Glass Slide Substrates Research Articles

Spectroscopic ellipsometry study on TiO 2 thin films modified by N 2–H 2 plasma surface treatment

We analyzed successfully the refractive index, n, and extinction coefficient, k, of three samples such as as-deposited single-phase anatase–TiO 2 polycrystalline thin films on slide glass substrates (#1), the sample surface-treated by N 2–H 2 mixed-gases plasma (#2), and the sample being additionally anneal-treated in N 2 gases (#3), by spectroscopic ellipsometry (SE). The double-layered film configuration named as the surface and the bulk layers is employed in SE analysis. The optical properties of the surface layer are confirmed to be important to explain the significant red shift of the absorption edge of both surface-treated samples observed in the preceding report. Particularly, the obtained imaginary part of complex dielectric constant of the surface layer of the samples #2 and #3 shows significant difference from that of the sample #1. This is due to the absorptive transitions not by solely anatase–TiO 2 but by mixed formation of TiO 2− x N x and TiN with metallic characteristics.

Tin-Diffused Glass Slab Waveguides Locally Covered with Tapered Thin TiO2 Films for Application as a Polarimetric Interference Sensor with an Improved Performance

Common soda lime slide glass substrates made by floating molten glass on the surface of molten tin contain a tin-diffused layer that is demonstrated to be a low-loss polarization-insensitive slab optical waveguide. In this study, such a tin-diffused waveguide was locally covered with a tapered thin TiO2 film to form a composite structure in which the zeroth-order transverse electric (TE0) and magnetic (TM0) modes are spatially separated from each other. This feature enables the composite structure to serve as a highly sensitive polarimetric interferometer. Moreover, a negligible modal birefringence of tin-diffused waveguides offers the polarimetric interferometer an improved performance relative to those fabricated earlier using single-mode potassium ion-exchanged glass waveguides. In situ detection of both the protein adsorption and a small change in refractive index of liquid was accomplished using the tin-diffused waveguide-based polarimetric interferometer. With horse heart myoglobin, adsorption from aqueous solution less than 0.125 monolayer coverage can cause the interferometer to yield a phase-difference change of delta phi = 2pi.

Structural and compositional characterization of N 2–H 2 plasma surface-treated TiO 2 thin films

The structural and compositional properties of three samples such as as-deposited single-phase anatase-TiO 2 polycrystalline thin films on slide glass substrates (No. 1), the sample surface-treated by N 2–H 2 mixed-gases plasma (No. 2), and the sample being additionally anneal-treated in N 2 gases (No. 3), are characterized by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The primitive lattice cells of three thin films are verified as distorted in comparison with that of bulk from the TEM results. This distortion of primitive lattice cell causes the increase of optical band gap for the films when we compared it with that of bulk, while the decrease of optical band gap should be attributed to the substitution of N into TiO 2. Higher concentration of nitrogen in sample No. 3 is confirmed by line-EDS profiles under scanning TEM (STEM) when compared with sample No. 2 and this confirms that plasma surface treatment is an effective way for N-doping in TiO 2.

Preparation and properties of polycrystalline CdSxxTe1-x1-x thin films for solar cells

The structural, optical and electrical properties of CdSxxTe1-x1-x thin films prepared by co_evaporation of powders of CdS and CdTe ha ve been studie d by x_ray diffraction, atomic force microscopy and optical transmittance spectr a measurements. Results show that the as_deposited CdSxxTe1-x1 -x thi n films are homogeneous, adherent and compact on the glass slides substrates wit hout pinhole and that their conductivity is n_type for x≥05 and p_type fo r xxTe1-x1-x thin f ilms are pol ycrystalline and show highly preferential orientation. The predominant direct op tical transitions were observed and the variation of the optical energy gap E gg is nonlinear with x. Given the values of lattice parameter and opt ical energy gap, the exact composition of the phase change at x=025 has been determined. The films are of a cubic phase for x025. After annealing there is no change in the structure of the films with a slight decrease in optical energy gap. Finally, a new structure of CdS/CdTe/Z nTe/ZnTe:Cu/Au solar cells with a CdSxxTe1-x1-x buffer l ayer has been proposed.

전자빔 증착법으로 제작한 Cu 박막의 부착력과 저항율 특성

In this thesis, We Fabricated Cu thin films of 1000 <TEX>$\AA$</TEX>, 3000 <TEX>$\AA$</TEX>, and 6000 <TEX>$\AA$</TEX> thickness on the single crystal sapphire, polycrystal alumina, and amorphous slide glass substrates deposited by electron beam evaporation(EBE) method. We investigated properties of resistivity and adhesion of these Cu thin films under various conditions, substrate temperature(room temperature, 10<TEX>$0^{\circ}C$</TEX>, 20<TEX>$0^{\circ}C$</TEX> under vacuum) and annealing temperatures(400 <TEX>$^{\circ}C$</TEX>, 600 <TEX>$^{\circ}C$</TEX> for 30 min after the deposition). We found that these adhesion was increased in order of slide glass, sapphire, and alumina. The adhesion of the Cu thin films on alumina was high value about 4 times, compared with that of the Cu thin films on slide glass. We found that these resistivities were decreased with increasing substrate temperature and thin film thickness. The resistivity(2.05 <TEX>$\mu$</TEX>Ω\ulcornercm) of the Cu thin films with 6000 <TEX>$\AA$</TEX> thickness at 200 <TEX>$^{\circ}C$</TEX> on the slide glass was low value, compared with that of aluminum(2.66 <TEX>$\mu$</TEX>Ω\ulcornercm).

Preparation and up-conversion luminescence of germania/γ-glycidoxypropyltrimethoxysilane organic–inorganic hybrid thin films dispersed with neodymium oxide nanocrystals

Germania/γ-glycidoxypropyltrimethoxysilane (GLYMO) organic–inorganic hybrid spin-coating films dispersed with neodymium oxide nanocrystals have been prepared by combining an inverse microemulsion technique and the low-temperature sol–gel technique. UV-Visible (UV-Vis) spectroscopy and Fourier transform infrared spectroscopy (FTIR) have been used to investigate the structural and optical properties of the hybrid thin films. Up-conversion emission properties of these hybrid thin films deposited on microscope glass slide and silicon substrates have been studied. The results indicate that an intense room-temperature yellow to violet up-conversion emission at 397 nm ( 4 D 3/2→ 4 I 13/2) is measured from the hybrid thin films heated at different temperatures upon excitation with a xenon lamp at the wavelength of 580 nm. In addition to this intense violet emission, a relative weak ultraviolet emission at 375 nm and a blue emission at 469 nm are also observed.

Optical band gap tuning and study of strain in CdS thin films

In this work we have taken advantage of the control of strains at the CdS films–substrate interfaces to obtain films with tunable energy band gap. We found that on decreasing the amount of strain at the layer–substrate interface, the energy band gap of the films also decreases. Thus, we could obtain CdS films with energy band gap between 2.26 and 2.5eV. The CdS films were deposited on glass slide substrates by the chemical bath deposition method using an ammonia-free cadmium–sodium citrate system. The amount of strain at the CdS–glass substrate interface was controlled by the amount of cadmium ions in the chemical deposition process. The higher the concentration of cadmium ions, the higher the amount of strain at the layer–substrate interfaces. The properties of the CdS films were determined by X-ray diffraction and optical transmission spectroscopy measurements.

Polyimide as a Plastic Substrate for the Flexible Organic Electroluminescent Device

AbstractIn this work, transparent flexible substrates based on polyimides(PI) with indium tin oxide (ITO) thin films for organic electroluminescent devices have been prepared. 2,2'-bis-(3,4- dicarboxyphenyl) hexafluoropropanedianhydride (6FDA) and 2,2'-bis-(trifluoromethyl)-4,4'- diaminobiphenyl (TFDB) PI films were used for transparent flexible substrates. ITO thin films were prepared at two substrate deposition temperatures of 25°C and 150°C with a typical radio- frequency (r.f.) planar magnetron sputtering system. The sheet resistance and the optical transmission properties of the fluorinated PI substrate were comparable with those for the slide glass substrate. The substrate properties are better when the deposition temperature is higher. SiO2 coating onto the fluorinated PI substrate by sol-gel reaction was also attempted to improve the optical transmission of the ITO/PI substrate. It was found that the coating of SiO2 affected on the morphology of the PI substrates.

The improvement of optical reactivity for TiO 2 thin films by N 2–H 2 plasma surface-treatment

To improve the optical reactivity of TiO 2 thin film in visible-light region, sputter-deposited anatase film on slide glass substrate with 1200 Å film thickness was surface-treated by N 2–H 2 mixed gases plasma and additionally anneal-treated in N 2 gases at 400°C for 2 h. The absorption edges of plasma-treated sample and plasma plus anneal-treated one shifted from 363 nm (3.4 eV) to 428 nm (2.9 eV), and 354 nm (3.5 eV) to 428 nm (2.9 eV), while the absorptance for the two corresponding samples increased by 16% and 26%, respectively, in comparison with the as-deposited sample. Spectral absorption is well explained by Tauc-plot extrapolated band-gap using extinction coefficient k obtained from spectroscopic ellipsometry for the surface layers of the three samples, even though in the case of plasma plus anneal-treated sample showed only nominal band-gap value (2.65 eV) due to the metallic behavior of extinction coefficient k in lower energy range (2.5 eV). X-ray photoemission spectroscopy reveals the formation of TiO 2− x N x and TiN deep into about 120 Å thickness from the film surface for both plasma-treated and plasma plus anneal-treated samples. Secondary ion mass spectrography also detected high concentration of N element at the surface of the two corresponding samples. From the fact of formation of TiN and TiO 2− x N x , N-doping in this work was proved as N substituted O in TiO 2 lattice. We confirmed this substitutional N-doping causes the narrowing of band-gap that resulted in the observed significant red shift of the absorption edge to the visible-light region.

Optical properties of PbS thin films chemically deposited at different temperatures

PbS thin films were deposited on glass slide substrates using the chemical bath deposition technique. The films were obtained in a reaction bath at temperatures of 10, 15, 20, 25 and 30 °C. The structure and surface morphology of the films were studied by X-ray diffraction and by atomic force microscopy measurements. The optical properties were determined from spectroscopy measurements of ellipsometry, transmission and reflection, in the energy range of 240–840 nm. In order to analyze the ellipsometry measurements, two models for the dielectric function of the films were considered, the Bruggeman's effective medium approximation and the Lorentz oscillator expression. From this analysis, the complex dielectric function ε( E)= ε 1( E)+ iε 2( E), thickness, roughness and void fraction of the films were examined as a function of temperature deposition. With the model obtained in the ellipsometry analysis, the optical spectra of reflection and transmission were calculated and compared with the measured spectra finding a good agreement.

Influence of working gas pressure on structure and properties of WO3 films reactively deposited by rf magnetron sputtering

Tungsten trioxide (WO3) films with thickness of 0.9–6.7 μm have been deposited on glass-slide substrates, using rf magnetron sputtering in an atmosphere of mixture 80% Ar and 20% O2. The as-deposited films had a dark metallic color, like the W target, at a working gas pressure PW of 1 mTorr. Yellow films resulted at a PW of 3 mTorr. With a further increase of PW, the film color changed to pale yellow. From the x-ray diffraction patterns, the as-deposited films were polycrystalline crystallizing in the monoclinic crystal structure with high c-axis orientation perpendicular to the film plane. The optical transmittance of the films deposited at a PW of 1 mTorr is nearly zero. However, the transmittance of the films deposited at other PW are larger than 70% in the wavelength, λ, ranging from 500 to 900 nm. With decreasing λ to 400 nm, the transmittance decreases steeply to zero. The λ at this absorption edge is longer than that in TiO2 and comes in the visible region. The surface morphology of the films depends on PW. This different morphology may be attributed to the effect of the substrate heating by plasma emission because of the high plasma density at higher PW. The morphology of the films may also depend on the crystallinity of the WO3 films. As PW increased, the surfaces of the films became rougher but the grain sizes of the films did not always become larger. The WO3 films deposited in this study may be used for the underlayer of TiO2 photocatalyst.

Tungsten nitride films grown via pulsed laser deposition studied in situ by electron spectroscopies

Tungsten nitride (WNx) films were grown on silicon and glass slide substrates by laser ablating a tungsten target in molecular nitrogen ambient. By in situ Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS), the films density, elemental composition and chemical state were determined. Ex situ, the films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Also, the transmittance and resistivity of the film on glass substrates were determined. The results show that the reaction of tungsten and nitrogen is effective; the nitrogen is integrated in the tungsten matrix changing gradually the electronic configuration, chemical states and film properties. Since with this preparation method the obtained films are of high quality, low resistivity and dense, this makes attractive to growth tungsten nitride films for technological applications.

Second harmonic generation at the interface of copper tetra-tert-butyl phthalocyanine Langmuir-Blodgett film/metal

Optical second harmonic generation (SHG) from the copper tetra-tert-butyl phthalocyanine (CuttbPc) Langmuir-Blodgett (LB) film deposited on a metal-coated glass slide substrate has been investigated. It is considered that the symmetry of the CuttbPc molecule may be broken by the space charge-induced electric field (SCIEF) due to the exchanged charges at the CuttbPc LB film/metal interface. A four-layer model is used to explain the nonlinear optical process in the CuttbPc LB film. The thickness dependence, polarized and incident angle dependence of SHG signal from CuttbPc LB films are calculated. The results of calculation show a good agreement with the experimental data. It is shown that electrostatic phenomena at the interface is correlated closely with SHG signal, and the SHG measurement is also a helpful tool for the detection of the space charge field at the interface.

Dependence of working gas pressure and ratio of Ar to O 2 on properties of TiO 2 films deposited by facing targets sputtering

TiO 2 films with thickness of 300–4000 nm have been reactively deposited on glass-slide substrates at an atmosphere of Ar and O 2 mixture, using the facing targets sputtering. Maximum deposition rate of the film was 13.3 nm/min. The crystal structure, the surface morphology, and the optical properties of films were estimated using X-ray diffractometry, atomic force microscopy, and spectrophotometer, respectively. Most of the films deposited for this study showed a transparency and had anatase crystal structure, while some of them showed semitransparency because of dim surface. When TiO 2 films were deposited with plasma exposure, four peaks of A(1 1 2), A(2 0 0), A(2 1 1) and A(2 2 0) were observed from the X-ray diffraction patterns, where A shows an anatase of TiO 2. On the other hand, two peaks of A(1 0 1) and A(2 0 0) were observed in TiO 2 films deposited with weak plasma exposure. The peak intensities of A(2 2 0) and A(1 0 1) decreased with increasing working gas pressure P W in the range of 0.13–1.07 Pa. The crystal orientation significantly depends on the degree of plasma exposure and P W. In TiO 2 films deposited at P W of 0.13 Pa with plasma exposure, the optical transmittance spectrum monotonically decreased with decreasing the wavelength from 700 to 350 nm. However, the changes in transmittance spectra of films deposited at various P W with weak plasma exposure were small. The surface of as-deposited TiO 2 films became rough with an increase of plasma exposure and a decrease of P W. The X-ray diffraction peak of (2 2 0) and the deposition rate of TiO 2 films deposited with strong plasma exposure increased with increasing the ratio of Ar to O 2. Consequently, it was found that crystal structure, surface morphology, and optical properties of as-deposited TiO 2 films were strongly affected by the working gas pressure, and the ratio of Ar to O 2.

Effects of plasma exposure on structural and optical properties of TiO2 films deposited by off-axis target sputtering

TiO 2 films with thickness of about 800–2300 nm have been reactively deposited on glass-slide substrates at an atmosphere of Ar and O2 mixture, using the off-axis target sputtering method. The maximum deposition rate of the film was 12.8 nm/min. The optical properties and the crystal structure of the films were measured using spectrophotometry, Raman spectroscopy, and x-ray diffractometry, respectively. Most of the films deposited in this study were transparent and had anatase crystal structure, while some of them were semitransparent. The A(101), A(112), A(211) and A(220) peaks were observed in the x-ray diffraction patterns, where A shows the anatase phase of TiO2. With increasing plasma exposure, the x-ray peak intensities IP of A(101) and A(112) gradually decreased, while the IP of A(211) and A(220) gradually increased. The IP depended strongly on the substrate position in this study. Moreover, the A(220) peak was significantly higher than other peaks when the TiO2 crystallites became larger. The anatase phase of the TiO2 films was also revealed in the Raman spectra with a Raman shift of 145 cm−1. With decreasing plasma exposure, the changes in the optical transmittance spectra of TiO2 films were very small at the wavelength of 350–900 nm. However, the transmittance spectra significantly depended on the wavelength with increasing plasma exposure. Consequently, it was found that the crystal structure and the optical properties of as-deposited TiO2 films were strongly affected by plasma exposure during film deposition.

Atomic force microscopy observation of TiO2 films deposited by dc reactive sputtering

A bombardment of energetic particles such as secondary electrons and recoiled ions ejected from the target plane is a very useful technique for modifying the structure of the film in reactive sputtering. It leads to interesting effects such as enhancement of reactivity, adatom mobility, and atomic peening. Therefore, the state on the surface of the as-deposited film may significantly depend on the bombardment condition. So, in this study, the relationship between the bombardment condition and the surface morphology of TiO2 films has been investigated in detail. TiO2 films with a thickness of about 0.8–2.3 μm were deposited by dc reactive sputtering on glass-slide substrates. The surface roughness of films was measured with atomic-force microscopy. The roughness parameter Ra on the surface of TiO2 films depended on the energy and the number of bombarding particles. After increasing the energy and the number of bombarding particles, Ra increased from 10 to 77 nm. Consequently, it was found that the surface morphology of TiO2 films strongly affected the plasma exposure to the growing film.

Effect of ZrO 2 addition on the structural, optical and electrical properties of MgO protective films

The effects of ZrO 2 additions on the physical as well as electrical properties of the MgO thin films, deposited on slide glass substrates by electron beam evaporation, have been investigated. As the ZrO 2 molar concentration ratio increased, the intensity ratio of the (200) peak relative to the (111) peak was observed to increase with a corresponding peak shift to lower diffraction angles as a result of the substitutional solid solution between Mg and Zr. The film density, which was calculated from the measured refractive index and the equivalent refractive index, had a maximum at a ZrO 2 molar concentration ratio of 3 mol% and gradually decreased and saturated with increasing ZrO 2 concentration ratio. At a ZrO 2 molar concentration ratio of 3 mol%, the deposited MgO-ZrO 2 layer exhibited lower discharge voltages compared to a conventional MgO layer, probably due to its increased density.

Synthesis of InSb Films by Reduction of Metal Alkoxide-Derived InSbO4.

A new synthetic route based on a solution chemistry was developed for a compound semiconductor indium antimonide (InSb). Considering the moisture sensitive properties of metal alkoxides, indium antimonide was synthesized by reduction of InSbO4, which was prepared by hydrolysis of the corresponding metal alkoxides as starting materials. InSb-alkoxide solution was prepared by two ways: one is mixed method in which In-alkoxide solution and Sb-alkoxide solution were mixed simply, and the other is continuous method using the reaction of indium chloride with Na-alkoxide in the presence of Sb-alkoxide in ethanol. Hydrolysis products by both methods were crystallized to InSbO4 by heat-treatment at 780°C in air. InSb was obtained by heat-treatment of hydrolysis product prepared by the continuous method at 400°C in H2, but it wasn't obtained from hydrolysis product prepared by the mixed method. The primary particle size of hydrolysis products was about 8nm in diameters. The wet hydrolysis product was well mixed with ethylcellulose and terpineol by a three-roll mill to form printing paste. The paste was screen-printed on slide glass substrates, transformed to InSb film by heat treatment at 400°C in H2.

イオンビームアシスト蒸着法を用いた酸化チタン薄膜へのクロム添加による光触媒特性への影響

The photocatalytic properties of Cr-doped TiO2 films was investigated by the immersion test in a methylene blue solution under UV light irradiation. The Cr/TiO2 films were prepared as follows; after TiO2 film was prepared on a slide glass substrate by He+-ion beam assisted reactive deposition method (He+-IBARD), Cr was doped into TiO2 films by Ar+-ion beam assisted deposition method (Ar+-IBAD).In the Ar+-IBAD method, Ar+ ion irradiation was carried out during Cr evaporation in order to form the mixing layer of Cr and TiO2. Ar+ ions played an important role to knock on Cr atoms into TiO2 film. The rate of absorbance change for blank of Cr/TiO2 film showed higher value than that of TiO2 film under UV light irradiation. In order to improve photocatalytic properties of Cr-doped TiO2 films, it was required that doped-Cr showed the metal state and amorphous structure.

Robust and efficient synthetic method for forming DNA microarrays.

The field of DNA microarray technology has necessitated the cooperative efforts of interdisciplinary scientific teams to achieve its primary goal of rapidly measuring global gene expression patterns. A collaborative effort was established to produce a chemically reactive surface on glass slide substrates to which unmodified DNA will covalently bind for improvement of cDNA microarray technology. Using the p-aminophenyl trimethoxysilane (ATMS)/diazotization chemistry that was developed, microarrays were fabricated and analyzed. This immobilization method produced uniform spots containing equivalent or greater amounts of DNA than commercially available immobilization techniques. In addition, hybridization analyses of microarrays made with ATMS/diazotization chemistry showed very sensitive detection of the target sequence, two to three orders of magnitude more sensitive than the commercial chemistries. Repeated stripping and re-hybridization of these slides showed that DNA loss was minimal, allowing multiple rounds of hybridization. Thus, the ATMS/diazotization chemistry facilitated covalent binding of unmodified DNA, and the reusable microarrays that were produced showed enhanced levels of hybridization and very low background fluorescence.