Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Nonstructural


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.

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.

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).