Glass Slide Substrates Research Articles

He+ induced changes in the surface structure and optical properties of RF-sputtered amorphous alumina thin films

High quality 50nm thick stoichiometric amorphous aluminium oxide films were reactively sputtered on microscope glass slide substrates. The films were exposed to energetic (2.20MeV) He+ at different ion fluences of 6×1012ion/cm2; 1×1013ion/cm2; 2×1013ion/cm2; 3×1013ion/cm2; and 4×1013ion/cm2. The effect of the ion irradiation on the optical, structural phase and surface properties of the alumina films was investigated via UV–VIS–NIR spectroscopy, X-ray diffraction analysis and the atomic force microscopy respectively. The transmission and absorption spectra of the irradiated films showed variation that depended on ion fluence. The refractive index, extinction coefficient, optical conductivity, dielectric constant and energy loss functions of the films were also affected by He+ irradiation. Optical band gap and films' structural phase were however not altered by the ion irradiation. The variation in optical constants induced by radiation was attributed to electronic excitation and increase in surface roughness of the films.

Synthesis and properties of PMMA‐ZrO2 organic–inorganic hybrid films

ABSTRACTIn this work we report the synthesis process and properties of PMMA‐ZrO2 organic–inorganic hybrid films. The hybrid films were deposited by a modified sol‐gel process using zirconium propoxide (ZP) as the inorganic (zirconia) source, methyl methacrylate (MMA) as the organic source, and 3‐trimetoxy‐silyl‐propyl‐methacrylate (TMSPM) as the coupling agent between organic and inorganic phases. The films were deposited by dip coating on glass slide substrates from a hybrid precursor solution containing the three precursors with molar ratio 1 : 0.25 : 0.25 for ZP, TMSPM, and MMA, respectively. After deposition, the hybrid thin films were heat‐treated at 100°C for 24 h. The macroscopic characteristics of the hybrid films such as high homogeneity and high optical transparence evidenced the formation of a cross‐linked, interpenetrated organic–inorganic network. The deposited PMMA‐ZrO2 hybrid films were homogeneous, highly transparent and very well adhered to substrates. Fourier Transform Infra‐Red measurements of the hybrid films display absorption bands of chemical groups associated with both PMMA and ZrO2 phases. The amounts of organic and inorganic phases in the hybrid films were determined from thermogravimetric measurements. The surface morphology and homogeneity of the hybrid films at microscopic level were analyzed by scanning electron microscopy and atomic force microscopy images. From the analysis of optical transmission and reflection spectra, the optical constants (refraction index and extinction coefficient) of the hybrid films were determined, employing a physical model to simulate the hybrid optical layers. The refraction index of the hybrid films at 532 nm was 1.56. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42738.

The Effects of O<sub>2</sub>:N<sub>2</sub> Gas Ratios on Structural, Optical, Electrical Properties of TiO<sub>x</sub>N<sub>y</sub> Thin Film Deposited by Reactive DC Magnetron Sputtering

In this work, titaniumoxynitride (TiOxNy) thin films were deposited on glass slide substrates by using reactive dc magnetron sputtering technique. The reactive gas ratios between O2and N2were studied in the range of 15-30% with a constant of Ar gas at 110 sccm and a time of 120 minutes. Microstructure, optical, and electrical properties of TiOxNythin films were analysis by using SEM, AFM, GIXRD, UV-VIS spectrophotometer, and 4-point probe measurements. We found that the thickness of the films decreases from 1.0 to 0.8 μm by increasing of O2gas ratios. The TiOxNythin films have smooth surface related to small nanograin size. The roughness of the films slightly decreases when O2gas ratios increase. From optical transmission spectra, we observed that the transparent of the films increases with different O2gas ratio and shifts the band gap from 2.67 to 3.32 eV. The resistivity of the films obviously increases from 3.04 x 10-3Ω-cm to 5.45 Ω-cm depending on O2gas ratio. These results indicate the phase changes of the TiOxNyfilms from metallic to oxide phases. The XRD spectra show poor crystalline TiN (220) and TiO2(021) at 15% of O2ratio and then the films become amorphous structure by increasing the O2gases. The O2:N2gas ratios also affects to the different concentration of oxygen and nitrogen into the TiOxNythin films that lead to the various structural, optical and electrical properties.

Nanostructured copper and copper oxide thin films fabricated by hydrothermal treatment of copper hydroxide nitrate

Metallic copper and copper oxide thin films were fabricated on surface of glass slide substrates. Copper oxide thin films were prepared by a hydrothermal method using an α-phase layered hydroxide, copper hydroxide nitrate as a precursor. Morphology, thickness and crystallite size of the obtained copper oxide thin films changed by changing the time of hydrothermal treatment. Accordingly, the copper oxide thin films showed various water contact angles and optical band gaps. As, the optical band gap of the nanostructured copper oxide thin films increased with an increase in hydrothermal time from 1.85 to 2.95 eV. Moreover, the water contact angles changed from 16.4 to 38.8° by changing the hydrothermal time. By a reductive hydrothermal-treatment route, the copper oxide thin film was reduced to metallic copper thin film without any particle growth.

English

The influence of dip times on the lead sulphide (PbS) thin films deposited on glass slide substrates via chemical bath deposition (CBD) technique using chemical precursors, nitrate, and thiourea, ) in alkaline medium at 300 K was investigated. The optical, structural and morphological studies were performed by UV-vis spectophotometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The XRD showed films of cubic (galena), crystalline in nature with the preferential (111) orientation. The optical studies showed films of direct band gaps in the range of 1.59-1.65 eV. Key words: Lead sulphide, thin films, lead sulphide (PbS), X-Ray diffraction, scanning electron microscope (SEM), bandgap.

Electrical and Physical Property of TiO<sub>2</sub> Films Prepared at Different Deposition Time

Titanium Dioxide film will be deposited on a glass slide substrate by spin coating technique which is the frequently used technique because of its easy operation and cheap due to the sol gel preparation. The deposited films were then characterized by cross section technique using Field Emission Scanning Electron Microscopy (FESEM) to investigate the thickness based on the number of coatings. Then by the same FESEM, the surface morphology was studied to see the grain size and the porosity of each film based on the number of coatings. AFM was used to see the uniformity of the thin film's surface. Then by using current voltage (IV) measurement, the electrical property of the film can be studied, from IV characterization the resistivity of the film will be calculated. In this investigation, it is found that by increasing the coating layer, the resistivity values were decreasing whereas the conductivity of the film is increasing since conductivity is the inverse of resistivity. The porosity of the film also increases with the coating layers.

ZnO thin films prepared at low annealing temperatures, from a novel, simple sol–gel precursor solution

ZnO thin films show a wide gamut of potential applications, mainly due to their optical and semiconducting properties. ZnO films have been prepared by the sol–gel technique; however, their preparation is rather laborious and the composition of the precursor solutions is relatively complex. In this work, we present the preparation of ZnO thin films by a novel sol–gel method, from a very simple precursor solution, based on zinc acetate and methyl alcohol. Transparent, well-adhered films were obtained on glass slide substrates, in the 100–500 °C annealing temperature range. A very noteworthy feature of the method is that polycrystalline ZnO thin films could be obtained at annealing temperatures as low as 100 °C. The films are transparent (80–90 %) in the visible and near-IR spectral ranges. They were characterized also by micro-Raman spectroscopy and SEM and their thickness was evaluated by profilometer measurements.

Accurate determination of thickness values and optical constants of absorbing thin films on opaque substrates with spectroscopic ellipsometry

The determination of the optical constants of absorbing films, particularly on opaque substrates, is a difficult problem when solely using spectroscopic ellipsometry. First, unwanted backside reflections are incoherent with the desired reflection from the front side, which makes the fitting of optical constants difficult. Second, the optical constants of substrate must be carefully characterized in advance, as any small absorption in the substrate would be mixed into the film’s overall optical constants. Third, thickness and optical constants are strongly correlated with each other, which may prevent a unique solution for absorbing films. For the above reasons, quartz, glass slide, cover glass and float glass substrates are studied. Backside reflections of the substrates are suppressed by index matching technique. The results show that the simple technique works well for substrate materials with refractive index in a range from 1.43 to 1.64, including materials such as fused silica, float glass, etc. in a spectral range from 190 nm to 1700 nm. The refractive index and extinction coefficient of the substrate are fitted by ellipsometricψdata and the normal spectral transmittance T0. The results are consistent with the literature reported. Finally, a Combined ellipsometry and transmission approach is used to determine the thickness values and optical constants of the diamond-like carbon (DLC) film coated on the quartz and the amorphous silicon (a-Si) film coated on the glass slide and cover glass accurately.

The influence of heat treatment on the crystallite size, dislocation density, stacking faults probability and optical band gap of nanostructured cadmium sulfide films

Nanocrystalline cadmium sulfide films were deposited on the ordinary glass slide substrates by chemical bath deposition. Two advanced X-ray diffraction analyses i.e. DIFFaX and eCMWP were applied and the microstructure of films was evaluated as a function of annealing temperature. The optical properties of samples were also studied, using the transmittance spectra in the wavelength range of 300–900nm. Based on our studies, we have found that with the elevation of annealing temperature, the crystallite size increases, however, the dislocation density, the fraction of stacking faults and the band gap energy decrease and the outer cut-off radius of dislocation does not appreciably change. We can also see that the energy gap follows the linear, inverse square and quadratic relation with uniform strain, crystallite size and dislocation density, respectively. Comparing the microstructure evaluated from eCMWP with the results of Scherrer formula and Williamson–Hall plot shows that there is no agreement between the results of advanced and early X-ray diffraction analysis.

Determination of Optical Properties of Undoped Amorphous Selenium (a-Se) Films by Dielectric Modeling of Their Normal-Incidence Transmittance Spectra

Normal-incidence specular transmittance T_exp (?) of undoped amorphous selenium ( a -Se) films of several thicknesses (0.25-1 ?m) thermally evaporated on thick microscopic glass-slide substrates upheld at temperatures near 30 o C (below glass transition temperature of undoped Se) has been measured at room temperature in the spectral wavelength?range 300-1100 nm. Above a threshold wavelength ?_c (~ 600 nm), their as-measured T_exp (?)-? curves display transmittance values near that of glass substrates and exhibit well-resolved interference-fringe maxima and minima, signifying good uniformity of fabricated a -Se films. Below?_c, the T_exp (?)-? curves decline progressively to zero transmittance, preceded by a tailing-like trend of possible structural disorder origin. The spectral dependencies of optical constants n(?) and?(?) of the studied a -Se films on ? were retrieved from iterative curve-fitting of their T_exp (?)-? data to theoretical T_theor (?)-formulations of an air-supported {thin film/thick substrate}-stack using the O’Leary-Johnson-Lim (OJL) interband-transition dielectric model, combined with a dielectric constant , representing the dielectric background at very high photon energies (at spectral wavelengths much smaller than measured). Regardless of the number of observed interference fringes, reliable simulation to the as-measured normal-incidence T_exp (?)-? spectra has been achieved, but were remarkably curve-fitted if we presume that a thin roughness layer (<5 nm) of selenium was formed on top of the fabricated undoped a -Se films. The retrieved n(?)-? spectra display a broad peak around??0.52 ?m, below which n(?) was found to vary with wavelength in accordance with a Sellmeier-like (Wemple-DiDominco) single-oscillator (normal) dispersion formula, with a static index of refraction n(E=0)=?(?_s )?2.42, where ?_s is the static dielectric constant of the material at zero photon energy , and an oscillator “average” bandgap energy of E_o?3.93 eV?2 E_g^opt, the optical (Tauc) bandgap energy. The values of E_g^opt of studied undoped a -Se films deduced from Tauc-like plots were around 1.92 eV (± 0.02 eV) and the retrieved values of OJL band-tailing energy parameter ? (Urbach-tail parameter ?_U) was found to be in the range 40-50 meV, slightly dependent on film thickness.

Broadband antireflection TiO2–SiO2 stack coatings with refractive-index-grade structure and their applications to Cu(In,Ga)Se2 solar cells

Introduction of broadband antireflection coatings (ARCs) is a promising method to enhance efficiency of solar cells. In this paper, the TiO2–SiO2 stack coatings with refractive-index-grade structure are proposed and have been successfully fabricated via sol–gel dip-coating technique. The structure, morphology, optical properties and wettability of TiO2–SiO2 stack coatings were systemically investigated. The broadband antireflection performance is improved over the solar spectrum with increase of solar transmittance by 7.80% and maximum transmittance of 99.16% at 550nm on glass slide substrates. The responding reflectance is largely reduced and the minimum values in visible and near-infrared regions are 0.40% and 0.05%, respectively. By introducing broadband ARCs, the efficiency of Cu(In,Ga)Se2 solar cells is increased from 11.20% to 12.15%, which reveals superiority and importance of TiO2–SiO2 stack coating as an outstanding antireflection material, having high potential for practical applications.

Development of microarray device for functional evaluation of PC12D cell axonal extension ability

In this study, we developed a microarray bio-MEMS device that could trap PC12D (rat pheochromocytoma cells) cells to examine the intercellular interaction effect on the cell activation and the axonal extension ability. This is needed to assign particular patterns of PC12D cells to establish a cell functional evaluation technique. This experimental observation-based technique can be used for design of the cell sheet and scaffold for peripheral and central nerve regeneration. We have fabricated a micropillar-array bio-MEMS device, whose diameter was approximately 10 μm, by using thick photoresist SU-8 on the glass slide substrate. A maximum trapped PC12D cell ratio, 48.5%, was achieved. Through experimental observation of patterned PC12D “bi-cells” activation, we obtained the following results. Most of the PC12D “bi-cells” which had distances between 40 and 100 μm were connected after 24 h with a high probability. On the other hand, “bi-cells” which had distances between 110 and 200 μm were not connected. In addition, we measured axonal extension velocities in cases where the intercellular distance was between 40 and 100 μm. A maximum axonal extension velocity, 86.4 μm/h, was obtained at the intercellular distance of 40 μm.

Influence of Sputtering Power on Structural and Optical Properties of Ta&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; Thin Films Prepared by DC Reactive Magnetron Sputtering

In this article, amorphous tantalum oxide thin films were deposited by dc reactive magnetron sputtering onto silicon (001) wafer and glass slide substrates. Sputtering power has been varied for optimizing thin film quality. The structural and optical properties of the Ta2O5 thin films were investigated by using X-ray diffraction, UV-Vis spectrophotometer and spectroscopic ellipsometry respectively. The XRD pattern result indicates that the films are amorphous. It was found that the growth rate was also increased with increasing dc power up to 250 W, and the maximum growth rate observed at 250 W was 0.25 nm/s. In addition, the refractive index and packing density of the films increases with increasing dc sputtering power.

Structural and Optical Properties of ZrO&lt;sub&gt;2&lt;/sub&gt; Thin Films Deposited by Reactive DC Unbalanced Magnetron Sputtering

Zirconium oxide (ZrO2) thin films were deposited on Si-wafer and glass slide substrates by reactive DC unbalanced magnetron sputtering at different deposition times. A pure metallic zirconium target (99.97%) was sputtered in a gas mixture of argon and oxygen. The crystal structure was characterized by GI-XRD (grazing-incidence X-ray diffraction) whereas surface morphologies and films thickness were evaluated by AFM (atomic force microscopy). The transmittance spectrum was measured by spectrophotometer. The optical constants of the as-deposited films were calculated by Swanepoel method. It was found that the ZrO2 films deposited on silicon substrates showed a highly monoclinic phase (-1 1 1). The as-deposited films showed high transmittance in visible range. The thickness and roughness varied from 155 nm to 502 nm and 3.1 nm to 3.6 nm, respectively, with increasing of deposition times. The optical constants namely refractive index (n) and extinction coefficient (k), at 550 nm, was about 1.9 - 2.1 and 0.0003 - 0.0009, respectively. In addition, the energy band gap (Eg) of the as-deposited film was approximately 4.17 eV.

In-situ fabrication of polyelectrolyte-CSH superhydrophilic coatings via layer-by-layer assembly

Abstract Superhydrophilic and antireflective coatings were fabricated via the layer-by-layer (LbL) assembly method with in situ precipitation of sodium silicate and calcium acetate on quartz or glass slide substrate. The influences of assembly conditions on the growth behavior, surface topologies, zeta potentials, wettability, antifogging behavior and transmittances of the multilayer coatings have been investigated in details. The results indicated that more than three deposition cycles with 3.27 g/L calcium silicate hydrates (CSH) solution were optimal condition for the fabrication of a superhydrophilic and antireflective coating structure of poly(ethyleneimine)/poly(sodium 4-styrenesulfonate) (PEI/PSS–CSH)3 with 98.0% of transmittance, and even 99.4% of (PEI/PSS–CSH)4 multilayer film. Additionally, the 3.0 bilayers of PEI–PSS/CSH coatings exhibited superior antifogging characteristics. This in situ formation of CSH nanoparticles in the LbL film offers a potential strategy to fabricate multifunctional films for a variety of technological applications.

Fabrication of ordered honeycomb structures and microspheres using polystyrene-block-poly(tert-butyl acrylate) star polymers

A series of novel honeycomb films of tri- and octa-arm polystyrene-b-poly(tert-butyl acrylate) star polymers prepared by atom transfer radical polymerization and nitroxide mediated radical polymerization, respectively, have been fabricated. The type of solvents, specifically their miscibility in water is one of essential parameters to construct ordered pore structures. The tri- and octa-arm star polymers yield well-ordered microporous film specifically in 10 to 30 g/L CHCl3 solution. The contact angle of glass slide substrate (54.57°) is adjusted to 41.06° by plasma treatment and to 12.21° by coating the glass slide with highly hydrophilic hyperbranched polyglycidol. The ordered honeycomb films are created on the hydrophobic substrates, but the ordered films are not formed on the hydrophilic substrates. Microspheres with the diameters ranging from hundreds of nanometers to several micrometers are also obtained by a slight modification of breath figure method.

Reusable conductimetric array of interdigitated microelectrodes for the readout of low-density microarrays

Low-density protein microarrays are emerging tools in diagnostics whose deployment could be primarily limited by the cost of fluorescence detection schemes. This paper describes an electrical readout system of microarrays comprising an array of gold interdigitated microelectrodes and an array of polydimethylsiloxane microwells, which enabled multiplexed detection of up to thirty six biological events on the same substrate. Similarly to fluorescent readout counterparts, the microarray can be developed on disposable glass slide substrates. However, unlike them, the presented approach is compact and requires a simple and inexpensive instrumentation. The system makes use of urease labeled affinity reagents for developing the microarrays and is based on detection of conductivity changes taking place when ionic species are generated in solution due to the catalytic hydrolysis of urea. The use of a polydimethylsiloxane microwell array facilitates the positioning of the measurement solution on every spot of the microarray. Also, it ensures the liquid tightness and isolation from the surrounding ones during the microarray readout process, thereby avoiding evaporation and chemical cross-talk effects that were shown to affect the sensitivity and reliability of the system. The performance of the system is demonstrated by carrying out the readout of a microarray for boldenone anabolic androgenic steroid hormone. Analytical results are comparable to those obtained by fluorescent scanner detection approaches. The estimated detection limit is 4.0ngmL−1, this being below the threshold value set by the World Anti-Doping Agency and the European Community.

Effects of Substrate on Piezoelectricity of Electrospun Poly(vinylidene fluoride)-Nanofiber-Based Energy Generators

We report the effects of various substrates and substrate thicknesses on electrospun poly(vinylidene fluoride) (PVDF)-nanofiber-based energy harvesters. The electrospun PVDF nanofibers showed an average diameter of 84.6 ± 23.5 nm. A high relative β-phase fraction (85.2%) was achieved by applying high voltage during electrospinning. The prepared PVDF nanofibers thus generated considerable piezoelectric potential in accordance with the sound-driven mechanical vibrations of the substrates. Slide glass, poly(ethylene terephthalate), poly(ethylene naphthalate), and paper substrates were used to investigate the effects of the intrinsic and extrinsic substrate properties on the piezoelectricity of the energy harvesters. The thinnest paper substrate (66 μm) with a moderate Young's modulus showed the highest voltage output (0.4885 V). We used high-performance 76, 66, and 33 μm thick papers to determine the effect of paper thickness on the output voltage. The thinnest paper substrate resulted in the highest voltage output (0.7781 V), and the numerical analyses of the sound-driven mechanical deformation strongly support the hypothesis that substrate thickness has a considerable effect on piezoelectric performance.

Comparison of DLC and N-Doped DLC Synthesized by RF-PECVD

Diamond-like carbon (DLC) films and nitrogen doped DLC (NDLC) were deposited on glass slide and H13 steel by plasma-enhanced chemical vapor deposition using a commercial RF 13.56 MHz (RF-PECVD). The films have been prepared from CH4 for DLC and CH4+N2 mixtures for NDLC. The deposition process was at 300°C under argon atmosphere for 120 min. Bonding energy and diamond like carbon characteristic of DLC and NDLC films have been characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. Thermalgravimetric Analyzer (TGA) was used to evaluate the thermal stability of the films which were scrapped off from a glass slide substrate. The mechanical properties was characterized, such as hardness by nanoindentation technique, scratch test by Rockwell diamond tip in progressive mode and friction coefficient have been measured in ambient air using a ball-on-disk tribometer.

Electrically regulated differentiation of skeletal muscle cells on ultrathin graphene-based films

The electrical conductivity of graphene provides a unique opportunity to modify the behavior of electrically sensitive cells. Here, we demonstrate that C2C12 myoblasts that were cultured on ultrathin thermally reduced graphene (TR-Graphene) films had more favorable cell adhesion and spreading compared to those on graphene oxide (GO) and glass slide substrates, comparable with conventional Petri dish. More importantly, we demonstrate that electrical stimulation significantly enhanced myoblast cell differentiation on a TR-Graphene substrate compared to GO and glass slide surfaces as confirmed by the expression of myogenic genes and proteins. These results highlight the potential applications of graphene-based materials for cell-based studies, bioelectronics, and biorobotics.