scholarly journals Impact of annealing on structural and optical properties of CoPc thin films

2015 ◽  
Vol 12 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Husam El-Nasser

The structural and optical properties of four samples of cobalt phthalocyanine (CoPc) thin films having almost the same thickness deposited onto silicon substrates by organic molecular beam deposition (OMBD) were investigated. The intensity distributions of the X-ray diffraction (XRD) patterns confirm the crystalline nature of the films and presents a single sharp dominant peak at 2q=6.9o (d=12.72 ) of the α-CoPc phase unit cells, which indicates to a preferential orientation (200) direction, then undergoes a phase transition into β- form in a preferential orientation (001) direction after annealing at 250 and 350◦C. Furthermore it was shown that an increasing in the crystallite size (L) occurs upon annealing. The small values of the roughness (7.04 nm, 7.2 nm) obtained from atomic force microscopy (AFM) measurements show relatively smooth and flat surfaces. Despite the identity of the samples deposition conditions, the post growth annealed films show different morphological features of a mean grain size about of 11-26 nm. The optical energy gap was estimated from the absorption coefficient using Tauc's relation.

2021 ◽  
Vol 13 (01) ◽  
pp. 33-42
Author(s):  
Mushtaq Talib Al-Helaly ◽  
◽  
Nathera A .Al-Tememee ◽  

The research included the preparation and then studying the structural and optical properties of the cobalt dioxide (CoO2)films. The latter films were prepared using a semi-computerized spray pyrolysis technique (SCSPT),. The X-ray diffraction gave polycrystalline nature with crystal system trigonal (hexagonal axes), and the Energy Dispersive X-ray spectroscopy (EDX) showed that all films contain the elements (Co and O) indicating formation of (CoO2) films with high purity. FTIR measurements showed of chemical bonds of CoO2 clearly. Scanning Electron Microscopy (SEM ) Showed clearly that the formed thin films under the optimum conditions were homogeneous, dense and compact, and Atomic Force Microscopy(AFM) results showed that the topography of the film surface where surface roughness was found to be 7.91 nm, root mean square was 9.69 nm., and the average granularity diameter was 78.00 nm. The optical properties (absorbance, absorption coefficient, extinction coefficient, refractive index, optical Conductivity, the real ε_(1 ) and imaginary ε_2 part of the dielectric constant )were decreased with increasing the wavelength, while the transmittance increases with increasing wavelength. The optical energy gap was (1.98eV) and this is a good optical energy gap values for photovoltaic applications.


2019 ◽  
Vol 12 (25) ◽  
pp. 56-61
Author(s):  
Kadhim A. Aadim

This paper reports the effect of Mg doping on structural and optical properties of ZnO prepared by pulse laser deposition (PLD). The films deposited on glass substrate using Nd:YAG laser (1064 nm) as the light source. The structure and optical properties were characterized by X-ray diffraction (XRD) and transmittance measurements. The films grown have a polycrystalline wurtzite structure and high transmission in the UV-Vis (300-900) nm. The optical energy gap of ZnO:Mg thin films could be controlled between (3.2eV and 3.9eV). The refractive index of ZnO:Mg thin films decreases with Mg doping. The extinction coefficient and the complex dielectric constant were also investigate.


2017 ◽  
Vol 14 (1) ◽  
pp. 75-79
Author(s):  
Baghdad Science Journal

In this research Bi2S3 thin films have been prepared on glass substrates using chemical spray pyrolysis method at substrate temperature (300oC) and molarity (0.015) mol. Structural and optical properties of the thin films above have been studied; XRD analysis demonstrated that the Bi2S3 films are polycrystalline with (031) orientation and with Orthorhombic structure. The optical properties were studied using the spectral of the absorbance and transmission of films in wavelength ranging (300-1100) nm. The study showed that the films have high transmission within the range of the visible spectrum. Also absorption coefficient, extinction coefficient and the optical energy gap (Eg) was calculated, found that the film have direct energy gap equal to 2.8 eV.


Author(s):  
Hanan R.A. Ali

Thin films of CdO have been prepared by spray pyrolysis technique. XRD analysis reveals that all the prepared samples were polycrystalline and have preferred orientation along [111] orientation. The surface topography was determined by AFM which indicate that surface roughness and rms roughness were increased by the increasing of substrate temperature. The optical energy gap were determined and its value lies between (2.4-2.5) eV.


2014 ◽  
Vol 11 (2) ◽  
pp. 518-526
Author(s):  
Baghdad Science Journal

Thin films of pure tin mono-sulfide SnS and tin mono-sulfide for (1,2,3,4)% fluorine SnS:F with Thicknesses of (0.85 ±0.05) ?m and (0.45±0.05) ?m respectively were prepared by chemical spray pyrolysis technique. the effect of doping of F on structural and optical properties has been studied. X-Ray diffraction analysis showed that the prepared films were polycrystalline with orthorhombic structure. It was found that doping increased the intensity of diffraction peaks. Optical properties of all samples were studied by recording the absorption and transmission spectrum in range of wave lengths (300-900) nm. The optical energy gap for direct forbidden transition and indirect allowed transition were evaluated It is found that for doping less than 2% the optical energy gap increases as the percentage of doping increases in the samples while for doping more than 2% the values of the optical energy gap decreases as the percentage of doping increases.


2021 ◽  
Vol 2114 (1) ◽  
pp. 012012
Author(s):  
Tamara S. Hussein ◽  
Ala F. Ahmed

Abstract In this study, the effect of grafting with Iron (Fe) ratios (0.1, 0.3 and 0.5) on the structural and optical properties of cadmium oxide films (CdO) was studied, as these films were prepared on glass bases using the method of pulse laser deposition (PLD). The crystallization nature of the prepared films was examined by X-ray diffraction technique (XRD), which showed that the synthesis of the prepared films is polycrystalline, and Atomic Force Microscope (AFM) images also showed that the increased vaccination with Iron led to an increase in the crustal size ratio and a decrease in surface roughness, The absorption coefficient was calculated and the optical energy gap for the prepared thin films. It was found the absorption decreases and the energy gap decreases with the increase of doping ratio.


2019 ◽  
Vol 27 (03) ◽  
pp. 1950124 ◽  
Author(s):  
MOHAMMED YARUB HANI ◽  
ADDNAN H. AL-AARAJIY ◽  
AHMED M. ABDUL-LETTIF

Nickel(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (NiTsPc) thin films were deposited on glass substrates at different substrate temperatures ([Formula: see text]) by chemical spray pyrolysis (CSP) technique. The substrate temperature varied from 110∘C to 310∘C in 50∘C steps. The substrate surface temperature is the main parameter that determines the film morphology and properties of the thin films. The structural properties of the deposited NiTsPc thin films were investigated by X-ray diffraction (XRD) and from the obtained results, it was shown that depositing thin films using 210∘C as [Formula: see text] results in higher crystallinity. Atomic force microscope (AFM) was employed to obtain the surface topography and to calculate the roughness and grain size. The smoothest thin film surface was obtained when using at 160∘C, while the highest roughness was obtained at 310∘C. The optical properties were investigated by ultraviolet visible (UV-Vis) spectrophotometer and fluorescence spectrophotometer. From the absorption spectra recorded in the wavelength range 190–1100[Formula: see text]nm, two absorption bands were observed, which are known as Soret and Q-band. By observing the absorption spectrum, it can be concluded that the deposited thin films at 110∘C–310∘C have direct energy gap. From Tauc plot relation, the energy gap ([Formula: see text]) was calculated. The values of the energy gap were between 3.05 and 3.14[Formula: see text]eV. It was observed that different [Formula: see text] highly affects the structural and optical properties of the deposited thin films. The crystallinity, grain size, roughness and the optical properties were strongly affected by the different substrate temperatures.


2020 ◽  
Vol 398 ◽  
pp. 140-146
Author(s):  
Kawther A. Khalaph ◽  
Zainab J. Shanan ◽  
Aqel Mashot Jafar ◽  
Falah Mustafa Al-Attar

Recently, lead iodide is the most materials employment in the perovskite solar cell application. This paper has studied the character of preparation, structural and optical properties of pbI2 materials. Structural properties are included investigation of the measurements X-Ray Diffraction (XRD), Scan Electron Microscopy (SEM), Fourier Transform InfraRed spectroscopy (FTIR) and Atomic Force Microscopy (AFM) tests to the PbI2 thin films samples. Optical properties are included the investigation UV-Vis test of the thin film samples deposited on glass substrates and investigated the Absorption, Transmittance and evaluated energy gap (Eg = 2.3 eV).


Author(s):  
Mahdi M. Mutter ◽  
Habiba Kadhum Atty ◽  
Areej Adnan Hateef

The purpose of this research is studying the effect of gamma radiation on the structural and optical properties of iron oxide Fe2O3thin films. The technique used for prepared the thin films was thermal chemical spray. The effect of Co60irradiation on the structural and optical properties of the thin films was investigated. The crystal structure were studied by XRD pattern. The surface tested from crack and defect was looke by used microscope image. The absorption and transmission spectra by used UV/VIS for the as deposited and irradiated thin films. The energy gap and absorption coefficient were studied. It's found that the energy gap for the un-irradiated sample was 2.3 eV and than after exposed to gamma radiation at (25,50,75,100 and 125) Gy the energy gap decreased and above 5o Gy was increasing. The absorption coefficient increased until (12x104) cm-1at 50 Gy and than was decreasing to (2x104) cm-1at 125 Gy. The effect of radiation on the structural and optical properties was positive at the levels of irradiation used.


2016 ◽  
Vol 30 (12) ◽  
pp. 1650140
Author(s):  
Haihua Tang ◽  
Shuang Liu ◽  
Xiang Zhou ◽  
Yunfei Liu ◽  
Dejun Chen ◽  
...  

Hydrogenated amorphous silicon (a-Si:H) thin films were prepared by radio frequency (RF) plasma enhanced chemical vapor deposition (RF-PECVD) technique with silane (SiH[Formula: see text] as reactive gas. The influence of process parameters on the morphological characteristics and optical properties of a-Si:H thin films were systematically investigated. When the RF power density was taken as the only variable, it firstly improves the smoothness of the surface with increasing the RF power density below the value of 0.17 W/cm2, and then exhibits an obvious degradation at further power density. The refractive index, extinction coefficient, optical energy gap initially increase and reach a maximum at 0.17 W/cm2, followed by a significant decrease with further RF power density. When the RF power density was taken as the only variable, the surface of a-Si:H thin films become smoother by increasing the reaction pressure in the investigated range (from 50 Pa to 140 Pa), and the refractive index, extinction coefficient, optical energy gap increase with increasing of reaction pressure. The effect of RF power density and the reaction pressure on the morphological characteristics and optical properties of a-Si:H thin films was obtained, contributing to the further studies of the performance and applications of a-Si:H thin films.


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