Spray Pyrolysis

This review explores the mechanisms of spray pyrolysis for cadmium telluride (CdTe) thin-film photocathodes, focusing on droplet dynamics, nucleation processes, and film formation pathways relevant to photovoltaic and photocathode applications. It critically synthesizes recent literature from 2020 up to the time of manuscript submission, emphasizing its role in tailoring CdTe thin-film quality and performance. A peer review of journal articles was conducted using databases including Google Scholar, Scopus, Web of Science, and ScienceDirect. The studies examined droplet behavior, gasto-particle and droplet-to-particle mechanisms, substrate conditions, and modeling approaches in spray pyrolysis with a CdTe-specific context. The review identifies two dominant pathways in film formation: droplet-to-particle (DTP), where precipitation occurs within droplets, and gas-to-particle (GTP), where vapor-phase nucleation predominates. Substrate temperature, precursor chemistry, atomizer type, and carrier gas flow were found to significantly influence film microstructure, crystallinity, and grain growth. Computational

In this study doped SnO 2 thin films have been prepared by spray pyrolysis technique using an alcoholic precursor solution consisting of stannic chloride (SnCl 4 .5H 2 O), ammonium fluoride (NH 4 F) and palladium chloride (PdCl 2 ). Optimization on the deposition parameters was done so as to obtain high quality thin films. The effect of varying the Fluorine content on the optoelectronic properties of F: SnO 2 thin films was studied. Data for transmittance and reflectance in the wavelength range from 300nm -2500nm was obtained using the solid spec 3700DUV spectrophotometer. Electrical characterization of the thin films was done using the four point probe method at room temperature. Post deposition treatment of the thin films by annealing in air then passivating in nitrogen gas environment was done in a tube furnace at 450 0 C. Sheet resistivity for the as prepared F: SnO 2 was found to be 0.4599 Ωcm and 0.00075 Ωcm being the highest and lowest sheet resistivity at 22.74 at% F and 16.41at% F doping in SnO 2 respectively. Low sheet resistivity of F: SnO 2 thin films is due substitutional incorporation of F ions instead of oxygen ions into the crystal lattice of SnO 2 thin films which increases free carrier concentration. The effect of annealing generally was found to improve on the electrical conductivity of the thin films which is due to increase in carrier mobility and density. Passivation on the other hand had a slight opposite effect. Effects of annealing and passivation on doped SnO 2 thin films band gap energy and their transparency was insignificant, rendering the doped SnO 2 thin films good choice for making a transparent thin film gas sensors.

Pd-F:SnO 2 thin films have been prepared by spray pyrolysis technique using an alcoholic precursor solution consisting of stannic chloride (SnCl 4 .5H 2 0), ammonium fluoride (NH 4 F) and palladium chloride (PdCl 2 ). Optimization on the deposition parameters has been done in order to obtain high quality thin films. The effect of varying the fluorine content on the optical properties of Pd-F:SnO 2 thin films were studied. Data for transmittance and reflectance in the wavelength range from 300nm -2500nm was measured using the solid spec 3700DUV spectrophotometer. The calculated optical band gap of the as prepared thin films has been found to range from 3.8eV to 4.11eV. Fluorine incorporation for Pd-F:SnO 2 has been found to have a narrowing effect on the band gap, but at its higher concentration the band gap has been seen to increase. The band gap narrowing is due to the incorporation of F -ions in the crystal lattice therefore giving rise to donor levels in the SnO 2 band gap which is an essential characteristic for the gas sensor applications. Both annealing and passivation have been found to have very insignificant change in optical band gap of Pd-F:SnO 2 .

We present a fully variational and strictly rigorous derivation of Hawking radiation within the framework of Vortex Field Theory (Dziabura, 2025). Starting from a microscopic action containing the vortex tensor ω_{μν}, the comoving four–velocity u^μ, and the gauge–invariant phase one–form Ξ_μ, we construct the emergent optical metric algebraically without approximation. By analytic continuation to Euclidean time, we prove that smoothness at the horizon uniquely fixes the imaginary–time periodicity to Δτ = 2π√(1−β)/κ, leading to an exact temperature scale

T_{VFT} = κ / (2π√(1−β)),

where κ is the surface gravity and β is the vortex–induced deformation parameter. We rigorously establish the KMS condition for phase fluctuations by constructing the Friedrichs self–adjoint extension of the fluctuation operator, ensuring that no ensemble hypothesis or series approximation is required. The resulting emission spectrum is Planck–weighted but structurally non–thermal: the greybody functions Γ_{ωℓ} are determined exactly by a horizon–localized Sturm–Liouville problem with boundary conditions fixed by energy finiteness. In the low–frequency regime, we compute the leading flux in terms of a geometric invariant ℒ₀ of the optical potential, showing cubic scaling with T_{VFT} and precise deviations from pure thermality. The undeformed limit β → 0 recovers the standard Hawking temperature T = κ/(2π), while the critical deformation β → 1⁻ yields a novel regime of finite but suppressed emission. These results provide the complete, repeatable, and approximation–free temperature equation for Hawking radiation in Vortex Field Theory.

Mossbauer effect studies of NiFe,O, were carried out in the temperature range from 300 up to 800 K. The analysis of the ME spectra gave the values of Debye temperature, the recoil free fraction, the mean square displacement, and velocity of both sites of the ferrite. An explanation is given for the higher value of the Debye temperature calculated from the infrared spectrum. MoDbauereffektmessungeii an NiFe,O, wurden im Temperaturbereich von 300 bis zu 800 K durchgefuhrt. Die Analyse der ME-Spektren ergab die Werte der Debye-Temperatur, des ruckstol3freien Anteils, der mittleren quadratischen Verschiebung und der Geschwindigkeit an beiden Plstzen des Ferrites. Eine Erklarung fur den hoheren Wert der Debye-Temperatur, die aus dem Infrarotspektrum berechnet wird, wird angegeben.

In this paper, thin films of copper oxide nanoparticles mixed with 2% wt of nickel oxide are deposited on glass and porous silicon (PS) substrates with orientation (111) etched at 30 minutes. The current density was varied from (10 to 50) mA/cm2 with a step of 10 utilizing pulsed laser deposition technique for the manufacture of hydrogen gas sensor. The films are annealed in air at 400 °C for two hours. The PL result of PS shows that the peak position is shifted to the higher wavelength region due to increase etching current. On the other hand, the atomic force microscopy shows an increase in average diameter with increasing etching current (10-30) mA then decrease. Moreover, the FTIR spectra of porous silicon exhibit that the pore surface includes a high density of dangling bonds of Si for original impurities such as hydrogen and fluorine, which are residuals from the electrolyte. Finally the sensitivity of the hydrogen gas sensor are increased with increasing operating temperature.

The deposition of a thin tin oxide film allows for the manufacture of modern gas sensors. Spray pyrolysis deposition is used to grow the required thin films, as it can be seamlessly integrated into a standard CMOS processing sequence. A model for spray pyrolysis deposition is developed and implemented within the Level Set framework. Two models for the topography modification due to spray pyrolysis deposition are presented, with an electric and a pressure atomizing nozzle. The resulting film growth is modeled as a layer by layer deposition of the individual droplets which reach the wafer surface or as a CVDlike process, depending on whether the droplets form a vapor near the interface or if they deposit a film only after surface collision.

Gas sensors are based on metal oxides, which likely will have a considerable impact on future smart phones, are analyzed by means of simulations. The deposition of a thin tin oxide film at the backend of a CMOS process has enabled the manufacture of integrated gas sensors. A spray pyrolysis technique is implemented for the deposition step, resulting in a thin tin oxide layer with good step coverage and uniformity. A simulation approach for spray pyrolysis deposition is presented, along with a discussion of the gas sensor operation. A sample model for H2 detection is suggested, while our research serves as a step to link the simulation of gassensitive material deposition and gas sensor operation.

Integration of thin tin oxide film formation into CMOS technology is a fundamental step to realize sensitive smart gas sensor devices. Spray pyrolysis is a deposition technique which has the potential to fulfil this requirement. A model for spray pyrolysis deposition is developed and implemented within a Level Set framework. Two models for the topography modification due to spray pyrolysis deposition are presented, with an electric and a pressure atomizing nozzle. The resulting film growth is modeled as a layer by layer deposition of the individual droplets which reach the wafer surface or as a CVD-like process, depending on whether the droplets form a vapor near the interface or if they deposit a film only after surface collision.

Preparation of highly conducting and transparent cadmium tin oxide () 4 2SnO Cd thin films by vacuum evaporation technique on glass substrate with thickness of (300, 600)nm is reported. The effect of thickness on structural, optical, and electrical properties of the films was investigated by using different techniques such as X-ray diffraction, atomic force microscopy, optical transmittance, and Hall measurement. The X-ray diffraction (XRD) studies revealed that the films are polycrystalline in nature with cubic structure and there are strong peaks at the direction (311), the intensity of the peaks increases with increasing thickness. The grain size varies between 19.1 and 21.4nm. The surface morphological was investigated by atomic force microscopy (AFM), which revealed the crystalline nature of the films. The optical parameters of the prepared films as transmittance, optical energy gap, refractive index, extinction coefficient, and the dielectric constants were found to be affecte...

Solar cells based on organic dye have been widely used for the reason of their simplicity of manufacture. A simple structure is composed of a colored layer of TiO2, an electrolyte and a counter electrode. In this study, the layers of TiO2, CdS and ZnO were deposited on conductive glass by different methods to replace organic dye. Metal organic chemical vapor deposition (MOCVD) method was used to prepare the TiO2 layer, chemical bath deposition (CBD) to prepare the CdS layer, and spray pyrolysis (SP) for the preparation of the ZnO layer. Morphological and structural studies have shown a homogeneous morphology of the superposition of TiO2/CdS/ZnO layers. XRD and SEM characterizations have shown that annealing of the CdS layer must be done under a controlled atmosphere in order to avoid the formation of cadmium oxide and to control the particle size. The aim of this work is the substitution of organic dye in the Grätzel cell by CdS(n)/ZnO(n + ) junction. Morphological and optical properties of TiO2/CdS/ZnO in addition to photovoltaic performance of this structure junction were investigated with different deposition times of the CdS layer. It is found that the nature of the substrate has no influence on the realization of the junction. It is noticed that each layer added leads to a decrease in the transmittance of the substrate. Characterization of the photovoltaic properties of cells based on the CdS/ZnO junction shows a higher yield compared to conventional cells based on organic dye. It is also recommended to undertake annealing under a controlled atmosphere such as nitrogen in order to eliminate the CdO secondary phase and decrease the size of the grains which may enhance the efficiency of the solar cells.

Metal oxide semiconductors are one of the most promising materials for photoelectrochemical production of hydrogen on account of a) easy availability, b) low cost, c) simple preparation methods and d) stability. The samples of undoped and (Cr/Fe) doped CuO were prepared using spraypyrolysis technique. XRD analysis r evealed the exclusive formation of CuO phase. Good adherence of films with substrate was confirmed by scotch tape method. The SEM analysis confirmed the granular surface of the film. Scherrer's calculation indicated the average grain size of the order of ~87 nm. Film samples were then converted into photoelectrodes by generating ohmic contact and photoelectrochemical behaviour was studied at pH 11 and 13 in NaOH. Enhanced photocurrent generation was observed in the sintered samples and also with the increase of electrolyte pH from 11 to 13, irrespective of nature and amount of dopant. However the variation in dopant concentration revealed a variable trend in the photocurrent generation.

The photoelectrochcmical properties o f copper oxide thiii film (p4ypc) on the SnO, F coated glass (conducting glass) picparcd by spray pyrolysis has been investigated as a (unction dopant and pH o( electrolyic ?<-iay difliactogiain pattern o( thin films confirm the cuprit oxide f('uO) phase. Mn-doped sam ples exhibited decreased photoelectrochcm ical lespDnse as compared to undoped CuO The onset o f photocurieni m uiulopcd CuO IS at ~I20 mV. while in Mn doped ( 'uO film s it is -3 7 5 mV The observed icvcisc effect o f Mn-doping tin the photoclcetrochermeal response of the films, ean he attiibuted to the possible neutralization of naturally oceunm g majority charge earners (holes) present m undoped coppci oMiIc with the extra eleelrons furnished by the dopant Mn atoms, particulaily. fiom then d orbitals Bcttei photoresponse has been obseived at pH 13 Keyword.s Fhotoelectiochcm ieal pioperiies, cupric oxide, conducting glass, spray pyiolysis PA(^S N os. 8115 Rs, 82 45.M p,

Synthesis of advanced ceramic materials with improved microstructure, finding widespread applications as photocatalysts, is a challenge before the chemists. This communication describes a wet chemical method based upon sol-gel technique, which is simple, fast and can be effectively used ...

Thin films of ZnO, ZnO:Cu, ZnO:N and ZnO:(Cu,N) have been deposited on glass substrate at temperature 350ºC by low cost spray pyrolysis (SP) technique at an ambient atmosphere. The X-ray diffraction (XRD) study revealed that the films are of mono-phasic polycrystalline in nature having wurtzite ZnO crystal structure. The preferential orientation of un-doped ZnO films is in the (002) plane which changes to (101) for N and Cu mono-doped and (Cu, N) co-doped ZnO films. Surface morphology studied by scanning electron microscopy (SEM) clearly shows the formation of rock shaped nanostructures and hexagonal crystalline grains. The atomic force microscopy (AFM) study revealed the formation of crystalline grains perpendicular to the surface and reduction of surface roughness with doping. The photoluminescence (PL) spectra of the un-doped and doped ZnO samples show well defined transitions of the near band edge (NBE) and deep level (DLE) emissions emerged from different defect states present ...

Perovskite oxides are receiving wide interest for photocatalytic and photoelectrochemical devices, owing to their suitable band gaps for solar light absorption and stability in aqueous applications. Herein, we assess the activity of PrFeO3 photocathodes prepared by using spray pyrolysis and calcination temperatures between 500 and 700 °C. Scanning electron microscopy shows corrugated films of high surface coverage on the conductive glass substrate. The electrochemically active surface area shows slight decreases with temperature increases from 500 to 600 and 700 °C. However, transient photocurrent responses and impedance spectroscopy data showed that films calcined at higher temperatures reduced the probabilities of recombination due to trap states, resulting in faster rates of charge extraction. In this trade‐off, a calcination temperature of 600 °C provided a maximum photocurrent of ‐130±4 μA cm−2 at +0.43 VRHE under simulated sunlight, with an incident photon‐to‐current conversio...

Cr-doped titanite (CaTiSiO 5 ) pigments were synthesized through spray pyrolysis of aerosols generated from aqueous solutions containing colloidal silica, calcium chloride, titanium(IV) oxychloride and chromium(III) nitrate. This process yielded amorphous powders with spherical morphology and broad size distribution (<10 mm) after thermal decomposition at 600 C. The titanite phase was obtained by further calcination at 800 C without any addition of flux agents. The brown color of the pigments can be attributed mainly to the existence of Cr(IV) ions occupying both, octahedral positions of Ti(IV) and tetrahedral position of Si(IV), together with a small amount of Cr(III) present as Cr 2 O 3 . The optimum pigment obtained by this method corresponded to a Cr/titanite mole ratio of 0.04.

For the first time copper gallium sulphide (CuGaS2) films were prepared using the brush plating method at various electrolyte temperatures between 30 and 80 degrees Celsius with a steady current density of 5.0mA cm-2 CuGaS2 photo electrodes that were coated at 80 degrees Celsius and then post-heated at various temperatures with Intensity-60 mW cm-2. CuGaS2 film electrode that was coated at a temperature of 80 degrees Celsius and post-heated at 525°C lead to variation in photocurrent with wavelength. CuGaS2 films coated at temperatures ranging from 30°C to 80°C displays photocurrent-characteristic curve. CuGaS2 photo electrode Mott Schottky graph with electrolyte temperature of 80°C and post-heat processing of 525°C.

Different thin films samples made of SnO 2 , F:SnO 2 , Pd: SnO 2 and and co-doped Pd-F: SnO 2 were deposited at a substrate temperature of 450 o C using optimized doping concentrations of F and Pd, thereafter the samples were annealed and passivated in a tube furnace at 450 o C. Optical and electrical methods were used in characterizing the thin film samples: The band gap energy for all samples was extracted from optical data using a proprietary software, Scout™ 98. The calculated band gap energy were found to be 4.1135eV for Pd:SnO 2 and 3.8014eV for F:SnO 2 being the highest and the lowest calculated band gap energies, respectively. The wide band gap energy has been attributed to the incorporation of Pd ions in crystal lattice of SnO 2 thin film for Pd:SnO 2 while for F:SnO 2 has been due to incorporation of F -ions in the crystal lattice of SnO 2 which gives rise to donor levels in the SnO 2 band gap. This causes the conduction band to lengthen resulting to a reduction in the band gap energy value. The electrical resistivity was done by measuring the sheet resistance of the SnO 2 , Pd:SnO 2 , F:SnO 2 and Pd-F:SnO 2 thin films. The undoped SnO 2 thin film had the highest sheet resistivity of 0.5992 Ωcm while F:SnO 2 had the lowest sheet resistivity of 0.0075 Ωcm. The low resistivity of F:SnO 2 results from substitution incorporation of F -ions in the crystal lattice of SnO 2 thin films, instead of O -ions which lead to an increase in free carrier concentration. The Pd-F:SnO 2 gas sensor device was tested for CO 2 gas sensing ability using a lab assembled gas sensing unit. The performance of the gas sensor device was observed that: the as prepared device was more sensitive to CO 2 gas than those subjected to annealing and passivation. The decrease in the sensitivity of the annealed Pd-F: SnO 2 gas sensor is attributed to decrease in grain boundary potential resulting from grain growth. This causes a decrement in adsorption properties of CO -and O -species by the annealed Pd-F: SnO 2 thin film. The sensitivity of passivated Pd-F: SnO 2 gas sensor was found to be the lowest. The low sensitivity is due to the effects of nitration and decrement in grain boundary potential resulting from grain growth, nevertheless, the sensitivity of the passivated Pd-F: SnO 2 thin film was found to be within the range for gas sensing applications.

In this report, we have prepared undoped and Mg-doped ZnO thin films by a modified successive ionic layer adsorption and reaction (SILAR) method. The structural, surface morphological, chemical compositional, and optical properties of pure and Mg-doped ZnO thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible (UV-VIS) spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy. The XRD patterns of undoped and doped films have wurtzite crystal structures with preferential orientation along the (101) plane, without any secondary phases. Addition of Mg into host ZnO influenced surface morphology of the film. Predominant nanorods-like surface morphology of undoped ZnO turned to be predominant nanoflowers-like surface morphology after addition of Mg. UV-VIS spectra showed that the energy band gap of films increased with increase Mg doping concentration. EDS and FT-IR spectroscopy confirmed the successful Mg doping. Gas sensing properties of the undoped and Mg-doped ZnO thin films were tested based on the electrical resistance changes upon exposure to different concentrations of a NO2 gas at 200°C operating temperature. Mg-doped ZnO (3 wt%) showed higher response compared to other wt% and exhibited the highest responses of 2.95, 9.51, and 9.93 when exposed to 25, 50, and 100 ppm concentrations of the NO 2 gas at 200°C, respectively. The response/recovery time of the Mg-doped ZnO thin film were 6/75, 14/88, and 14/89 s at 25, 50, and 100 ppm, respectively.

The single cells were characterized with respect to performance and long term behavior (&gt; 1000 h) including load and thermal cycling. As can be seen in Fig. 3, current densities of 0.18 A/cm (750°C), 0.43 A/cm (850°C) and 0.7 A/cm (950°C) were realized at a cell voltage of 0.7 V. The long term stability and thermocycling behavior was acceptable for mono-layer cathodes, performance and degradation were in good agreement with the standard type cathode compositions and microstructures. 0.05 0.1 0.2 0.5 1 2 5 10 20 50 100 200 50

The main objectives of H. C. Starck's internal development program for powders used in SOFC applications are to meet the cost targets of the customers as well as the performance requirements during cell operation. Optimization of LSM-powder engineering process resulted in very homogenous powders with good crystallographic properties. The morphological properties can be adapted to customer requirements, the primary particle size can be varied in the range of few micrometers down to submicron powders. Electrochemical performance tests of electrolyte supported single cells with cathodes based on these LSM-powders were conducted at the IWE, Universität Karlsruhe (TH). The single cells were characterized with respect to performance and long term behavior (> 1000 h) including load and thermal cycling. Current densities of 0.18 A/cm2 (750°C), 0.43 A/cm2 (85O°C) and 0.7 A/cm2 (950°C) were achieved at a cell voltage of 0.7 V. The long term stability and thermal cycling behavior was acceptable for mono-layer cathodes; and performance and degradation were in good agreement with the standard type cathode compositions and microstructure.

Abstract- Crystallites of ZnO and Zn0.99Co0.01O have been grown on glass substrate by wet chemical decomposition of zinc/cobalt-amino complexes in aqueous medium. Structural properties of grown crystallites were investigated by the help of X-ray Diffractometer, Scanning Electron Microscope and Energy Dispersive X-ray spectroscope. Keywords- Doped ZnO; Different morphologies

Semiconductors are solids with crystalline structures. In solids, electron orbitals overlap and creating energy bands due to atomic bonds / overlap. In the solid state, electrons do not remain permanently bound to an atom; they constantly shuttle back and forth between surrounding atoms, as if to maintain the bond/relationship.

Structural studies on In 2 S 3 thin films deposited by vacuum thermal evaporation on glass substrates at a temperature of 240 o C, followed by annealing at 330°C and 400°C are presented. It was shown that the films were of amorphous in nature before annealing and after annealing the films became polycrystalline and showed β-In 2 S 3 structure. The grain size increased and followed the usual crystal growth process as the annealing temperature increased. The annealing-induced changes of surface roughness were characterized by atomic force microscopy. In 2 S 3 naniesionych metodą termicznego osadzenia na szkło w próżni w temperaturach od 240 o C i kolejnym wygrzewaniem w temperaturach 330 o C i 400 o C. Ustalono że warstwy miały amorficzną naturę przed wygrzewaniem, po wygrzewaniu wykazywały strukturę polikrystaliczną typu β-In 2 S 3 . Rozmiar ziaren powiększał się na skutek aktywnej nuklearyzacji i to przyczyniało się do zwykłej krystalizacji ze wzrostem temperatury. Zmiany zostały przeanalizowane za pomocą AFM. (Wpływ obróbki temperaturowej na termicznie naparowane cienkie warstwy In 2 S 3 ).

In this work, we have carried out a comparative research of the nanoscale modification of the surface morphology of polycrystalline SnS films on glass substrates with two different preferred growth orientations during sputtering in inductively coupled argon plasma. We report a new effect of polycrystalline SnS film surface smoothing during plasma treatment, which can be advantageous for the fabrication of multilayer solar cell devices with SnS absorption layers.

Films of pure tin oxide SnO2 and in presence of antimony atoms (SnO2-Sb) deposited onto glass substrates have shown a sufficiently high energy gap to be transparent in the visible region, a high electrical mobility and a carrier concentration which displays a good electrical conductivity [1]. In this work, the effects of polycrystalline silicon substrate on the optical properties of pure and Sb doped tin oxide is investigated. We used the APCVD (atmospheric pressure chemical vapour deposition) technique, which is a low-cost and simple technique, under nitrogen ambient, for growing this material. A series of SnO2 and SnO2-Sb have been deposited onto polycrystalline silicon substrates with different contents of antimony atoms at the same conditions of deposition (substrate temperature, flow oxygen, duration and nitrogen atmosphere of the reactor). The effect of the substrate in terms of morphology and nonlinear optical properties, mainly the reflectance, was studied. The reflectance i...

The flame spray pyrolysis (FSP) synthesis of silica particles from two different precursors, tetraethylorthosilicate (TEOS) and silicic acid which have significantly different volatilities, was investigated. The size and morphology of the particles produced using various concentrations of precursors and flame temperatures were examined. Significantly different volatilities of the precursors affected the particle formation mechanism. Two different particle formation mechanisms, vapor phase reaction (VPR) and intradroplet reaction (IDR), are proposed based on the relative time scale for the evaporation of sprayed precursor droplets and for particle formation at the same process conditions. VPR resulted in silica agglomerates with small primary particles of around 10 nm sizes. IDR resulted in isolated and spherical silica particles with the sizes of around 650 nm from silicic acid.

ZnO lms were deposited on glass substrates by ultrasonic spray pyrolysis technique at a substrate temperature of 300 ± 5 • C. All of the lms have been annealed at 500 • C temperature for dierent time (1, 2, and 3 h) to improve the optical, electrical and surface properties. The eect of annealing time on the lms of physical properties has been investigated. UV-Vis spectrophotometer has been used for transmittance measurements. Also, band gap values of the lms have been determined by optical method. Atomic force microscopy has been used to have information the surface morphology and roughness values of the lms. Thicknesses, refractive index and extinction coecient values of the lms have been determined by spectroscopic ellipsometry technique. The electrical conduction mechanisms and resistivity of the lms were investigated using two probe technique. After all the investigations it was concluded that annealing time has a dramatic eect especially on the surface, optical properties and electrical resistivity values of ZnO lms. From the results of these investigations, the application potential of the lms for solar cell devices as transparent electrode was searched.

The structural and room temperature luminescent characteristics of rare earth doped yttrium-aluminum oxide films deposited by the spray pyrolysis technique at low temperatures have been studied as a function of the deposition parameters such as substrate temperature and dopant concentration. The spraying solution is prepared by mixing yttrium and aluminum chlorides in water, and the incorporation of the rare earth dopants is achieved by adding chloride salts of these elements to this solution. The photoluminescent emission from Tb-and Eu-doped films have the spectral characteristics typical of radiative transitions among the electronic energy levels associated with the 3+ ionized states of these atoms. The Ce doped films, on the other hand, present a blue emission that is associated with transitions within the energy states of the CeCl 3 molecule used for the doping process of the film. The X-ray diffraction measurements of these films indicated poor crystallinity in general, with small crystalline peaks and a broad amorphous component that tend to be reduced as the deposition temperature is increased.

Nanostructured copper oxide (CuO) thin films have been synthesized onto the glass substrates from aqueous solutions of copper (II) acetate monohydrate precursor salt by a cost effective spray pyrolysis technique at various substrate temperatures between 473 and 673 K. The effects of varying substrate temperature on the structure, surface morphology, optical and electrical properties of the synthesized CuO thin films were studied. Scanning Electron Microscopic (SEM) images revealed agglomerated nanoparticles on the surface of CuO thin films. X-Ray Diffraction (XRD) analysis revealed monoclinic structure with the predominant (̅ 111) orientation of the synthesized films. Crystallite size increased (9.15 to 10.29 nm) with the increase of substrate temperature. In UV-vis-NIR spectroscopy, CuO thin films showed higher transparency in the NIR region. An optical band gap of CuO thin film was found in the range of 2.04-2.49 eV. Transmittance and band gap decreased with the increase of substrate temperature up to 573 K and found to increase at 673 K. On the other hand, extinction coefficient and refractive index increased with the increase of substrate temperature up to 573 K and decreased afterwards. Electrical resistivity of CuO thin films was found in the range 1.16 ×10 3-4.61 ×10 3 Ω-m and decreased with the increment of the substrate temperature up to 573 K. Activation energies of CuO thin film were found in the range 0.08-0.57 eV. Hence, we report the influence of substrate temperature for the synthesis of nanostructured CuO thin films, best fit for optoelectronic applications.

Undoped and manganese (Mn)-doped zinc oxide (ZnO) thin films have been deposited onto glass substrates at 300 • C using a low cost spray pyrolysis technique. Structural, optical and electrical properties of the as-deposited films have been investigated. Scanning electron microscopy images show the existence of clusters with well-defined nucleation centers consisting of highly dense ganglia-like fibers over a large area around the nucleation center. Chemical compositions of the ZnO and Mn-doped ZnO thin films are studied by using energy dispersive X-ray (EDX) analysis. X-ray diffraction spectra depict that the films have polycrystalline wurtzite structure. The average crystallite sizes are calculated in the range of 8-16 nm by Williamson-Hall method and found in good agreement with Scherer method. Optical transmittance of the films is about 80% in the visible region. Bandgap energy is tuned to 2.83 eV from 3.10 eV with increasing Mn doping. Electrical resistivity at room-temperature decreases significantly with increasing Mn doping as well as increasing temperature from 300-440 K. The activation energies in the temperature ranges 300-350 K and 350-440 K are found to be in the range of 0.25-0.16 eV and 0.35-0.59 eV, respectively. Hall Effect measurements show that the thin films have negative Hall coefficient indicating n-type conductivity at room-temperature. Carrier concentration is found to be of the order of 10 18 cm-3 .

Pure and magnesium (Mg) doped zinc oxide (ZnO) thin films were prepared onto clean glass substrate by spray pyrolysis (SP) technique at the substrate temperature of 300°C. Various optical parameters such as absorption co-efficient, band gap energy, refractive index, extinction coefficient of the thin films were studied using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300-2500 nm. Optical band gap increased from 3.24 to 3.46 eV with the increase of Mg concentration from 0 to 40%. Transmittance and refractive index of the Mg doped ZnO thin films decreased due to the increase of Mg concentration. The EDX spectra confirmed the increase of Mg and consequent reduction in Zn content in the Mg doped ZnO thin films. Pure and Mg- doped ZnO films were annealed at 425°C for 1 hour. X-ray diffraction (XRD) study of the annealed films showed hexagonal type of polycry-stalline structure with the preferred orientation along (101) plane with some other peaks (100), (002), (102), ...

High-energy spectroscopy has been used to study the electronic structure and valence state of new ternary intermetallic CeM2P2 (M=Fe, Co, Ni) compounds which crystallize in the ThCr2Si2 types. The calculations of electron energy bands E(k) and partial DOS for compounds were performed by the semi- relativistic linear muffin-tin orbital method without considerations of spin-orbit interactions. Effective filling numbers of electrons in different bands of components in CeM2P2 (M=Fe, Co, Ni) compounds have been calculated. Analysis of the results of calculations showed that the degree of occupation of spd-valence orbital of components varies and differs considerably from of external electrons in isolated atoms. The occupancy of d-orbital of M in the CeM2P2 compounds was shown to be significantly larger than in an isolated state. The electron configuration of P in compounds can be described as s1.4p2.8. LIII – absorption spectra Ce in the ternary CeM2P2 (M=Fe, Co, Ni) compounds were obtai...

The valence band electronic structure of compounds with the HfFe2S2 crystal lattice type has been established for the first time based on X-ray emission spectroscopy measurements. Band structure and theoretical spectra of X-ray emission bands of atoms located in non-equivalent crystallographic positions are calculated by means of the LMTO method. A satisfactory agreement between theoretical and experimental data is achieved. As it can be seen from the performed calculations and experimental data, the s-states of Si hybridize with the p-states Sc (Hf) and Fe and are located at the bottom of valence band. Contribution of the s-symmetry electrons to the chemical bond is substantially different for Si atoms located in non-equivalent crystallographic positions. 57Fe Mossbauer absorption measurements confirm iron atoms occupying non-equivalent positions in the crystal lattice

Very simple and low-cost raw material was used to prepare Al2O3 nano-thin films Only Al(No3)3-9H2O and 2-methoxy ethanol were used to prepare the required thin films employing spray pyrolysis method at low substrate temperature. The FTIR results ensure the formation of the Al-O bond which appears at different absorption peaks. Effect of substrate temperatures reveals the dependence of Al-O bond formation on the variation of substrate temperatures from 200 up to 400oC. This was confirmed by the x-ray diffraction results which ensure the formation of the Al2O3 amorphous structure. SEM results insure the formation of nanostructure Al2O3 thin films.

Titanium dioxide (TiO2) nanoparticles containing iron, silicon, and vanadium are synthesized using multiple diffusion flames. The growth of carbon-coated (C-TiO2), carbon-coated with iron oxide (Fe/C-TiO2), silica-coated (Si-TiO2) and vanadiumdoped (V-TiO2) TiO2 nanoparticles are demonstrated using a single-step process. Hydrogen, oxygen, and argon are utilized to establish the flames, with titanium tetraisopropoxide (TTIP) as the precursor for TiO¬2. For the growth of Fe/C-TiO2 nanoparticles, TTIP is mixed with xylene and ferrocene. While for the growth of Si-TiO2 and V-TiO2, TTIP is mixed with hexamethyldisiloxane (HMDSO) and vanadium (V) oxytriisopropoxide, respectively. The synthesized nanoparticles are characterized using high-resolution transmission electron microscopy (HRTEM) with energy filtered TEM for elemental mapping (of Si, C, O, and Ti), x-ray diffraction (XRD), Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), nitrogen adsorption BET surface area analysis, and thermogravimetric analysis. Anatase is the dominant phase for the C-TiO2, Fe/C-TiO2, and Si-TiO2 nanoparticles, whereas rutile is the dominant phase for the V-TiO2 nanoparticles. For C-TiO2 and Fe/C-TiO2, the nanoparticles are coated with about 3-5 nm thickness of carbon. The iron based TiO2 nanoparticles significantly improve the catalytic oxidation of carbon, where complete oxidation of carbon occurs at a temperature of 470oC (with iron) compared to 610oC (without iron). With regards to Si-TiO2 nanoparticles, a uniform coating of 3 to 8 nm of silicon dioxide is observed around the TiO2 particles. This coating mainly occurs due to variance in the chemical reaction rates of the precursors. Finally, with regards to V-TiO2, vanadium is doped within the TiO2 nanoparticles as visualized by HRTEM and XPS further confirms the formation of V4+ and V5+ oxidation states.

In this work we present some results of a systematical study of structural and optoelectronic properties of Zn O:In thin films obtained by spray pyrolysis when the acidity and the solvent used in starting solution were varied. Structure of our samples was derived from X ray diffraction and conventional electron microscopy observations.

The results of a systematic study of the electrical. optical. structural and surface properties ofthin ZnO:ln films are presented. The films were deposited by the spray pyrolysis technique. The spraying solution was zinc acetate diluted in methanol and the indium doping was achieved by adding indium acetate, indium nitrate and indium sulfate atdifferent concentrations up to [In]1 [Zn] <:: 3 at%. The films grown atlow temperature show regular and unifonnly smooth surfaces with no texturizatlon, Films grown athigh temperature show rough surfaces. All the films are polycrystalllne and grow with a (101) preferred orientation. The electrical resistivity measured at room temperature shows a minima in all cases "as a function of the substrate temperature. The lowest value. p=2X 10-) nem, was obtained bydoping with indium acetate at 11 [InJ/fZn] ""3 at% concentration. For films about 0.6 p.m thick the average transmiUance was better than 85%. A shift in (he energy gap due to a variation in the carrier concentration was observed. This shift is explained with a model in which the Burstein-Moss effect and the electron-electron exchange interaclion are considered.

Gallium, aluminum, and indium-doped ZnO (ZnO:Ga, ZnO:Al, and ZnO:In) films have been deposited by the chemical spray method on sodocalcic substrates. The effect of different dopant elements, a post-annealing treatment in vacuum, and the film thickness on the electrical, optical, structural, and morphological properties of the films has been investigated. The best electrical properties were observed in the thickest indium-doped ZnO films; the lowest electrical resistivity was of the order of 10 À3 O cm. In general, the optical transmittance value in the visible spectrum oscillated around of 87% in the thinnest films. The structural and morphological properties of ZnO:Ga and ZnO:Al films are similar, as in both cases the (0 0 2) orientation is dominant on the rest of the peaks, and both surfaces have a rough appearance. In the case of ZnO:In films, the (1 0 1) was the preferential growth orientation, and the surfaces seem to be smoother than the corresponding ZnO:Ga and ZnO:Al films.

Indium doped zinc oxide (ZnO:In) thin solid films were deposited on soda-lime glass substrates by the ultrasonic spray pyrolysis technique. The effect of the substrate temperature on the electrical, morphology, and optical characteristics of ZnO:In thin films was studied. It was found that, as the substrate temperature increases, the electrical resistivity decreases, reaching a minimum value in the order of 7.3 Â 10 À 3 O cm, at 415 1C. Further increase in the substrate temperature results on an increment on the electrical resistivity of the thin solid films. All the samples were polycrystalline with a welldefined wurtzite structure. The preferred growth shows a switching from a random orientation at low substrates temperatures to (0 0 2) in the case of films deposited at the highest substrate temperature used. As the substrate temperature increases, the corresponding surface morphology changes from an almost faceted pyramidal to round-shaped form. The optical transmittance of the films in a interval of 400 to 700 nm is around 70%, with a band gap value in the order of 3.45 eV.

PEDOT/PMVP coated pores inside a track-etch membrane can occur not withstanding the fact that the active site of the enzyme is hidden deeply inside the insulating protein shell. Further research is ongoing to elucidate this intriguing phenomenon and evaluate its potential for biosensor applications. Synthesis of the PEDOT and PMVP/PEDOT-Coated Track-Etch Membranes: A nucleopore track-etch membrane (diameter = 36 mm, pore size = 0.8 lm) was placed in a stirred solution of 3.5 g (21.5 mmol) ferric chloride in 12 mL of an acetonitrile/water solution (5:1 v/v). Subsequently, 350 mg (2.46 mmol) EDOT dissolved in 0.5 mL of acetonitrile was added at room temperature. After the appropriate time, the track-etch membrane was rinsed with water and the PEDOT on the surface of the membrane was removed by carefully wiping with a tissue. PMVP was added to the ferric chloride solution for the synthesis of the PMVP/PEDOT membranes. Immobilization of GOx: Typically, a track-etch membrane was mounted in an Amicon cell and 10 mL of a glucose oxidase solution (5 mg/mL) with or without DEAE (10 mg/mL) in aqueous PBS (0.1 M, pH 7.4) was placed in the cell and stirred for at least 30 min at a temperature of 4 C. Subsequently, the membrane was dried overnight over CaCl 2 in a desiccator at 4 C. The sensors were stored in PBS (pH 7.4) at 4 C. Amperometric Biosensor Measurements: To perform amperometric measurements, the glucose sensors were placed in a flow cell in an aqueous PBS buffer (pH 7.4) and connected to a potentiostat. The potential was set to the desired value. After the background current had diminished sufficiently to a stable value, glucose was added to the buffer solution and the resulting current was monitored.

Pure and doping with Zn material on CeO 2 films were formed on the substrate at 250 °C and further it was annealing at 350 °C in the atmosphere for 2 h using spray pyrolysis technique. Noticeable variation in the crystallite size, porosity, band gap and room temperature sensing response was observed due to Zndoping. The sensing studies namely response of resistivity, sensitivity and response-recovery characteristics of both films were compared at 32 °C. The appreciable sensing response was observed for doping with Zn ions into CeO 2 film in formaldehyde at a lower detection (0.5 ppm) at 32 °C.

Effect of annealing temperature on the properties of CdS thin films are carried out in this work. Nanocrystalline cadmium sulphide (CdS) thin films were prepared using spray pyrolysis deposition (SPD) technique and the structural, optical and electrical properties were investigated for different annealing temperature (as deposited, 300, 400 & 500 C). The surface morphology and compositional properties studied by SEM and EDX respectively. The crystal structure of CdS thin film was studied by X-ray diffraction. The crystallite size and lattice constant of SPD CdS thin films were investigated. The optical parameters such as transmittance, absorption coefficient and energy band gap of the films with thermal annealing temperature was investigated by UV/VIS spectrophotometer. The variation of band gap values of CdS thin film samples were found to be in the range of 2.51 to 2.8 eV. Electrical resistivity measurements were carried out in fourprobe Vander Pauw method at different temperature. So CdS films may be a good candidate for suitable application in various optoelectronic devices.

Abstract: An asymmetrical factorial experiment approach was used for improved gas/odor discrimination using thick film gas sensor data. The results revealed that the gases/odors(G), sensors(S), concentrations of gases(C), and interactions between GXS were found to be significant at 1 % level of significance while the interaction between GXC was significant at 5 % level. It indicated that the gas/odor, Methanol (CH3OH) and Acetone (CH3COCH3) were at par while Propanol (C3H7OH) was different at 1 % level of significance. Among the sensors S2 and S4 were at par while S1 and S3 differed significantly at 1 % level. The initial concentrations differed significantly while they did not differ at the later stages. Among the interaction of GXS, the sensor S1 and S4 were at par under Methanol, S2 and S3 were at par under Propanol and S2 and S4 were at par under Acetone respectively.

The focus of this study was to develop a method to demonstrate the feasibility of obtaining useful and high-value resources from Phoenix dactylifera residues and, to determine the physical and chemical properties of the ash of dates-palm-tree remains. Date-palm leaves and fiber samples were combusted for 50 s, using an Nd: YAG laser with 40 W output power. It was found, that combustion of one gram of agricultural waste could be completed in 50 s and 40 W by laser while 10 g required 1.5-10 min and 300-800 W power by microwave and at least 2 h with 1500 W power for conventional heating for 10 g. The subjects of this treatment, the leaves and fiber samples, before and after combustion were investigated by X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR). The XRD results of the palm-fiber after combustion reveal that the samples were crystallized with a rhombohedral phase of acetamide and hatrurite, orthorhombic finite, and Ca 4 Si 2 O 6 (CO 3)(OH) 2 , and a monoclinic phase of ikaite properties. The XRD patterns of palm-leaf after combustion reveal that the samples were crystallized with orthorhombic hillebrandite, rhombohedral acetamide, and the monoclinic phase of each karpatite, morganite, and howlite. Finally, the FTIR exhibited several absorbance peaks, assigned to silica.

The effect of 170 MeV Au 13þ irradiation on photoelectrochemical (PEC) and structural properties of CuO thin films has been investigated. The X-ray diffractograms of post-irradiated CuO thin films showed diffused nature towards higher theta value with the appearance of crystalline peaks, indicative of some randomization taking place at higher fluence, i.e. 10 13 ions cm À2 . While, upon irradiation, the size of particles/grains decreased, the band gap energy also marginally shifted. ERDA analysis indicated no change in stoichiometry of thin films even at higher fluence. The observed decrease in photoelectrochemical response, upon irradiation, has been attributed to the creation of greater number of kink sites/dislocations, which seemingly act as recombination centers for photogenerated charge carriers.