Engineering and Technology Journal

Due to the significance of Nb₂O₅ as a promising industrial and biomedical material and the importance of Raman analyses to identify nanostructural molecular responsivity for various applications, this study aims to investigate Nb₂O₅ molecular bands that emerged under the impact of the Raman scattering phenomenon. Besides other advantages, Raman scattering analyses can provide a further investigation of the nanostructural polycrystalline phases supporting the XRD analyses. A pulsed laser was selected as the deposition technique for Nb₂O₅ thin films prepared with four different parameters. The selection of the pulsed laser deposition (PLD) method was due to the insufficient studies and investigations of Nb₂O₅ nanostructures prepared via this method. The deposition parameters included the laser energy per pulse, substrate temperature, laser wavelength, and the number of laser pulses. Each preparation parameter was studied in a range, and one obtained value was optimized or selected for investigating the next parameter. Q-switched Nd:YAG pulsed laser was employed for this purpose. Orthorhombic (T-Nb₂O₅) and monoclinic (H-Nb₂O₅) were obtained and investigated. XRD analysis was incorporated to confirm the resulting Nb₂O₅ phases. Previous studies and observations of Niobium (V) oxide molecular Raman scattering bands were also listed for comparison purposes. The results of this study were well-agreed with the previously obtained results.

In this study, thin films of pure iron oxide (Fe3O4) were prepared using pulsed
laser deposition technique under vacuum (2×10-3 mbar) using Nd: YAG laser at
different laser energies (700, 800, 900, and 1000 mJ) on quartz slides at the
substrate temperature of 200 °C with different thickness (170,190, 220, and 250
nm). The prepared thin films were examined using different techniques. The Xray diffraction showed a polycrystalline structure of cubic Fe3O4 phase, enhanced
its crystallinity, and increased the crystalline size when increasing the laser energy
to 1000 mJ. The results revealed that high transparency samples decreased pulse
laser energy. As the laser pulse power increases, the transparency decreases from
91% to 61%, where optical properties deteriorate significantly. The bandgap
values were detected to be 3.9 eV, 3.75 eV, 3.21 eV, and 3 eV when the laser
energies were increased with thickness (170– 250) nm. In addition, the extinction
coefficient, dielectric constants, optical constants, and refractive constants were
studied

In this study, Tungsten Trioxide thin films were successfully synthesized at different substrate temperatures by pulse laser deposition. Structural, morphological and electrical properties of WO3 thin films, were investigated by X-ray diffraction (XRD), Atomic Force Microscope AFM), Scanning Electron Microscope (SEM), Hall Effect and sensing measurements.
The results was indicated that WO3 thin films prepared at 450ᵒC was optimum condition where sensitivity toward H2S gas has been measured, sensitivity was higher than other films preparation at (250ᵒC,350ᵒC) temperature.

Zinc sulfide (ZnS) thin films were deposited on a glass and n-type Silicon wafer substrates at
temperature range from 50 - 200 Co using pulsed laser deposition (PLD) technique. The
structural, morphological, optical and electrical properties of the films have been investigated.
The XRD analyses indicate that ZnS films have zinc blende structures with plane (111)
preferential orientation, whereas the diffraction patterns sharpen with the increase in substrate
temperatures. The Atomic Force Microscopy (AFM) Images shows the particle size and surface
roughness of the deposited ZnS thin film at substrate temperature 50 and 150 Co were about
62.90nm, 74.68nm respectively. Also we noticed that the surface roughness is increased at
substrate temperature 150 Co compared with temperature 50 Co. At 200 Co the formed films
exhibit a good optical property with 80% transmittance in the visible region. The electrical
properties confirmed that they depend strongly on the bias voltage and the amount of current
produced by a photovoltaic device which is directly related to the number of photons absorbed.
C-V results demonstrated that the fabricated heterojunction is of abrupt type.

In this work, NiO thin films have synthesized by pulsed laser deposition on glass substrates with different substrate temperature (100, 200, 300)°C, using Q-switching Nd:YAG laser. Structure and optical properties have carried out by using FTIR, AFM and UV- Vis spectroscopy. FTIR spectraconformed of NiO bonding and AFM images show the increase in grain size with temperature. The optical transmission results show that the transparency of the NiO films is greater than 85% in the visible region which increases with the increasing substrate temperature, While the energy band gap was decreased with increasing substrate temperature.

This work includes the deposition of WO3 as a thin film on glass substrates by pulsed laser deposition method. The influence of Oxygen pressure on the structural and optical properties of tungsten trioxide films was investigated. The X-ray diffraction results show that the structure of the films changes from amorphous to crystalline at an Oxygen pressure higher than 10-2 mbar. The color of WO3 films formed at Oxygen pressure of 10-2 mbar is translucent white and it changes to pale blue with increasing the Oxygen pressure. From UV-visible spectroscopy the distinct variations in the transmission spectra and optical energy gap of the thin films were also observed. The optical band gap of the prepared films determined at different Oxygen pressures and it is found to be 3-3.1-3.12 eV at Oxygen pressures of 10-2 -2×10-1 -5×10-1 mbar respectively.

For this paper, films have been grown under various deposition conditions in order to understand the effect of processing on the film properties and to specify the optimum condition, namely substrate at temperatures of 400°C, oxygen pressure (2×10-1) mbar, laser fluence 400 mJ, and with different Mg doping (x=0, 0.02, 0.04, 0.06), using double frequency Q-switching Nd:YAG laser beam (wavelength 532nm), repetition rate (1-6) Hz and the pulse duration of (10 ns), to deposit MgxZn1-xO films on glass substrates with thickness of about 200±10 nm for all MgxZn1-xO films at different deposition condition and the number of laser pulses was 100 pulses. The X-rays spectra revealed that the presence of diffraction peaks indicates that the polycrystalline of the films depended strongly on the Mg-content in the layers. All the grown films is (101) as predominant reflection. The Scanning Electron Microscopy (SEM) images, the average grain size less than 50 nm. From the study of atomic force microscopy (AFM), we can determine the root mean square (RMS) surface roughness of Mg doped ZnO films. The optical properties were characterized by the transmittance and absorption spectroscopy at room temperature, measured in the range from (300 - 900) nm. For all the films, the average transmittance in the visible wavelength region λ = (400 - 800) nm is greater than (70%). The maximum value of the transmittance is greater than (95%) was obtained for these films. (Eg) values of MgxZn1-xO thin films are (3.37, 3.59, 3.82, and 4)eV corresponding to the Mg-content (x = 0, 0.02, 0.04 and 0.06) respectively. In other word, the optical band gap of MgxZn1-xO thin films become wider as Mg-content increases and can be precisely controlled between 3.37 and 4eV.

In this paper, the synthesis of nanostructure tin oxide SnO2 thin films on (0001) sapphire substrates using a pulsed 532 nm Nd: YAG laser is presented. Deposition of films is achieved at three different substrate temperatures 300,400,500ºC. The influence of substrate temperature on the structural and optical properties of tin oxide films are discussed and analyzed. We have shown the results of x-ray diffraction that all films prepared with the installation of multi crystalline (tetragonal) and directional prevalent (101) for all modds before and after annealing. These films are highly transparent (63–79%) in visible region, and transmittance of the films depends on substrate temperature. The band gap of the films varies from 3.45 eV to 3.61 eV for various temperatures. The morphology of deposited films was characterized by scanning electron microscope (SEM) and atomic force microscope (AFM), with increasing substrate temperature, both the grain size and surface roughness increase.
We have also investigated the photoluminescence (PL) emission of the simples produced by PLD. The absorption of very intense PL emission for the films at temperature T= 500 ºC. The photoluminescence (PL) spectrum of the SnO2 exhibits visible light emission with a peak at 602 nm.

This paper addresses the structure, morphological and optical properties of copper oxide (CuO) thin film deposited by pulsed laser deposition (PLD) method on Sapphire substrate of 150nm thickness. The film deposited at substrate temperature (400ºC). The atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and UV-VIS transmission spectroscopy were employed to characterize the size, morphology, crystalline structure and optical properties of the prepared thin film. The surface properties were characterized using (AFM), indicate that the average grain size less than 100nm, the surface roughness (2.69nm) and the root mean square is (3.58nm). The FTIR spectra shown strong band at about 418 cm-1and 530 cm-1 related to CuO. From the UV-VIS transmission the energy band gap (1.7eV).

In this work, mixed oxide (TiO2-SnO2) thin films were grown on Si (111) and glass substrates by pulsed laser deposition (PLD) method. The influences of increasing amounts of SnO2 were investigated. The X-ray diffraction results show the peaks position of the plane was shifted towards higher angle values with increasing amounts of SnO2. The surface morphology of the deposits materials was also studied by using a scanning electron microscope(SEM) The results show that, the grain sizes decreases with increasing SnO2 content from the largest value (53.6)nm to smallest value (25.5) nm. From UV-visible spectroscopy, the distinct variations in the transmission spectra, and optical energy gap, of the thin films were also observed.

In this work, a double frequency Q-switching Nd:YAG laser beam (λ=532nm, laser fluence 1.2 J/cm2 ,repetition rate 10 Hz and the pulse duration 7ns) has been used, to deposit TiO2 thin films pure on glass and Si (111) substrates .The structure properties of pure TiO2 were investigated by means of x-ray diffraction. As a result, it has been found that film structure and properties strongly depended on substrate temperature. X-ray diffraction (XRD) showed that at substrate temperatures higher than 300 °C the structure of the deposited thin films changed from amorphous to crystalline corresponding to the tetragonal TiO2 anatase phase.The surface morphology of the deposits materials have been studied using scanning electron (SEM) and atomic force microscopes (AFM). The grain size of the nanoparticles observed at the surface depended on the substrate temperature, where 500°C was the best temperature and partial pressure of oxygen 5×10-1 mbar was the best pressure during the growth process. RMS roughness increased with increasing substrate temperature (Ts) which are (11.2nm) for thin films deposited at (500)ºC.UV-VIS transmittance measurements have shown that our films are highly transparent in the visible wavelength region, with an average transmittance of ~90% which makes them suitable for sensor applications . The optical band gap of the films has been found to be 3.2 eV for indirect transition and 3.6 eV for direct transition at 400˚C.The sensitivity toward CO gas has been measured under 50 ppm.

Nanostructured Tin oxide thin films were deposited on the Si (111) substrate using pulsed laser deposition technique at different substrate temperatures (200, 300,400 and 500 °C) in an oxygen pressure (5*10-1 mbar). The structure and morphology of the as-deposited films indicate that the film crystallinity and surface topography are influenced by the deposition temperature by changing from an almost amorphous to crystalline nanostructure and rougher topography at a higher substrate temperature. Hall Effect has been studied to estimate the type of carriers, from the result we deduced that the SnO2 thin films are n-type.

In this work, MgxZn1-xO thin films were synthesized by pulsed laser deposition technique, the morphology and optical properties of MgxZn1-xO films were characterized by Atomic force microscopy (AFM) and UV-VIS spectroscopy. The MgxZn1-xO films have been deposited on sapphire substrates with different Mg contents (x= 0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1), using double frequency Q-switching Nd:YAG laser (532nm), repetition rate (6 Hz) and a pulse duration of (7 ns).
The present of hexagonal and cubic structure of MgxZn1-xO thin films was shown from X-ray diffraction measurement. The optical transmission results show that the transparency of the MgxZn1-xO films are greater than 85% in the visible region which increases with the increasing of Mg content. The absorption can be extended to lower wavelength range with higher magnesium contents, which can improve the transparency in the ultraviolet wavelength range. The band gap energy was found to be changed to the higher energy side with the increasing of Mg concentration. By changing Mg content from x=0 to x=1, the optical band gap of MgxZn1-xO films can be tuned from 3.4 eV to 5.9 eV, while the refractive index decreases from (1.96 – 1.75) as Mg-content increases from (0 to 1) at constant wavelength 400nm. This provides an excellent opportunity for bandgap engineering for optoelectronic applications. It is found from the AFM studies that the surface roughness of the films decreases with increasing the Mg content and the smallest grain size (33.8nm) with Mg content (1).

In this work, Nanostructured TiO2 thin films were grown by pulsed laser deposition (PLD) technique on glass substrates at 300 °C. TiO2 thin films were then annealed at 400-600 °C in air for a period of 2 hours. Effect of annealing on the structure, morphology and optical properties were studied. The X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) measurements confirmed that the films grown by this technique have good crystalline tetragonal mixed anatase and rutile phase structure and homogeneous surface. The study also reveals that the RMS value of thin films roughness increased with increasing annealing temperature .The optical properties of the films were studied by UV-VIS spectrophotometer. The optical transmission results shows that the transmission over than ~65% which decrease with the increasing of annealing temperatures. The allowed indirect optical band gap of the films was estimated to be in the range from 3.49 to 3.1 eV. The allowed direct band gap was found to decrease from 3.74 to 3.55 eV with the increase of annealing temperature. The refractive index of the films was found from 2.27 -2.98 at 550nm. The extinction coefficient increase with annealing temperature.

This work includes the deposition of SnO2 as a thin film on Si (111) by using the pulsed laser deposition method. The influences of oxygen pressure on the structural properties of Tin dioxide films were investigated. The X-ray diffraction results show that the structure of the films change from high polycrystalline to worse polycrystalline at an oxygen pressure of 10mbar. The surface morphology of the deposits materials was also studied by using a scanning electron microscope (SEM) and atomic force microscope (AFM). The results show that, the grain sizes of the nano particles observed at the surface depends on the oxygen pressure. As the pressure of the O2 gas increases the densities of the particles increases too. An oxygen pressure of 5×10-1 mbar was found the best pressure for the growth process. While the RMS roughness was seen to increase with increasing oxygen pressure. It was equal to (11.3 nm) for thin films deposited at (300)ºC.

In this study, the optical and structure properties of MgxZn1-xO thin films is reported. The MgxZn1-xO thin films were prepared on Glass substrates by Q-switch second harmonic Nd:YAG laser deposition technigue with wavelength of 532nm from a ZnO target mixed with Mg of (0-0.3) wt% , and the films deposited at temperature (250°C).
The optical properties were characterized by transmittance and absorption spectroscopy measurements. For all the films the average transmission in the U.V (200-900) nm wavelength region was over 85% and the absorption edge shifted to a shorter wavelength as the magnesium concentration increased. The optical energy gap of MgxZn1-xO thin films, measured from transmittance spectra could be controlled between (3.3eV and 4.2eV) by adjusting magnesium concentration. X-ray diffraction was used to investigate the structure of the film. The refractive index of hexagonal MgxZn1-xO thin films decreases with the Mg concentration increase, such as at the wavelength of (500nm) the refractive index decreases from 1.93 to 1.85 as x increase from 0.15 to 0.3. The extinction coefficient and the complex dielectric constant were also investigate.