SYNTHESIS AND CHARACTERIZATION OF NANOCRYSTALLINE Co-DOPED ZnO THIN FILMS PREPARED BY CHEMICAL SPRAY PYROLYSIS FOR OPTOELECTRONIC APPLICATIONS

Author(s):  
FAEZ M. HASSAN ◽  
AUS A. NAJIM

ZnO:Co thin films were synthesized by the chemical spray pyrolysis (CSP) on glass substrates. Then, investigated the impact of Co doping concentration on its physical properties. XRD analyses show that all films have a polycrystalline structure of hexagonal ZnO. The crystallite size increased from 18[Formula: see text]nm to 25[Formula: see text]nm with Co doping concentrations. Furthermore, the unit cell volume increased from 47.485[Formula: see text]Å to 47.831[Formula: see text]Å, and the Zn–O bond length expanded from 1.97588[Formula: see text]Å to 1.98071[Formula: see text]Å. SEM observations reveal the formation of fiber-like nanostructures in the Co-doped thin films. The diameter of nanofibers increased with Co doping concentration from 260[Formula: see text]nm to 700[Formula: see text]nm. The optical characteristics were studied by the UV-Visible spectrophotometer and manifest the optical transparency vary with Co doping. In addition, the band gap decreases from 3.27[Formula: see text]eV to 2.73[Formula: see text]eV with increasing Co doping concentrations. The conductivity varied from 3.35[Formula: see text]S[Formula: see text][Formula: see text][Formula: see text]m[Formula: see text] to 19.88[Formula: see text]S[Formula: see text][Formula: see text][Formula: see text]m[Formula: see text] with Co doping concentrations. Empirical models were proposed to evaluate the correlated variables with excellent accuracy with the experimental data. The best result was accomplished in ZnO:Co1% films, where good transparency and high conductivity were achieved.

2019 ◽  
Vol 60 ◽  
pp. 63-75 ◽  
Author(s):  
Naoual Houaidji ◽  
Mejda Ajili ◽  
Baghdadi Chouial ◽  
Najoua Turki Kamoun ◽  
Kenza Kamli ◽  
...  

Transparent conducting Cobalt-fluorine co-doped tin oxide (SnO2: (Co, F)) thin filmswere deposited onto preheated glass substrates using the chemical spray pyrolysis method. The ([Co2+]/[Sn4+]) atomic concentration ratio (y)in the spray solution was varied between 0 and 5 at. %. The structural, electrical, optical and photoluminescence properties of these films were studied. It is found that the thin films are polycrystalline with a tetragonal crystal structure corresponding to SnO2 phase having a preferred orientation along the (200) plane. Transmission and reflection spectra reveal the presence of interference fringes indicating thickness uniformity and surface homogeneity of the deposited thin films. The electrical resistivity (ρ), volume carrier concentration density (Nv), surface carrier concentration density (Ns) and Hall mobility (μ) of the synthesized thin films were determined from the Hall Effect measurements in the Van der Paw-configuration and the following results were obtained: n-type conductivity in all deposited films, a low resistivity of 1.16×10-2 Ω.cm, and a high Hall mobility of 15.13×102 cm2.V-1.s-1with Co concentration equals to 3 at. %. These results show that the electrical properties of these thin films where greatly improved making them suitable as ohmic contact in photovoltaic application devices.


2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Reem S. Khaleel ◽  
◽  
Mustafa Sh. Hashim ◽  
Samer Gh. Majeed ◽  
◽  
...  

The deposition of metal oxides powder faces several problems, including poor adhesion to the bases deposited on them, the presence of many cracks, poor thickness control, and other disadvantages. The current study gives a new and simple idea to deposit thin films using two ZnO powders with nano and microparticle sizes on glass substrates. This was done by transforming the powders to Zinc acetate and then using chemical spray pyrolysis to deposit ZnO thin films. Scanning electron microscope (SEM) images showed that the prepared film from the nanopowder (ZnONano) lost the independence of powder’s nanoparticles and became a homogeneous film with nano projections. But the deposited one from the micro powder (ZnOMicro) had both nanorods and nanoplates. The different shapes and sizes of ZnO particles in ZnOMicro powder were disappeared after the Spray process. The two deposited films were homogeneous, crack-free and there were controllable thicknesses during the deposition. X-ray spectroscopy (EDS) was used to measure weights and atomic percentages of elements for the deposited films. The structures of the deposited films were approximately identical as the X-ray diffraction (XRD) technique showed. The optical properties of these two films were studied and their parameters were measured and calculated.


2020 ◽  
Vol 65 ◽  
pp. 13-26
Author(s):  
Naoual Houaidji ◽  
Mejda Ajili ◽  
Baghdadi Chouial ◽  
Najoua Turki Kamoun ◽  
Kenza Kamli ◽  
...  

The aim of this work is the production and the characterisation of (SnO2: (Mn, F)) thin films with appropriate optoelectronic properties required for application as ohmic contacts in photovoltaic application devices. Transparent conducting Manganese-fluorine co-doped tin oxide (SnO2: (Mn, F)) thin films have been deposited onto preheated glass substrates using the chemical spray pyrolysis (CSP) method. The ([Mn2+]/[Sn4+]) atomic concentration ratio (y) in the spray solution is varied between 0 and 8 at. %. The structural, the opto-electrical and the photoluminescence properties of these thin films have been studied. It is found that the deposited thin films are polycrystalline with a tetragonal crystal structure corresponding to SnO2 phase having a preferred orientation along the (200) plane. Transmission and reflection spectra reveal the presence of interference fringes indicating the thickness uniformity and the surface homogeneity of the deposited samples. Photoluminescence behaviour of Mn-F co-doped SnO2 thin films was also studied. Photoluminescence spectra reveal the presence of the defects like oxygen vacancies in the materials. In addition, The electrical resistivity, volume carrier concentration, surface carrier concentration and electrical mobility were determined from Hall Effect measurements and the following results were obtained: n-type conductivity in all the deposited thin films, a low resistivity of 1.50×10-4 Ω cm, and a high electrical mobility of 45.40 cm2 V-1 s-1 with Mn co-doping concentration equals to 7 at. %. These experimental results show that the electrical properties of these thin films where greatly improved making them suitable as ohmic contacts in photovoltaic applications devices.


Author(s):  
Khalid Haneen Abass

Fe2O3 thin films that doped by NiO were obtained on glass substrates by the chemical spray pyrolysis technique, and annealed at 450 °C and 500 °C. The effect of annealing on optical properties was studied by recording the absorbance spectra using UV-Visible spectrophotometer. The refractive index decreases with increasing annealing temperature, such as an optical band gap that decreases from 2.68 eV before annealing to 2.58 eV after annealing of 500 °C. Absorption coefficient and extinction coefficient increase with increasing annealing temperature.


2018 ◽  
Vol 4 (5) ◽  
pp. 542-545 ◽  
Author(s):  
R. Shabu ◽  
A. Moses Ezhil Raj

As major attention has been paid to transition metal oxide semiconductor suitable for solar cell, photo detector and gas sensor, present study embark on the structural, optical and electrical characterization of Ag doped CuO thin films prepared using chemical spray pyrolysis technique at the constant substrate temperature of 350 �C. For Ag doping, various concentrations of silver acetate (0.5-3.0 wt.%) was used in the sprayed precursor solution. Confirmed monoclinic lattice shows the tenorite phase formation of CuO in the pure and Ag doped films. The optical band gap of the films was in the range of 2.4 -3.4 eV. A minimum resistivity of 0.0017x103 ohmcm was achieved in the 0.5 wt.% Ag doped film, and its optical band gap was 2.74 eV.


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