In this paper, thin films of copper oxide nanoparticles mixed with 2% wt of nickel oxide are depo... more 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.
Nanostructured tin dioxide (SnO 2 ) thin films were prepared by thermal oxidation of Sn, which we... more Nanostructured tin dioxide (SnO 2 ) thin films were prepared by thermal oxidation of Sn, which were ground and embedded in methanol then it was deposited on a glass substrate utilizing casting method. The deposited films were examined for their morphology, and crystal structure by transmission electron microscopy (TEM) scanning electron microscopy (SEM), and X-ray diffraction (XRD) technique. In most cases, it was found that SnO 2 thin films had a tetragonal phase, predominantly grown on preferred (110) and (200) planes. The deposited thin films have grain size was about 82 nm. The sensing properties of SnO 2 against NO 2 gas were studied as a function of working temperature and time under optimal condition. The sensitivity, response time and recovery time were calculated with different operating temperatures.
We prepared polythiophene (PTH) with single wall carbon nanotube (SWCNT) nanocomposite thin films... more We prepared polythiophene (PTH) with single wall carbon nanotube (SWCNT) nanocomposite thin films for Nitrogen dioxide (NO2) gas sensing applications. Thin films were synthesized via electrochemical polymerization method onto (Indium tin oxide) ITO coated glass substrate of thiophene monomer with magnesium perchlorate and different concentration from SWCNT (0.012 and 0.016) % in the presence130mL of Acetonitrile used. X-ray diffraction (XRD), Field Emission Scanning Electron microscopy (FE-SEM), Atomic Force Microscope (AFM) and Fourier Transform Infrared Spectroscopy (FT-IR) were used to characterized these nanocomposite thin films. The response of these nanocomposite for NO2 gas was evaluated via monitoring the change time in presence 25% NO2 of with electrical resistance at (40, 80,120,160 and 200)°C. We can observe that the PTh/SWCNT films show a higher sensitivity as compare to pure PTH.
In this work, a reactive DC magnetron sputtering technique was used to prepare TiO2 thin films. ... more In this work, a reactive DC magnetron sputtering technique was used to prepare TiO2 thin films. The variation in argon and oxygen gases mixing ratios (4:1, 2:1, 1:1, 1:2, 1:4) was used to achieve optimal properties for gas sensing. In addition, an analysis of the optical XRD properties of TiO2 thin films is presented. High-quality and uniform nanocrystalline films were obtained at a working gas pressure of 0.25 mbar and 1:4 (Ar/O2) gas mixture. The optical properties showed a transparent thin film with uniform adherence to the substrate. The average transmission of the TiO2 films deposited on the glass substrates was higher than 95% over the range of 400 to 800 nm. The optical band gap varied from 3.84 eV to 3.93 eV as a function of oxygen/argon ratios. The XRD pattern showed that the films have an amorphous structure, which is shifted to polycrystalline with increasing oxygen to argon ratio. The sensitivity, response time, and recovery time were measured for TiO2 thin films usin...
Optical properties of chromium oxide (Cr2O3) thin films which were prepared by pulse laser deposi... more Optical properties of chromium oxide (Cr2O3) thin films which were prepared by pulse laser deposition method, onto glass substrates. Different laser energy (500-900) mJ were used to obtain Cr2O3 thin films with thickness ranging from 177.3 to 372.4 nm were measured using Tolansky method. Then films were annealed at temperature equal to 300 °C. Absorption spectra were used to determine the absorption coefficient of the films, and the effects of the annealing temperature on the absorption coefficient were investigated. The absorption edge shifted to red range of wavelength, and the optical constants of Cr2O3 films increases as the annealing temperature increased to 300 °C. X-ray diffraction (XRD) study reveals that Cr2O3 thin films are amorphous; while the crystal structure of annealed Cr2O3 films is rhombohedral after annealing at 300 °C for two hour. AFM studies of Cr2O3 thin films exhibit a smooth and well dispersed on the surface.
Chromium oxide (Cr 2 O 3 ) thin films were prepared by the pulsed laser deposition (PLD) techniqu... more Chromium oxide (Cr 2 O 3 ) thin films were prepared by the pulsed laser deposition (PLD) technique onto glass substrates using different laser pulse energies (500–900 mJ). The thickness of the prepared films ranged from 177.3 to 372.4 nm. The X-ray diffraction (XRD) study revealed that Cr 2 O 3 thin films are amorphous, but they converted to the rhombohedral crystalline structure with space symmetry group after annealing at 300 °C for two hours. Furthermore, the atomic force microscopy (AFM) exhibited the formation of smooth and well-dispersed surfaces. The optical measurements in the wavelength range between 300 and 1100 nm confirmed that the optical energy gap of the prepared films decreased with increasing laser pulse energy, and a transition of the indirect type with a band gap of ≈ 3.90 eV was determined. The effect of the operation temperature on thin films’ sensitivity has been studied with the aim of optimizing the operation temperature as well as the response and recovery time for the prepared Cr 2 O 3 thin films.
Abstract In this work, nanograined ZnO films with various CuO contents (between 2 at% and 10 at%)... more Abstract In this work, nanograined ZnO films with various CuO contents (between 2 at% and 10 at%) were synthesized by pulsed-laser deposition method. The films with (2, 4, and 6 at%) contain only ZnO peaks with wurtzite structure. The peaks at the CuO (with cubic lattice) become visible in the X-ray diffraction spectra at (8 and 10 at%). Also, the X-ray diffraction patterns of porous silicon showed a broadening in the FHWM with increasing etching time. From atomic force microscopy of the prepared samples, a decrease in the average diameter of the particles with increasing etching time was observed. The photoluminescence spectroscopy showed that the blue shift was increased with etching time. We have studied the operation temperature of gas sensors fabricated from the prepared samples at different environment temperatures and found that the maximum sensitivity was about 75.88 for 10 min porous silicon time.
In this paper, thin films of copper oxide nanoparticles mixed with 2% wt of nickel oxide are depo... more 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.
Nanostructured tin dioxide (SnO 2 ) thin films were prepared by thermal oxidation of Sn, which we... more Nanostructured tin dioxide (SnO 2 ) thin films were prepared by thermal oxidation of Sn, which were ground and embedded in methanol then it was deposited on a glass substrate utilizing casting method. The deposited films were examined for their morphology, and crystal structure by transmission electron microscopy (TEM) scanning electron microscopy (SEM), and X-ray diffraction (XRD) technique. In most cases, it was found that SnO 2 thin films had a tetragonal phase, predominantly grown on preferred (110) and (200) planes. The deposited thin films have grain size was about 82 nm. The sensing properties of SnO 2 against NO 2 gas were studied as a function of working temperature and time under optimal condition. The sensitivity, response time and recovery time were calculated with different operating temperatures.
We prepared polythiophene (PTH) with single wall carbon nanotube (SWCNT) nanocomposite thin films... more We prepared polythiophene (PTH) with single wall carbon nanotube (SWCNT) nanocomposite thin films for Nitrogen dioxide (NO2) gas sensing applications. Thin films were synthesized via electrochemical polymerization method onto (Indium tin oxide) ITO coated glass substrate of thiophene monomer with magnesium perchlorate and different concentration from SWCNT (0.012 and 0.016) % in the presence130mL of Acetonitrile used. X-ray diffraction (XRD), Field Emission Scanning Electron microscopy (FE-SEM), Atomic Force Microscope (AFM) and Fourier Transform Infrared Spectroscopy (FT-IR) were used to characterized these nanocomposite thin films. The response of these nanocomposite for NO2 gas was evaluated via monitoring the change time in presence 25% NO2 of with electrical resistance at (40, 80,120,160 and 200)°C. We can observe that the PTh/SWCNT films show a higher sensitivity as compare to pure PTH.
In this work, a reactive DC magnetron sputtering technique was used to prepare TiO2 thin films. ... more In this work, a reactive DC magnetron sputtering technique was used to prepare TiO2 thin films. The variation in argon and oxygen gases mixing ratios (4:1, 2:1, 1:1, 1:2, 1:4) was used to achieve optimal properties for gas sensing. In addition, an analysis of the optical XRD properties of TiO2 thin films is presented. High-quality and uniform nanocrystalline films were obtained at a working gas pressure of 0.25 mbar and 1:4 (Ar/O2) gas mixture. The optical properties showed a transparent thin film with uniform adherence to the substrate. The average transmission of the TiO2 films deposited on the glass substrates was higher than 95% over the range of 400 to 800 nm. The optical band gap varied from 3.84 eV to 3.93 eV as a function of oxygen/argon ratios. The XRD pattern showed that the films have an amorphous structure, which is shifted to polycrystalline with increasing oxygen to argon ratio. The sensitivity, response time, and recovery time were measured for TiO2 thin films usin...
Optical properties of chromium oxide (Cr2O3) thin films which were prepared by pulse laser deposi... more Optical properties of chromium oxide (Cr2O3) thin films which were prepared by pulse laser deposition method, onto glass substrates. Different laser energy (500-900) mJ were used to obtain Cr2O3 thin films with thickness ranging from 177.3 to 372.4 nm were measured using Tolansky method. Then films were annealed at temperature equal to 300 °C. Absorption spectra were used to determine the absorption coefficient of the films, and the effects of the annealing temperature on the absorption coefficient were investigated. The absorption edge shifted to red range of wavelength, and the optical constants of Cr2O3 films increases as the annealing temperature increased to 300 °C. X-ray diffraction (XRD) study reveals that Cr2O3 thin films are amorphous; while the crystal structure of annealed Cr2O3 films is rhombohedral after annealing at 300 °C for two hour. AFM studies of Cr2O3 thin films exhibit a smooth and well dispersed on the surface.
Chromium oxide (Cr 2 O 3 ) thin films were prepared by the pulsed laser deposition (PLD) techniqu... more Chromium oxide (Cr 2 O 3 ) thin films were prepared by the pulsed laser deposition (PLD) technique onto glass substrates using different laser pulse energies (500–900 mJ). The thickness of the prepared films ranged from 177.3 to 372.4 nm. The X-ray diffraction (XRD) study revealed that Cr 2 O 3 thin films are amorphous, but they converted to the rhombohedral crystalline structure with space symmetry group after annealing at 300 °C for two hours. Furthermore, the atomic force microscopy (AFM) exhibited the formation of smooth and well-dispersed surfaces. The optical measurements in the wavelength range between 300 and 1100 nm confirmed that the optical energy gap of the prepared films decreased with increasing laser pulse energy, and a transition of the indirect type with a band gap of ≈ 3.90 eV was determined. The effect of the operation temperature on thin films’ sensitivity has been studied with the aim of optimizing the operation temperature as well as the response and recovery time for the prepared Cr 2 O 3 thin films.
Abstract In this work, nanograined ZnO films with various CuO contents (between 2 at% and 10 at%)... more Abstract In this work, nanograined ZnO films with various CuO contents (between 2 at% and 10 at%) were synthesized by pulsed-laser deposition method. The films with (2, 4, and 6 at%) contain only ZnO peaks with wurtzite structure. The peaks at the CuO (with cubic lattice) become visible in the X-ray diffraction spectra at (8 and 10 at%). Also, the X-ray diffraction patterns of porous silicon showed a broadening in the FHWM with increasing etching time. From atomic force microscopy of the prepared samples, a decrease in the average diameter of the particles with increasing etching time was observed. The photoluminescence spectroscopy showed that the blue shift was increased with etching time. We have studied the operation temperature of gas sensors fabricated from the prepared samples at different environment temperatures and found that the maximum sensitivity was about 75.88 for 10 min porous silicon time.
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