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Showing papers on "Evaporation (deposition) published in 2005"


Journal ArticleDOI
TL;DR: In this article, the authors report the technical progress that has occurred in the last decade in the development of Cd-free buffer layers for Cu(In,Ga)Se2-based thin-film solar cells and modules.

329 citations


Journal ArticleDOI
TL;DR: Based on the appearance of the as-synthesized products, this paper showed that substrate temperature and catalyst are the critical factors for controlling the size and the structure of various kinds of ZnS nanostructures, such as nanorods, nanowires, nanobelts and nanosheets.
Abstract: ZnS nanostructures with different morphologies, sizes, and microstructures were synthesized by the evaporation of ZnS nano-powders. Based on the appearance of the as-synthesized products, we show that substrate temperature and catalyst are the critical factors for controlling the size and the structure of various kinds of ZnS nanostructures, such as nanorods, nanowires, nanobelts, and nanosheets. Within a certain temperature range, products with a specific morphology can be obtained. Therefore, it may be possible to obtain ZnS nanostructures with a specific morphology by controlling the reaction temperature and catalyst. This represents an important step toward the design and control of nanostructures. High-resolution electron microscopy revealed that most of the nanorods and nanowires grew along the [100] direction, whereas most of the nanobelts and nanosheets grew along [001]. Photoluminescence properties and growth mechanisms of these as-synthesized ZnS nanostructures are discussed.

269 citations


Journal ArticleDOI
TL;DR: The results show the sensitivity of the electrochemical properties of metallic nanoparticles at relatively large sizes (approximately 50 nm) and an electrochemical Ostwald ripening mechanism driven by the size dependence of the work function and standard electrode potential is proposed.
Abstract: Thermally evaporated silver nanoparticles on conducting substrates spontaneously evolve in size when immersed in pure water. The process was studied using scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and optical absorption spectroscopy. The particles are proposed to reform through an electrochemical Ostwald ripening mechanism driven by the size dependence of the work function and standard electrode potential. We also discuss prior literature experiments where this process appears to occur. Our results show the sensitivity of the electrochemical properties of metallic nanoparticles at relatively large sizes (∼50 nm).

267 citations


Journal ArticleDOI
TL;DR: In this article, large-area quasialigned nanotips of tungsten oxide have been grown by a two-step high-temperature, catalyst-free, physical evaporation deposition process.
Abstract: Large-area, quasialigned nanotips of tungsten oxide have been grown by a two-step high-temperature, catalyst-free, physical evaporation deposition process. The tungsten oxide nanotips are single crystalline with growth direction of [010]. The tungsten oxide nanotips exhibit excellent field-emission properties with a low threshold field (for an emission current density of 10mA∕cm2) ∼4.37MV∕m and uniform emission from the entire arrays, as well as high time stability. These results make tungsten oxide nanotip arrays a competitive candidate for field-emission displays.

221 citations


Journal ArticleDOI
TL;DR: In this paper, single crystalline TiO 2 nanowires have been successfully grown on alumina substrates using a high-frequency (350-KHz) dielectric heater at 1050-°C by a two-step of thermal evaporation method without using any catalyst.

167 citations


Journal ArticleDOI
TL;DR: Results indicated that the stimulated emission in these NWs involves the electron-hole plasma (EHP) and Farby-Perot (F-P) optical resonant processes at room temperature.
Abstract: Aligned CdS nanowires (NWs) were obtained through a simple thermal evaporation process with highly active CdS nanoparticles as the evaporation source. These NWs show prominent optical waveguides behavior under a continuous-wave (CW) laser excitation. Excitation intensity-dependent photoluminescence (PL) measurements show that these NWs exhibited both broad and supernarrow stimulated emission (lasing) under intense pulse optical excitation at room temperature. Raman scattering and time-resolved PL measurements were used to investigate the optical properties. The results indicated that the stimulated emission in these NWs involves the electron-hole plasma (EHP) and Farby-Perot (F-P) optical resonant processes at room temperature.

156 citations


Journal ArticleDOI
TL;DR: In this paper, the surface properties of flat titanium flat thin films were investigated by using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements.

154 citations


Journal ArticleDOI
TL;DR: In this article, a new chemical vapour deposition setup for the generation of anti-adhesive coatings on Si stamps used in nano-print lithography has been developed This is suitable for controlled co-evaporation of more than one type of silane by directly injecting a premixed silane into an evacuated deposition reactor through a septum.
Abstract: A new chemical vapour deposition setup for the generation of anti-adhesive coatings on Si stamps used in nanoimprint lithography has been developed This is suitable for controlled co-evaporation of more than one type of silane by directly injecting a premixed silane into an evacuated deposition reactor through a septum This process was found to be very flexible and resulted in reproducible coatings A surface coated with a mixture of mono- and trichlorosilanes shows a higher water contact angle than those of individual coatings, which is attributed to the interaction between the two types of silane molecules In addition, the influence of process parameters, eg water content, temperature and number of imprints, on the coating quality will be discussed

129 citations


Journal ArticleDOI
TL;DR: In this article, a modified thermal evaporation technique was used to obtain films of nanostructured WO3 with high surface roughness for gas-sensing applications.

127 citations


Journal ArticleDOI
TL;DR: In this paper, thin film solar cells were produced by using Cu2ZnSnS4 (CZTS) as an absorber, which could be successfully formed by the vapor phase sulfurization of precursors prepared by the electron-beam evaporation on the soda-lime glass substrates.
Abstract: Aiming to develop the solar cells free from both environmental contaminants and rare metals, thin film solar cells were produced by using Cu2ZnSnS4 (CZTS) as an absorber. CZTS thin films could be successfully formed by the vapor phase sulfurization of precursors prepared by the electron-beam evaporation on the soda-lime glass substrates. The atomic ratio of Cu/(Zn+Sn) was varied from nearly 0.5 to 1.2 to investigate the influence of the composition on the surface morphology and the optical properties. In order to optimize the sulfurization condition, we varied the sulfurization temperature from 510°C to 550°C. As the results, the value of the conversion efficiency of 4.53% was obtained for the cell of which CZTS absorber sulfurized at 520°C.

124 citations


Journal ArticleDOI
TL;DR: In this paper, a comprehensive study of the optical and transient photoconductive properties of pentacene and functionalized pentaene thin films was performed using x-ray diffraction, atomic force microscopy, and scanning electron microscopy.
Abstract: We present a comprehensive study of the optical and transient photoconductive properties of pentacene and functionalized pentacene thin films grown by evaporation or from solution onto a variety of substrates. The transient photoconductivity was studied over picosecond time scales using time-resolved terahertz pulse spectroscopy. The structure and morphology of the films were assessed using x-ray diffraction, atomic force microscopy, and scanning electron microscopy. Regular pentacene films grown by evaporation under similar conditions but on different substrates yielded polycrystalline films with similar morphology and similar optical and transient photoconductive properties. Single exponential or biexponential decay dynamics was observed in all of the regular pentacene films studied. Functionalized pentacene films grown by evaporation at two different substrate temperatures (as well as from solution) yielded significant variations in morphology, resulting in different optical-absorption spectra and transient photoconductivities that could be correlated with film structure. The lower limit of the charge-carrier mobility, estimated from the amplitude of the transient photoconductive response, was ∼0.02–0.04cm2∕Vs in the case of regular pentacene films and ∼0.01–0.06cm2∕Vs in the case of functionalized pentacene films, depending on the film morphology. The best functionalized pentacene films exhibited transient photoconductivity values reaching ∼30%–40% of those obtained in functionalized pentacene single-crystal samples, and showed similar power-law decay dynamics. We also report on terahertz pulse generation from voltage-biased pentacene thin films.

Journal ArticleDOI
TL;DR: In this article, a novel approach of depositing thin stimulating layer of various metals/oxides below the ITO film was tried and tested, and the response of the film with MgO catalytic layer on sensitivity and selectivity was observed.

Journal ArticleDOI
TL;DR: In this article, a Pd electrode was deposited by evaporation on the surface of the film to make a sensor configuration of Pd (top electrode)/oxide film/Ti (bottom electrode).
Abstract: Porous oxide thin films were prepared by anodic oxidation of a Ti plate in H 2 SO 4 and HF solutions. The film (s-TiO 2 ) prepared in the H 2 SO 4 solution was a mixture of anatase and rutile and contained micron-size pores. In contrast, no crystal phase appeared in the film (f-TiO 2 ) prepared in the HF solution, while the film showed submicron-size pores. A Pd electrode was deposited by evaporation on the surface of the film to make a sensor configuration of Pd (top electrode)/oxide film/Ti (bottom electrode). Both the thin film sensors exhibited a fast response to H 2 and fast recovery at 250 °C in air as well as in N 2 atmosphere. The magnitude of the response of s-TiO 2 was superior to that of f-TiO 2 , especially in N 2 atmosphere. The H 2 response of s-TiO 2 at 250 °C in air was found to vary significantly with the pretreatment conditions: additional pretreatment at 600 °C for 1 h in N 2 resulted in a deteriorated H 2 response especially in air, in comparison with that just after the firing at 600 °C for 1 h in air for ensuring the electrical contact. Thus, the surface oxidation state and morphology of the Pd electrode was suggested to affect the H 2 response of the sensors. It was revealed that the s-TiO 2 sensor without additional treatment in N 2 showed superior H 2 -sensing performance to the N 2 -treated s-TiO 2 sensor when operated in N 2 atmosphere. In addition, the response to N 2 -diluted H 2 was larger than that to air-diluted H 2 , and the interference from water vapor was negligible in N 2 atmosphere.

Journal ArticleDOI
TL;DR: In this paper, a vapor−liquid mechanism was proposed for the formation of CdS multipod-based structures, such as tetrapod-like microrods, and long branched nanowires, without the use of a catalyst.
Abstract: CdS multipod-based structures, such as flowerlike microstructures, tetrapod-like microrods, and long branched nanowires, were selectively prepared by atmospheric pressure thermal evaporation of CdS nanoparticles without the use of a catalyst. The morphologies could be well controlled by simply adjusting the deposition position. The phase structures, morphologies, and optical properties of the products were investigated by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, and photoluminescence spectroscopy. A vapor−liquid mechanism was proposed for the formation of CdS multipod-based structures. The present synthetic route is expected to be applied to the synthesis of other II−VI groups or other group's semiconducting materials with controllable morphologies.

Journal ArticleDOI
TL;DR: In this article, a single source vacuum thermal evaporation method was used to synthesize and deposit indium sulphide thin films on glass substrates and the films were analyzed by X-ray diffraction (XRD) and spectrophotometric measurements.

Journal ArticleDOI
TL;DR: In this paper, the in situ coating process of MgO or CuO on SBA-15 is anatomized by adding simple precursor salts into the synthetic system, recovering the composites via evaporation and subsequent calcination.

Journal ArticleDOI
TL;DR: In this paper, a detailed high-resolution electron microscopy analysis showed that the center core of T-ZnO nanorods consists of four hexagonal grains with a twin-like relation.
Abstract: Tetrapod zinc oxide (T-ZnO) nanorods have been synthesized by evaporation and recondensation of metallic Zn under ambient conditions. The total sizes of the T-ZnO nanostructures range from 300nmto15μm with leg diameters of about 30to650nm, depending on the deposition temperature. A detailed high-resolution electron microscopy analysis showed that the center core of T-ZnO nanorods consists of four hexagonal grains with a twinlike relation. The nucleation and growth mechanism has been generated on the basis of energy considerations during a phase transition from a fullerenelike ZnO cluster to a nanometer-sized tetrahedron, which is directly visible in our high-resolution transmission electron microscopy investigations.

Journal ArticleDOI
TL;DR: In this paper, the authors showed that the ablation threshold in air is less than half those measured in vacuum, and that this difference is caused by the existence of a long-lived transient nonequilibrium surface state at the solid-vacuum interface.
Abstract: We report here experimental results on laser ablation of metals in air and in vacuum in similar irradiation conditions. The experiments revealed that the ablation thresholds in air are less than half those measured in vacuum. Our analysis shows that this difference is caused by the existence of a long-lived transient nonequilibrium surface state at the solid-vacuum interface. The energy distribution of atoms at the surface is Maxwellian-like but with its high-energy tail truncated at the binding energy. We find that in vacuum the time needed for energy transfer from the bulk to the surface layer to build the high-energy tail, exceeds other characteristic timescales such as the electron-ion temperature equilibration time and surface cooling time. This prohibits thermal evaporation in vacuum for which the high-energy tail is essential. In air, however, collisions between the gas atoms and the surface markedly reduce the lifetime of this nonequilibrium surface state allowing thermal evaporation to proceed before the surface cools. We find, therefore, that the threshold in vacuum corresponds to nonequilibrium ablation during the pulse, while thermal evaporation after the pulse is responsible for the lower ablation threshold observed in air. This paper provides direct experimental evidence of how the transient surface effects may strongly affect the onset and rate of a solid-gas phase transition.

Journal ArticleDOI
TL;DR: In this article, BaTiO3 and SrRuO3 epitaxial heterostructures on different single-crystalline substrates were fabricated by pulsed laser deposition.
Abstract: Ferroelectric thin films of BaTiO3 and BaTiO3∕SrRuO3 epitaxial heterostructures on different single-crystalline substrates were fabricated by pulsed laser deposition The BaTiO3 films of 100–400nm thickness show high structural perfection and c-axis-oriented growth For the electrical characterization of the BaTiO3 in a thin-film capacitor structure, Pt top electrodes were deposited by e-beam evaporation The results are compared to the current experimental and theoretical models Special consideration is given to the model of charge injection from the electrodes

Journal ArticleDOI
TL;DR: In this article, ZnO nanopushpins with very thin and flat cap on top of the nanorods and regular hexagonal nanotubes were obtained in the same run of growth in different regions.
Abstract: ZnO nanostructures with peculiar morphology were synthesized in large quantities via catalyst-free thermal evaporation. Both ZnO nanopushpins with very thin and flat cap on top of the nanorods, and regular hexagonal nanotubes, can be obtained in the same run of growth in different regions. The ZnO nanopushpins and nanotubes were characterized by using scanning electron microscopy and transmission electron microscopy. Cathodoluminescence measurements revealed that the emission from oxygen vacancy overwhelmed that of the near band gap in the as-grown ZnO nanotube arrays.

Journal ArticleDOI
TL;DR: The mechanism of biaxial alignment for yttria-stabilized zirconia (YSZ) and La1−xCaxMnO3 (LCMO) films that were fabricated by ion-beam-assisted deposition (IBAD) was examined in this paper.
Abstract: The mechanism of biaxial alignment was examined for yttria-stabilized zirconia (YSZ) and La1−xCaxMnO3 (LCMO) films that were fabricated by ion-beam-assisted deposition (IBAD). Films that were deposited with both dual-ion-beam deposition and ion-assisted electron-beam evaporation were studied. The film texture formation was mostly dependent on the ratio of ion bombardment to molecule arrival and on the angle of the incident ions with respect to the substrate. Results were not dependent on the deposition technique. The observed IBAD YSZ and IBAD LCMO biaxial alignment did not occur because of ion channeling. It has been shown that the preferred film orientation develops because of anisotropy of ion-induced damage on various crystal surfaces.

Journal ArticleDOI
TL;DR: In this paper, high-ordered cadmium sulphide (CdS) nanoparticle arrays were fabricated on silicon (Si) substrates using ultrathin alumina membranes as evaporation masks.
Abstract: Highly ordered cadmium sulphide (CdS) nanoparticle (NP) arrays were fabricated on silicon (Si) substrates using ultrathin alumina membranes as evaporation masks. The CdS NPs are polycrystalline and are composed of ultrasmall closely packed nanocrystallites. These crystallites increase in size as the duration of the CdS evaporation process increases. When the thickness of the NPs changes from about 10 to 50 nm, the size of the crystallites increases from about 5–14 to 20–40 nm. Photoluminescence measurements on the CdS NP arrays show a strong emission spectrum with two subbands that are attributed to band-edge and surface-defect emissions. The peak position and width of the band-edge emission band are closely related to the size of the crystallites in the CdS NPs.

Journal ArticleDOI
08 Feb 2005-Langmuir
TL;DR: This brand new CO(2)-expanded liquid particle deposition technique allows for the targeted deposition of particles and results in more uniform and lower defect metal nanoparticle thin films than are provided by conventional solvent evaporation techniques.
Abstract: Deposition of nanoparticles into uniform, wide-area thin films using CO2 as an antisolvent is presented. Ligand-stabilized silver particles are controllably precipitated from organic solvents by pressurizing and expanding the solution with carbon dioxide. Subsequent addition of carbon dioxide as a dense supercritical fluid provides for removal of the organic solvent while avoiding the surface tensions common to evaporating solvents that are detrimental to nanoscale assemblies and structures. This brand new CO2-expanded liquid particle deposition technique allows for the targeted deposition of particles and results in more uniform and lower defect metal nanoparticle thin films than are provided by conventional solvent evaporation techniques.

Journal ArticleDOI
TL;DR: In this article, a thin film was grown by selenization of sequentially evaporated metallic precursors, which showed single-phase chalcopyrite structure with preferential orientation in the (1 − 1 2 ) direction after 500°C selenisation.

Journal ArticleDOI
TL;DR: In this paper, the conjugated polyelectrolyte poly(9,9-bis[6′-(N,N, N,N,-trimethylammonium)hexyl]fluorene-co-alt-1,4-phenylene) bromide (PFN+Br−) was drop cast onto substrates patterned with micrometer-sized interelectrode (Au) gaps.
Abstract: Planar light-emitting electrochemical cells (LECs) were prepared by drop casting the conjugated polyelectrolyte poly(9,9-bis[6′-(N,N,N,-trimethylammonium)hexyl]fluorene-co-alt-1,4-phenylene) bromide (PFN+Br−) onto substrates patterned with micrometer-sized interelectrode (Au) gaps. When operated at room temperature (RT), such LECs exhibit a gap-size-dependent turn-on voltage for light emission, but when operated at 140°C, the turn-on voltage is essentially gap-size independent and close to the band gap of PFN+Br−. This temperature dependence is consistent with operation below and above the melting temperature (Tm=130°C) of PFN+Br− and is consequently a signature of anion mobility. The RT morphology of PFN+Br− is dependent on the film preparation process: slow evaporation of the solvent via drop casting produces a partially crystalline film, while a fast evaporation via spin casting produces a glassy film. The glassy spin-cast film can, however, be transformed into a partially crystalline film by slow cool...

Journal ArticleDOI
TL;DR: In this article, the in-plane alignment of the honeycomb packed mesochannels is strictly controlled by using a substrate with a rubbing-treated polyimide coating in the evaporation induced self-assembly process.
Abstract: A novel strategy for the preparation of a mesoporous silica film, in which the in-plane alignment of the honeycomb packed mesochannels is strictly controlled, is developed. The highly aligned porous structure is achieved by using a substrate with a rubbing-treated polyimide coating in the evaporation induced self-assembly process. It is shown that the controlled porous structure is formed over the entire thickness of the film and that the alignment distribution is much narrower than that in the films prepared by the conventional process based on a heterogeneous nucleation and growth mechanism. In the present process, the aligned porous structure would be formed through a directional lamellar-to-hexagonal phase transition from the substrate surface toward the air/film interface. The new formation mechanism as well as the lower process temperature enables the observed strict alignment control of the mesochannels.

Journal ArticleDOI
TL;DR: In this paper, a Ga-doped zinc oxide (ZnO) thin film was grown on a moving glass substrate by reactive plasma deposition (RPD), which offers the advantage of low ion damage, low deposition temperature, large area deposition and high growth rates.

Journal ArticleDOI
Jun Zhang1, Yongdong Yang1, Baolong Xu1, Feihong Jiang1, Jianping Li1 
TL;DR: In this paper, a simple efficient thermal evaporation technique, oxidizing zinc foils and in situ evaporating at 700 °C in air without the presence of catalyst and carrier gas, was developed to control the growth of the different morphologies of ZnO nano- and micro-structures.

Journal ArticleDOI
TL;DR: In this article, water ice was used as a matrix for the biotechnologically important guest material, polyethylene glycol (PEG), for concentrations from 0.5 to 4.5 wt.%.

Journal ArticleDOI
TL;DR: In this article, a CO2 laser set up in continuous wave mode was used to evaporate MoO3 thin films, which were then used for X-ray photoelectron spectroscopy (XPS) and optical transmittance measurements in the visible range.