Borosilicate Glass Substrates Research Articles

Growth, differentiation, and migration of osteoblasts on transparent Ni doped TiO2 thin films deposited on borosilicate glass

A simple and cost effective dip coating method was used to deposit thin films of amorphous (AM) or anatase (AN) titanium dioxide (TiO(2)) on borosilicate glass substrates, either with or without prior doping of TiO(2) with nickel (Ni) cations by a specially designed sol gel technique. The objective of the study was to compare the physicochemical and biological properties of these films and assess their use in orthopedic implants or for in vitro cell biological studies. Analytical techniques such as XRD and XPS, in combination with ATR-FTIR and SEM revealed that only AN films, prepared by controlled heating up to 450°C, irrespective of prior doping with Ni, contained significant crystalline structures of variable morphologies. This observation could be linked to the carbon and oxygen contents and the availability of functional groups in the films. Cell biological studies revealed that Ni doping of TiO(2) in both AM and AN films improved the adhesion, spreading, proliferation, differentiation, and migration of MC3T3 cells. Our studies provide a new approach to prepare optically transparent metal surfaces, with tunable physicochemical properties, which could be suitable for eliciting optimal osteoinductive cell responses and permit the detailed in vitro cell biological studies of osteoblasts.

Growth of superhydrophobic Zinc oxide nanowire thin films

The growth of ZnO nanowire films by the annealing of Zn films deposited onto borosilicate glass and quartz substrates, at 500°C, is demonstrated. The as deposited Zn films are polycrystalline with triangular grains aligned along the plane of the substrate. On annealing to 500°C, the Zn films transform in to polycrystalline ZnO films comprised entirely of nanowires. The ZnO nanowires are 15–100nm in diameter and about 500nm long. Wettability studies reveal that the ZnO nanowire films on quartz are superhydrophobic with contact angle as high as 153°. The wettability is reversible under UV irradiation making these films extremely suitable for self-cleaning applications. The growth of nanowires by this technique is attractive since it does not involve very high temperatures and the use of catalysts.

Ultrafast laser inscription of Bragg-grating waveguides using the multiscan technique

We report the fabrication of high-strength (>30 dB) first order Bragg-grating waveguides in borosilicate glass substrates using ultrafast laser inscription. The cross section of each waveguide was controlled using the well known multiscan fabrication technique, where the desired waveguide cross section is constructed by scanning the sample through the laser focus multiple times. In order to fabricate high-strength gratings, it was therefore necessary to precisely control and spatially synchronize the refractive index modulations imprinted in the material by each scan. The Bragg-grating waveguides were inscribed using a femtosecond fiber laser that was externally modulated using an acousto-optic modulator. The required precision in the laser modulation was thus achieved by triggering the acousto-optic modulator using a position sensitive trigger signal supplied by the substrate translation stages themselves.

2D or not 2D: Structural and charge ordering at the solid-liquid interface of the 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ionic liquid

Molecular dynamics simulations of a 5 nm-thick layer of the ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate, [(OH)C2C1im][BF4], over silica, alumina and boro-silicate glass substrates have been performed. The structure of the ionic liquid at the solid-liquid interface has been interpreted taking into account the corresponding normal density profiles, lateral interfacial structure, orientational ordering and planar density contours. Comparisons with experimental data suggest that the adsorption and stratification process of ionic liquids over solid substrates can be correctly modeled using a realistic rendition of a non-uniform amorphous substrate such as a glass material.

Silicon-on-glass pore network micromodels with oxygen-sensing fluorophore films for chemical imaging and defined spatial structure

Pore network microfluidic models were fabricated by a silicon-on-glass technique that provides the precision advantage of dry etched silicon while creating a structure that is transparent across all microfluidic channels and pores, and can be imaged from either side. A silicon layer is bonded to an underlying borosilicate glass substrate and thinned to the desired height of the microfluidic channels and pores. The silicon is then patterned and through-etched by deep reactive ion etching (DRIE), with the underlying glass serving as an etch stop. After bonding on a transparent glass cover plate, one obtains a micromodel in oxygen impermeable materials with water-wet surfaces where the microfluidic channels are transparent and structural elements such as the pillars creating the pore network are opaque. The advantageous features of this approach in a chemical imaging application are demonstrated by incorporating a Pt porphyrin fluorophore in a PDMS film serving as the oxygen-sensing layer and a bonding surface, or in a polystyrene film coated with a PDMS layer for bonding. The sensing of a dissolved oxygen gradient was demonstrated using fluorescence lifetime imaging, and it is shown that different matrix polymers lead to optimal use in different ranges of oxygen concentration. Imaging with the opaque pillars in between the observation direction and the continuous fluorophore film yields images that retain defined spatial structure in the sensor image.

Improvement in micro-structural and mechanical properties of zinc film by surface treatment with low temperature argon plasma

Nanocrystalline zinc films were deposited on gold coated borosilicate glass substrates by thermal evaporation method using zinc powders as the source material and then treated with argon plasma at various temperatures. From X-ray diffraction study, the as-deposited films are found to be metallic Zn and polycrystalline in nature. The crystalline nature improves with the increase of temperature up to 200°C and decreases with the further increase of temperature to 300°C. The binding energy observed for Zn 2p3/2, and the binding energy separation between Zn 2p3/2 and Zn 2p1/2 in the X-ray photoelectron spectrum indicate that the films are metallic zinc films. Transmission electron microscopic study shows hexagonal shaped grains having size ∼58nm upon treatment with Ar plasma. It is clearly shown the grain growth and distinct grain boundary with the increase in temperature. The average Young's modulus (E) and hardness (H) are measured to be 84GPa and 4.0GPa for as-deposited film, whereas 98GPa and 5.8GPa for plasma treated film at 200°C. The enhancement in mechanical properties is attributed to improvement in crystalline nature of the film and better interlinking between grains and boundaries.

Radio frequency plasma enhanced chemical vapor based ZnO thin film deposition on glass substrate: A novel approach towards antibacterial agent

In the present study, the structural, optical and antibacterial properties of ZnO thin films are reported. ZnO thin films are deposited on borosilicate glass substrates by radio frequency plasma enhanced chemical vapor deposition (PECVD) using oxygen as process gas. The crystallinity of the deposited films is improved upon annealing at 450 °C in air for 1.5 h and the polycrystalline nature of the films is further confirmed by selected area electron diffraction. The particle size of the annealed film (thickness 476 nm) is found to be ∼34 nm from the transmission electron microscopic observation. Energy dispersive X-ray spectrum indicates the stoichiometric deposition of ZnO films. The films are highly transparent (transmittance >85%) in the visible region of electromagnetic spectrum. The films exhibit excellent antibacterial effect towards the growth of Escherichia coli and Pseudomonas aeruginosa.

Controlled Nanostructuring of Ag Films by Ion Beam Sputter Deposition for Surface Plasmon Resonance Applications

The growth of Ag nanostrucutres on borosilicate glass substrates by ion beam sputter deposition in the Ar ion energy range from 150 to 600 eV is demonstrated. Rates of deposition as low as 0.01 nm/s are achieved at an Ar ion energy of 150 eV. This leads to the formation of a random array of nearly spherical Ag particles with a mean size of approximately 100 nm, separated by distances of similar order of magnitude. The particles organize themselves into arrays over lengths of at least 10 microm. As the thickness is increased from 3 to 18 nm there is a transition in morphology from an array to linear chains and finally a dense continuous film. There is a similar microstructural evolution as a function of increasing ion energy. The plasmon resonances can be tuned depending on shape, size and interparticle distances. As the thickness of the films increase, the main plasmon peaks can be tuned from 380 to 680 nm. The spheroidal shape of the particles induces additional peaks (localized surface plasmons) centered around 430 +/- 10 nm. Detailed simulations have been carried out based on Maxwell Garnett theory to distinguish the effects of shape and size on plasmon resonances. It is demonstrated that shape rather than the size of the particles has a stronger influence on the shift in plasmon resonances.

Growth, optical, and electrical properties of silicon films produced by the metal-induced crystallization process

Amorphous Si (a-Si) and Ni films were deposited by electron beam evaporation on to borosilicate glass (BSG) substrate maintained at ambient temperature. The BSG/a-Si/Ni stack was subjected to post deposition annealing in air at various temperatures from 200 to 500 °C for 1 h. Electron diffraction was employed to characterize the crystallographic phases appearing on the stacks that were depending on initial conditions. Clear evidence of the formation of hexagonal Si and fcc NiSi2 was shown by TEM. In parallel, an increase of refraction index was observed. Electrical resistivity measurements showed that resistance is of the order of kilo ohms in the as-deposited films, increasing sharply to giga ohms in films annealed at T higher than 300 °C. A large band gap of 2.23 eV which is the combined contribution from a-Si, wurtzite-Si, and Ni silicide phases, is observed.

Low temperature uniaxial growth of conducting LaNiO3 thin films on glass substrates with RbLaNb2O7 seed layer

Conducting LaNiO3 thin films have been fabricated on the borosilicate glass substrates with and without the uniaxial oriented RbLaNb2O7 seed layer by an excimer laser assisted metal organic deposition process with a KrF laser irradiation at 400°C in air. The LaNiO3 thin film prepared on the seed layer had a very high Lotgering factor at F(100)=0.971, indicating highly (100)-oriented growth. The obtained LaNiO3 thin films with and without the seed layer showed low resistivity values, 4.42 and 1.02 mΩ cm at room temperature, respectively. The ρ value of the (100)-oriented LaNiO3 film on the seed layer was comparably lowered to that of the films prepared at high process temperatures reported in the previous reports.

MOCVD of ZnO Films from Bis(Ketoiminato)Zn(II) Precursors: Structure, Morphology and Optical Properties

AbstractTwo closely related bis(ketoiminato) zinc precursors, which are air stable and possess favorable properties for metal‐organic (MO)CVD, are successfully employed for the growth of ZnO films on silicon and borosilicate glass substrates at temperatures between 400 and 700 °C. The as‐deposited films are investigated by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X‐ray photoelectron spectroscopy (XPS), nuclear reaction analysis (NRA), as well as by UV‐vis absorption spectroscopy and photoluminescence (PL) measurements. The structure, morphology, and composition of the as‐grown films show a strong dependence on the substrate temperature. The formation of pure and (001)‐oriented wurtzite‐type stoichiometric ZnO is observed. PL measurements are performed both at room temperature and 77 K, revealing a defect‐free emission of ZnO films.

Effects of irradiation conditions on the lateral grain growth during laser crystallization of amorphous silicon films on borosilicate glass substrates

The effects of preheating laser power and pulse laser energy on the size and crystallinity of laterally grown grains by dual-laser crystallization of amorphous silicon (a-Si) films on borosilicate glass substrates were investigated. Plasma-enhanced chemical vapor deposition was adopted for the deposition of the a-Si films in order to reduce the process temperature and thus the diffusion of metal impurities from the glass substrate to the deposited a-Si films. It was found that the preheating laser power is critical in enhancing grain size, whereas the pulse laser energy is closely related to crystal quality. It is demonstrated that by properly adjusting the process conditions, laterally grown grains of 50-μm size could be obtained.

Probing the effect of nitrogen gas on electrical conduction phenomena of ZnO and Cu-doped ZnO thin films prepared by spray pyrolysis

Zinc oxide (ZnO) and Cu-doped ZnO (CZO) thin films were prepared on borosilicate glass substrates by spray pyrolysis technique. The X-ray diffraction study revealed that Cu doping caused a reduction in crystallite size. AFM study showed an increase in roughness with doping. This is attributed to the aggregation of particles to form clusters. From transmission electron microscopy analysis, the particle size is measured to be in the range 30–65 nm (average particle size 48 nm) for undoped ZnO, whereas it is in the range 24–56 nm (average particle size 40 nm) for CZO film. The electrical resistivity of the thin films was investigated in the presence of air as well as N2 mixed air at different temperatures in the range 30–270 °C. The change in resistivity properties was explained on the basis of conduction phenomena within the grain along with the grain boundaries as well as Cu- and N2-induced defect states. The thermal activation energy of ZnO was found to be in the range 0.04–0.7 eV and dependent on Cu doping and N2 level in air.

Nanocrystalline Thin Films TiO<sub>2</sub> Prepared by Different Concentration of Organic Acid and their Photocatalytic Activity

In this work, TiO2thin films were deposited on borosilicate glass substrates by sol-gel dip coating method and calcined at 500 °C for 15 min(heating rate3°C/min). The TiO2sol was prepared by fixing concentration of titaniumtetraisopropoxide(TTIP), TritonX-100 surfactant, ethanol and conc hydrochloric acid but amounts of acetyl acetone (Acac ) were various as 4, 6 and 8 mole respectively. After calcination process, all the TiO2thin films were homogeneous and transparent. Several techniques , such as X-ray diffraction (XRD), UV-Vis spectroscopy, Environment Scanning Electron Microscope (E-SEM), atomic force microscopy (AFM) and BET surface area analysis were used to characterize the prepared TiO2thin film. Spectra of XRD showed that the crystal structure was anatase phase with the crystal sizes of 9.05 – 12.57 nm. According to BET surface area analysis, the surface area , pore volume and pore size of TiO2were in the range of 66.35-82.53 m2/gm , 0.1194-0.1301 cm3/g and 57-71 A0respectively. The photodegradation of Reactive Blue 19 by the prepared TiO2thin films showed decomposition rate of 97.58% , 95.03 % and 94.48% for the thin films prepared by using 4, 6 and 8 mole AcAc respectively.

Growth and optical properties of chromium borate thin films

The present study focuses on the process of fabrication of chromium borate films using e-beam evaporation technique. The growth and optical properties of CrBO 3 thin films in the thickness range of 2–5 μm deposited by e-beam evaporation on to borosilicate glass substrates is reported for the first time. All films were deposited at ambient temperature using CrB 2 as the source material. Electron diffraction studies revealed the low-temperature growth of nanocrystalline CrBO 3 films. Raman and FT-IR spectra of the films exhibit signatures of three co-ordinated boron clearly signifying the formation of the borate. The spectral transmission of CrBO 3 films shows that films of the order of 2 micron are highly transparent (≈80%) in the visible region. The refractive index at 750 nm varies from 1.6 to 1.7 and the band gap is of the order of 2.4–2.8 eV. Nanoindentation measurements performed on the films indicate that the films are soft with hardness of the order of 0.5–1 GPa.

Wide band gap and p-type conductive Cu-Nb-O films

Cu–Nb–O films with a thickness of ca. 150 nm were prepared on borosilicate glass substrates using CuNbO3 ceramic target at substrate temperature of 500 °C by pulsed laser deposition. The X-ray diffraction patterns showed that the Cu–Nb–O films were amorphous or an aggregation of fine crystals. The post-annealed film at 300 °C in N2 gas showed 80% transmission in visible light (band gap = 2.6 eV) and high p-type conductivity of 21 S cm–1. The Cu–Nb–O film with a thickness of 100 nm, fabricated from the target with a composition of Cu/Nb = 0.9, showed the highest p-type conductivity of 116 S cm–1. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Rare Earth Doped SnO<SUB>2</SUB> Nanoscaled Powders and Coatings: Enhanced Photoluminescence in Water and Waveguiding Properties

Luminescent Eu3+ and Er3+ doped SnO2 powders have been prepared by Sn4+ hydrolysis followed by a controlled growth reaction using a particle's surface modifier in order to avoid particles aggregation. The powders so obtained doped with up to 2 mol% rare earth ions are fully redispersable in water at pH > 8 and present the cassiterite structure. Particles size range from 3 to 10 nm as determined by Photon Correlation Spectroscopy. Rare earth ions were found to be essentially incorporated into the cassiterite structure, substituting for Sn4+, for doping concentration smaller than 0.05 mol%. For higher concentration they are also located at the particles surface. The presence of Eu3+ ions at the surface of the particles hinder their growth and has therefore allowed the preparation of new materials consisting of water redispersable powders coated with Eu(3+)-beta diketonate complexes. Enhanced UV excited photoluminescence was observed in water. SnO2 single layers with thickness up to 200 nm and multilayer coatings were spin coated on borosilicate glass substrates from the colloidal suspensions. Waveguiding properties were evaluated by the prism coupling technique. For a 0.3 microm planar waveguide single propagating mode was observed with attenuation coefficient of 3.5 dB/cm at 632.8 nm.

Vanadium dioxide thin film with low phase transition temperature deposited on borosilicate glass substrate

A nanostructured vanadium dioxide (VO 2) thin film showing a low metal-insulator transition temperature of 30 °C has been fabricated through reactive ion beam sputtering followed by thermal annealing. The thin film was grown on borosilicate glass substrate at the temperature of 280 °C with a Si 3N 4 buffer layer. Both scanning electron microscopy and atomic force microscopy images have been taken to investigate the configuration of VO 2 thin film. The average height of the crystallite is 20 nm and the grain size ranges from 40 nm to 100 nm. The transmittance measured from low to high temperatures also reveals that the film possesses excellent switching property in infrared light at critical transition temperature, with switching efficiency of 52% at 2600 nm. This experiment paves the way of VO 2 thin film's application in smart windows.

Highly Parallel Planar Patch Clamp for Ion Channel Screening

To meet the ever increasing demand for higher throughput in ion channel screening and safety testing, new platforms are being introduced allowing for yet more throughput whilst retaining data quality. A new platform recording from 96 cells at a time with giga-seals, with continuous recording during compound application and addition of multiple compounds to each of the 96 cells being recorded will be described. This new platform vastly increases throughput, while reducing the cost per data point. Borosilicate glass substrates containing microstructured apertures are used for parallel patch clamp experiments. In the figure below, a screenshot of an experiment on 96 cells in a parallel is displayed. Shown are raw current responses of CaV3.2 channels expressed in HEK293 cells to a current voltage relationship step protocol.Recordings from various ligand- and voltage-gated ion channels on this platform will be shown.View Large Image | View Hi-Res Image | Download PowerPoint Slide

TiO2 thin films on soda-lime and borosilicate glass prepared by sol–gel processing: influence of the substrates

TiO2 films were deposited on soda-lime and borosilicate glass substrates, their optical and microstructural properties were investigated. X-ray diffraction showed significant differences between the sample series. Films deposited on the upper surface of soda-lime glass substrates showed higher indices of refraction than those prepared on the lower surface that had been in contact with the tin bath during float glass production. Results indicate that these differences not only result from different optical properties of the TiO2 backbone material due to alkali contamination but that also different film porosities can measured by ellipsometric porosimetry.