Borosilicate Glass Substrates Research Articles

Optical Band Gap Estimation of ZnO Nanorods

The optical band gap energy of ZnO nanorods was estimated by different methods found in literature. These nanorods were deposited onto TiO2 covered borosilicate glass substrates by aerosol assisted chemical vapor deposition. Characterization techniques were employed to reveal the crystalline structure, surface morphology and optical properties of the sample. The analysis proved that hexagonal cross-section ZnO nanorods in the wurtzite phase were grown onto a TiO2 buffer thin film of anatase. Variations in the components of transmittance and reflectance were associated with the development of a rough surface. Such fluctuations were correlated with the equations employed to estimate the optical band gap. The different methods indicated band gap values of 3.17 to 3.24 eV. The energy band gap of 3.24 eV agrees to that reported in the literature for ZnO nanorods. Fluorescence spectroscopy confirmed the accuracy of the mathematical predictions since an emission at 380 nm (3.26 eV) was seen.

Study of deposition parameters for the fabrication of ZnO thin films using femtosecond laser

Femtosecond (fs) pulsed laser deposition (fs-PLD) of ZnO thin film on borosilicate glass substrates is reported in this work. The effect of important fs-PLD parameters such as target–substrate distance, laser pulse energy and substrate temperature on structure, morphology, optical transparency and luminescence of as-deposited films is discussed. XRD analysis reveals that all the films grown using the laser energy range 120–230 μJ are polycrystalline when they are deposited at room temperature in a ~10−5 Torr vacuum. Introducing 0.7 mTorr oxygen pressure, the films show preferred c-axis growth and transform into a single-crystal-like film when the substrate temperature is increased to 100 °C. The scanning electron micrographs show the presence of small nano-size grains at 25 °C, which grow in size to the regular hexagonal shape particles at 100 °C. Optical transmission of the ZnO film is found to increase with an increase in crystal quality. Maximum transmittance of 95 % in the wavelength range 400–1400 nm is achieved for films deposited at 100 °C employing a laser pulse energy of 180 μJ. The luminescence spectra show a strong UV emission band peaked at 377 nm close to the ZnO band gap. The shallow donor defects increase at higher pulse energies and higher substrate temperatures, which give rise to violet-blue luminescence. The results indicate that nano-crystalline ZnO thin films with high crystalline quality and optical transparency can be fabricated by using pulses from fs lasers.

Deposition of Copper Oxide Coatings with an Atmospheric Pressure Plasma Source: II – Characterization of the Films

Copper oxide films have been deposited successfully on borosilicate glass substrates with a copper containing nitrogen plasma at atmospheric pressure. This was done by using a non‐thermal DC jet with a sacrificial electrode as copper source. The produced films have been systematically investigated by different methods, including scanning electron microscopy and X‐ray photoelectron spectroscopy (XPS). It is demonstrated that various copper morphologies, such as nanoflakes, can be produced by non‐thermal atmospheric pressure plasma sources. The XPS data suggest that the nanostructures produced in the deposition process consist mostly of Cu(II)O. The dominant shape of these nanoparticles is flake‐like with a high aspect ratio. Furthermore, it is shown that the temperature during the deposition process is well below 70 °C, and thus, enables copper oxide deposition on heat sensitive materials.

Light-induced atom desorption from glass surfaces characterized by X-ray photoelectron spectroscopy

We analyzed the surfaces of vitreous silica (quartz) and borosilicate glass (Pyrex) substrates exposed to rubidium (Rb) vapor by X-ray photoelectron spectroscopy (XPS) to understand the surface conditions of alkali metal vapor cells. XPS spectra indicated that Rb atoms adopted different bonding states in quartz and Pyrex. Furthermore, Rb atoms in quartz remained in the near-surface region, while they diffused into the bulk in Pyrex. For these characterized surfaces, we measured light-induced atom desorption (LIAD) of Rb atoms. Clear differences in time evolution, photon energy dependence, and substrate temperature dependence were found; the decay of LIAD by continuous ultraviolet irradiation for quartz was faster than that for Pyrex, a monotonic increase in LIAD with increasing photon energy from 1.8 to 4.3 eV was more prominent for quartz, and LIAD from quartz was more efficient at higher temperatures in the range from 300 to 580 K, while that from Pyrex was almost independent of temperature.

Mechanical Strength and Broadband Transparency Improvement of Glass Wafers via Surface Nanostructures.

In this study, we mechanically strengthened a borosilicate glass wafer by doubling its bending strength and simultaneously enhancing its transparency using surface nanostructures for different applications including sensors, displays and panels. A fabrication method that combines dry and wet etching is used for surface nanostructure fabrication. Specifically, we improved the bending strength of plain borosilicate glass by 96% using these surface nanostructures on both sides. Besides bending strength improvement, a limited optical transmittance enhancement of 3% was also observed in the visible light wavelength region (400–800 nm). Both strength and transparency were improved by using surface nanostructures of 500 nm depth on both sides of the borosilicate glass without affecting its bulk properties or the glass manufacturing process. Moreover, we observed comparatively smaller fragments during the breaking of the nanostructured glass, which is indicative of strengthening. The range for the nanostructure depth is defined for different applications with which improvements of the strength and transparency of borosilicate glass substrate are obtained.

Highly conductive and transparent Ga-doped ZnO thin films deposited by chemical spray pyrolysis

Undoped and Ga doped ZnO thin films were deposited on borosilicate glass substrates via a simple but effective chemical spray pyrolysis technique. The samples were characterised by X-ray diffractometer, UV–vis spectrophotometry, Scanning electron microscopy and I–V measurements. The structural, morphological and optical properties were studied as a function of increasing Ga doping concentration from 0 to 7 at.%. XRD results revealed that the films were polycrystalline with hexagonal wurtzite crystal structure. Increasing Ga dopant concentration decreased the crystallite size from 74 to 19nm whilst the band gap, dislocation density and lattice strain shifted to higher values. All the films exhibited high transmittance of about 85% in the entire visible spectral range. Lowest resistivity of 1.47×10−4Ωcm was obtained at 3 at.% Ga concentration.

Ion beam induced defects in CVD graphene on glass

Single layer graphene grown by chemical vapor deposition (CVD) method on Cu foil and then transferred onto a borosilicate glass substrate was used in the experiments. The graphene samples were irradiated by singly charged ions of helium, nitrogen, argon or krypton at the energy of 100 keV up to fluence ranging from 1 × 1011 cm− 2 to 1 × 1016 cm− 2. Raman spectroscopy was used for the detection of defect size and density in graphene caused by ion irradiation. The ion induced defect size and density were determined from the Raman spectra measurements. The applicability of the SRIM code for simulation of defects generation by ions in graphene was tested. Finally, the controlled generation of the defects in graphene by using ion implantation was verified.

Influence of nitrogen doping on the properties of ZnO films prepared by radio-frequency magnetron sputtering

In this study, zinc oxide thin films were prepared through magnetron sputtering on alkali-free borosilicate glass substrates, with a direct current plasma system adopted to increase the degree of dissociation of N2 gas. The N2/(Ar+N2) flow ratio was varied from 0 to 0.7 during the preparation process to investigate its influence on the properties of the ZnO films. All of the ZnO thin films grew along the preferential (002) crystal plane, with the diffraction intensity of the (103) plane increasing upon increasing the N2/(Ar+N2) flow ratio. The transmittance, as well as the optical band gap, in the wavelength range of visible light (400–700nm) decreased upon increasing the N2/(Ar+N2) flow ratio. By doping nitrogen at a N2/(Ar+N2) flow ratio of greater than 0.2, the conduction behavior effectively became p-type; nevertheless, the resistivity increased upon increasing the N2/(Ar+N2) flow ratio, due to the increasing Vo concentration and the decreasing grain size of the ZnO films. Among the ZnO films, the film grown at a N2/(Ar+N2) flow ratio of 0.3 exhibited the optimal performance for application as a transparent conducting oxide.

ChemInform Abstract: Methylammonium Bismuth Iodide as a Lead‐Free, Stable Hybrid Organic—Inorganic Solar Absorber.

AbstractPhase‐pure (MeNH3)3Bi2I9 (MBI) thin films are deposited on borosilicate or quartz glass substrates via first spin coating a BiI3 solution in DMF and annealing (100 °C, 30 min) and secondly, spin coating a MeNH3I solution in anhydrous iPr‐OH on top followed by annealing (100 °C, 1 h).

Manufacturing of membranes by laser ablation in SiC, sapphire, glass and ceramic for GaN/ferroelectric thin film MEMS and pressure sensors

AlGaN/GaN-based high electron mobility transistors (HEMTs), Schottky diodes and/or resistors have been presented as sensing devices for mechanical or chemical sensors operating in extreme conditions. Creation of appropriate diaphragms and/or cantilevers out of substrate materials is necessary for further improvement of sensing properties of such MEMS sensors. The sensitivity of the AlGaN/GaN based MEMS pressure sensor can be modified by membrane thickness. In case of SiC as substrate material of the epitaxial AlGaN/GaN heterostructure layers, we applied laser ablation technique for micromachining of the membranes. We were able to verify the feasibility of this process by fabrication of micromechanical membrane structures also in bulk 3C-SiC, borosilicate glass, sapphire and Al2O3 ceramic substrates by femtosecond laser (520 nm) ablation. On a 350 µm-thick 4H-SiC substrate we produced an array of 275 µm deep and 1000---3000 µm in diameter blind holes without damaging the 2 µm GaN layer at the back side. Our experiments indicate that pinhole defects in the ablated membranes are affected by ripple structures related to the polarization of the laser. We developed an ablation technique inhibiting the formation of pin holes caused by laser induced periodic surface structures (LIPSS).

Morphologically manipulated Ag/ZnO nanostructures as surface enhanced Raman scattering probes for explosives detection

The detection of secondary explosive molecules (e.g., ANTA, FOX-7, and CL-20) using Ag decorated ZnO nanostructures as surface enhanced Raman scattering (SERS) probes is demonstrated. ZnO nanostructures were grown on borosilicate glass substrates by rapid thermal oxidation of metallic Zn films at 500 °C. The oxide nanostructures, including nanosheets and nanowires, emerged over the surface of the Zn film leaving behind the metal residue. We demonstrate that SERS measurements with concentrations as low as 10 μM, of the three explosive molecules ANTA, FOX-7, and CL-20 over ZnO/Ag nanostructures, resulted in enhancement factors of ∼107, ∼107, and ∼104, respectively. These measurements validate the high sensitivity of detection of explosive molecules using Ag decorated ZnO nanostructures as SERS substrates. The Zn metal residue and conditions of annealing play an important role in determining the detection sensitivity.

MOLYBDENUM TRIOXIDE THIN FILMS DOPED WITH GOLD NANOPARTICLES GROWN BY A SEQUENTIAL METHODOLOGY: PHOTOCHEMICAL METAL-ORGANIC DEPOSITION (PMOD) AND DC-MAGNETRON SPUTTERING

Gold nanoparticles (AuNPs) were deposited by DC-magnetron sputtering onto molybdenum trioxide (MoO3) thin films grown by Photochemical Metal- Organic Deposition (PMOD) on Si(100) and borosilicate glass substrates. The chemical, optical and morphology properties of the films were studied by UV/ Vis Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), and X-Ray Diffraction (XRD). SEM revealed that AuNPs formed after 5 s of sputtering. AuNPs are spherical and have both an average diameter of 18 nm and a relatively narrow size distribution. As the deposition time increases, larger structures are formed by an aggregation of AuNPs. XPS studies of the AuNP/MoO3 films on Si(100) showed the presence of Mo(VI) and Mo(V), which indicated that the films were primarily non-stoichiometric molybdenum oxides. The occurrence of oxygen vacancies in the substrate play an important role to stabilize the AuNPs.

Sputtering of silicon and glass substrates with polyatomic molecular ion beams generated from ionic liquids

The effect of irradiating 1-ethyl-3-methylimidazolium positive (EMIM+) or dicyanamide negative (DCA–) ion beams using an ionic liquid ion source was characterized concerning its sputtering properties for single crystalline Si(100) and nonalkaline borosilicate glass substrates. The irradiation of the DCA– ion beam onto the Si substrate at an acceleration voltage of 4 and 6 kV exhibited detectable sputtered depths greater than a couple of nanometers with an ion fluence of only 1 × 1015 ions/cm2, while the EMIM+ ion beam produced the same depths with an ion fluence 5 × 1015 ions/cm2. The irradiation of a 4 kV DCA– ion beam at a fluence of 1 × 1016 ions/cm2 also yields large etching depths in Si substrates, corresponding to a sputtering yield of Si/DCA– = 10, and exhibits a smoothed surface roughness of 0.05 nm. The interaction between DCA– and Si likely causes a chemical reaction that relates to the high sputtering yield and forms an amorphous C-N capping layer that results in the smooth surface. Moreover, s...

Lithographic Microfabrication of a 16-Electrode Array on a Probe Tip for High Spatial Resolution Electrochemical Localization of Exocytosis.

We report the lithographic microfabrication of a movable thin film microelectrode array (MEA) probe consisting of 16 platinum band electrodes placed on top of a supporting borosilicate glass substrate. These 1.2 μm wide electrodes were tightly packed and positioned parallel in two opposite rows within a 20 μm × 25 μm square area and with a distance less than 10 μm from the edge of the glass substrate. We demonstrate the ability to control and place the probe in close proximity to the surface of adherent bovine chromaffin cells and to amperometrically record single exocytosis release events with high spatiotemporal resolution. The two-dimensional position of single exocytotic events occurring in the center gap area separating the two rows of MEA band electrodes and that were codetected by electrodes in both rows was determined by analysis of the fractional detection of catecholamine released between electrodes and exploiting random walk simulations. Hence, two-dimensional electrochemical imaging recording of exocytosis release between the electrodes within this area was achieved. Similarly, by modeling the current spikes codetected by parallel adjacent band electrodes positioned in the same electrode row, a one-dimensional imaging of exocytosis with submicrometer resolution was accomplished within the area. The one- and two-dimensional electrochemical imaging using the MEA probe allowed for high spatial resolution of exocytosis activity and revealed heterogeneous release of catecholamine at the chromaffin cell surface.

Stainless-Steel Thin Film as Passive Radiative Cooling Materials

Spectrally selective glazing system attracts great attention for energy efficient radiator applications. The present work reports the possibility of a specific shield (Stainless steel/Borosilicate glass) to provide passive cooling for the purpose of reducing the use of classical active method. Radiative cooling devices require a convective shield that blocks all incoming solar radiation, but should selectively reemit radiation in the “atmospheric-window” region. In this study, borosilicate glass substrate coated with a stainless steel thin film was prepared by thermal evaporation and low pressure (6.3 × 10-3 bar) DC plasma sputtering, in order to achieve the radiative cooling effect. The optical properties of the optimal thickness thin film were measured in the wavelength range of 0.3-20 μm by an OL-750 double-beam spectroradiometer. The thin film has high visible band reflectance with high infrared band emissivity across the full 8-13 μm; which indicates that stainless steel thin film can be used as good radiative cooling material.

Electronic transport in highly conducting Si-doped ZnO thin films prepared by pulsed laser deposition

Highly conducting (ρ = 3.9 × 10−4 Ωcm) and transparent (83%) polycrystalline Si-doped ZnO (SiZO) thin films have been deposited onto borosilicate glass substrates by pulsed laser deposition from (ZnO)1−x(SiO2)x (0 ≤ x ≤ 0.05) ceramic targets prepared using a sol-gel technique. Along with their structural, chemical, and optical properties, the electronic transport within these SiZO samples has been investigated as a function of silicon doping level and temperature. Measurements made between 80 and 350 K reveal an almost temperature-independent carrier concentration consistent with degenerate metallic conduction in all of these samples. The temperature-dependent Hall mobility has been modeled by considering the varying contribution of grain boundary and electron-phonon scattering in samples with different nominal silicon concentrations.

English

Practical application of graphene require accurate determination of the number of layers. In this paper we demonstrate a reliable and efficient approach for determining the number of graphene layers. Plots of contrast spectra against number of graphene layers transferred on Borosilicate glass substrates for RGB image, R, G, and B channels were found to increase linearly. The R channel contrast values for one to four graphene layers were found to be 0.076(R), 0.083(R), 0.090(R), and 0.097(R) respectively. Similarly, the G contrast channel values were obtained as - 0.032(G), -0.023(G), -0.015(G), and -0.007(G) whereas B channel gives 0.004(B), 0.011(B), 0.019(B), and 0.026(B) for SLG, BLG, Tri-layer and Tetra-layer graphene respectively. The contrast values for SLG in RGB transmission regions were found to be 0.076(R), -0.032 (G), and 0.004(B). Our experimental results deviate from theoretical contrast of SLG transferred on SiO2 (285nm )/Si, Quartz, Al2O3 (72 nm)/Si and Hexagonal-BN crystal substrate. This deviation is shown to arise from the unappreciable optical absorption of the Borosilicate substrate in the visible spectrum range. Contrast imaging is therefore a reliable method with the R contrast channel providing the highest contrast leading into increased resolution of the detection level of samples.

Laser Modification of Silicon and Borosilicate Glass Wettability for Micro-Fluidic Systems

A laser modification method to control the surface wettability of a silicon and borosilicate glass substrate is proposed and demonstrated. The wettability of the silicon surface decreases after 2.5 W laser irradiation without a change in surface morphology. When the laser power is greater than 4 W, it results in the formation of a 10-nm-deep groove and the wettability increases. These phenomena are caused by changes in the number of surface groups and morphology, respectively. On the other hand, the glass surface is modified by infrared laser irradiation and the treated surface is highly hydrophilic. Surface analysis by FT-IR indicates that the modification is the result of an increase in the number of silanol groups. The proposed modification method is applied to micro-fluidic systems. A modified line can function as a surface micro-channel. Furthermore, with a gradient in wettability, the micro-channel has the ability to self-transport water droplets.

Effect of Annealing on the Development of Fully Transparent Ternary V-O-Na-Si Mixed Metal Oxide Thin Films from Polymer-Assisted Dip-Coated V2O5

Both transparent oxides and transparent conductive oxides are of particular research interest for future applications in flexible, optically transparent thin film transistors and luminescent devices. We report the formation of a transparent oxide material based on the interdiffusion of Na-O and Si-O species with dip-coated V2O5 thin films on a borosilicate glass substrate. The deposition process used a facile solution processed dip-coating technique in the high-rate draining regime. Liquid precursors of vanadium alkoxide and alkoxide-polyethylene glycol mixtures were used for thin film deposition. We examine the effect of annealing condition on the phase conversion process, morphology and optical transmittance due to the conversion of the V2O5 films to completely transparent ternary mixed metal oxide thin films. The work also examines the role of polymer-assisted deposition on the development of the V-O-Na-Si transparent thin films during different annealing conditions. Polymer-assisted V2O5 thin films on glass are shown to convert to optically clear thin films during annealing, with a transparency >95% across the visible spectrum, and a blue-shift of the absorption edge to maintain >90% transparency at 380 nm.

Fabrication of Novel Transparent Touch Sensing Device via Drop-on-Demand Inkjet Printing Technique.

PSS) and dielectric poly(methylsiloxane) were deposited on a desired area to form a capacitive touch sensor structure. The properties of the printed sensors (optical transparency, electrical resistance and touch sensing performance) were investigated with varying PSS printing passes. A novel transparent touch sensor fabricated with an all-inkjet-printing method is demonstrated for the first time. This process holds industrially viable potential to fabricate transparent touch sensors with an inkjet printing technique on both rigid and flexible substrates for a wide range of applications.