Electrochromic performance of NiVxOy thin films deposited onto flexible PET/ITO substrates by reactive plasma sputtering for flexible electrochromic devices

An investigation was conducted on the electrochromic properties of plasma sputtered-nickel-vanadium oxide thin films on 40 Ω/□ flexible polyethylene terephthalate/indium tin oxide substrates. Metallic Ni_0.93V_0.07 target, sputtered by radio frequency power with argon gases and reacted with oxygen gases at room temperature (23 °C), was proven to provide extraordinary electrochromic performance. Cyclic voltammetry switching measurements found that only low driving voltages from − 1 V to 1 V were needed to provide reversible Li⁺ ion intercalation and deintercalation. The light modulation with up to 52% of transmittance variation, optical density change of 0.446 and color efficiency of 63.8 cm²/C at a wavelength of 550 nm was obtained for 200 cycles of Li⁺ intercalation and deintercalation in a 1 M LiClO₄-propylene carbonate electrolyte.     

Electrochromic performance of PECVD-synthesized WOxCy thin films on flexible PET/ITO substrates for flexible electrochromic devices

Electrochromic performance of WO_xC_y films deposited onto 60 Ω/□ flexible PET (polyethylene terephthalate)/ITO (indium tin oxide) substrates by low temperature plasma-enhanced chemical vapor deposition (PECVD) was investigated. It was proven that extraordinary electrochromic performance was provided when the precursor [tungsten carbonyl, W(CO)₆; TC] vapor, carried by argon gas, was mixed with air gas and synthesized by radio frequency (r.f.) power at room temperature (23 °C). Cyclic voltammetry switching measurements found that only low driving voltages from − 1 V to 1 V were needed to provide reversible Li⁺ ion intercalation and de-intercalation. The light modulation with up to 63.6% of transmittance variation at a wavelength of 650 nm was obtained for 150 cycles of Li⁺ intercalation and de-intercalation in a 0.1 M LiClO₄-PC (propylene carbonate) electrolyte.     

Patterning of ITO films on flexible substrates by using self-assembled monolayer

The patterning of indium tin oxide (ITO) films on flexible polyester (PET) substrates by using a self-assembled monolayer (SAM) of octadecyltrimethoxysilane (OTMS) was investigated. After a SAM is deposited on ITO films, the ITO surface hydrophilicity and electron transfer characteristics are altered. The contact angle and electrochemical cyclic voltammetry analyses indicate the optimal process to form a SAM on ITO films operated in a low-humidity environment at 25 ºC for 24 h. The AFM observation shows that the ITO films covered by a SAM can be protected during etching in an oxalic solution, which means a SAM can well play the role of a photoresist during lithographic process.     

Crystallization of chemically vapor deposited molybdenum and mixed tungsten/molybdenum oxide films for electrochromic application

The paper deals with investigation of Mo oxide and mixed W/Mo oxide films showing high electrochromic performance. Films are deposited on Si and conductive glass substrates using pyrolytical decomposition at 200 °C of Mo and W hexacarbonyls in Ar/O₂ atmosphere. The study is focused on structural transformation of the films in dependence on deposition and annealing process parameters. In case of conductive glass substrate (typical for electrochromic devices), the crystallization process in Mo oxide films is almost completed at 400 °C forming triclinic MoO_2.89 and orthorhombic MoO₃ crystalline phases. The structure of mixed W/Mo oxide films is triclinic crystalline phase of tungsten oxide matrix with Mo atoms as substitutes. Discussed are, as well, differences in the crystallization process for the same films, when the substrate is Si. All the films show electrochromic effect, the mixed W/Mo oxide films expressing stronger electrochromic effect with superior color efficiency and optical modulation.     

Low temperature synthesis of GaN films on ITO substrates by ECR-PEMOCVD

GaN films were deposited on indium tin oxide (ITO) coated glass substrates at various deposition temperatures using an electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition (ECR-PEMOCVD). The TMGa and N₂ are applied as precursors of Ga and N, respectively. The crystalline quality and photoluminescence properties of as-grown GaN films are systematically investigated as a function of deposition temperature by means of X-ray diffraction analysis (XRD), reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), and room temperature photoluminescence (PL). The results show that the dense and uniformed GaN films with highly c-axis preferred orientation are successfully achieved on ITO glass substrates under optimized deposition temperature of 430 °C, and the room temperature PL spectra of the optimized GaN film show an intense near-band-edge luminescence located at 360 nm. The obtained GaN/ITO/glass structure was especially attractive for transparent optoelectronics applications with inexpensive ITO/glass substrate.     

Effects of oxygen addition on electrochromic properties in low temperature plasma-enhanced chemical vapor deposition-synthesized MoOxCy thin films for flexible electrochromic devices

Electrochromic organomolybdenum oxide (MoO_xC_y) films are deposited onto 60 Ω/□ flexible polyethylene terephthalate/indium tin oxide substrates by low temperature plasma-enhanced chemical vapor deposition (PECVD) using a precursor of molybdenum carbonyl vapor, which is carried by argon gas, mixed with oxygen gas and synthesized by radio frequency power at room temperature (23 °C). The MoO_xC_y films with modified surface morphology and compositions of varying oxygen contents are proven to offer noteworthy electrochromic performance. Porous surface of the MoO_xC_y film (398 nm thick) provides Li⁺ ion diffusion coefficient value of 1.7 × 10^− 10 cm²/s for Li⁺ de-intercalation at a potential scan rate of 2 mV/s. High x/y value at high surface composition of oxygen to carbon in the MoO_xC_y film offers light modulation with transmittance variation of up to 63% and coloration efficiency of 36 cm²/C at a wavelength of 800 nm for 200 cycles of Li⁺ intercalation and de-intercalation. PECVD-synthesized MoO_xC_y thin films show promising electrochromic properties for applications in flexible electrochromic devices.     

Study of InAlN thin films deposited on silicon,ITO/PET,and ITO/GLASS substrates at room temperature for its possible use in solar cells

Journal of Materials Science: Materials in Electronics - The semiconductor material of ternary alloy of Indium and Aluminum nitride (InxAl1-xN) has interesting properties for potential...     

Pulsed laser deposition of indium tin oxide films on flexible polyethylene naphthalate display substrates at room temperature

Pulsed laser deposition was used to deposit high-quality indium tin oxide (ITO) thin solid films on polyethylene napthalate (PEN) flexible display substrates. The electrical, optical, microstructural, mechanical and adhesive properties of the functional thin layer were investigated as a function of a narrow range of background oxygen gas pressure at room temperature, which is the most desirable thermal condition for growing transparent conducting oxides on flexible display polymer substrates. ITO films (240 ± 35 nm thick) deposited on PEN at room temperature in the range of 0.33 to 2.66 Pa background oxygen pressure are observed to exhibit low electrical resistivity (~ 10^− 4 Ω cm) and high optical transmission (~ 90%). Electromechanical uniaxial tensile testing, of the hybrid thin structures, results in crack onset nominal strains of around 2%. The ITO surface adhesion reaches a maximum at 1.33 Pa deposition pressure.     

Room-temperature formation of low refractive index silicon oxide films using atmospheric-pressure plasma

This study aims to apply atmospheric-pressure (AP) plasma to the fabrication of single-layer anti-reflection (AR) coatings with porous silicon oxide. 150 MHz very high-frequency (VHF) excitation of AP plasma permits to enhance the chemical reactions both in the gas phase and on the film-growing surface, increasing deposition rate significantly. Silicon oxide films were prepared from silane (SiH4) and carbon dioxide (CO2) dual sources diluted with helium. The microstructure and refractive index of the films were studied using infrared absorption and ellipsometry as a function of VHF power density. It was shown that significant increase in deposition rate at room temperature prevented the formation of a dense SiO2 network, decreasing refractive index of the resulting film effectively. As a result, a porous silicon oxide film, which had the lowest refractive index of 1.24 at 632.8 nm, was obtained with a very high deposition rate of 235 nm/s. The reflectance and transmittance spectra showed that the low refractive index film functioned as a quarter-wave AR coating of a glass plate.     

Structure of polycrystalline silicon films deposited at low temperature by plasma CVD on substrates exposed to different plasma

Polycrystalline silicon (poly-Si) films were deposited on glass substrates (corning 7059) at 300°C by a plasma enhanced chemical vapor deposition (PECVD) from a SiH₄/SiF₄ mixture. All poly-Si films were prepared under the same deposition conditions on the substrates subjected to nitrogen, hydrogen and/or CF₄ plasma with different gas pressures, just before deposition of the poly-Si films. Effects of such pretreatments for substrates on the structural properties of the resultant poly-Si films have been investigated. The Si film deposited on the substrates without any pretreatments was amorphous. However, formation of a strong 〈110〉 preferentially oriented poly-Si with improved crystallinity was obtained for the films deposited on the glass substrate after plasma pretreatments, which exhibit smoother surfaces. This result was interpreted in terms of a removal of weak Si–Si bonds during nucleation and the subsequent grain growth.     

电子束低温蒸发ITO膜增透、增反特性研究

本实验是在低温条件下，采用电子柬蒸发制备ITO透明导电薄膜，通过监测电阻来控制薄膜的厚度，通过控制薄膜厚度研究了增透和增反两种效果的ITO膜的制备及膜的光学特性。当膜厚达170nm和83nm时透过率和反射率可达95％和6％。     

Chemical and electrical characteristics of low temperature plasma enhanced CVD silicon oxide films using Si2H6 and N2O

Silicon oxide films have been deposited at low temperatures in the range of 30–250 °C using Si₂H₆ and N₂O by conventional plasma enhanced chemical vapor deposition technique. The dependencies of deposition temperatures on the film properties are studied. The leakage current and the etch rate of these low temperature films compare favorably to films deposited by silane and TEOS at higher temperatures, respectively.     

Enhanced photoelectrochemical activity of the TiO2 /ITO nanocomposites grown onto single-walled carbon nanotubes at a low temperature by nanocluster deposition

High-resolution transmission electron microscopy (HRTEM) is used to observe a TiO2/ITO-coated composite nanostructure grown onto single-walled carbon nanotubes (SWCNTs). The SWCNTs, indium tin oxide (ITO), and TiO2 mixtures of anatase (A) and rutile (R) are clearly distinguished in the HRTEM images. The thickness of the SWCNT was about 3 nm, and the TiO2 shell included different polycrystalline structures.     

Thin films of iron oxide by low pressure MOCVD using a novel precursor: tris(t-butyl-3-oxo-butanoato)iron(III)

Deposition of thin films of iron oxide on glass has been carried out using a novel precursor, tris(t-butyl-3-oxo-butanoato)iron(III), in a low-pressure metalorganic chemical vapor deposition (MOCVD) system. The new precursor was characterized for its thermal properties by thermogravimetry and differential thermal analysis. The films were characterized by X-ray diffraction (XRD), transmission electron microscopy, scanning electron microscopy, and by optical measurements. XRD studies reveal that films grown at substrate temperatures below ∼550 °C and at low oxygen flow rates comprise only the phase Fe₃O₄ (magnetite). At higher temperatures and at higher oxygen flow rates, an increasing proportion of α-Fe₂O₃ is formed along with Fe₃O₄. Films of magnetite grown under different reactive ambients—oxygen and nitrous oxide—have very different morphologies, as revealed by scanning electron microscopic studies.     

Electrical charge conductivity behavior of electrodeposited Cu2O/ZnO heterojunction thin films on PET flexible substrates by impedance spectroscopy analysis

The bottom-up self-assembly Cu₂O/ZnO heterojunction thin films electrodeposited on indium tin oxide flexible substrate (polyethylene terephthalate, PET) have been investigated by impedance spectroscopy. It is used to study the electric conductivity of the Cu₂O/ZnO heterojunction thin films combined electric modulus and impedance plots. The electric modulus and impedance as a function of the frequency analysis show the distribution of the relaxation times due to the hopping of charge carriers among defects in the Cu₂O/ZnO heterojunction thin films. The values of activation energies derived from the electric modulus and impedance are found to be 0.42 and 0.40 eV, respectively, which is close to the activation energy (0.28 eV) of dc electrical conductivity and activation energy of ac conductivity (0.45–0.14 eV at the range of 100 Hz–1 MHz) in the temperature range over 303–423 K.     

The synthesis of LiBH4 films under low hydrogen pressure at ambient temperature

Lithium borohydride (LiBH₄) films were first fabricated under low hydrogen pressure (5-70 Pa) at ambient temperature by pulsed laser deposition (PLD). The atomistic structures and chemical compositions of the films were investigated. It was found that during the formation process of LiBH₄, the intermediate compound Li₂B₁₂H₁₂ was formed. As the hydrogen pressure increased up to 70 Pa, the relative weight percent of LiBH₄ was over 70 wt.% even at ambient temperature. Moreover, the stress of the films was decreased as the hydrogen pressure increased.     

An X-ray fourier line shape analysis of hexagonal tellurium films III: Vacuum evaporated onto air-cleaved mica substrates at low temperature (133 K)

As a continuation of a series of studies of hexagonal tellurium films deposited onto glass at room temperature and low temperature (133 K), investigations were carried out on the growth structure of tellurium films 331–800 nm thick (for normal vapour incidence) and 260–1129 nm thick (for oblique vapour incidence) deposited by vacuum evaporation at various rates of deposition onto air-cleaved mica substrates at a temperature of 133 K. Since mica is a crystalline substrate it was used to study its influence on the growth structures and preferred orientation. Considering the cases of normal and oblique vapour incidence for both high and low rates of deposition, a small domain or crystalline size effect (about 115–160 Å), appreciable microstrains (2.2–5.0)×10^-3 in the domains and a near-isotropy in the size and strain parameters were observed from a detailed Fourier analysis of X-ray diffraction profiles. The results obtained from the analysis of fault-affected reflections (H - K = 3N±1, L₀ odd or even) show that the intrinsic stacking faults (probability α) are totally absent and the presence of growth stacking faults (probability β) is also negligible. The dislocation density ϱ is about 10¹¹ cm^-2 and a c axis texture is found to develop in the films. The average residual internal stresses σ and lattice parameter changes Δa and Δc, obtained from line shift analysis, are small. From a comparison of the results obtained for the different cases it appears that the changes in the angle of deposition or the rate of deposition as well as the nature of the substrate (mica) do not markedly affect the growth structures and orientation of the films deposited at this lower temperature.     

Influence of VI/II ratios on the growth of ZnO thin films on sapphire substrates by low temperature MOCVD

We investigated the structural, electrical, and optical properties of ZnO thin films grown at different VI/II ratios on sapphire substrates by metalorganic chemical vapor deposition. Transmission electron microscopy and X-ray diffraction revealed the epitaxial nature with a reduced dislocation density of the ZnO films grown at increased VI/II ratios. The carrier concentration of the films increased to 4.9 × 10¹⁸ cm^− 3 and their resistivity decreased to 1.4 × 10^− 1 Ω cm at a VI/II ratio of 513.4 μmol/min. The ZnO films also showed good optical transmittance (> 80%) in the visible and near-infrared wavelength regions. The room temperature PL revealed a strong band-edge emission with a weak deep level emission, suggesting the good crystalline quality of the ZnO films on the sapphire substrates. Furthermore, the intensity ratio of the band-edge emission to the deep-level emission (I_UV/I_Vis) increased with increasing VI/II ratio.