Insulating Glass Substrate Research Articles

Effect of insulating glass substrate and conductive on SnS thin films physical properties grown by spray syringe pump method

Effect of insulating glass substrate and conductive on SnS thin films physical properties grown by spray syringe pump method

Functionalization of insulating substrate and its hybridization with carbon fibers

In this work, surface functionalization of an insulating glass substrate was performed and it was hybridized with conducting carbon fiber materials, carbon coils. Glass substrate was carried out via different chemical treatments, then an amine terminated self-assembled monolayer was introduced on its surface. Carbon coils were also treated with nitric acid. These surface modified carbon coils, glass substrates, and carbon coils immobilized on glass substrates were analyzed through different analytical tools. Finally, hybridization of carbon coils on glass substrates resulted only in functionalized glass (amine terminated) surfaces via chemical bonding, while the un-functionalize glass substrate did not. Thus, such a stable, recognized practice can apply to fabricate simple microarrays to bind carbon materials or biomolecules for further application.

Physical vapor deposition of an oriented metal–organic framework HKUST-1 thin film on an insulating substrate

This study reports the synthesis of a (111)-oriented HKUST-1 ([Cu3(BTC)2], BTC = 1,3,5-benzenetricarboxylate) thin film on an insulating glass substrate using a combination of physical vapor deposition and solvent vapor annealing.

Thin Film Photodetectors Based on Zinc Oxide Nanoinks

Zinc oxide (ZnO) has many useful properties for electronics and optoelectronics including wide band gap, large exciton binding energy, low-cost, ease of processing and availability [1]. This has led to increased interest and development of thin film electronics, transparent conductors, solar cells, light-emitting diodes, lasers, photodetectors and various sensors based on ZnO materials [2, 3]. The high surface areas and tunable properties of ZnO nanostructures make them particularly suitable for applications such as sensing and photonic devices [4, 5].In this work, we present results on nanostructured ZnO thin film photodetectors fabricated using nanoparticle inks (nanoinks) obtained via planetary ball milling (PBM) of bulk powders. PBM [6] is an emerging solution-based nanofabrication approach that can quickly produce nanoink suspensions at low-cost by nanoscale grinding, without complex processing and suitable for thin film coating of various materials on different substrates [7]. The thin film photodetector devices were fabricated by depositing PBM ZnO nanoink onto flat insulating glass substrates followed by contact formation as shown schematically in Fig. 1a: PBM was performed using ZnO powder in ethylene glycol (EG) or deionized (DI) water solvent (a.k.a. colloidal grinding) with zirconia grinding beads. The grinding speed and time were varied between 200 and 1000 rpm and 10 min. and 60 min., respectively. A few μL of the resulting ZnO nanoink was used to coat the substrate surface and dried at ~ 100 °C. Lastly, two electrical contacts to the resulting films were made using silver paint and copper tape. Analysis of ZnO films after deposition showed they consist of nanostructured particles with sizes reaching below 100 nm, as displayed in the scanning electron microscopy (SEM) and atomic force microscopy (AFM) images in Fig. 1b, depending on grinding conditions (speed, time).The optical properties of the ZnO thin films were evaluated via photoluminescence measurements (Fig. 1c), which, in addition to interband transitions in the UV, displayed longer wavelength emission peaks due to surface and bulk defect states. Such deep level states are dependent on grinding parameters and thus allow the accessible spectrum for the nanostructured ZnO films to be extended into the visible region in a tunable manner. Two-terminal photoconductance data of the ZnO PBM nanoink thin film devices were obtained using a probe station and precision source-measure unit, with and without illumination, under ambient atmosphere and at room temperature. Fig. 1d shows current vs. voltage curves obtained for a typical photodetector device, which display current increasing proportional to incident light intensity. This behavior can be explained by electron-hole pair creation and desorption of surface oxygen species (leading to vacancies that act as donors) upon photon absorption, which leads to an increase in conductance. This is consistent with previous studies where ZnO thin films have been used for photoconductive sensor applications, validating PBM nanoink as a suitable synthesis technique for the active material in photodetectors.Compared to standard ZnO thin films, the PBM nanoink method allows both particle dimensions and surface states to be tailored and optimized for different photodetector applications in a straightforward manner by adjusting grinding conditions. In particular, both UV and visible light detection can be tuned via the solution-based ZnO nanoink approach presented without additional material/chemical processing. Such PBM nanoinks thus offer the potential of realizing low-cost photodetectors and multifunctional thin film coatings for applications in optoelectronics, imaging, environmental monitoring and communications.

Comprehensive Study on Nebulizer-Spray-Pyrolyzed Eu-Doped PbS Thin Films for Optoelectronic Applications

PbS films in undoped state and with various Eu contents (1 wt.%, 3 wt.%, and 5 wt.%) have been coated effectively on insulating glass substrates by a nebulized spray pyrolysis route. The effects of Eu doping on various properties including the photosensitivity of the PbS films were systematically analyzed. X-ray diffraction (XRD) analysis of the materials revealed a polycrystalline nature with crystallites showing simple cubic structure oriented along (200) direction. Based on the XRD data, the crystallite size, dislocation density, and lattice strain of the films with different doping concentrations were calculated and are consistently discussed. The secondary phase Eu3O4 formed when the Eu doping level was higher in the host solution. The Raman peaks detected at 190 cm−1, 236 cm−1, and 465 cm−1 confirmed formation of PbS. Scanning electron microscopy was used to reveal the morphology of the films as a function of the dopant concentration. Important optical properties including the bandgap, absorption coefficient, dielectric constant, index of refraction, and coefficient of extinction of the films are systematically reported. Optical study of the films revealed a variation of the bandgap from 2.14 eV to 2.81 eV with increasing Eu doping level. The 3 wt.% europium-doped PbS film showed better photosensitivity at 100 W/m2 compared with the other films based on current–voltage (I–V) measurements.

Synthesis of vertically aligned carbon nanoflakes by hot-wire chemical vapor deposition: Influence of process pressure and different substrates

The vertically aligned carbon nanoflakes thin films were synthesized on Si (100) and alkali free borosilicate glass substrates at relatively low substrate temperature of 400 °C, without any catalyst or surface pre-treatment, using hot-wire chemical vapor deposition (HWCVD) technique. Raman Spectroscopy studies reveal that the crystallinity of the films increases with increase in process pressure. Our studies show that HWCVD is a versatile technique for the synthesis of these films at low temperature compared to plasma enhanced CVD on both semiconducting Si as well as insulating glass substrates.

Highly sensitive 3C-SiC on glass based thermal flow sensor realized using MEMS technology

This paper presents a silicon carbide (SiC) based thermal flow sensor on a transparent and electrically insulating glass substrate via anodic bonding process. The paper elaborates on the fabrication steps of the thermal flow sensor. Three resistive heater size configurations of dimensions 100 μm × 100 μm, 300 μm × 300 μm, and 1000 μm × 1000 μm were fabricated. The thermoresistive properties of 3C-SiC on glass were investigated from ambient temperature to 443 K. The characterization of the SiC heater and temperature sensors revealed a high thermoresistive effect with a temperature coefficient of resistance (TCR) of approximately −20,716 ppm/K at ambient temperature(298 K) and −9367 ppm/K at 443 K respectively. The performance of the sensors was evaluated based on the sensitivity of the flow sensor. For a turbulent flow velocity of 7.4 m/s, the sensitivity of the sensor operating in the constant -voltage mode is 0.091 s/m with a power consumption of 133.50 mW for the 1000 μm × 1000 μm heater. Finally, a study on the flow direction was conducted to confirm the operation of 2-D direction independent hot-film flow sensor. Results indicated that the performance of the sensor remained the same when the flow direction was perpendicular to SiC heater and sensor respectively. However, the best sensitivity was achieved by passing air flow perpendicular to the sensing elements. The high TCR of the single crystalline 3C-SiC material, the relatively low power consumption on the order of milliwatts and the high sensitivity of our sensor demonstrates its potential use for high temperature flow sensing applications.

Seed-free electrodeposition of ZnO bi-pods on electrophoretically-reduced graphene oxide for optoelectronic applications

Large areas of reduced graphene oxide (rGO) films were obtained by electrophoretic deposition onto insulating glass substrate. ZnO nanostructures were directly grown on the rGO films by single-step electrodeposition method. The properties of ZnO nanostructures were evaluated as a function of deposition mode onto rGO electrodes with different stoichiometry. Atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetrical analysis (TGA), transmission measurements, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed to characterize the obtained materials. Bi-pod morphology was observed for ZnO electrodeposited on rGO films by pulsed current elelctrodeposition. The obtained ZnO/rGO hybrid structures show high potential for highly transparent optoelectronic nanodevices.

Preparation of large-area porous anodic alumina on insulating substrates

Porous anodic alumina (PAA) has been widely used for the development of various functional nanostructures and nanomaterials. However, the fabrication of wafer-scale PAA on insulating substrate is not very well developed. Here we report an aluminum evaporation and scan-anodization method to produce large high-quality PAA film on insulating glass substrate directly. The PAA film shows good adhesion to the glass substrate and an excellent transmittance of >90% was achieved over a broad spectrum from 600nm to 2000nm in wavelength. The proposed large-scale process is likely to open up the way to use the PAA film on insulating substrate for optical applications.

Synthesis of conducting transparent few-layer graphene directly on glass at 450 °C

Post-growth transfer and high growth temperature are two major hurdles that research has to overcome to get graphene out of research laboratories. Here, using a plasma-enhanced chemical vapour deposition process, we demonstrate the large-area formation of continuous transparent graphene layers at temperatures as low as 450 °C. Our few-layer graphene grows at the interface between a pre-deposited 200 nm Ni catalytic film and an insulating glass substrate. After nickel etching, we are able to measure the optical transmittance of the layers without any transfer. We also measure their sheet resistance directly and after inkjet printing of electrical contacts: sheet resistance is locally as low as 500 Ω sq−1. Finally the samples equipped with printed contacts appear to be efficient humidity sensors.

Electrophoretic deposition of high quality transparent conductive graphene films on insulating glass substrates

Graphene is a promising material for transparent conductive films (TCFs) because of its high electrical conductivity and excellent optical transparency over a wide spectral range. We have previously reported on an inexpensive means of producing graphene-based TCFs using chemically derived graphene flakes. However, the deposition of chemically derived graphene can yield poor stacking of graphene flakes, which degrades the electrical conductivity of the resulting films. Here, we describe an alternative approach for producing large areas of TCFs based on electrophoretic deposition of graphene onto glass substrates using charged graphene oxide flakes. This method enabled the deposition of highly stacked graphene films onto insulating glass substrates with potential for TCFs.

Electrochemical properties of interface formed by interlaced layers of DNA- and lysozyme-coated single-walled carbon nanotubes

Multifunctional coatings were produced by the layer by layer assembly of single-walled carbon nanotubes (SWNT) dispersed in DNA and lysozyme (LSZ) on an insulating glass substrate. The electrochemical properties of these mechanically robust biocoatings were characterized for the first time using scanning electrochemical microscopy (SECM) and impedance spectroscopy (IS). SECM surface analysis demonstrated an increase in tip current with a corresponding increase in the number of oppositely polarized interlaced layers, indicating that subsequent layers were not electrically insulated from each other and a direct correlation exists between SECM feedback response and the number of layers. The rate of charge transport was also dependent on the chemical composition/polarity of the outermost surface layer. Coatings terminating in SWNT-DNA resulted in more positive feedback than those terminating in SWNT-LSZ. IS analysis demonstrated that the SWNT-DNA had a low charge transfer resistance in comparison with SWNT-LSZ, which is consistent with the results obtained by SECM. These results enable enhanced fundamental understanding and prediction of the electrical properties of SWNT-biopolymer layers with controlled interlaced polarities and orientation. Furthermore, these finding highlight the potential for SWNT-biopolymers in electronic and sensing applications.

Prospects for the Application of Scanning Electrochemical Microscopy in Ionic Liquids

Prospects have been assessed for the application of the technique of scanning electrochemical microscopy (SECM) in viscous ionic liquids. Use of the Fc0/+ redox couple (Fc = ferrocene) to obtain microelectrode approach curves revealed that the required steady state behaviour needed for analysis of data relevant to conducting platinum and insulating glass substrates is moderately easy to achieve in a 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) ionic liquid. However, in the more highly viscous 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, where significantly lower diffusion coefficients are encountered, approach-curve data that conform to steady state theory are only found with very small microelectrodes (e.g., ≤2 μm diameter), very slow electrode–substrate approach rates (e.g., ≤0.05 μm s–1), and long equilibration times (e.g., 50 s). A comparison is provided with SECM approach curves acquired in aqueous media. SECM images of an Ag substrate in contact with [BMIM][BF4] also are presented and are of only slightly inferior quality to images obtained in water.

Determination of the electron beam irradiated area by using a new procedure deriving from the electron beam lithography technique

The study of the charge trapping properties in non-conductive solids by means of a Scanning Electron Microscope requires the knowledge of both the injected charge and the current densities over the irradiated sample area. The aim of this paper is to set-up an experimental technique leading to a more accurate determination of this area. After investigation of the parameters which influence the determination of the irradiated area size by using the electron beam lithography technique (electron beam energy, resist thickness and nature of the substrate), we describe a new experimental procedure derived from this technique. In this procedure, we replace the usual resist develop process by a direct SEM resist surface imaging immediately after the irradiation step. Thus, we find that the irradiation area on insulating glass substrate is considerably wider than that on conducting copper substrate. Moreover, a SEM contrast inversion is observed. These different behaviours are interpreted by considering the charging ability of glass and the conductivity nature of copper.

Enhancement of electron mobility in nanocrystalline silicon∕crystalline silicon heterostructures

We report on an effective way to obtain high electron mobility (∼103cm2∕Vs) in lowly doped hydrogenated nanocrystalline silicon (nc-Si:H) thin films by constructing nc-Si:H∕crystalline Si (c-Si) heterostructures. The enhancement has been demonstrated in a comparative study on nc-Si:H thin films grown on p- and n-type c-Si, as well as insulating glass substrates through temperature- and magnetic-field-dependent Hall-effect measurements. The effect has been attributed to the ordered structure and narrow boundaries between the nanograins, with the help of microstructure pictures from high-resolution transmission electron microscopy. In addition to the detailed individual transport information of carriers in the nc-Si:H systems, we observe clear evidence for the formation of a two-dimensional electron gas at the nc-Si:H∕c-Si interfaces. These results are discussed within the framework of the Boltzmann theory and the quantum interference theory.

High-pitch metal-on-glass technology for pad pitch adaptation between detectors and readout electronics

Modern High Energy Physics and Astrophysics strip detectors have increased channel density to levels in which their connection with the readout electronics has become very troublesome due to high pad pitch. Also, direct wire bonding is prevented by the fact that typically detector's pad pitch and electronics' pad pitch do not agree. A high pitch metal-on-glass technology is presented, that allows pad pitch adaptation between detectors and readout electronics. It consists of high density metal lines on top of an insulating glass substrate. A photoresist layer is deposited covering the metal tracks for passivation and protection The technology is tested for conductivity, bondability, bonding pull force, peel of, and radiation hardness, and it is an established technology in the clean room of the CNM Institute in Barcelona. This technology has been chosen by the ATLAS Collaboration for the pad pitch adapters of the SCT Endcap Modules, by the Compton Camera Collaboration, and by other REP experiments for the interconnection between detectors and readout electronics.

Formation of copper electrodeposits on an untreated insulating substrate

We report here the electrodeposition of copper on an insulating glass substrate withoutintroducing additives into the electrolyte and/or metallic clusters on the surface of thesubstrate. The deposit morphology, which varies from compact film to dense-branchingpatterns, can be achieved by changing the concentration and pH of the electrolyte, and theelectric current in electrodeposition. The grain size of the electrodeposits is analysed forvarious growth conditions. We find that finer copper grains can be easily achieved at largeelectric current, high pH and low electrolyte concentration. We explain, using the theory ofnucleation, why a metallic layer may develop horizontally over an insulating glass plate.

Dielectrophoretic fluidic cell fractionation system

This paper presents the development and experimental verification of a DEP fluidic system capable of fractionation of intact biological cells in suspension into purer subpopulations. This was accomplished by employing a specially shaped nonuniform electric field, synthesized by microfabricated planar microelectrode arrays, housed on an insulating glass substrate. To improve the efficiency of cell sorting, the microelectrodes are individually biased by a variable frequency alternating current (ac) voltage source, which allows us to exploit both positive and negative dielectrophoresis (DEP) to affect cell separation. Furthermore, through suitable establishment of a cell stream supported by sheath flow, such fractionation is achieved in a continuous fashion. The proposed DEP fluidic fractionation may be configured to operate in three (3) different modes. In this work, however, a detailed account is only presented for one mode of operation. The simulation of the electric field and force profiles, together with the experimental results obtained on model cells (plant protoplasts), confirm our theoretical predictions and furthermore demonstrate improvements in both separation efficiency and throughput over a wide range of frequencies (10 Hz to 5 kHz).

A wireless batch sealed absolute capacitive pressure sensor

This paper reports the development of an absolute wireless pressure sensor that consists of a capacitive sensor and a gold-electroplated planar coil. Applied pressure deflects a 6 μm-thin silicon diaphragm, changing the capacitance formed between it and a metal electrode supported on a glass substrate. The resonant frequency of the LC circuit formed by the capacitor and the inductor changes as the capacitance changes; this change is sensed remotely through inductive coupling, eliminating the need for wire connection or implanted telemetry circuits. The sensor is fabricated using the dissolved-wafer process and utilizes a boron-doped silicon diaphragm supported on an insulating glass substrate. The complete sensor measures 2.6mm×1.6 mm in size and incorporates a 24-turns gold-electroplated coil that has a measured inductance of 1.2 μH. The sensor is designed to provide a resonant frequency change in the range 95–103 MHz for a pressure change in the range 0–50 mmHg with respect to ambient pressure, providing a pressure responsivity and sensitivity of 160 kHz/mmHg and 1553 ppm/mmHg, respectively. The measured pressure responsivity and sensitivity of the fabricated device are 120 kHz/mmHg and 1579 ppm/mmHg, respectively.

Single-crystal ferroelectric microwave capacitor fabricated by separation by hydrogen implantation

Microwave ferroelectric capacitors have been fabricated using separation by hydrogen ion implantation and transfer of a 500 nm thick single-crystal SrTiO3 layer to an insulating glass substrate. The capacitor films are of high quality with a measured quality factor of nearly 100 at 10 GHz.