Adjusting Film Thickness Research Articles

Adjusting indium-tin-oxide film thickness to improve electrochemical corrosion resistance of gate driver on array

Common narrow-bezel display suffers from the abnormal display in the high-temperature and high-humidity environments, resulting in an early device failure. Improving electrochemical corrosion resistance of gate driver on array (GOA) may overcome the drawback of the display. Adjusting film thickness of indium tin oxide (ITO) on GOA through-hole is proposed to in situ improve the electrochemical corrosion resistance. Nano-ITO film with four different thicknesses were deposited in a direct-current magnetron sputter system. A systematic investigation was conducted on their microstructure and photoelectric performances, and a high-temperature and high-humidity display test was employed for field test. The 80.1-nm film exhibited superior surface smoothness and photoelectric performance, and the assembled GOA unit presented the best electrochemical corrosion resistance. We demonstrated that adjusting ITO film thickness may prevent the intrusion from water vapor and reduce the generation of resistance heat.

Quantitative analysis of biomolecule release from polystyrene-block-polyethylene oxide thin films.

Block copolymers have garnered recent attention due to their ability to contain molecular cargo within nanoscale domains and release said cargo in aqueous environments. However, the release kinetics of cargo from these thin-films has not yet been reported. Knowledge of the release quantities and release profiles of these systems is paramount for applications of these systems. Here, Polystyrene-block-poly(ethylene oxide) (PS-b-PEO) was co-assembled with fluorescein isothiocyanate isomer I-lysozyme (FITC-LZ) and fluorescein isothiocyanate isomer I-TAT (FITC-TAT), such that these molecular cargos arrange within the PEO domains of the thin films. We show that high loading ratios of cargo/PS-b-PEO do not significantly impact the nanostructure of the films; however, a loading limit appears to be present with aggregates of protein forming at the microscale with higher loading ratios. The presence of lysozyme (LZ) within the films was confirmed qualitatively after aqueous exposure through photo-induced force microscopy (PiFM) imaging at the Amide I characteristic peak (∼1650 cm-1). Furthermore, we demonstrate that LZ maintains activity and structure after exposure to the polymer solvent (benzene/methanol/water mix). Finally, we demonstrate quantitatively 20-80 ng cm-2 of cargo is released from these films, depending on the cargo incorporated. We show that the larger molecule lysozyme is released over a longer time than the smaller TAT peptide. Finally, we demonstrate the ability to tune the quantity of cargo released by altering the thickness of the PS-b-PEO thin-films during fabrication.

Aramid nanofiber-derived carbon aerogel film with skin-core structure for high electromagnetic interference shielding and solar-thermal conversion

Being as lightweight and thin as possible is highly desirable for electromagnetic interference (EMI) shielding materials in electronic devices as the high requirement in miniaturization and weight reduction. Constructing three-dimensional (3D) porous conductive architecture into two-dimensional (2D) film provides one of the feasible strategies. Herein, pyrolytic carbon aerogel films from aramid nanofiber (ANF) with novel skin-core structure containing compact film skin and 3D porous nanofiber network core were fabricated by a facile method. The abundant conjugate aromatic structure in backbone endows ANF-derived carbon aerogel film with a high conductivity of 1029.5 S/m. Remarkably, the high electrical conductivity, as well as the 3D porous skin-core structure, which not only constructs the interconnected electron transmission paths but also significantly extends the propagation path of EM waves, enables the carbon aerogel film a high EMI shielding effectiveness (SE) of 41.4 dB at low density (54.4 mg/cm3) and thin thickness (162 μm) with high specific shielding effectiveness (SSE/t) of up to 47122.6 dB cm2/g. Besides, ANF-derived carbon aerogel film exhibits an excellent photothermal conversion ability, which greatly broadens the application environment. More interestingly, the easy and flexible preparation method with adjustable film thickness, density and area makes large-scale production of carbon aerogel film possible.

Formation of Various Polymeric Films via Surface‐Initiated ARGET ATRP on Silicon Substrates

The growth of various polymeric films such as neutral, zwitterionic, and anionic ones was investigated over time from the initiator‐immobilized silicon substrates. The polymerization reactions were carried out under ambient conditions via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) without any predeoxygenating process. Each of the examined polymeric films showed linear/exponential growth over reaction times according to the measurement of ellipsometric film thickness. The successful formation of various polymeric films was further proved by X‐ray photoelectron spectroscopy, contact angle goniometry, and measurement of surface free energies. We think that this study can provide a basis for other researches that require to graft polymers with the adjustable film thickness for modulating chemical/physical properties at interfaces.

Multi-Layered Mesoporous TiO2 Thin Films: Photoelectrodes with Improved Activity and Stability

This work aims at the identification of porous titanium dioxide thin film (photo)electrodes that represent suitable host structures for a subsequent electrodeposition of plasmonic nanoparticles. Sufficient UV absorption and electrical conductivity were assured by adjusting film thickness and TiO 2 crystallinity. Films with up to 10 layers were prepared by an evaporation-induced self-assembly (EISA) method and layer-by-layer deposition. Activities were tested towards the photoelectrochemical oxidation of water under UV illumination. Enhanced activities with each additional layer were observed and explained with increased amounts of immobilized TiO 2 and access to more active sites as a combined effect of increased surface area, better crystallinity and improved transport properties. Furthermore, films display good electrochemical and mechanical stability, which was related to the controlled intermediate thermal annealing steps, making these materials a promising candidate for future electrochemical depositions of plasmonic noble metal nanoparticles that has been further demonstrated by incorporation of gold.

The Influence of Polymer Blends on Regulating Chondrogenesis

The influence of polymer blend coatings on the differentiation of mouse mesenchymal stem cells was investigated. Polymer blending is a common means of producing new coating materials with variable properties. Stem cell differentiation is known to be influenced by both chemical and mechanical properties of the underlying scaffold. We therefore selected to probe the response of stem cells cultured separately on two very different polymers, and then cultured on a 1:1 blend. The response to mechanical properties was probed by culturing the cells on polybutadiene (PB) films, where the film moduli was varied by adjusting film thickness. Cells adjusted their internal structure such that their moduli scaled with the PB films. These cells expressed chondrocyte markers (osterix (OSX), alkaline phosphatase (ALP), collagen X (COL-X), and aggrecan (ACAN)) without mineralizing. In contrast, cells on partially sulfonated polystyrene (PSS28) deposited large amounts of hydroxyapatite and expressed differentiation markers consistent with chondrocyte hypertrophy (OSX, ALP, COL-X, but not ACAN). Cells on phase-segregated PB and PSS28 films differentiated identically to those on PSS28, underscoring the challenges of using polymer templates for cell patterning in tissue engineering.

Influence of Film Thickness on Dielectric Properties of Y and Mn Alternately Doped BST Films

By adjusting film thickness, smooth and dense Mn and Y alternately doped Ba0.6Sr0.4TiO3 (Mn/Y-BST) films have been designed and prepared by improved sol-gel method, and the structure and dielectric properties of the films have been studied. X-ray diffraction (XRD) reveals that all films grow along (110) orientation, doped Mn2+ ions or Y3+ ions show acceptor doping, and thicker film shows stronger crystallization. Atomic force microscope (AFM) shows the films are relatively smooth without obvious cracks or pinholes. Scanning electronic microscope (SEM) indicates that from substrate to surface the films show nodular microstructures to columnar ones without obvious interface among nodular microstructure layers. Compared to pure BST film or Mn or Y doped BST films, all alternately doped films show markedly improved structures and dielectric properties, which is strongly dependent on film thickness. 6-layer Mn/Y-BST film shows best structure and combination of dielectric properties with dielectric loss of 1.18%, tunability of 38% and figure of merit (FOM) of 32.2 at 100 kHz.

Fast switching electrochromic devices for displays

This article features the application of electrochromic (EC) devices for displays and the efforts made to improve the switching speed and contrast performance of these devices. The article primarily focuses on the layer-by-layer (LbL) assembly deposition technique to deposit thin films of EC materials ranging from organic, inorganic and conducting polymers. Device sizes were varied for comparison of the performance of the lab-made prototype device with the commercially available “small pixel” size displays. EC devices fabricated by LbL assembly, as shown with poly(3,4-ethylenedioxythiophene) results, obtained with a switching speed of less than 30 ms and make EC flat-panel displays possible by adjusting film thickness, device size and type of material. The high contrast value (84%) for ruthenium purple suggests that its LbL films can be used for low-power consumption displays where contrast, and not fastest switching, is of prime importance.

V6O13films by control of the oxidation state from aqueous precursor to crystalline phase

An aqueous deposition process for V(6)O(13) films is developed whereby the vanadium oxidation state is continuously controlled throughout the entire process. In the precursor stage, a controlled wet chemical reduction of the vanadium(V) source with oxalic acid is achieved and monitored by (51)Vanadium Nuclear Magnetic Resonance ((51)V-NMR) and Ultraviolet-Visible (UV-Vis) spectroscopy. The resulting vanadium(IV) species in the aqueous solution are identified as mononuclear citrato-oxovanadate(IV) complexes by Electron Paramagnetic Resonance (EPR) and Fourier Transform Infra-Red (FTIR) spectroscopy. This precursor is successfully employed for the deposition of uniform, thin films. The optimal deposition and annealing conditions for the formation of crystalline V(6)O(13), including the control of the vanadium oxidation state, are determined through an elaborate study of processing temperature and O(2) partial pressure. To ensure a sub 100 nm adjustable film thickness, a non-oxidative intermediate thermal treatment is carried out at the end of each deposition cycle, allowing maximal precursor decomposition while still avoiding V(IV) oxidation. The resulting surface hydrophilicity, indispensable for the homogeneous deposition of the next layer, is explained by an increased surface roughness and the increased availability of surface vanadyl groups. Crystalline V(6)O(13) with a preferential (002) orientation is obtained after a post deposition annealing in a 0.1% O(2) ambient for thin films with a thickness of 20 nm.

Facile Preparation of Highly Oriented Poly(vinylidene fluoride) Langmuir–Blodgett Nanofilms Assisted by Amphiphilic Polymer Nanosheets

We describe a facile and novel method for preparing highly dense Langmuir–Blodgett (LB) nanofilms of poly(vinylidene fluoride) (PVDF) with precisely adjustable film thickness from several to hundreds of nanometers, assisted by amphiphilic poly(N-dodecylacrylamide) (pDDA) nanosheets. Even at a molar mixing ratio of PVDF:pDDA up to 50:1, the high collapse surface pressure of 44.4 mN/m obtained using this method is a breakthrough for the preparation of PVDF LB nanofilms, which is devoted to the resulting high-density PVDF nanofilms. As shown by FTIR and XRD measurements, the mixed LB nanofilms without any postprocessing comprised dominant ferroelectric β phase of ∼95% and negligible paraelectric α phase. Furthermore, through control of the surface pressure, controllable PVDF crystal morphologies were achieved. Moreover, β phase PVDF dominates in all cases. After applying a dc bias of 5 V through a conductive cantilever, the local polarized pattern on the surface of a nine-layer mixed LB nanofilm observed using Kelvin probe force microscopy indicates that it is possible to induce all dipoles in one direction in the mixed LB nanofilm, which is promising for application in low-voltage nanoelectronics.

Control of Crystal Structure of BiFeO3 Epitaxial Thin Films by Adjusting Growth Conditions and Piezoelectric Properties

The effects of epitaxial strain on the crystal structure and piezoelectric properties of (100) BiFeO3 thin films were investigated. The epitaxial strain of BiFeO3 thin films grown by pulsed laser deposition was controlled by adjusting film thickness and growth temperature. From the results of X-ray diffraction reciprocal space mapping and in-plane piezoelectric force microscopy, it is found that the crystal structure of BiFeO3 thin films is a rhombohedral structure with tetragonal distortion, and that the extent of tetragonal distortion increases with decreasing film thickness and growth temperature. From the voltage-strain curves of the films, electric field strain is dominated by the piezoelectric effect in the low-voltage region, while the electrostrictive effect appears in the high-voltage region. It was found that piezoelectric strain increases with increasing extent of tetragonal distortion, which suggests that the piezoelectric properties of BiFeO3 thin films can be improved using a mixture of two types of structural distortion.

Field emission mechanism from a single-layer ultra-thin semiconductor film cathode

Field emission (FE) from a single-layer ultra-thin semiconductor film cathode (SUSC) on a metal substrate has been investigated theoretically. The self-consistent quantum FE model is developed by synthetically considering the energy band bending and electron scattering. As a typical example, we calculate the FE properties of ultra-thin AlN film with an adjustable film thickness from 1 to 10 nm. The calculated results show that the FE characteristic is evidently modulated by varying the film thickness, and there is an optimum thickness of about 3 nm. Furthermore, a four-step FE mechanism is suggested such that the distinct FE current of a SUSC is rooted in the thickness sensitivity of its quantum structure, and the optimum FE properties of the SUSC should be attributed to the change in the effective potential combined with the attenuation of electron scattering.

Adjusting Film Thickness

RETURN TO ISSUEPREVNewsNEXTAdjusting Film ThicknessKontro's new heat exchanger adjusts film thickness of material being processed by a movabie rotorCite this: Chem. Eng. News 1955, 33, 18, 1912–1913Publication Date (Print):May 2, 1955Publication History Published online5 November 2010Published inissue 2 May 1955https://doi.org/10.1021/cen-v033n018.p1912Copyright © 1955 AMERICAN CHEMICAL SOCIETYArticle Views3Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (293 KB) SUBJECTS:Thickness,Thin films Get e-Alerts