Magnetic resonance spectroscopy of hydrogen shallow donors in aluminum-doped zinc oxide prepared by sol–gel processing

Hydrogen shallow donors in sol–gel-prepared pristine and Al-doped ZnO systems have been investigated by electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) measurements. It is shown that the hydrogen shallow donors in the Al-doped ZnO system mostly occupy the interstitial sites as in the case of the pristine ZnO system. Our high-resolution NMR measurements sensitively reflected the slightly distinct lattice environments in the pristine and Al-doped ZnO systems.     

Study of the electric field and wall voltage in a high pressure ac-PDP cell by laser induced fluorescence spectroscopy

The electric field in a surface discharge type ac-PDP cell with He or He/Xe(0.1%) mixture has been measured over a wide range of pressure (5－50 kPa) using laser induced fluorescence detection. The wall voltage was estimated from the measured electric field. The Stark manifolds of triplet atomic helium Rydberg state (2s^3S) with principal quantum numbers (n=8 and 9) have been used to measure the electric field, as the lifetime of 2s^3S is longer than the single atomic helium Rydberg state (2s^1S) in high pressure discharge. Comparison of the Stark manifolds between the n=9 and n=8 shows that the measurement accuracy of electric field can be increased by 10%. The maximum electric field strength during discharge and the wall voltage at the end of pulse decreases with the increase of pressure. The comparison of He and He/Xe(0.1%) discharge at 13 kPa showed that He/Xe gas mixture discharge can accumulate more wall charge on MgO surface and the electric field was somewhat higher than those of pure helium discharge during pulse off period under the same discharge conditions.     

Quantum explanation for time—phase relations in radiation of the plasma induced by laser ablating aluminum

1　ＩＮＴＲＯＥＸＰＥＲＩＭＥＮＴＥｘｐｅｒｉｍｅｎｔａｌｓｅｔｕｐｗａｓｓｈｏｗｎｉｎＦｉｇ .1,ｅｘｈａｕｓｔｉｖｅｄｅｓｃｒｉｐｔｉｏｎｓｏｎｔｈｅｓｅｔｕｐａｎｄｔｈｅｐｒｏｃｅｓｓｏｆａｃｑｕｉｒｉｎｇｄａｔａｈａｓａｌｒｅａｄｙ ｇｉｖｅｎｉｎｒｅｌａｔｉｖｅｄｏｃｕｍｅｎｔ[1] ,ｎｏｗｗｅｄｏｅｘｃｅｓｓｉｖｅｄｅｓｃｒｉｐｔｉｏｎｎｏｌｏｎｇｅｒ .2　ＲＥＳＵＬＴＡＮＤＤＩＳＣＵＳＳＩＯＮＲｅｓｕｌｔ:ｅａｒｌｉｅｒｓｐｅｃｔｒａｏｆｔｈｅｐｌａｓｍａｒａｄｉａｔｉｎｇｗｅｒｅｓｈｏｗ…     

Investigation of the ferroelectric–relaxor crossover in Ce-doped BaTiO3 ceramics by impedance spectroscopy and Raman study

BaCe _x Ti_{1? x} O₃ (x?=?0.06, 0.10, and 0.20) solid solutions were prepared via conventional the solid-state reaction and sintered at 1500°C for 4?h, resulting in dense single phase ceramics with homogeneous microstructures. The electric field dependence of permittivity of the BaCe _x Ti_{1? x} O₃ ceramics was investigated in detail, together with the ferroelectric–paraelectric phase transition features. A transformation from normal to relaxor ferroelectrics was observed by increasing the Ce concentration. For low-Ce content, a substitution of Ce on both A and B site positions was proposed from the dielectric study and confirmed by Raman analysis.     

Energy transfer in chemical dimers of porphyrins and chlorins by the methods of selective laser spectroscopy at 1.8–10 K

The methods of selective laser spectroscopy applied at 1.8–10 K to a glass-forming tetrahydrofuran-toluene (3∶1) mixture have revealed that in the dimers of tetrapyrrole compounds (ethane-bis-octaethylporphyrins, ethane-bis-Zn-octaethylchlorins, heterodimers of Zn-cyclopentane porphyrins) the exciton interactions (V₁₂≈118 cm⁻¹) and S-S-transfer of energy (of probability F≈11 sec⁻¹) are implemented under conditions of substantial inhomogeneous broadening (δF_1/2≈50 cm⁻¹). Upon excitation of a donor component in the dimers, one observes a strong quenching of its emission, the disappearance of the fine structure in the fluorescence spectra, a decrease in the efficiency of spectral hole burning by, approximately, an order of magnitude, and a 12-fold increase in their halfwidth. To whom correspondence should be addressed. Reported at the VIIIth International Conference on Spectroscopy of Porphyrins and Their Analogs, Minsk, September 22–26, 1998. Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 500–504, July–August, 1999.     

Neutron diffraction study of the nano-inhomogeneities of the sphalerite crystal structure induced by magnetoactive 3d ions in II–VI solid solutions

It is shown by means of the thermal neutron diffraction method that, during the doping of Zn-chalcogenide semiconductor crystals with 3d ions, elongated distortions whose spatial topology depends on the type of impurity can be formed in the sphalerite modification based on the initial crystal structure. Experimental results are discussed using the concept of vibronic interaction induced by foreign ions with partially filled outer electron shells in the cubic crystal field.     

Optical–thermal simulation applied to the study of the pattern effects induced by the sub-melt laser anneal process in advanced CMOS technologies

We present a study of the temperature non-homogeneities induced by millisecond laser annealing in advanced CMOS technologies at die level. Because of the design, the device layout at the wafer surface introduces during this anneal significant spatial variations of optical absorption and heat transfer that can induce temperature non-uniformities over the die, often called ‘pattern effects’. These temperature variations are becoming a major issue, since they are the origin of significant device properties dispersion. A complete optical and thermal simulation set has been developed to estimate the temperature variations induced by the topologies at the wafer surface during the laser anneal process. The modelling has been validated by either a comparison with another software or reflectometry and electrical measurements on real structures. This work demonstrates that the temperature variations are caused either by optical coupling or by thermal properties dispersion present at the wafer surface at the anneal step. Finally, we demonstrate that the impact of the thin-film interferences and diffraction phenomena is the critical issue for these pattern effects.     

Influence of post-deposition annealing on the structural,optical and electrical properties of Li and Mg co-doped ZnO thin films deposited by sol–gel technique

Lithium (Li) and magnesium (Mg) co-doped zinc oxide (ZnO) thin films were deposited by sol–gel method using spin coating technique. The films were deposited on glass substrates and annealed at different temperatures. The effects of annealing temperature on the structural, optical and electrical properties of the deposited films were investigated using X-ray diffraction (XRD), Ultraviolet–Visible absorption spectra (UV–VIS), photoluminescence spectra (PL), X-ray photo electron spectroscopy (XPS) and Hall measurements. XRD patterns indicated that the deposited films had a polycrystalline hexagonal wurtzite structure with preferred (0 0 0 2) orientation. All films were found to exhibit a good transparency in the visible range. Analysis of the absorption edge revealed that the optical band gap energies of the films annealed at different temperatures varies between 3.49 eV and 3.69 eV. Room temperature PL spectra of the deposited films annealed at various temperatures consist of a near band edge emission and visible emission due to the electronic defects, which are related to deep level emissions, such as oxide antisite (O_Zn), interstitial zinc (Zn_i), interstitial oxygen (O_i) and zinc vacancy (V_Zn) which are generated during annealing process. The influence of annealing temperature on the chemical state of the dopants in the film was analysed by XPS spectra. Ion beam analysis (Rutherford back scattering) experiments were performed to evaluate the content of Li and Mg in the films. Hall measurements confirmed the p-type nature of the deposited films.     

Dispersive liquid–liquid microextraction based on solidification of floating organic drop for separation and preconcentration of malachite green before its determination by flow injection spectrophotometry

ABSTRACT

A simple and fast dispersive liquid–liquid microextraction based on solidification of floating organic drop has been developed for the separation and preconcentration of malachite green in water samples prior to its determination by flow injection spectrophotometry. Sodium lauryl sulfate, an anionic surfactant, was used for the ion-pair formation with malachite green. The factors affecting the ion-pair formation and extraction were optimized. Under the optimized conditions (volume of 1-undecanol as the extraction solvent, 40 μL; the volume of ethanol as the disperser solvent, 100 μL; sodium lauryl sulfate concentration, 7.5 × 10^?7 mol L^?1, and the pH of the sample, ～3.0), the calibration graph was linear over the range of 0.8–25 µg L^?1 with the detection limit of 0.3 µg L^?1 and the preconcentration factor of 750. The relative standard deviation at 7 µg L^?1 (n = 6) was found to be 2.1%. The developed method was successfully applied to the determination of malachite green in river water and fish farming water samples.     

High-resolution spectroscopy of 16 bands of OCS in the region 1975–2140 cm−1 for diode laser calibration

The spectrum of OCS with natural isotopic abundances has been measured in the 1975- to 2140-cm^?1 region with near-Doppler-limited resolution using a Fourier transform spectrometer. Sixteen bands have been analyzed, including the following five bands for the first time at high resolution:

     

13.

The changes in phase composition of the subsurface layer of an ultrafine-grained Al–Mg–Li alloy during its deformation under superplasticity conditions     

E. V. Naydenkin  K. V. Ivanov 《Russian Physics Journal》2014,56(9):1018-1024

     

14.

A mathematical model to predict the grain size of nanocrystalline CdS thin films based on the deposition condition used in the sol–gel spin coating method     

M. Thambidurai  N. Muthukumarasamy  N. Murugan  Dhayalan Velauthapillai  S. Agilan  R. Balasundaraprabhu 《Applied Physics A: Materials Science & Processing》2011,104(4):1129-1136

Design of experiment (DOE) based on central composite design (CCD) has been employed for the development of a mathematical model correlating the important process parameters like thiourea concentration (U), annealing temperature (A), rotational speed (S), and annealing time (T) of the spin coating process for the preparation of CdS thin films. The experiments were conducted as per the design matrix. Nanocrystalline CdS thin films have been prepared using cadmium nitrate and thiourea as precursors by sol gel spin coating method using the results of the mathematical model. The prepared CdS films have been characterized and the crystal structure and grain size of the samples were analyzed using X-ray diffraction technique. The adequacy of the developed models was checked by analysis of variance (ANOVA) technique. The accuracy of prediction has been carried out by conducting confirmation test. Using this model, the main effect of process parameters on grain size of CdS films have been studied. These parameters were optimized to obtain minimum grain size using the Microsoft excel solver. The results have been verified by depositing CdS films using the optimized conditions. These films have been characterized using X-ray diffraction technique and the grain size is found to be 8.8 nm. The high resolution transmission electron microscopy (HRTEM) analysis showed the grain size of the prepared CdS film to be ∼7 nm. UV–vis spectroscopy analysis revealed that CdS films exhibited quantum confinement effect.     

15.

Design a sensitive optical thin film sensor based on incorporation of isonicotinohydrazide derivative in sol–gel matrix for determination of trace amounts of copper (II) in fruit juice: Effect of sonication time on immobilization approach     

《Ultrasonics sonochemistry》2018

A new selective and sensitive optical sensor based on the incorporation of new synthesized N′-(2-hydroxy-5-iodobenzylidene) isonicotinohydrazide (HIBIN) as an effective reagent into the nanoporous of a transparent glass like material through the sol–gel process was developed which was suitable for the determination of copper (II) ions in aqueous solutions. The thin film sensors were constructed by spin-coating of prepared sol onto glass plate and their surface morphology were studied by field emission scanning electron microscopy (FE-SEM) and atomic force microscope (AFM) technique. Influence of sonication time on immobilization of HIBIN into silica matrix was investigated through calculation of leaching percentage. The Results shown that sonication time of 35 min is suitable to give more stable thin films without fluctuation in sensitivity and response time of presented sensor for a long period of time. The proposed optical sensor can be used for determination of copper (II) ions in the range of 9.1 × 10⁻⁸–1.12 × 10⁻⁵ mol L⁻¹with a detection limit of 1.8 × 10⁻⁸ mol L⁻¹. It also showed relative standard deviation 3.4 and 0.72% for reproducibility and repeatability respectively, along with a fast response time about of 2 min. The constructed optode is stable in wet conditions and could be stored for at least 6 weeks without observing any change in its sensitivity. The developed sensor was successfully applied to the determination of copper (II) in fruit juice and water samples which results were confirmed by atomic absorption spectrometry method.     

16.

A new sol–gel processing routine without chelating agents for preparing highly transparent solutions and nanothin films: engineering the role of chemistry to design the process     

Rouholah Ashiri 《哲学杂志》2015,95(1):1-11

The great sensitivity of titanium alkoxides to hydrolysis makes their sol–gel transformation very fast and thus difficult to control. A method was proposed to alleviate this drawback. Preparation of highly transparent solutions and nanothin films is another objective of the present research. Employing nanoemulsion method and optimizing the processing conditions, a clear solution of well-dispersed nanosized particles was obtained. With the proposed process BaTiO₃ precursor sols and nanothin films with enhanced optical transparency towards the visible were prepared. The optimal formulation of the sol consists of acetic acid, barium acetate, 2-propanol, TTIP and deionized water with 6:1:1:1:150 M ratios, respectively. It was found that the reduction of the temperature in the initial stage of mixing of precursors controls the size of the forming species and accordingly improves the stability and transparency of the sol. The results also showed that the applied modifications and optimizations significantly downsize the particles within the sol to the nanometric scale and accordingly result in a significant improvement in the optical response of the products.     

17.

The effect of Mg doping on the dielectric and tunable properties of Pb0.3Sr0.7TiO3 thin films prepared by sol–gel method     

Xiaohua Sun  Xiuneng Li  Shuang Hou  Caihua Huang  Jun Zou  Meiya Li  Tianyou Peng  Xing-zhong Zhao 《Applied Physics A: Materials Science & Processing》2014,114(3):777-783

Mg doped Pb_0.3Sr_0.7TiO₃ (PST) thin films were fabricated by the sol–gel method on a Pt/Ti/SiO₂/Si substrate. The microstructure, surface morphology, dielectric and tunable properties of PST thin films were investigated as a function of Mg concentration. It is found that proper Mg doping dramatically improves the dielectric loss (0.0088 @ 1 MHz), furthermore, the crystallinity, dielectric constant, and tunability of films simultaneously decrease with the increase of Mg content. The 2 mol% Mg doped PST thin film shows the highest figure of merit (FOM) value of 36.8 for its the smallest dielectric loss and upper tunability. The dependence of Rayleigh coefficient on the doping concentration was examined, which indicated that the reduction of dielectric constant and tunability of films should be related to the $\mathrm{Mg}''_{\mathrm{Ti}}$ – $\mathrm{V}_{\mathrm{O}}^{\bullet\bullet}$ defect dipoles pinning the domain wall motion of residual polar clusters in PST.     

18.

The effects of sintering temperatures on dielectric,ferroelectric and electric field-induced strain of lead-free Bi0.5(Na0.78K0.22)0.5TiO3 piezoelectric ceramics synthesized by the sol–gel technique     

《Current Applied Physics》2010,10(6):1367-1371

Lead-free Bi_0.5(Na_0.78K_0.22)_0.5TiO₃ (BNKT) piezoelectric ceramics were synthesized by the sol–gel technique. The effects of sintering temperatures on the crystal structure, microstructure, densification, dielectric, ferroelectric and electric field-induced strain behaviors of the BNKT ceramics were investigated. X-ray diffraction patterns exhibited a pure perovskite structure from 1075 to 1150 °C. A scanning electron microscopy study revealed an increase in grain size with increasing sintering temperature. The density of the ceramics sintered at 1150 °C reaches a maximum value of 5.55 g/cm³, which is 96% of the theoretical density. BNKT ceramics sintered at an optimum temperature of 1150 °C exhibited a high remnant polarization of 18.5 μC/cm², a high electric field-induced strain of 0.20% and dynamic piezoelectric coefficient d₃₃¹ = (S_max/E_max) of 247 pm/V.     

19.

The temperature dependence of the effective refractive index of TE1 and TM1 modes in optical sol–gel waveguides over a wide temperature range     

N. E. Nikolaev  S. V. Pavlov  N. S. Trofimov  T. K. Chekhlova 《Journal of Russian Laser Research》2012,33(6):536-541

We obtain the temperature dependences of the effective refractive index on the parameters of the sol?Cgel film. We found and explain the differences in the temperature characteristics of the sol?Cgel waveguides for the transverse electric (TE) and transverse magnetic (TM) modes. We consider the features of these dependencies and make physical interpretations of them under high-temperature conditions.     

20.

High performance liquid chromatography with on-line dual quantum cascade laser detection for the determination of carbohydrates, alcohols and organic acids in wine and grape juice     

J. Kuligowski  G. Quintás  B. Lendl 《Applied physics. B, Lasers and optics》2010,99(4):833-840

In the present study the simultaneous use of two quantum cascade lasers (QC-lasers) was investigated for the on-line detection in high performance liquid chromatography (HPLC). An optical set-up based on three gold mirrors and a ZnSe beam splitter was used to direct the emitted laser light trough a liquid flow cell with an optical path length of 52 μm onto a mercury-cadmium-telluride (MCT) detector. Using the separation of eight components of wine and grape juice as an example, on-line dual QC-laser detection in HPLC could be shown successfully for the first time.     

16O13C32S	1000-0000	2009.228 cm?1
16O13C32S	1110-0110	2002.427 cm?1
18O12C32S	1000-0000	2026.147 cm?1
16O12C32S	0400-0000	2104.828 cm?1
16O12C32S	0510-0110	2115.169 cm?1

A mathematical model to predict the grain size of nanocrystalline CdS thin films based on the deposition condition used in the sol–gel spin coating method

Design of experiment (DOE) based on central composite design (CCD) has been employed for the development of a mathematical model correlating the important process parameters like thiourea concentration (U), annealing temperature (A), rotational speed (S), and annealing time (T) of the spin coating process for the preparation of CdS thin films. The experiments were conducted as per the design matrix. Nanocrystalline CdS thin films have been prepared using cadmium nitrate and thiourea as precursors by sol gel spin coating method using the results of the mathematical model. The prepared CdS films have been characterized and the crystal structure and grain size of the samples were analyzed using X-ray diffraction technique. The adequacy of the developed models was checked by analysis of variance (ANOVA) technique. The accuracy of prediction has been carried out by conducting confirmation test. Using this model, the main effect of process parameters on grain size of CdS films have been studied. These parameters were optimized to obtain minimum grain size using the Microsoft excel solver. The results have been verified by depositing CdS films using the optimized conditions. These films have been characterized using X-ray diffraction technique and the grain size is found to be 8.8 nm. The high resolution transmission electron microscopy (HRTEM) analysis showed the grain size of the prepared CdS film to be ∼7 nm. UV–vis spectroscopy analysis revealed that CdS films exhibited quantum confinement effect.     

Design a sensitive optical thin film sensor based on incorporation of isonicotinohydrazide derivative in sol–gel matrix for determination of trace amounts of copper (II) in fruit juice: Effect of sonication time on immobilization approach

A new selective and sensitive optical sensor based on the incorporation of new synthesized N′-(2-hydroxy-5-iodobenzylidene) isonicotinohydrazide (HIBIN) as an effective reagent into the nanoporous of a transparent glass like material through the sol–gel process was developed which was suitable for the determination of copper (II) ions in aqueous solutions. The thin film sensors were constructed by spin-coating of prepared sol onto glass plate and their surface morphology were studied by field emission scanning electron microscopy (FE-SEM) and atomic force microscope (AFM) technique. Influence of sonication time on immobilization of HIBIN into silica matrix was investigated through calculation of leaching percentage. The Results shown that sonication time of 35 min is suitable to give more stable thin films without fluctuation in sensitivity and response time of presented sensor for a long period of time. The proposed optical sensor can be used for determination of copper (II) ions in the range of 9.1 × 10⁻⁸–1.12 × 10⁻⁵ mol L⁻¹with a detection limit of 1.8 × 10⁻⁸ mol L⁻¹. It also showed relative standard deviation 3.4 and 0.72% for reproducibility and repeatability respectively, along with a fast response time about of 2 min. The constructed optode is stable in wet conditions and could be stored for at least 6 weeks without observing any change in its sensitivity. The developed sensor was successfully applied to the determination of copper (II) in fruit juice and water samples which results were confirmed by atomic absorption spectrometry method.     

A new sol–gel processing routine without chelating agents for preparing highly transparent solutions and nanothin films: engineering the role of chemistry to design the process

The great sensitivity of titanium alkoxides to hydrolysis makes their sol–gel transformation very fast and thus difficult to control. A method was proposed to alleviate this drawback. Preparation of highly transparent solutions and nanothin films is another objective of the present research. Employing nanoemulsion method and optimizing the processing conditions, a clear solution of well-dispersed nanosized particles was obtained. With the proposed process BaTiO₃ precursor sols and nanothin films with enhanced optical transparency towards the visible were prepared. The optimal formulation of the sol consists of acetic acid, barium acetate, 2-propanol, TTIP and deionized water with 6:1:1:1:150 M ratios, respectively. It was found that the reduction of the temperature in the initial stage of mixing of precursors controls the size of the forming species and accordingly improves the stability and transparency of the sol. The results also showed that the applied modifications and optimizations significantly downsize the particles within the sol to the nanometric scale and accordingly result in a significant improvement in the optical response of the products.     

The effect of Mg doping on the dielectric and tunable properties of Pb0.3Sr0.7TiO3 thin films prepared by sol–gel method

Mg doped Pb_0.3Sr_0.7TiO₃ (PST) thin films were fabricated by the sol–gel method on a Pt/Ti/SiO₂/Si substrate. The microstructure, surface morphology, dielectric and tunable properties of PST thin films were investigated as a function of Mg concentration. It is found that proper Mg doping dramatically improves the dielectric loss (0.0088 @ 1 MHz), furthermore, the crystallinity, dielectric constant, and tunability of films simultaneously decrease with the increase of Mg content. The 2 mol% Mg doped PST thin film shows the highest figure of merit (FOM) value of 36.8 for its the smallest dielectric loss and upper tunability. The dependence of Rayleigh coefficient on the doping concentration was examined, which indicated that the reduction of dielectric constant and tunability of films should be related to the $\mathrm{Mg}''_{\mathrm{Ti}}$ – $\mathrm{V}_{\mathrm{O}}^{\bullet\bullet}$ defect dipoles pinning the domain wall motion of residual polar clusters in PST.     

The effects of sintering temperatures on dielectric,ferroelectric and electric field-induced strain of lead-free Bi0.5(Na0.78K0.22)0.5TiO3 piezoelectric ceramics synthesized by the sol–gel technique

Lead-free Bi_0.5(Na_0.78K_0.22)_0.5TiO₃ (BNKT) piezoelectric ceramics were synthesized by the sol–gel technique. The effects of sintering temperatures on the crystal structure, microstructure, densification, dielectric, ferroelectric and electric field-induced strain behaviors of the BNKT ceramics were investigated. X-ray diffraction patterns exhibited a pure perovskite structure from 1075 to 1150 °C. A scanning electron microscopy study revealed an increase in grain size with increasing sintering temperature. The density of the ceramics sintered at 1150 °C reaches a maximum value of 5.55 g/cm³, which is 96% of the theoretical density. BNKT ceramics sintered at an optimum temperature of 1150 °C exhibited a high remnant polarization of 18.5 μC/cm², a high electric field-induced strain of 0.20% and dynamic piezoelectric coefficient d₃₃¹ = (S_max/E_max) of 247 pm/V.     

The temperature dependence of the effective refractive index of TE1 and TM1 modes in optical sol–gel waveguides over a wide temperature range

We obtain the temperature dependences of the effective refractive index on the parameters of the sol?Cgel film. We found and explain the differences in the temperature characteristics of the sol?Cgel waveguides for the transverse electric (TE) and transverse magnetic (TM) modes. We consider the features of these dependencies and make physical interpretations of them under high-temperature conditions.     

High performance liquid chromatography with on-line dual quantum cascade laser detection for the determination of carbohydrates, alcohols and organic acids in wine and grape juice

In the present study the simultaneous use of two quantum cascade lasers (QC-lasers) was investigated for the on-line detection in high performance liquid chromatography (HPLC). An optical set-up based on three gold mirrors and a ZnSe beam splitter was used to direct the emitted laser light trough a liquid flow cell with an optical path length of 52 μm onto a mercury-cadmium-telluride (MCT) detector. Using the separation of eight components of wine and grape juice as an example, on-line dual QC-laser detection in HPLC could be shown successfully for the first time.