Alkali-free Borosilicate Glass Research Articles

Phosphorus Dopant Diffusion, Activation, and Annealing. Using Infrared Laser for Synthesis of n-Type Silicon Thin Film

Thin film of oriented crystalline intrinsic polysilicon films were grown on alkali-free borosilicate glass substrate using hot-wire chemical-vapor-deposition (HWCVD) technique. A layer as a source of phosphorus dopant on top of intrinsic polysilicon films were introduced in two different approaches: (i) spinon one-micrometer-thick phosphorus dopant and (ii) phosphorus ion implantation. We investigate the possibility of dopant diffusion, activation, and annealing, using the irradiation of 1064 nm wavelength infrared laser. The annealing is performed under various conditions. The laser power and scan speed are varied to ensure the suitable laser annealing condition. We carry out resistivity measurements to validate the laser annealing process. For structural investigation, we use several characterization techniques, such as scanning electron microscopy, high-resolution X-ray diffraction, photoluminescence spectroscopy, and confocal Raman spectroscopy measurements. We use optical transmission spectra for determining optical characteristics of the film. The electrical measurement shows that the phosphorous-doped n-type polysilicon films are suitable as an emitter layer in photovoltaic device.

Zn dopant effect on growth, morphology, texture and mechanical properties of SnO2 thin films

When tin oxide thin film is doped with Zn, it grows textured and improves its mechanical properties. The material was synthesized on alkali-free borosilicate glass substrates by spray pyrolysis technique. The elemental composition was determined by X-ray energy dispersive spectroscopy and X-ray photoelectron spectroscopy. The morphology and microstructure of films were examined by electron microscopy techniques, they shown different shapes of crystalline particles according to the dopant content. From X-ray diffraction patterns processed by Rietveld refinement methodology was determine lattice parameters, crystallite sizes and micro strain; it showed that the textural growth of the films depend on the Zn dopant quantity content. The mechanical property was studied as a function of dopants amount, it enhancement due to the texture direction growth. For optimized Zn doped quantity in the film, local measurement of hardness and elastic modulus increased from 12 to 23 GPa and from 137 to 195 GPa, respectively. According to the Zn content, the materials show good correlation between elastic module values and (200) texture growth direction parallel to the substrate.

Separation control by a microfabricated SDBD plasma actuator for small engine turbine applications: influence of the excitation waveform

Small engines will be finding increasing applications in unmanned aerial vehicles (UAVs), drones and helicopters. However, their turbomachines exhibit lower efficiencies than those of large scale engines. In this context, the aerodynamic losses in the low-pressure turbines (LPTs) are largely accountable to flow separation at low Reynolds numbers operation, i.e. in cruise conditions. Active flow control is a promising technology to suppress separation, thus reducing losses, fuel consumption rates and therefore emissions.The present paper is focused on the experimental investigation of the potentialities of a Single Dielectric Barrier Discharge Plasma Actuator (SDBDPA) to reattach the separated flow at a Reynolds number of 2⋅104. The influence of the high voltage (HV) waveform supplying the SDBDPA on both flow separation control and device power dissipation was studied.The investigated SDBDPA was manufactured by microfabrication techniques. Photolithography ensured thin metal deposition with high manufacturing reliability control. Due to the possible device degradation during operation, emphasis was put in selecting thin film materials that could withstand the plasma environment. Schott alkali-free borosilicate glass substrate was chosen as dielectric, while a multilayer tungsten (W)/titanium nitride (TiN) as electrode material.The experimental approach comprised the actuator testing over a curved wall plate, designed with a shape to reproduce the suction surface of a LPT rotor blade and installed in closed loop wind tunnel test section. The SDBDPA was located at the front side of the adverse pressure gradient area, in order to control flow separation.Different HV excitation waveforms (sinus, triangle and square) and amplitudes were tested and compared, aiming to identify the input signal that gave the best flow control authority and device energy conversion efficiency. The applied voltage and the discharge current were acquired in order to determine the actuator dissipated power. Two-dimensional (2-D) flow velocity measurements were carried out by laser Doppler velocimetry (LDV) and particle image velocimetry (PIV).Velocity results showed that the extension of the separation area was reduced by actuation. Moreover, when the actuator was on, the boundary layer thickness and the negative velocity magnitude decreased. Their reduction increased with the applied voltage (i.e. higher power dissipations). At comparable peak-to-peak applied voltages, the sinus waveforms slightly outperformed the other waveforms; however, while the sinus and triangle ones had comparable power dissipation, the square wave always dissipated the most.

Corrosion Resistance of Chromium-Containing Refractories in Molten Alkali-Free Borosilicate Glass E

Information is provided for chromium-containing refractory used in founding alkali-free borosilicate glass E. It is shown that melted and cast chromespinelid refractory KhPL-85 developed, containing 80% Cr2O3 with respect to corrosion resistance in molten glass E, is at the same level as industrial chromium oxide refractories.

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

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

UV and visible photoluminescence emission intensity of undoped and In-doped ZnO thin film and photoresponsivity of ZnO:In/Si hetero-junction

Undoped zinc oxide (ZnO) and indium-doped (ZnO:In) thin films were grown at different temperatures (250–400°C) on alkali-free borosilicate glass and n-Si (100) substrates by Ultrasonic Spray Pyrolysis method. The structural, compositional, optical and electrical properties of ZnO films were investigated by X-ray diffraction, Scanning Electron Microscopy, Rutherford Back Scattering Spectroscopy, Fourier Transform Infrared spectroscopy, photoluminescence (PL) and the four-point probe technique. The predominance of ultraviolet (UV) and blue emission intensities was found to be closely dependent on the resistivity of the film. The visible emission band (peaking at 432nm) prevails for low film resistivity, ranging from 10−2 to 1Ω·cm. By contrast, for higher resistivity (>1Ω·cm), there is a predominance of the UV band (382nm). The PL and photoresponsivity results of fabricated ZnO:In/n-Si(100) heterojunctions prepared at different temperatures are discussed. The maximum spectral response of the ZnO:8%In/Si heterojunction diode fabricated at 250°C was about 80mA/W at zero bias. The highlighted results are attractive for the optoelectronic applications.

Structural, morphological and optical properties of TiO2 films prepared using aqueous sol–gel methods

The influence of the preparation conditions on the structural, morphological and optical properties of TiO2 thin films deposited on silicon substrate (Si), indium tin oxide coated glass (ITO) and alkali-free borosilicate glass (AFG), respectively is studied in this work. The X-ray diffraction analysis revealed that all TiO2 samples had a polycrystalline structure. The TiO2 films coated on Si showed a mixed phase of anatase and rutile while in the case of those on ITO and AFG only the pure anatase phase was observed. The crystallite size within the TiO2 thin films varied with the calcinations temperature, solvent lateral chain and catalyst type. The optical transmittance, band gap, reflective index and porosity were strongly affected by the annealing temperature, substrate nature and solvent.

Fusion-cast chromium-bearing refractories — the most durable materials in aggressive melts

Information is presented on fusion-cast materials that have been developed in recent years on the basis of the systems Cr2O2–Al2O3–ZrO2–SiO2, Cr2O3–MgO–SiO2, and Cr2O3–MgO–Al2O3. Such materials have good service properties in mineral melts at high temperatures. It is shown that fusion-cast chromium-bearing refractories KhPL-85 and KhMG are as corrosion-resistant as chromium-oxide-based ceramic refractories in melts of alkali-free borosilicate glass E and basalt fibers.

Trimethoxyboroxine as an ‘oxygen-transfer’ reagent: a non-aqueous ‘sol–gel’ route to alkali-free borosilicate glass

A synthesis of alkali-free borosilicate gel from Si(OEt)4 and (MeO)3B3O3 in non-aqueous solvents is reported; the formation of the gel proceeds via rapid transesterification/oxygen transfer with elimination of B(OR)3; removal of volatiles from the gel, followed by drying (60 oC, 12 h) and furnacing in air (600 oC, 20 min) resulted in alkali-free borosilicate glass.

Preparation of B<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> Coating Films by the Sol-Gel Method

Alkali-free borosilicate glass films have been prepared from boron triisoproxide and silicon tetraethoxide by the sol-gel method. It was found that the optical transmission of these films decreased, accompanied with the increase in surface roughness, with increasing humidity of the atmosphere in the coating process. The X-ray diffraction patterns and the wavelength dependence of the optical loss proved that the above findings resulted from the deposition of crystalline H3BO3 by the attack of water in the atmosphere. Transparent B2O3-SiO2 films containing up to 30 mol% B2O3 were obtained in the dry atmosphere below 20% relative humidity.