scholarly journals The effect of heat treatment on the optical properties of organic semiconductor (NiPc/C60) thin films

2019 ◽  
Vol 16 (39) ◽  
pp. 33-41
Author(s):  
Atheer M. Mkhaiber
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Optical Properties ◽  
Optical Absorption ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Optical Absorption Spectra ◽  
Optical Energy Gap ◽  
Optical Energy ◽  
Glass Substrates

Thin films of the blended solution of (NiPc/C60) on glass substrates were prepared by spin-coated method for three different ratios (100/1, 100/10 and 100/100). The effects of annealing temperature and C60 concentration on the optical properties of the samples were studied using the UV-Vis absorption spectroscopy and FTIR spectra. The optical absorption spectrum consists of two main bands, Q and B band, with maxima at about (602-632) nm and (700-730) nm for Q1 and Q2 respectively, and (340-375) nm for B band. The optical energy gap were determined from optical absorption spectra, The variation of optical energy gap with annealing temperature was nonsystematic and this may be due to the improvement in crystal structure for thin films. While the energy gap decreased by increasing the concentration of C60 approaches from the energy gap of this compound.

scholarly journals Composition and Optical Dispersion Characterization of Nanoparticles ZnO-NiO Thin Films: Effect of Annealing Temperature

2013 ◽  
Vol 13 ◽  
pp. 78-86 ◽  
Author(s):  
Saad F. Oboudi ◽  
Nadir F. Habubi ◽  
Ghuson H. Mohamed ◽  
Sami S. Chiad
Keyword(s):  
Thin Films ◽  
Oscillator Strength ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Dispersion Parameters ◽  
Optical Energy Gap ◽  
Optical Energy ◽  
Optical Dispersion ◽  
Glass Substrates ◽  
Before And After

Thin films of ZnO0.7NiO0.3 have deposited on glass substrates at room temperature by using thermal evaporation technique under vacuum 10-5 mbar. The optical properties and dispersion parameters of the films have been studied. Changes in direct optical energy band gap of films were confirmed before and after annealing. The optical energy gap Eg decreased from 3.11 to 2.86 eV with increasing of annealing temperature to 200 °C. Some of the optical absorption parameters, such as optical dispersion energies Eo and Ed, Urbach tails EU , dielectric constant ε, the average values of oscillator strength So, and wavelength of single oscillator λo have been reported. An increase in the annealing temperature causes an increase in the average oscillator strength from 62.02 to 87.71 eV.

scholarly journals Effect of Pb percentage on optical parameters of PbxCd1-xSe thin films

2019 ◽  
Vol 14 (29) ◽  
pp. 1-7
Author(s):  
Farah Q. Kamil
Keyword(s):  
Thin Films ◽  
Thermal Evaporation ◽  
Energy Gap ◽  
Optical Measurements ◽  
Optical Parameters ◽  
Optical Energy Gap ◽  
Optical Energy ◽  
Glass Substrates

PbxCd1-xSe compound with different Pb percentage (i.e. X=0,0.025, 0.050, 0.075, and 0.1) were prepared successfully. Thin filmswere deposited by thermal evaporation on glass substrates at filmthickness (126) nm. The optical measurements indicated thatPbxCd1-xSe films have direct optical energy gap. The value of theenergy gap decreases with the increase of Pb content from 1.78 eV to1.49 eV.

EFFECT OF DEPOSITION TEMPERATURE ON THE PROPERTIES OF TIO2 THIN FILMS DEPOSITED BY MOCVD

2016 ◽  
Vol 23 (02) ◽  
pp. 1650001 ◽  
Author(s):  
ZAKI S. KHALIFA
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Deposition Temperature ◽  
Energy Gap ◽  
Organic Chemical ◽  
Tio2 Thin Films ◽  
Optical Energy Gap

Crystal structure, microstructure, and optical properties of TiO2 thin films deposited on quartz substrates by metal-organic chemical vapor deposition (MOCVD) in the temperature range from 250[Formula: see text]C to 450[Formula: see text]C have been studied. The crystal structure, thickness, microstructure, and optical properties have been carried out using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), atomic force microscope (AFM), and UV-visible transmittance spectroscopy, respectively. XRD patterns show that the obtained films are pure anatase. Simultaneously, the crystal size calculated using XRD peaks, and the grain size measured by AFM decrease with the increase in deposition temperature. Moreover, the texture of the films change and roughness decrease with the increase in deposition temperature. The spectrophotometric transmittance spectra have been used to calculate the refractive index, extinction coefficient, dielectric constant, optical energy gap, and porosity of the deposited films. While the refractive index and dielectric constant decrease with the increase of deposition temperature, the porosity shows the opposite.

scholarly journals Influence of Doping on Optical Properties of (CdS:Fe+3)Thin Films Prepared by Chemical Spray pyrolysis

2019 ◽  
Vol 30 (1) ◽  
pp. 193
Author(s):  
Karrar Mahdi Saleh
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spray Pyrolysis ◽  
Energy Gap ◽  
Nitrate Solution ◽  
Constant Thickness ◽  
Chemical Spray Pyrolysis ◽  
Optical Energy Gap ◽  
Optical Energy ◽  
Chemical Spray

In the present work, undoped CdS and doped with iron CdS:Fe+3 thin films have been prepared by chemical spray pyrolysis method on glass substrate with different temperature from cadmium nitrate solution with constant thickness(450 ± 5 nm), and study the effect of the percentage of doping with iron on optical properties of prepared films. The optical properties have been studied from transmittance and absorbance spectral within wavelengths range (380-900 nm). The results showed that all the prepared films has direct electronic transitions and optical energy gap between (2.31-2.44 eV). They also showed that the transmittance and optical energy gap of films prepared from nitrate solution increase with increasing of substrate temperature, then transmittance start downward with the continued increase in temperature (400, 450 oC), and a decrease in the optical energy gap with increasing doping percentage with iron.

scholarly journals Study of the Influence of Annealing Temperature on the Structural and Optical Properties of ZnTe Prepared by Vacuum Thermal Evaporation Technique

2018 ◽  
Vol 31 (1) ◽  
pp. 50
Author(s):  
Sarmad M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
High Smoothness ◽  
Evaporation Technique ◽  
20 Nm

   The ZnTe alloy was prepared as  deposited thin films on the glass substrates at a thickness of 400±20 nm using vacuum evaporation technique at pressure (1 × 10-5) mbar and room temperature. Then the thin films under vacuum (2 × 10-3 mbar) were annealing at (RT,100 and 300) °C for one hour. The structural properties were studied by using X-ray diffraction and AFM, the results show that the thin films had approached the single crystalline in the direction (111) as preferred orientation of the structure zinc-blende for cubic type, with small peaks of tellurium (Te) element for all prepared thin films. The calculated crystallite size (Cs) decreased with the increase in the annealing temperature, from (25) nm before the annealing to (21) nm after the annealing. The images of atomic force microscopy of all thin films appeared a homogenous structure and high smoothness through roughness values ​​that increased slightly from (1.4) nm to (3.4) nm. The optical properties of the ZnTe at (RT,100 and 300) °C were studied transmittance and absorbance spectrum as a function of the wavelength. The energy gap was found about (2.4) eV for the thin films before the annealing and increased slightly to (2.5) eV after annealing at 300 °C  

scholarly journals Annealing effect on the optical properties of organic semiconductor Alq3: C60 blend thin films

2019 ◽  
Vol 16 (39) ◽  
pp. 1-10
Author(s):  
Lamiaa K. Abbas
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Bulk Heterojunction ◽  
Chemical Bonds ◽  
Optical Energy Gap ◽  
Heat Treated ◽  
Infra Red ◽  
Uv Visible

The effect of heat treatment using different annealing temperatures on optical properties of bulk heterojunction blend (BHJ) Alq3: C60 thin films which are fabricated by the spin coating technique were investigated in this study. The films have been coated on a glass substrate with speed of 2000 rpm for one min and treated with different annealing temperature (373, 423 and 473) K under vacuum. The optical properties and the chemical bonds structure of blends as-deposited and heat treated have been studied by UV-Vis spectroscopic and Fourier Transform-Infra Red (FTIR) measurements respectively. The results of UV visible show that the optical energy gap decreasing with increasing the annealing temperature for the ratio (100:1) while decreasing with increasing the annealing temperature for ratio (100:10). The FTIR spectra measurement were applied to know the type of the bonds of Alq3: C60 BHJ thin films.

scholarly journals Effects of Annealing on the Structural and Optical Properties of V2O5 Thin Films Prepared by RF Sputtering for Humidity Sensor Application

2021 ◽  
pp. 3536-3544
Author(s):  
Bakr F. Hassan ◽  
Mohammed J. Dathan ◽  
Anas A. Abdallah
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Rf Sputtering ◽  
Rf Magnetron Sputtering ◽  
Xrd Analysis ◽  
Structural And Optical Properties ◽  
Glass Substrates ◽  
V2o5 Thin Films

     In this work, vanadium pentoxide (V2O5) thin films were prepared using rf magnetron sputtering on silicon wafer and glass substrates from V2O5 target at 200 °C substrate temperature, followed by annealing at 400 and 500 °C in air for 2 h. The prepared thin films were examined by X-ray diffraction (XRD), forier transform infra-red spectroscopy (FTIR), UV-visible absorbance, and direct current coductivity to study the effects of annealing temperature on their structural and optical properties. The XRD analysis exhibited that the annealing promoted the highly crystallized V2O5 phase that is highly orientated along the c direction. The crystalline size increased from 22.5 nm to 35.4 nm with increasing the annealing temperature to 500 °C. The FTIR spectroscopy showed the enhancement of the characteristics band for the V2O5 with increasing annealing temperature to 500 °C. The optical study showed that the energy gap for the sample deposited on glass slides decreased from 2.85 eV, for as deposited sample, to 2.6 eV upon annealing the sample to 500 °C. There was a linear dependence between sensitivity and relative humidity (RH) at the range from 25% to 70%, while the behavior was exponential  at high RH range.

scholarly journals The Structural and Optical Properties of Cobalt dioxide (CoO2 )Thin Films deposited via (SCSP) Technique for photovoltaic applications

2021 ◽  
Vol 13 (01) ◽  
pp. 33-42
Author(s):  
Mushtaq Talib Al-Helaly ◽  
◽  
Nathera A .Al-Tememee ◽  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Energy Gap ◽  
Spray Pyrolysis Technique ◽  
Film Surface ◽  
Structural And Optical Properties ◽  
Optical Energy Gap ◽  
Optical Energy ◽  
X Ray ◽  
Photovoltaic Applications

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.

scholarly journals Influence of annealing temperature on the structural and optical properties of As30Te70 thin films

2017 ◽  
Vol 35 (2) ◽  
pp. 335-345 ◽  
Author(s):  
A.M. Abd-Elnaiem ◽  
M. Mohamed ◽  
R.M. Hassan ◽  
A.A. Abu-Sehly ◽  
M.A. Abdel-Rahim ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Glass Transition ◽  
Extinction Coefficient ◽  
Chalcogenide Glasses ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Optical Parameters ◽  
Optical Energy Gap

Abstract Chalcogenide glasses have attracted much attention largely due to their interesting physical and chemical properties. Though few published articles exist on the As-Te system, little is known about the optical properties of eutectic or near eutectic composition of As-Te system upon heat treatment. Therefore, this paper reports the effects of annealing temperature on the structural and optical parameters of As30Te70 thin films. The bulk and thin films of 150 nm thick As30Te70 chalcogenide glasses were prepared by melt-quenching and thermal evaporation techniques, respectively. The glass transition and crystallization reactions of the bulk samples were investigated using differential scanning calorimetry (DSC). The influence of annealing temperature on the transformation of the crystal structure was studied by X-ray diffraction (XRD), while the surface morphology of the annealed samples was examined using scanning electron microscope (SEM). The optical band gap, refractive index and extinction coefficient were also calculated. The DSC scans showed that the melting temperature remains constant at 636.56 K. In addition, other characteristic temperatures such as the glass transition temperature, the onset crystallization temperature, and the crystallization peak temperature increase with increasing the heating rate. The crystalline phases for the as-prepared and annealed films consist of orthorhombic As, hexagonal Te, and monoclinic As2Te3 phases. Furthermore, the average crystallite size, strain, and dislocation density depend on the annealing temperature. The optical absorption results revealed that the investigated films have a direct transition, and their optical energy gap decreases from 1.82 eV to 1.49 eV as the annealing temperature increases up to 433 K. However, the refractive index, extinction coefficient, dielectric constant and the ratio of free carrier concentration to its effective mass, increase with increasing the annealing temperature.

scholarly journals The role of annealing temperature on the optical energy gap and Urbach energy of Se:2%Sb thin films

2008 ◽  
Vol 5 (2) ◽  
pp. 249-252
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Urbach Energy ◽  
Energy Gap ◽  
Localized States ◽  
Structural Defects ◽  
Indirect Transition ◽  
Optical Energy Gap ◽  
Optical Energy

The optical energy gap(Eopt) and the width of the tails of localized states in the band gap (?E) for Se:2%Sb thin films prepared by thermal co-evaporation method as a function of annealing temperature are studied in the photon energy range ( 1 to 5.4)eV.Se2%Sb film was found to be indirect transition with energy gap of (1.973,2.077, 2.096, 2.17) eV at annealing temperature (295,370,445,520)K respectively. The Eopt and ?E of Se:2%Sb films as a function of annealing temperature showed an increase in Eopt and a decrease in ?E with increasing the annealing temperature. This behavior may be related to structural defects and dangling bonds.

Sign in / Sign up

Export Citation Format

Share Document