Corning Glass Research Articles

Self-assembled Au nanoparticles on heated Corning glass by dc magnetron sputtering: size-dependent surface plasmon resonance tuning

We report on the growth of Au nanoparticles on Corning glass by direct current magnetron sputtering and on the optical absorption of the films. The substrate temperature was kept to relatively high temperatures of 100 or 450 °C. This lead to the growth of Au nanoparticles instead of smooth Au films as the surface energy of Au is much larger than the one of glass. The size of the particles depended on the substrate temperature and deposition time and was shown to follow a logarithmic normal distribution function. Both, the surface plasmon resonance position and bandwidth, were found to depend upon the average particle size. The surface plasmon resonance position showed a 75 nm continuous blue shift from 14 nm down to 2.5 nm average particle size. Thus, we have shown how to tune the nanoparticle size and surface plasmon resonance of Au by varying the substrate temperature and deposition time. The experimental results are reproduced reasonably using a method which is based on the size- and wavelength-dependent complex dielectric function of Au within the framework of the Mie theory for the optical properties of metallic nanospheres.

Structural and electrical properties of sputtering power and gas pressure on Ti-dope In2O3 transparent conductive films by RF magnetron sputtering

Transparent conductive titanium-doped indium oxide (ITiO) films were deposited on Corning glass substrates by RF magnetron sputtering method. The effects of RF sputtering power and Ar gas pressure on the structural and electrical properties of the films were investigated experimentally, using a 2.5wt% TiO2-doped In2O3 target. The deposition rate was in the range of around 20–60nm/min under the experimental conditions of 5–20mTorr of gas pressure and 220–350W of RF power. The lowest resistivity of 1.2×10−4Ωcm, the average optical transmittance of 75%, the high hall mobility of 47.03cm2/Vs and the relatively low carrier concentration of 1.15E+21cm−3 were obtained for the ITiO film, prepared at RF power of 300W and Ar gas pressure of 15mTorr. This resistivity of 1.2×10−4Ωcm is low enough as a transparent conducting layer in various electro-optical devices and it is comparable with that of ITO or ZnO:Al conducting layer.

TiO2-Based Ultraviolet Photodetectors

This study demonstrates that anatase TiO2 thin films were grown on Corning glass substrates by radio frequency magnetron sputtering and were then used to fabricate metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors (PDs) with different contact electrodes (Ag or Au). With a 320-nm illumination and 5 V applied bias, the responsivities for the Ag/TiO2/Ag and Au/TiO2/Au MSM PDs were 4.31 and 16.6 A/W, respectively. Additionally, the photoconductive gain and Schottky barrier height at the Ag/TiO2 and Au/TiO2 interfaces were also discussed in the investigation.

Deposition temperature effects on optical and structural properties of amorphous silicon carbide films

Hydrogenated amorphous silicon carbide thin films (a–SiC:H) were elaborated by DC magnetron sputtering technique by using 6H–SiC as target. The a–SiC:H films of 0.9–1.5 µm thicknesses were deposited at different temperatures of 250, 350, 450 and 550°C on p–type Si(100) and Corning glass 9075 substrates. The deposited films (a–SiC:H) were investigated by Infrared Spectroscopy (FTIR), spectrophotometry (UV–visible–NIR), Secondary Ion Mass Spectrometry (SIMS), and photoluminesence spectroscopy. The previous results of the FTIR measurements reveal the existence of a band located at 775 cm−1, which corresponds to Si–C stretching vibration of SiC amorphous, whereas the Si–C bonds of SiC crystalline is around 810 cm−1. The optical gap varies between 1.9 and 2.10 eV as a function of films' thicknesses and temperature. In addition, the PL spectra of the elaborated films show that the intensity increases when the deposition temperature increases.

An efficient urea biosensor based on laser ablated ZnO thin film

ABSTRACTZinc oxide (ZnO) thin film deposited onto indium tin oxide (ITO) coated Corning glass substrates using pulsed laser deposition (PLD) technique has been used as a matrix for realization of an efficient urea biosensor after immobilization of urease (Urs) enzyme onto the surface of ZnO. The bioelectrode (Urs/ZnO/ITO/glass) is found to be exhibiting an enhanced sensitivity of 22μΑmΜ−1cm−2 towards urea over a wide detection range of 5-200 mg/dl. The relatively low value of Michaelis menten constant (Km= 0.94mM) indicates high affinity of the immobilized urease towards the analyte (urea). The prepared biosensor retains 90% of its activity for more than 10 weeks. The observed enhanced response characteristics of bioelectrode are attributed to the growth of the matrix (highly c-axis oriented ZnO thin film) with desired surface morphology and high electron communication feature. The results confirm the promising application of PLD grown ZnO thin film as an efficient matrix for urea detection.

Structural and Electrical Properties of Titanium-Doped Indium Oxide Films Deposited by RF Sputtering

Titanium-doped indium oxide (ITiO) is a high-quality transparent conducting oxide commonly used as the contact for photovoltaic. The transparent conductive titanium-doped indium oxide (ITiO) films were deposited on Corning glass substrates by RF magnetron sputtering method. The effects of RF sputtering power and Ar gas pressure on the structural and electrical properties of the films were investigated experimentally, using a 2.5 wt% TiO2 -doped In2O3 target. The deposition rate was in the range of around 20 to 60nm/min under the experimental conditions of the gas pressure and the RF Magnetron sputtering power. In this case, the lowest resistivity of 1.2×10-4-cm and the average optical transmittance of 75% were obtained for the ITiO film, prepared at RF power of 300W and Ar gas pressure of 15 mTorr. This resistivity of 1.2×10-4-cm is low enough as a transparent conducting layer in various electro-optical devices and it is comparable with that of ITO or ZnO:Al conducting layer.

Structural and Magnetic Studies of CoCr Thin Films Prepared by Physical Vapor Deposition

We use physical vapor deposition (PVD) to produce, under vacuum, CoCr thin films onto Si (100) and glass substrates. The thicknesses of the samples were measured with a DEKTAK 150 profilometer and the micro structural properties were studied using a Siemens D500 X-ray diffractometer. The static magnetic characterization was done by means of an Alternating Gradient Field Magnetometer (A.G.F.M.) 2900 MicroMag. The films deposited on Corning glass are amorphous. Among all the samples deposited on Si(100) with thickness ranging from 100 nm to 340 nm, only those with thickness 163 nm, 178 nm and 340 nm are polycrystalline and present a hexagonal close-packed (h.c.p.) structure with 〈0001〉 texture. The magnetization curve study infers that all the samples present a planar ferromagnetic anisotropy. The maximum saturation magnetization M s value being 400 emu/cm3, the coercive field decreases vs. thickness beyond a maximum value (178 nm). All these results will be presented and discussed.

Copper telluride thin films grown by pulsed laser deposition

Copper telluride thin films were deposited by pulsed laser deposition on Corning glass substrates using powders of Cu2Te as target. Films were grown at substrate temperatures ranging from room temperature to 300°C. The structural, compositional and electrical properties were analyzed as a function of the growth temperature. The X-ray diffraction shows that the crystalline structure of the films is strongly related to the growth temperature. The EDS analysis indicates that the stoichiometry of the CuxTe films depends on the growth temperature. For a substrate temperature of 300°C a Cu2Te film with hexagonal phase was obtained.

Au doping of CdS polycrystalline films prepared by co-sputtering of CdS–Cd-Au targets

Au doped CdS polycrystalline films were grown on Corning glass substrates at room temperature by co-sputtering from a CdS–Cd–Au target. Elemental Cd and Au were placed onto the CdS target covering small areas. The electrical, structural, and optical properties were analyzed as a function of Au content. The Au doped CdS polycrystalline films showed a p-type semiconductor nature. It was found that the electrical resistivity drops and the carrier concentration increases as a consequence of Au incorporation within the CdS lattice. In both cases, the changes were of several orders of magnitude.

Structural, Optical, and Luminescence Properties of Reactive Magnetron Sputtered Tungsten Oxide Thin Films

Tungsten oxide (WO3) thin films were deposited on to unheated Corning glass and silicon substrates by RF magnetron sputtering of metallic tungsten target at various oxygen partial pressures in the range 4×10-2–1×10-1 Pa. The influence of oxygen partial pressure on the structure and surface morphology and the optical and photoluminescence properties of the films were investigated. X-ray diffraction studies revealed that the deposited films were amorphous in nature. Fourier transform infrared transmission spectra confirmed that the presence of stretching vibration of W-O-W and deformation of W-O bonds related to the WO3. The optical transmittance of the films at wavelengths >500 nm increased from 62% to 85% with the increase of oxygen partial pressure. The optical band gap of the films increased from 3.00 to 3.14 eV and the refractive index of the films decreased from 2.26 to 2.08 with the increase of oxygen partial pressure from 4×10−2 to 1×10−1 Pa, respectively. The photoluminescence studies indicated that the intense blue emission which was assigned to band-to-band transition was observed at oxygen partial pressure of 6×10−2 Pa.

Physical properties of CdTe:Cu films grown at low temperature by pulsed laser deposition

CdTe:Cu films were grown by pulsed laser deposition on Corning glass slides at a substrate temperature of 300 °C. The thin films were grown using CdTe and Cu2Te powders, varying the Cu2Te concentration from 3 to 10 wt. %. The structural, compositional, optical, and electrical properties were analyzed as a function of the nominal copper concentration. X-ray diffraction shows that films have CdTe cubic phase. The compositional analysis indicates that CdTe:Cu films grown with lower Cu content have Te excess, on the other hand, films with higher Cu content have Te deficiencies. The electrical measurements showed that CdTe:Cu films grown with low Cu content present lowest resistivity.

Effect of the substrate temperature on the physical properties of molybdenum tri-oxide thin films obtained through the spray pyrolysis technique

Abstract Polycrystalline molybdenum tri-oxide thin films were prepared using the spray pyrolysis technique; a 0.1 M solution of ammonium molybdate tetra-hydrated was used as a precursor. The samples were prepared on Corning glass substrates maintained at temperatures ranging between 423 and 673 K. The samples were characterized through micro Raman, X-ray diffraction, optical transmittance and DC electrical conductivity. The species MoO 3 (H 2 O) 2 was found in the sample prepared at a substrate temperature of 423 K. As the substrate temperature rises, the water disappears and the samples crystallize into α-MoO 3 . The optical gap diminishes as the substrate temperature rises. Two electrical transport mechanisms were found: hopping under 200 K and intrinsic conduction over 200 K. The MoO 3 films' sensitivity was analyzed for CO and H 2 O in the temperature range 160 to 360 K; the results indicate that CO and H 2 O have a reduction character. In all cases, it was found that the sensitivity to CO is lower than that to H 2 O.

Comparative study on the thickness-dependent properties of ITO and GZO thin films grown on glass and PET substrates

The thickness-dependent properties of amorphous Sn-doped In2O3 (ITO) and polycrystalline Ga-doped ZnO (GZO) films grown on polyethylene terephthalate (PET) with a polymeric hard coating were compared with those deposited on Corning glass. The film thickness varied from 20 to 1310 nm. The electrical properties of the ITO films on PET were almost similar to those of the ITO films on glass. On the other hand, GZO films showed slightly poorer electrical properties when deposited on PET, but the difference was marginal. The electrical properties of amorphous ITO films were independent of film thickness, but polycrystalline GZO films exhibited monotonicallyimproving behavior with increasing thickness, mainly due to enhanced crystallinity and increased grain size with increasing film thickness. Although the air-referenced transmittance spectra of films on PET were about 2–3% lower than those on glass due to the lower transmittance of PET, the substrate-referenced optical transmittances of films on PET were higher than those on glass, reflecting the somewhat coarse structure of films on PET. Both the ITO and the GZO films on PET with a polymeric hard coating were shown to yield properties comparable to those oof both films on glass.

Carbon Dioxide Entrainment During High-Frequency Oscillatory Ventilation: A Model Analysis

High-frequency ventilation got its start in the United States from a paper by Dr Mirosolav Klain, an anesthesiologist who described a high-frequency jet ventilator (HFJV)[1][1] he built using a fluidic control circuit purchased as a demonstration kit from Corning Glass Works.[2][2] Based on his

Separation of carboxylic acids in human serum by isotachophoresis using a commercial field-deployable analytical platform combined with in-house glass microfluidic chips

Portable and field deployable analytical instruments are attractive in many fields including medical diagnostics, where point of care and on-site diagnostics systems capable of providing rapid quantitative results have the potential to vastly improve the productivity and the quality of medical care. Isotachophoresis (ITP) is a well known electrophoretic separation technique previously demonstrated as suitable for miniaturization in microfluidic chip format (chip-ITP). In this work, a purpose-designed ITP chip compatible with a commercial end-used targeted microfluidic system was used to study different injection protocols and to evaluate the effect of the length of the separation channel on the analytical performance. The in-house ITP chips were made from Corning glass and compared to the commercial DNA chip for the ITP separation of anions from the hydrodynamic injection of human serum. Using the in-house ITP chip the isotachophoretic step of lactate from human serum was approximately two times longer. The results of this research suggested that microfluidic ITP with indirect fluorescence detection is a viable technique for separation of organic acids in human serum samples, especially when a chip with suitable design is used.

Hexagonal CdTe films with Te excess grown at room temperature by laser ablation

CdTe thin films were grown by laser ablation using a Nd:YAG laser at wavelengths of 1064nm and 532nm, on Corning glass substrates at room temperature. CdTe powders were used as target for deposition of the films. The growth time was 10min and the films were deposited in vacuum. X-ray diffraction shows that films have hexagonal phase. EDS analysis indicates that the films grew with excess of Te, which indicates that CdTe films have p-type conductivity.

Effect of Oxygen Partial Pressure on the Electrical and Optical Properties of DC Magnetron Sputtered AmorphousTiO2Films

Titanium dioxide (TiO2) thin films were deposited on p-Si (100) and Corning glass substrates held at room temperature by DC magnetron sputtering at different oxygen partial pressures in the range9×10−3–9×10−2 Pa. The influence of oxygen partial pressure on the structural, electrical, and optical properties of the deposited films was systematically studied. XPS studies confirmed that the film formed at an oxygen partial pressure of6×10−2 Pa was nearly stoichiometric. TiO2films formed at all oxygen partial pressures were X-ray amorphous. The optical transmittance gradually increased and the absorption edge shifted towards shorter wavelengths with the increase of oxygen partial pressure. Thin film capacitors with configuration of Al/TiO2/p-Si have been fabricated. The results showed that the leakage current density of films formed decreased with the increase of oxygen partial pressure to6×10−2Pa owing to the decrease in the oxygen defects in the films thereafter it was increased. The current transport mechanism in the TiO2thin films is shown to be Schottky effect and Fowler-Nordheim tunnelling currents.

Thermal expansion coefficient and thermomechanical properties of SiNx thin films prepared by plasma-enhanced chemical vapor deposition

We present a new method based on fast Fourier transform (FFT) for evaluating the thermal expansion coefficient and thermomechanical properties of thin films. The silicon nitride thin films deposited on Corning glass and Si wafers were prepared by plasma-enhanced chemical vapor deposition in this study. The anisotropic residual stress and thermomechanical properties of silicon nitride thin films were studied. Residual stresses in thin films were measured by a modified Michelson interferometer associated with the FFT method under different heating temperatures. We found that the average residual-stress value increases when the temperature increases from room temperature to 100°C. Increased substrate temperature causes the residual stress in SiN(x) film deposited on Si wafers to be more compressive, but the residual stress in SiN(x) film on Corning glass becomes more tensile. The residual-stress versus substrate-temperature relation is a linear correlation after heating. A double substrate technique is used to determine the thermal expansion coefficients of the thin films. The experimental results show that the thermal expansion coefficient of the silicon nitride thin films is 3.27×10(-6)°C(-1). The biaxial modulus is 1125 GPa for SiN(x) film.

Hydrogen passivation of polycrystalline silicon thin films

The influence of post-hydrogenation on the electrical and optical properties of solid phase crystallized polycrystalline silicon (poly-Si) was examined. The passivation of grain-boundary defects was measured as a function of the passivation time. The silicon dangling-bond concentration decreases with increasing passivation time due to the formation of Si-H complexes. In addition, large H-stabilized platelet-like clusters are generated. The influence of H on the electrical properties was investigated using temperature dependent conductivity and Hall-effect measurements. For poly-Si on Corning glass, the dark conductivity decreases upon hydrogenation, while it increases when the samples are fabricated on silicon-nitride covered Borofloat glass. Hall-effect measurements reveal that for poly-Si on Corning glass the hole concentration and the mobility decrease upon post-hydrogenation, while a pronounced increase is observed for poly-Si on silicon-nitride covered Borofloat glass. This indicates the formation of localized states in the band gap, which is supported by sub band-gap absorption measurments. The results are discussed in terms of hydrogen-induced defect passivation and generation mechanisms.

Correlation of plume dynamics and oxygen pressure with VO2 stoichiometry during pulsed laser deposition

Vanadium dioxide thin films have been deposited on Corning glass substrates by a KrF laser ablation of V2O5 target at the laser fluence of 2 J cm−2. The substrate temperature and the target-substrate distance were set to 500 ∘C and 4 cm, respectively. X-ray diffraction analysis showed that pure VO2 is only obtained at an oxygen pressure range of 4×10−3–2×10−2 mbar. A higher optical switching contrast was obtained for the VO2 films deposited at 4×10−3–10−2 mbar. The films properties were correlated to the plume-oxygen gas interaction monitored by fast imaging of the plume.