The semiconductor's realization is a very significant stage of optoelectronics devices. In this work, an elaboration of the TiO2 semiconductor is made with various solution flow rates via spray ...pyrolysis. The structural and optical properties of pure TiO2 are investigated with several characterization techniques which include: X‐ray diffraction (XRD), Raman spectroscopy, and UV–vis spectrophotometry. The XRD of elaborated TiO2 layers exhibits nanocrystalline nature with a preferential orientation at the (101), a unique phase of anatase TiO2. The apparition of vibration modes in Raman spectra confirms the TiO2 formation with a single phase. The produced TiO2 has an optical transmission varying from 90% to 70% in the visible wavelength. The energy band gaps are 3.42, 3.32, and 3.28 eV for the TiO2 elaborated at 1, 1.5, and 2 mL min−1, respectively which prove the semiconducting properties of TiO2. All other optical parameters such as refractive index (n), extinction coefficient (k), and dielectric constant (εr, εi) vary with the variation of solution flow rate. These investigations discover that the properties of TiO2 layers can be adjusted by solution flow rate. It seems that the process of spray pyrolysis provides a facile way to control the quality of TiO2 thin layers.
TiO2 crystal with anatase phase is successfully prepared from titanium (IV) propoxide in a mixture of ethanol and water. The elaboration is controlled by a low‐cost spray pyrolysis technique. The impact of solution flow rate is investigated on the structural and optical properties of TiO2 thin layers. The average transmittances of the samples are near 90%.
In this present work, we applied Taguchi’s plan of experimentation as a numerical tool to develop a TiO2 gas sensor. This plan permits us to reduce the number of experimentations and obtain the ...optimal conditions of factors involved in the development of the sensitive layer. The focal concept is to optimize the TiO
2
thin film conductivity by using an L9 (3
3
) orthogonal array based on three important factors of spray pyrolysis deposition (A, concentration of Ti
4+
; B, deposition temperature; and C, spray pyrolysis time). These factors are varied to select the best deposition conditions and to obtain the best conductivity of TiO2 thin films. From the calculation of signal-to-nose ratio (S/N) and the analysis of variance (ANOVA) based on the conductivity values of thin films, the optimal combination of factors is A
2
B
3
C
3
, which corresponds to the concentration Ti
4+
= 0.3 kmol/m
3
, the deposition temperature T = 500°C and the spray time = 15 min. The validation test confirmed that this combination of deposition parameters is the most optimal to improve the most important TiO2 thin film properties. X-ray diffraction shows a high privileged direction along the (101) plane, large crystallite size of 21.43 nm and low dislocation density of 2.17 × 10
−3
nm
−2
. The Raman modes located at 143 cm
−1
, 391 cm
−1
, 512 cm
−1
and 633 cm
−1
confirmed the purity of anatase TiO
2
. The images of scanning electron microscopy showed the growth of compact and granular film with an average of grain size of 66.76 nm. The optical analysis showed a transparent semiconductor with large band gap of 3.33 eV. The electrical measurement displayed a good conductivity of TiO
2
equal to 280.06 × 10
−6
(S m
−1
). These outcome properties make TiO
2
thin film an attractive material for gas sensor applications.
The semiconductor realization is a very significant stage in gas sensor application. Herein, the Mn3O4 semiconductor was deposited using chemical spray pyrolysis. The effect of deposition temperature ...on structural, vibrational optical and electrical Mn3O4 thin layers properties were investigated through: X‐ray diffraction, Raman spectroscopy, UV‐visible spectrophotometer, and two points electrometers respectively. The X‐ray diffraction showed the appearance of spinel phase of tetragonal Mn3O4 with strong formation direction along (101) plan and without any secondary phase indicating the formation of pure Mn3O4. The Raman spectroscopy confirmed the results obtained in XRD and certified the high‐quality formation of Mn3O4. In addition, the crystallinity improvement (the increase of crystallite size and the decrease of dislocation density) was caused by the increasing of deposition temperature from 350 °C to 450 °C. Optical properties such as transmittance, absorbance and band gap energy were extracted by UV‐Visible spectrophotometer. Thus, low transmittance, high absorbance and small band gap energy were observed at the highest substrate temperature (450 °C). The electrical conductivity showed good values between 4.83 and 13.89 mS.cm−1. These properties make Mn3O4 an appropriate material to be used as a sensitive layer in gas sensors applications.
Herein, Mn3O4 thin layer is successfully prepared by chemical spray pyrolysis technique. The impact of deposition temperature has been investigated on structural, optical, and electrical properties of Mn3O4 thin layers. The obtained results display a significant superiority in crystallinity with a high crystallite size, low dislocation density, and optical properties of low transmission and high absorption than other literature results.
In this study, the effect of controlled conditions on the optical properties of tin monosulfide (SnS) thin films was successfully investigated by the chemistry spray pyrolysis deposition method on ...glass substrates. The Taguchi model is reported to find the most important factor for the deposition process of SnS thin films with orthogonal L9 (34) alignment. We also derive the band gap energy from transmittance data used to determine S/N relation. The selected influencing parameters are: tin-Sn- and sulfide-S concentrations, deposition substrate temperature (°C) Td and deposition time (min). The results show that the deposited film has a uniform, pure orthorhombic SnS phase and smooth morphology. Energy dispersive X-ray spectroscopy (EDS) utilizes the chemical composition of the prepared layers. In addition, the UV–Vis transmittance spectrum of the obtained film via the optimum conditions showed low transmittance in the visible region. Also, the SnS thin film shows the best gap interstitial energy of 1.52 eV. However, the SnS thin films produced by optimizing the Taguchi model display good optical properties and suggest that SnS thin films may be one of the potential solar cell absorbers in photovoltaic devices.
•Effect of controlled conditions on the optical properties of Tin monosulfide (SnS) thin films was successfully investigated by the chemistry spray pyrolysis deposition method on glass substrates.•Optimization of the preparation conditions based on Taguchi design to elaborate The SnS thin films via the low-cost spray pyrolysis technique.•Elaboration via the optimal conditions and study of structural, morphology and optical properties of SnS thin films.•X-ray diffraction and Raman spectroscopy show the formation of pure SnS thin films with a good morphology.•The motivating optical properties show that the SnS absorber layers can be low-cost and suitable material for the photovoltaic solar cells.
This study investigates the sources and characteristics of PM
10
pollution in Tetouan city, Morocco, by employing a combination of chemical mass closure, source-receptor modelling (namely positive ...matrix factorization, PMF), and air mass trajectory statistical analyses (concentration weighted trajectory, CWT). It provides compelling evidence that using such a combination is a powerful approach for studying the composition and sources of PM
10
in the Tetouan region. The PMF analysis identifies four PM
10
sources, namely Vehicle Exhaust, Secondary Aerosols, Nitrate + Biomass Burning, and Fresh Sea Salt, with distinct seasonal contributions. CWT analysis reveals the Mediterranean Basin as the primary source region, with influences from populated areas in northern Morocco, southern Europe, and marine emissions. PM
10
mass closure highlights the abundance of Dust, Particulate Organic Matter (POM), and Water-Soluble Inorganic Ions (WSI), accounting for the majority of the mass. The low OC/EC ratio advocates that carbonaceous aerosols primarily originate from local traffic emissions. Diagnostic of WSI ratios shows that the NH
4
+
/SO
4
2−
ratio indicated an ammonium-poor environment and suggested an acidic nature of the PM
10
aerosols, while the SO
4
2−
/NO
3
−
ratio reflects the combined influence of stationary and mobile sources, with a partial contribution from industrial activities throughout the year. These findings are expected to shed light on the chemical composition, origin of emission sources, and transport pathways of PM
10
in the region, contributing to the understanding of air pollution in the south western Mediterranean.
Abstract
The semiconductor realization is a very significant stage in gas sensor application. Herein, the Mn
3
O
4
semiconductor was deposited using chemical spray pyrolysis. The effect of deposition ...temperature on structural, vibrational optical and electrical Mn
3
O
4
thin layers properties were investigated through: X‐ray diffraction, Raman spectroscopy, UV‐visible spectrophotometer, and two points electrometers respectively. The X‐ray diffraction showed the appearance of spinel phase of tetragonal Mn
3
O
4
with strong formation direction along (101) plan and without any secondary phase indicating the formation of pure Mn
3
O
4
. The Raman spectroscopy confirmed the results obtained in XRD and certified the high‐quality formation of Mn
3
O
4
. In addition, the crystallinity improvement (the increase of crystallite size and the decrease of dislocation density) was caused by the increasing of deposition temperature from 350 °C to 450 °C. Optical properties such as transmittance, absorbance and band gap energy were extracted by UV‐Visible spectrophotometer. Thus, low transmittance, high absorbance and small band gap energy were observed at the highest substrate temperature (450 °C). The electrical conductivity showed good values between 4.83 and 13.89 mS.cm
−1
. These properties make Mn
3
O
4
an appropriate material to be used as a sensitive layer in gas sensors applications.
Herein, the cobalt oxide thin films are elaborated by spray pyrolysis technique. The effect of temperature of substrates on several properties of cobalt oxide is studied. The thin layers are ...characterized by using X‐ray diffraction (XRD), Raman spectrometry (RS), and UV–vis spectrophotometer. The XRD analysis shows that Co3O4 thin layers have been formed along preferential orientation. The RS displays the characteristic vibration modes of cobalt oxide phase, which confirms the formation of a single phase of spinel Co3O4 thin layers. The UV–vis spectrophotometer allows us to investigate the optical properties such as the absorbance, the transmittance, and the optical bandgap. The variation of electrical properties with the variation of temperature deposition confirms the high impact of the effect that study to make the cobalt oxide an important candidate for gas sensor devices.
Co3O4 thin layer is successfully prepared by spray pyrolysis technique. The impact of deposition temperature has been investigated on structural, optical, and electrical properties of Co3O4 thin layers. The obtained results display a significant superiority in crystallinity with a high crystallite size, low dislocation density, and optical properties of low transmission (<7%) and high absorption (>2) than other literature results.
Cu
2
ZnSnS
4
(CZTS) thin films have been prepared via sol–gel method and deposited on ordinary glass substrates by dip-coating technique. The chemical composition of Cu/(Zn + Sn) ratio was varied ...between 0.85, 0.95 and 1.05 to study its effect on structural, optical, morphological, compositional and electrical properties of deposited films. The films were investigated using different techniques such as X-ray diffractometer (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), UV–vis spectrophotometer and four-point probe method. The X-ray diffraction showed the single kesterite phase with the preferential orientation along (112) plane. The crystallites size was found to be between 6.95 and 9.30 nm. Raman scattering measurements for CZTS films deposited at Cu/(Zn + Sn) equal to 0.85 and 1.05 were confirmed the presence of pure CZTS phase by the characteristic peak at 332 cm
−1
. The morphological properties show a dense surface morphology and the elemental composition indicates CZTS films with a near-stoichoimetric composition. The optical properties were calculated using transmittance and absorbance data in the wavelength range between 450 and 850 nm. The obtained band gap energy values were found to be between 1.41 and 1.47 eV. The electrical sheet resistance showed values between 0.68 and 1.07 × 10
3
Ω square
−1
. A best sheet resistance and favorable optical band gap make our dip-coated CZTS thin films suitable to be used as an absorber layer for photovoltaic applications.
A high transparent Cu doped ZnS thin films were successfully deposited by the spray pyrolysis method at different deposition times. X-ray diffraction (XRD) patterns showed that all films were ...monocrystalline with the wurtzite crystal structure. A small variation in the optical band gap for all films was observed, indicating that the variation of deposition time doesn't affect strongly the bandgap. The average crystallite size of prepared thin films was calculated using Scherrer's formula and found to be in the range 29–33 nm. The crystallite size and microstrain of samples were investigated. Raman scattering spectra indicate the presence of different phonon modes and different peaks of Photoluminescence spectra for all samples which confirmed the presence of the elements Zn, S, and Cu with a comparison to the previous reported work. Using scanning electron microscope (SEM) images of elaborated thin films show a spherical with agglomeration. UV–visible measurements revealed height transmittance in the visible range for all growth time.
Display omitted
•The influence of Deposition time on physical properties Cu doped ZnS thin films using spray pyrolysis.•The structural and optical study using XRD, Raman and photoluminescence of Cu doped ZnS thin films.•Optical properties demonstrate the use of the materials in Photovoltaic and optoelectronic devices.
In this work, we synthesis Cu
2
ZnSnS
4
(CZTS) thin films by sol–gel method associated to dip-coating technique on the ordinary glass substrates. We investigated the effect of dip-coating speed on ...the structural, morphological, optical and electrical properties of films at various speeds 30, 40, 50 and 60 mm/min, respectively. The films have been characterized by different characterization techniques such as: X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), UV–Visible spectrophotometer and four point probe method. XRD spectra showed pure kesterite CZTS with a preferential orientation along (112) plane. Raman scattering measurement showed the peak at 332 cm
−1
correspond to pure CZTS phase. XPS analysis confirmed the presence of Cu, Zn, Sn and S elements on the surface of deposited CZTS. SEM images showed an improvement in density and uniformity with increasing dip-coating speed. The band gap energy is decreased with increasing of dip-coating speed in the range of 1.38–1.45 eV. The electrical conductivity increased between 4.90 and 5.81 (Ω.cm)
−1
. These characteristics make the deposited CZTS film a suitable material as an absorber layer in photovoltaic devices.
