Optical Quartz Research Articles

Physical properties of Cu and Dy co-doped ZnO thin films prepared by radio frequency magnetron sputtering for hybrid organic/inorganic electronic devices

Copper (Cu) and dysprosium (Dy) co-doped zinc oxide (ZnO) thin films were fabricated by radio frequency magnetron sputtering (RF-magnetron sputtering) using a homemade target having the atomic percentage of Cu and Dy of 1%, onto optical glass substrates and quartz substrates. The structural, morphological, optical, and electrical properties of fabricated ZnO:(Cu, Dy) structures were analyzed and discussed. It was found that all samples have hexagonal Würtzite structure. Optical transmission measurements indicate values larger than 75% in the 400–2500 nm ranges. The current-voltage characteristics of hybrid heterojunctions based on ZnO:(Cu, Dy) and poly(3-hexylthiophene-2.5-diyl) (P3HT) or copper (II) phthalocyanine (CuPc) thin films were acquired in the dark, in ambient atmosphere, and they exhibit the typical diode behavior, almost free of electrical hysteresis.

Study of the influence of tool rake angle in ductile machining of optical quartz glass

The SPH simulation model of optical quartz glass was established to study the ductile machining process with different tool rake angles. The material removal mode, stress distribution, cutting force, and subsurface damage during machining were analyzed. The critical cutting depths of brittle-ductile transition under different tool rake angles were obtained. The simulation results show that the tool negative rake angle is better than the positive rake angle in promoting the ductile machining of optical quartz glass. When the tool rake angle is negative, significant compressive stress which suppresses the crack generation by reducing the stress intensity factor KI is generated in the chip forming area, thus realizing the ductile machining of optical quartz glass. The greater the tool negative rake angle is, the more stable the cutting force and the greater the critical cutting depths of brittle-ductile transition are. When the tool negative rake angle is greater than − 35°, the subsurface damage of the optical quartz glass is aggravated, and the subsurface residual stress is complicated. When the tool negative rake angle ranges from − 15° to − 35°, the optical quartz glass is not only machined in a stable ductile region but also has less subsurface damage. Finally, nano-scratch experiments were carried out, and the critical depths of the brittle-ductile transition obtained by the experiments are basically consistent with the simulation results, which verify the correctness of the simulation results. The research results in this paper could provide a theoretical basis for the optimal selection of tool rake angle in the ductile machining of optical quartz glass.

Dressing Technology for the East Sayan Quartzites

The research results are presented for dressability of quartzites from the Garga quartzite region of the East Sayan. From the detailed analysis of the structure, texture, mineral and fluid inclusions in the chemical constitution, bright veined quartzites and coaly veined quartzites were distinguished in the Urda-Gargan block. Both kinds are readily dressed up quartz concentrates of deep concentration. The fist quartzite kind can be used in manufacturing of transparent optical quartz glass, whereas the second variety is a promising feedstock for carbothermal production of silicon.

Investigation of design parameters in generating antifouling and lubricating surfaces using hydrophilic polymer brushes

ABSTRACTLong‐term stability of hydrophilic surface coatings that prevent fouling, cell adhesion and present a lubricious interface for biomaterials has been widely investigated in recent years. As an alternative to the gold standard poly(ethylene glycol) (PEG), poly(2‐oxazoline)‐based coatings are promising due to their higher stability against oxidative degradation in comparison to PEG. In this study, we compare the antifouling and tribological properties of PEG and poly(2‐methyl‐2‐oxazoline) (PMOXA) brush structures as a function of structural design parameters such as grafting density, chain length, and the monomer solubility. Brush properties such as hydration (number of H2O molecules per monomer), shear modulus, and serum adsorption as a function of design parameters were estimated using optical waveguide lightmode spectroscopy and quartz crystal microbalance/dissipation techniques. At high monomer surface densities, PMOXA showed approximately three times higher structurally associated H2O molecules per monomer in comparison to PEG brushes, leading to stiffer PMOXA brushes. We found that the chain stiffening of PMOXA brushes lead to higher macroscopic coefficients of friction; however presented similar adsorbed serum mass (high antifouling properties) when compared to PEG brushes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47659.

Impact of the Solvation State of Lead Iodide on Its Two‐Step Conversion to MAPbI3: An In Situ Investigation

AbstractProducing high efficiency solar cells without high‐temperature processing or use of additives still remains a challenge with the two‐step process. Here, the solution processing of MAPbI3 from PbI2 films in N,N‐dimethylformamide (DMF) is investigated. In‐situ grazing incidence wide‐angle X‐ray scattering (GIWAXS) measurements reveal a sol–gel process involving three PbI2‐DMF solvate complexes—disordered (P0) and ordered (P1, P2)—prior to PbI2 formation. When the appropriate solvated state of PbI2 is exposed to MAI (methylammonium Iodide), it can lead to rapid and complete room temperature conversion into MAPbI3 with higher quality films and improved solar cell performance. Complementary in‐situ optical reflectance, absorbance, and quartz crystal microbalance with dissipation (QCM‐D) measurements show that dry PbI2 can take up only one third of the MAI taken up by the solvated‐crystalline P2 phase of PbI2, requiring additional annealing and yet still underperforming. The perovskite solar cells fabricated from the ordered P2 precursor show higher power conversion efficiency (PCE) and reproducibility than devices fabricated from other cases. The average PCE of the solar cells is greatly improved from 13.2(±0.53)% (from annealed PbI2) to 15.7(±0.35)% (from P2) reaching up to 16.2%. This work demonstrates the importance of controlling the solvation of PbI2 as an effective strategy for the growth of high‐quality perovskite films and their application in high efficiency and reproducible solar cells.

Human Serum Albumin Adsorption Kinetics on Silica: Influence of Protein Solution Stability.

Adsorption kinetics of human serum albumin (HSA) on silica substrates was studied using optical waveguide lightmode spectroscopy (OWLS) and quartz microbalance (QCM) techniques. Measurements were performed at pH 3.5, 5.6, and 7.4 for various bulk suspension concentrations and ionic strengths. The diffusion coefficient measurements showed that for pH 3.5 the HSA molecules are stable for NaCl concentrations from 10-3 to 0.15 M. This allowed us to precisely determine the mass transfer rate coefficients for the OWLS and QCM cells. The experimental data were adequately interpreted in terms of a hybrid random sequential adsorption model. The OWLS maximum coverage of HSA at pH 3.5, which is equal to 1.3 mg m-2, agrees with the QCM result and with previous results derived from streaming potential measurements. Thus, the results obtained at pH 3.5 served as reference data for the analysis of adsorption kinetics at higher pHs. In this way, it was confirmed that the adsorption kinetics of HSA molecules at pH 5.6 and 7.4 was considerably slower than at pH 3.5. This effect was attributed to aggregation of HSA solutions and interpreted in terms of a theoretical model combining the Smoluchowski aggregation theory with the convective diffusion mass transfer theory. New analytical equations were derived that can be used for the interpretation of other protein adsorption from unstable solutions.

Optimized birefringent filter design for broadly tunable multicolor laser operation of Nd-based lasers: Nd:YAG example

Nd-based gain media has more than 30 emission lines in the near infrared, potentially providing a very rich set of lines for multicolor laser operation. On the other hand, owing to the methods employed, most of the two-color laser experiments with Nd-systems demonstrated dual-wavelength operation in only one pair of wavelengths. In this work, we have numerically investigated the performance of off-surface optic axis crystal quartz birefringent filters (BRFs) as frequency selective elements in two-color laser operation of Nd-doped gain media. Our analysis has shown that a crystal quartz BRF with an optic axis diving by 25° into the plate could provide two-color laser operation in more than 40 pairs of Nd lines in properly designed cavities. The two-color operation wavelengths could be adjusted by simple rotation of the BRF about an axis normal to the surface. Fine adjustment of the angle via a motorized rotation stage fed by an error signal from a balanced detector could provide control of power in each lasing line. To our knowledge, such diversity in wavelength selection has not been achieved from any Nd-based system before, showing the potential of the method.

Particle behavior and its contribution to film growth in a remote silane plasma

Time-dependent behavior of particles measured using the laser light scattering method in a remote silane plasma has been investigated using both optical emission spectroscopy and quartz crystal microbalance. Laser-scattered particles were observed from 0.3 s after the plasma ignition and scattering increased rapidly until 3.0 s. In the 0–0.3 s region where no particles were observed, SiH and Hβ emission intensity as well as Si/SiH and Hβ/SiH intensity ratios increased rapidly. Laser-scattered particles decreased in number, 3.0 s after plasma discharge, but the deposition rate measured using the quartz crystal microbalance increased linearly. The relationships between time-resolved images of particle movements and their contribution to film deposition as well as plasma characteristics such as SiH and Hβ are presented. The results show that the particles contributing to film growth at the early stage of plasma are much higher in number than those in the stabilized state.

In situ viscoelastic properties and chain conformations of heavily hydrated carboxymethyl dextran layers: a comparative study using OWLS and QCM-I chips coated with waveguide material

Hydration, viscoelastic properties and dominant structure of thin polymer layers on the surface of waveguide material were evaluated using optical waveguide lightmode spectroscopy (OWLS) and quartz crystal microbalance (QCM) methods. The fundamentally different principles of the two applied label-free biosensors enable to examine analyte layers from complementary aspects, e.g. to determine the amount of bound water in hydrated layers. In this study, a new QCM instrument with impedance measurement (QCM-I) is introduced. Its specially designed sensor chips, covered by thin film of waveguide material, supply identical surface as used in OWLS sensors, thus enabling to perform parallel measurements on the same type of surface. Viscoelastic analysis of the measured data was performed by our evaluation code developed in MATLAB environment, using the Voinova’s Voigt-based model. In situ deposition experiments on the ultrathin films of poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) were conducted for instrumental and code validation. Additionally, a novel OWLS-QCM data evaluation methodology has been developed based on the concept of combining hydration and viscoelastic data with optical anisotropy results from OWLS measurements. This methodology provided insight into the time-dependent chain conformation of heavily hydrated nano-scaled layers, resulting in unprecedented structural, hydration and viscoelastic information on covalently grafted ultrathin carboxymethyl dextran (CMD) films. The measured mass values as well as hydration and viscoelastic properties were compared with the characteristics of PLL-g-PEG layers.

The LUCID-2 Luminometer

The LUCID-2 detector is the main online and offline luminosity monitor of the ATLAS experiment. It provides 104 different luminosity measurements from different algorithms for each of the thousands of LHC bunches. The new detector is using the quartz windows of 10 mm diameter photomultipliers and optical quartz fibers as the Cherenkov medium. A main challenge for a luminometer is to keep the efficiency constant during years of data-taking. LUCID-2 is using an innovative calibration system based on radioactive Bi-207 sources deposited on the quartz window of the readout photomultipliers.

Linear and nonlinear optical properties of new azo aminosalicylic acid derivatives

4-(3-Allyl-4-oxo-2-thioxo-thiazolidin-5-ylazo) salicylic acid (4-ATS) and 5-(3-allyl-4-oxo-2-thioxo-thiazolidin-5-ylazo) salicylic acid (5-ATS) were synthesized and characterized by different spectroscopic techniques. The XRD patterns of 4-ATS and 5-ATS in powder form were recorded and found to be polycrystalline with monoclinic crystal system. Thin films of 4-ATS and 5-ATS were successfully prepared by thermal evaporation technique onto optical flat quartz substrates. Linear and nonlinear optical properties of 4-ATS and 5-ATS were investigated by spectrophotometric measurements. The spectral distribution of refractive index of 5-ATS thin films showed normal dispersion in the non-absorbing region of spectra, while 4-ATS showed nonlinear response. The optical energy gap and the electronic transition type for 4-ATS and 5-ATS were calculated. The electronic absorption and emission spectra were recorded for pristine and UV-irradiated 4-ATS and 5-ATS thin films. The absorption coefficient spectra for 4-ATS and 5-ATS were found to decrease with increasing UV exposure time, while the intensity of emission spectra for both of the derivatives were enhanced with increasing UV exposure time. Recovery in dark reversed the effect of UV- radiation.

The low-temperature solubility of helium in quartz

The solubility of helium in α- and β-quartz single crystals, optical quartz crystals, and Pyrex glass has been studied by the method of thermal desorption of helium from crystals preliminarily saturated in the gaseous phase in the temperature range T = 323–1123 K and saturated vapor pressure P = 0.6–31 MPa. It has been shown that the behavior of the solubility of helium in quartz crystals is described by exponential dependences on the reciprocal temperature. The solubility of helium in quartz single crystals is almost independent of temperature. For all kinds of samples, the solubility varies in proportion to the saturated vapor pressure and attains values of (6.2 ± 0.3) × 1015 cm–3 in single crystals for P = 25.5 MPa, T = 873 K, and (8.64 ± 0.04) × 1019 cm–3 in optical quartz for P = 31 MPa and T = 373 K. It has been shown that the solubility of helium in quartz single crystals can increase upon an increase in the concentration of defects in the crystal as a result of multiple thermal cycling of samples in the course of measurements. Possible mechanisms of the dissolution of helium in quartz have been studied, and the results have been compared with those obtained by other authors.

Thin and ultrathin films of palladium oxide for oxidizing gases detection

Thin and ultrathin films of palladium oxide are set forth as promising materials for oxidizing gas detection. Thin and ultra thin PdO films were prepared by thermal oxidation at dry oxygen of previously formed Pd layers on polished poly-Al2O3, SiO2/Si (100), optical quality quartz, and amorphous carbon/KCl substrates. By high-resolution transmission electron microscopy and high-resolution scanning electron microscopy it has been found that thickness was about 5–10nm and 30–35nm for ultrathin and thin PdO films, respectively. By high-energy electron diffraction and X-ray analysis it has been established that oxidation of initial Pd layers at T=770–1070K led to formation of homogenous polycrystalline PdO films. At ozone and nitrogen dioxide detection PdO films prepared by oxidation at T=870K have shown the good values of sensitivity, signal stability, operation speed, and reproducibility of sensor response. In comparison with other materials, palladium oxide thin and ultrathin films have some advantages at gas sensor fabrication. Firstly, at rather low operating temperatures PdO films have shown good values of functional parameters. Secondly, the synthesis procedure of binary PdO films is rather simple and is compatible with planar processes of microelectronic industry.

The recrystallized grain size piezometer for quartz: An EBSD‐based calibration

AbstractWe have reanalyzed samples previously used for a quartz recrystallized grain size paleopiezometer, using electron backscatter diffraction (EBSD). Recrystallized and relict grains are separated using their grain orientation spread, which acts as a measure of intragranular lattice distortion and a proxy for dislocation density. For EBSD maps made with a 1 μm step size, the piezometer relationship is D = 103.91 ± 0.41 ∙ σ−1.41 ± 0.21 (for root‐mean‐square mean diameter values). We also present a “sliding resolution” piezometer relationship, D = 104.22 ± 0.51 ∙ σ−1.59 ± 0.26, that combines 1 μm step size data at coarser grain sizes with 200 nm step size data at finer grain sizes. The sliding resolution piezometer more accurately estimates stress in fine‐grained (<10 μm) samples. The two calibrations give results within 10% of each other for recrystallized grain sizes between 10 μm and 100 μm. Both piezometers match the original light optical microscopy quartz piezometer within error.

Red-diode-pumped Cr:Nd:GSGG laser: two-color mode-locked operation

We have investigated in detail the continuous-wave (cw) and mode-locked performance of a diode-pumped Cr:Nd:GSGG laser. State-of-the-art single-mode and multimode laser diodes around 665 nm were used as pump sources. In cw operation, we have demonstrated lasing thresholds as low as 14 mW, slope efficiencies as high as 23.4%, and output powers up to 738 mW. The free running emission wavelength was 1061 nm. Lasing could also be obtained at 1051, 1058, 1065, 1068, 1072, 1103, and 1111 nm lines. A saturable Bragg reflector was used to initiate and sustain mode-locking where the Cr:Nd:GSGG laser produced 6-ps-long pulses around 1061 nm with an average power of 160 mW. The repetition rate was 142.65 MHz, resulting in pulse energies of 1.1 nJ and peak powers of 175 W. An off-surface optical axis quartz birefringent filter (BRF) was inserted inside the laser cavity at Brewster’s angle to obtain two-color cw and mode-locked laser operation at the 1051 and 1058 nm and 1058 and 1061 transition pairs, resulting in cw powers up to 60 mW and cw mode-locked average powers up to 45 mW. Unlike many other methods applied for two-color mode-locked laser operation, usage of the BRF enabled regulation of the ratio of the power in each line by fine adjustment of its rotation angle. The method could potentially be used for other gain media as well, which could simplify development of multicolor solid-state laser systems.

Microstructure and electrical properties of palladium oxide thin films for oxidizing gases detection

Palladium oxide thin and ultrathin films have been presented as promising materials for detection of oxidizing gases. PdO films were prepared by thermal oxidation of previously formed Pd layers on different substrates: SiO2/Si (100), Si (100), optical quality quartz, and KCl (100) with a buffer layer of amorphous carbon. By X-ray analysis, reflection high-energy electron diffraction, and high resolution transmission electron microscopy investigations it has been established that homogenous polycrystalline PdO films (thickness was about 5–40nm) were formed by oxidation at dry oxygen at temperatures T=770–870K. The experimental results of X-ray analysis and transmission electron microscopy have shown that the increase in oxidation temperature led to uniformity and enlargement of crystalline grains in homogeneous PdO films. It has been found that the energy band gap values increased monotonically from ΔEg=2.15eV to 2.3eV for PdO films with p-type conductivity oxidized at Тan=670K and 1070K, respectively. At ozone detection PdO films fabricated on polished poly-Al2O3 have shown high values of sensitivity, signal stability, and reproducibility of sensor response. For fabrication of gas sensors the application of PdO thin and ultrathin films has some advantages in comparison with other materials because PdO films have shown good values of sensor functional parameters, and their synthesis procedure is rather simple and is compatible with planar processes of the microelectronic industry also.

Thermal effect on the optical and morphological properties of TiO2 thin films obtained by annealing a Ti metal layer

Titanium metal layers of different thicknesses were deposited on optical glass, quartz and ceramic at 50 °C and 150 °C substrate temperatures with the help of magnetron deposition. The metal layers were converted into a rutile phase of TiO2 at different annealing temperatures. The effect of thermal annealing on the morphology and the refractive index of the thin film was investigated. The film’s quality and roughness were found to depend on the substrate’s temperature during metal film deposition and on the annealing temperature. The TiO2 thin films obtained on ceramic and glass substrates were seem to show less surface roughness at low substrate temperature as compared to the quartz substrate.

Analysis of the Test Method of Quartz Glass Optical Homogeneity

The optical quartz glass is widely applied in optical system , photo communications，inertial navigation，etc.It must have high optical homogeneity. Optical homogeneity of the optical quartz glass directly affects the wavefront quality of the optical transmission system, and changes the wavefront aberration of the system. How to accurately determine the optical homogeneity of the quartz glass is especially important. Currently，the method of test for optical homogeneity mainly used by interference principle. This paper analyzes various existing interference measurement method and test equipment. Summarized the advantages and disadvantages of various test methods，using range and measurement accuracy.

Reversible sensing of heavy metal ions using lysine modified oligopeptides on porous silicon and gold

Phytochelatins (PCs), oligomers of glutathione, naturally chelate heavy metals (HMs) in aqueous solution; small peptides such as these cannot be used as covalently bound bioprobes on transducer surfaces due to their propensity to induce corrosion of standard sensor supports such as gold and porous silicon (PSi). In this work, we chemically modify a commercial PC oligopeptide with a six poly-lysine (Lys) chain, thereby changing its isoelectric point from 4.2 to 6.9. PC-Lys bioprobes were successfully immobilized on both PSi multilayers and flat gold surfaces. The interaction of PC-Lys and HM ions, namely Lead (II), Cadmium (II) and Arsenic (III) in aqueous solution was quantified by optical spectroscopic reflectometry and quartz crystal microgravimetry. As a result, it was proven that the biomolecular interactions are reversible and the affinities between PC-Lys complex and HM ions are in the range of 10−12M.

The structural and electrical properties of samarium doped ceria films formed by e-beam deposition technique

Sm2O3-doped CeO2 (Sm0.15Ce0.85O1.925, SDC) thin films were formed by e-beam evaporation method. Thin films were formed evaporating micro powders (particle size varied from 0.3 to 0.5μm). The influence of deposition rate on formed thin film structures and surface morphology were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersion spectrometry (EDS), and atomic force microscopy (AFM). The deposition rate of formed SDC thin films was changed from 2 to 16Å/s. The electrical properties were investigated as a function of frequency (0.1–106Hz) at different temperatures (473–873K).The formed SDC thin ceramic films repeat the crystallographic orientation of the initial powders using different substrates and different deposition rate. It was determined that crystallites size and samarium concentration are decreasing by increasing the deposition rate. The crystallites size decreased from 17.0nm to 10.4nm when SDC thin films were deposited on Alloy 600 (Fe-Ni-Cr), and decreased from 13.7nm to 8.9nm when were used optical quartz substrate.The best ionic conductivity σtot=1.66Sm−1 at 873K temperature, activation energy ΔEa=0.87eV (σg=1.66Sm−1, σgb=1.66Sm−1) was achieved when 2Å/s deposition rate was used. The grain size (in the formed SDC thin films) was ~83nm in this case.