (FTO). When used as a working electrode, the FTO glass coated with PS templates provided arrayed cavities to accommodate ZnO crystals under potentiostatic deposition and was ultimately covered by ordered, porous ZnO films after removal of PS templates. The morphologies of the samples were examined by field-emission scanning electron microscopy and crystallographic information for the samples was obtained from X-ray powder diffraction measurements. The results indicate that ZnO films fabricated by electrochemical deposition show excellent template replication over large areas and exhibit the typical wurtzite structure. - Highlights: • PS templates with tunable layers assembled by a floating-transfer technique are presented. • ZnO films with controllable morphologies are prepared by using electrochemical deposition. • With a binary PS template, hierarchical ZnO films are obtained.  More>>

This paper reports the study of growth kinetics of ion beam sputtered aluminum thin films. Dynamic scaling theory was used to derive the kinetics from atomic force microscopy (AFM) measurements. AFM imaging revealed that surface incorporates distinctly different morphologies. Variation in deposition times resulted in such distinctiveness. The growth governing static (α) as well as dynamic (β) scaling exponents has been determined. The exponent α decreased as the deposition time increased from 3 to 15 min. Consequently, the interfacial width (ξ) also decreased with critical length (L{sub c}), accompanied with an increase in surface roughness. Surface diffusion becomes a major surface roughening phenomenon that occurs during deposition carried out over a short period of 3 min. Extension of deposition time to 15 min brought in bulk diffusion process to dominate which eventually led to smoothening of a continuous film. - Highlights: • Growth kinetics of ion beam sputtered Al-thin films was studied by dynamic scaling theory. • AFM images display different morphologies for different deposition times. • The growth governing scaling exponents (α and β) was determined. • Considered four different responsible smoothening/roughening phenomena.  More>>

(200)-oriented Eu-doped cerium oxide thin films were fabricated, on fused silica substrates by a chemical solution deposition method. The thin films obtained were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and photoluminescence measurements. Ce with valence state 4 + is confirmed to be predominant in Eu-doped CeO{sub 2} thin films. All the thin films were dense and crack-free, and showed bright orange-red emissions under ultraviolet light excitation, originated from the {sup 5}D{sub 0} → {sup 7}F{sub 1} and {sup 5}D{sub 0} → {sup 7}F{sub 2} transitions of Eu{sup 3+} ions. Structure distortions induced by Eu-doping affected the light emission of electric dipole transition {sup 5}D{sub 0} → {sup 7}F{sub 2}. The strongest photoluminescent intensity was observed in the thin films with a Eu-doping content x of 0.08, indicating the existence of concentration quenching effect of photoluminescence. Lifetime study of photoluminescence indicated that the decrease of lifetime was originated from augmented pathway for deactivating excited Eu{sup 3+} ions. Our study suggests that Eu{sup 3+}-doped CeO{sub 2} thin films have potential applications in optoelectronic devices. - Highlights: • Ce{sub 1−x}Eu{sub x}O{sub 2} thin films were prepared by chemical solution deposition. • The thin films show strong red-orange emission. • There is concentration quenching effect of photoluminescence. • Eu-doping leads to structure distortion of the thin films. • The thin films have potential applications in optoelectronic devices.  More>>

Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films were prepared by sol–gel method and sulfurization process. The effects of the sulfurization temperature on the structural, morphological, compositional, and opto-electrical properties of the CZTS films were investigated. X-ray diffraction and Raman spectroscopy analyses confirmed the formation of CZTS films. With increasing sulfurization temperature, the crystallinity of the films was enhanced, which was accompanied by metallic deficiency, especially tin loss. When the sulfurization temperature was increased from 460 to 540 °C, the optical band-gap value decreased from 1.63 to 1.38 eV, while the resistivity and mobility increased from 1.415 to 1313 Ω·cm and from 0.372 to 7.231 cm{sup 2}/V·s, respectively. The best CZTS film properties with a bandgap of 1.47 eV, resistivity of 581.5 Ω·cm, carrier concentration of 2.165 × 10{sup 16} cm{sup −3} and mobility of 1.411 cm{sup 2}/(V·s) were achieved at a sulfurization temperature of 500 °C, and make the films suitable as absorbers for solar cells. - Highlights: • The Cu{sub 2}ZnSnS{sub 4} (CZTS) films were prepared by sol–gel method following sulfurization. • The sulfurization temperature has the effects on the electrical properties. • The tin loss is increased with the increasing sulfurization temperature. • The secondary phases like ZnS make the electrical properties worse. • The CZTS films sulfurized at 500 °C have the best opto-electrical characteristics.  More>>

Nano-layers of ZnO (thickness 2–300 nm) were deposited on the surface of p-Si(100), SiO{sub x}/p-Si(100), and n-Si(111) using the atomic layer deposition technique. Morphology, microstructure, and electronic structure of the ZnO/Si(100), ZnO/SiO{sub x}/Si(100), and n- Si(111) films were characterized using scanning electron microscopy, X-ray diffraction and reflectometry, and X-ray photoelectron spectroscopy. The layers have good adhesion to the substrate, polycrystalline structure, and uniform thickness. Starting from the thickness of 4 nm, the hexagonal crystal structure of zincite (wurtzite-type) could be detected with a weak texture changing from [100] to [001] with increasing thickness of the layer. Desorption of H{sub 2}O and CO{sub 2} at ∼ 10{sup −4} Pa from the surface under irradiation with visible light (λ > 500 nm)—the interval of ZnO transparency—was measured by mass-spectrometry. This proves a sensitization of the photocatalytically active ZnO films to the visible light by silicon substrate and opens possibilities of using the composite Si/ZnO materials. - Highlights: • ZnO films (2–300-nm thick) were deposited on Si(100) by atomic layer deposition. • Si substrate sensitizes ZnO nano-layer to the visible light (λ > 500 nm). • Si/ZnO heterojunction can act as a visible-light-sensitive photocatalyst.  More>>

Platinum, palladium and silver films with different microstructures have been prepared on differently orientated yttrium-stabilised zirconia (YSZ) substrates by pulsed laser deposition and then annealed at temperatures between 200 °C and 850 °C. Thereby, an influence of the type of metal, of the microstructure of the as-prepared film and of the orientation of the substrate on the annealing behaviour could be determined. The following annealing effects were observed for platinum, palladium and silver films: i) sharpening of the film boundary, ii) smoothing of the film surfaces, iii) sharpening of the texture [thereby: reduction of the fraction of small angle and twin grain boundaries], iv) grain growth and accordingly reduction of the fraction of grains as well as v) grooving at grain boundaries, vi) void formation at the metal|YSZ-interface, vii) hole formation within the films and viii) reduction of the fraction of droplets. In the case of palladium films also ix) oxidation [between 300 °C ≤ T < 750 °C] and stronger de-wetting phenomena than for platinum [with x) waving of the film and xi) island formation at T ≥ 750 °C] have been found. Silver films are not oxidised, but show stronger de-wetting phenomena than platinum and palladium, with xi) island formation and xii) evaporation of the silver at T ≥ 550 °C. Interestingly, silver films on (111) orientated YSZ are thermally much more stable than silver films on the other orientated substrates up to 750 °C. The annealing effects were described by interface, grain boundary and surface energy minimization. - Highlights: • The thermal stability of Pt, Pd and Ag films has been investigated up to 850 °C. • Annealing effects are e.g. reduction of the fraction of twins and island formation. • Pd is also oxidised between 300 °C ≤ T < 750 °C. • Annealing effects depend on type of metal and on its initial microstructure. • Annealing effects depend also on the orientation of substrate.  More>>

Bismuth vanadate, Bi{sub 4}V{sub 2}O{sub 11}, and related compounds with various metal (Me) substitutions, Bi{sub 4}(Me{sub x}V{sub 1−x}){sub 2}O{sub 11−δ}, show some of the highest ionic conductivities among the known solid oxide electrolytes. Films of Cu and Ti substituted bismuth vanadate were prepared by an aerosol deposition method, a spray coating process also described as room temperature impact consolidation. Resultant films, several microns in thickness, were dense with good adhesion to the substrate. Scanning electron microscopy and high temperature X-ray diffraction were used to monitor the effects of temperature on the structure and microstructure of the film. The particle size remained nano-scale while microstrain decreased rapidly up to 500 °C, above which coarsening and texturing increased rapidly. Impedance measurements of films deposited on inter-digital electrodes revealed an annealing effect on the ionic conductivity, with the conductivity exceeding that of a screen printed film, and approaching that of bulk ceramic. - Highlights: • Cu and Ti doped bismuth vanadate films were prepared by aerosol deposition (AD). • Dense 3–5 μm thick films were deposited on alumina, silicon and gold electrodes. • Annealing of the AD-layer increases the conductivity by 1.5 orders of magnitude. • Effect of temperature on structure and microstructure was investigated.  More>>

A facile process to fabricate icephobic surfaces was developed by spin-coating the polydimethylsiloxane-b-poly(fluorinated acrylate) (PDMS-b-PFA) block copolymers on the substrate. The surface microstructure and chemical composition of the block copolymer films can be adjusted by changing the PDMS content. Icephobic properties of the copolymer surface were mainly ascribed to “flexible-hard” microphase separation and the ratio of fluorine to silicon. The appropriate microphase domain size and the fluorine/silicon ratio could weaken the interaction of ice and copolymer surface and delay icing of water droplets on the copolymer surface. The copolymers containing 15 wt.% PDMS showed the most outstanding icephobicity by depressing the interaction between ice and the copolymer surface. - Highlights: • PDMS-b-PFA block copolymers with different PDMS contents were synthesized. • Surface microstructure can be adjusted by changing the content of PDMS. • The ratio of fluorine/silicon increased with the decrease of the PDMS content. • Ice adhesion and shear strength were decreased by the synergistic effect of silicon and fluorine.  More>>