Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Pulsed Laser Deposition


Preparation and Study the Characteristics of Tungsten Trioxide Thin Films for Gas Sensing Application

Suaad.S.Shaker

Engineering and Technology Journal, 2016, Volume 34, Issue 4, Pages 462-469

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.

A Study on the Structural, Optical and Electrical Properties of Tungsten TrioxideWO3Thin Film for Gas Sensing Applications

Adawiya J. Haider; Huda A. Mutasher

Engineering and Technology Journal, 2015, Volume 33, Issue 8, Pages 1473-1482

The pulsed laser deposition method, PLD, has been used in this project to deposit the pure Wo3 The aim was to study the influence of temperature on surface morphology of the deposits materials using Atomic Force Microscope measurements at different temperatures of (RT,300 ,400)°C. The structural characteristics of the films prepared on glass substrates have been studied by using X-ray diffraction and AFM. These tests show that there is a direct relationship between the grain sizes of the nanoparticles observed at the surface and influence of temperature which means as temperature increases there will be a similar enhancement in the grain size as well. Additionally, we were able to find that the best of temperature was 400ᵒC. Furthermore, the characterizations of the gas sensing of these thin films were strongly influenced by the surface morphology. It has been also found that nanocrystalline Wo3 gas sensing material was presented a better sensitivity as temperature increases

Characterization of CuO:NiO/PS Hydrogen Gas Sensor

Isam M. Ibrahim; Yahya R. Hathal; Fuad T. Ibrahim; Mudhafar H. Ali

Engineering and Technology Journal, 2015, Volume 33, Issue 6, Pages 1066-1074

Thin films of copper oxide nanoparticles mixed with 6% nickel oxide are deposited on glass and Si substrates with orientation (111) utilizing pulsed laser deposition technique for the manufacture of hydrogen gas sensor. The films are annealed in air at 400 °C for two hours, then the structural and morphological properties are characterized using x-ray diffraction and atomic force microscopy. The results of CuO:NiO/Si films are exhibited a polycrystalline monoclinic CuO and cubic NiO phases. In addition, the peak of Si located at 28.3º which refer to (111) direction. Furthermore, this peak becomes very broad with varying full width at half maximum for etching current density of 30 mA/cm2 at time of 30 min which confirms the formation of pores on the crystalline silicon surface. On the other hand, the average diameter of 84.31 nm and 34.98 nm for CuO:NiO on a glass substrate and PS, respectively, were obtained. A sponge-like structure is produced for PS which reveal that a part of pores transform to a larger structure. The peak sensitivity of 204.8% was observed at optimum operating temperature of 350°C.

Synthesis of TiO2/Pd/Multi-Walled Carbon Nano-Structures by Hydrothermal Technique and deposited it on n-Si substrate as TiO2/Pd/MWCNTs:n-Si Heterojunction by Pulsed Laser Deposition

Saif M. Alshrefi; Dunia K. Mahdi; Zainab S.Sadik

Engineering and Technology Journal, 2015, Volume 33, Issue 5, Pages 867-883

Carbon nanostructures (CNTs) have been prepared by a Hydrothermal deposition technique based on the polymer Polyethylene glycol (PEG) dissolved in water and Ethanol alcohol of a new carbon sources materials mixed with (PdCl2) as a catalyst mixed with Sodium hydroxide (8gm NaOH) using Parr reactor at temperature (190°C) and forming the hybrid composite material (TiO2/Pd/MWCNTs) by the same way. Thence, deposited heterojunction material (TiO2/Pd/MWCNTs:n-Si) using the Pulsed Laser Deposition Technique (PLD), on the substrate of n-silicon wafer. The obtained (MWCNTs & TiO2/Pd/MWCNTs) are investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray Photo-electron Spectroscopy (XPS). Normal MWCNTs are formed multi-walled carbon nanotubes (MWCNTs) and carbon nanosheets (CNSs) but in little bit amount. MWCNTs were obtained as main products with lengths of (1.6–3 μm) and diameters of (30-60 nm) could be synthesized at as low temperature as (190°C). Deconvolution of the (C1s ) peaks which characteristic of C-C bonds, showed a main peak at (284.96 and 285.04 eV) with total amount (74.96 and 30.64 at%) for the product of MWCNTs and TiO2/Pd/MWCNTs composite respectively. Current – voltage characteristics of heterojunction showed that forward bias current change exponentially approximately with applied voltage at dark and this agreement with tunneling–recombination model. Also (I-V) characteristics under illumination of TiO2/Pd/MWCNTs heterojunction deposited on p-Si substrate (η=10.5) efficiency in Solar Cell.

Oxygen Effect on Structural and Optical Properties of WO3 Films by Pulsed Laser Deposition

Ruaa W.Gabbar; Adawiya J. Haider

Engineering and Technology Journal, 2014, Volume 32, Issue 6, Pages 1068-1073

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.

Physical Properties of Nanostructure Sno2 Thin Films Growth on Al2O3 Substrate by Pulsed Laser Deposition

Kasem Salman Kasem

Engineering and Technology Journal, 2014, Volume 32, Issue 5, Pages 957-965

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.

Morphological and Optical Properties of Cuo/Sapphire Thin Films Prepared by Pulsed Laser Deposition

Afnan k. Yousif; Ban A. Bader; Rana O. Mahd

Engineering and Technology Journal, 2014, Volume 32, Issue 5, Pages 892-898

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).

Preparation and Characterization of (Tio2-Sno2) Thin Films by Pulsed Laser Deposition

Saja H.Rashed; Adawiya J. Haider; Samar Younis

Engineering and Technology Journal, 2014, Volume 32, Issue 4, Pages 658-665

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.

Effect of Substrate Temperature on Nanostructure Titanium Dioxide Thin Films Prepared By PLD

Khaled Z.Yahya; Adawiya J. Haider; Heba Salam Tarek; Raad M. S. Al-Haddad

Engineering and Technology Journal, 2014, Volume 32, Issue 3, Pages 434-443

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.

Influence of Deposition Temperature on Structure and Morphology of Nanostructured Sno2 Films Synthesized By Pulsed Laser Deposition (PLD)

Suaad .S.Shaker; Adawiya J. Haider

Engineering and Technology Journal, 2014, Volume 32, Issue 3, Pages 453-460

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.

Effects of Mg Concentration of MgxZn1-XO Nanostructure Thin Films by PLD on Optical and Topographical Properties

Ali J.Addie; Jehan A.Saimon; Adawiya J.Haidar

Engineering and Technology Journal, 2013, Volume 31, Issue 7, Pages 846-858

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).

Oxygen Effect on Nanostructure Sno2 Films and Morphology by Pulsed Laser Deposition

Suaad .S.Shaker; Adawiya J. Haider

Engineering and Technology Journal, 2013, Volume 31, Issue 2, Pages 232-238

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.