The fluorine doped cadmium oxide samples have been deposited at 250
°C by ultrasonic spray pyrolysis method. X-ray diffraction patterns of the CdO:F samples have revealed that the samples are ...polycrystalline with cubic sodium chloride structure. The texture coefficients calculated for various planes at different fluorine concentrations indicate that the samples have exhibited (1
1
1) and (2
0
0) preferential orientations. The lattice parameters for cubic structure of each diffraction plane have been calculated. The crystallite size of the samples being nearly constant until 4% of fluorine doping showed reasonable decrease above this concentration value. The macro strain and dislocation density vary with fluorine concentrations.
Thin films of CdS nanoparticles were synthesized by the chemical bath deposition (CBD) technique to investigate humidity response characteristics. The morphology and the crystal structure of CdS thin ...films were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The quartz crystal microbalance (QCM) technique was used to measure the water vapor adsorption and desorption rates of CdS thin films. The dynamic Langmuir model was used to analyze the kinetics of the moisture adsorption and desorption process under relative humidity (RH) between 17 and 85% RH. Our results indicate that CdS thin films have a great affinity to humidity at room temperature.
The CdO:F samples have been deposited onto microscope glass substrates at 250
°C by ultrasonic spray pyrolysis method. With the incorporation of fluorine into CdO, the direct optical transition has ...shifted towards the shorter wavelengths, and the transparency of the material has increased at a given wavelength above the fundamental absorption edge. The shift in the absorption edge is explained by means of the Moss–Burstein effect, which is also supported with the results of the current–voltage characteristics. Here, a correlation has been established between the band broadening and the increase in conductivity due to the increase in carrier density.
We have studied the structural and electrical properties of Zn sub(1-x)Cd sub(x)O alloy films deposited by ultrasonic spray pyrolysis technique. XRD measurement indicated that pure ZnO and CdO ...samples had single phases with hexagonal wurtzite and cubic structures, respectively. However, Zn sub(1-x)Cd sub(x)O alloy films with x = 0.59 and 0.78 exhibited mixtures of a hexagonal wurtzite ZnO phase and a cubic CdO phase. Analysis of thermally stimulated current spectra of Zn sub(1-x)Cd sub(x)O alloy films revealed the existence of a number of overlapped peaks each characterized by different trap energy levels located in the range of 0.033-0.215 eV below the conduction band. We have used curve fitting method for the evaluation of the trap parameters of the alloy films. The values of attempt-to-escape frequency nu, capture cross-section S and concentration of the traps N sub(t) have been determined.
In this work, zinc oxide semiconducting films belonging to the II-VI group have been produced by successive ionic layer adsorption and reaction (SILAR) method on glass substrates with 10, 15, 20 and ...25
cycles at room temperature. Following the deposition, the samples were dried in air at 400
°C for 1
h. The films were characterized by X-ray diffraction, field emission scanning electron microscopy and optical absorption measurement techniques. The X-ray diffractions of the films showed that they are hexagonal in structure. The crystallite size of ZnO films varied between 34 and 38
nm accordingly with the number of SILAR cycles. The material has exhibited direct band gap transition with the band gap values lying in the range between 3.13 and 3.18
eV. The red shift is observed in the absorption edge as the cycles increased. Transmission of the films decreased from 65 to 40% with increasing the number of cycles.
Polycrystalline ZnS semiconducting films have been prepared by ultrasonic spray pyrolysis technique in the form of planar and sandwich configurations using amorphous and ZnO coated glass substrates. ...Deposition of ZnS films by the spray pyrolysis has been studied extensively by several investigators and the process parameters have been optimized to obtain films with good characteristics. However we report for the first time the preparation of ZnS films sandwiched between top and bottom electrodes on the transparent conducting ZnO films that have been produced by the spray pyrolysis technique. The produced ZnS films have been crystallized in a wurtzite structure. The electrical properties of the samples having planar and sandwich structures have been measured in dark at room temperature by applying the voltage values between 0.01 and 100 V.
The fluorine doped cadmium oxide (CdO:F) samples have been deposited at 250 °C by ultrasonic spray pyrolysis method. Cadmiumacetat-dihydrat and ammonium fluoride have been taken as a source of ...cadmium and fluorine-dopant respectively. The thickness of the CdO:F samples was about 1.4 μm. X-ray diffraction pattern of the CdO:F samples has revealed that the samples are polycrystalline with cubic sodium chloride structure. There are shifts of the
d values (interplanar spacing) for CdO:F samples with respect to standard CdO film. The lattice parameters for cubic structure have been calculated using the Bragg equation. The texture coefficients calculated for various planes at different fluorine concentrations indicate that the samples have exhibited (111) and (200) preferential orientations.
▶ We have studied the structural and electrical properties of Zn
1−
x
Cd
x
O alloy films deposited by ultrasonic spray pyrolysis technique. ▶ The trap energy, the capture cross-section, the ...attempt-to-escape frequency and the concentration of the traps in Zn
1−
x
Cd
x
O films are reported. ▶ The effect of the Cd incorporation into ZnO material on trapping levels was investigated by the TSC measurements. Two overlapped peaks were registered at levels of 0.033 and 0.197
eV in ZnO sample by the curve fitting technique. The observed trap energy levels for ZnO film is thought to originate from zinc interstitials and oxygen vacancies. However, the incorporation of Cd into Zn
1−
x
Cd
x
O alloy films with
x
=
0.59 have resulted in two trapping centers with activation energies of 0.118 and 0.215
eV. The observed trap levels in Zn
0.41Cd
0.59O alloy film are related to oxygen adsorption in the sample.
We have studied the structural and electrical properties of Zn
1−
x
Cd
x
O alloy films deposited by ultrasonic spray pyrolysis technique. XRD measurement indicated that pure ZnO and CdO samples had single phases with hexagonal wurtzite and cubic structures, respectively. However, Zn
1−
x
Cd
x
O alloy films with
x
=
0.59 and 0.78 exhibited mixtures of a hexagonal wurtzite ZnO phase and a cubic CdO phase. Analysis of thermally stimulated current spectra of Zn
1−
x
Cd
x
O alloy films revealed the existence of a number of overlapped peaks each characterized by different trap energy levels located in the range of 0.033–0.215
eV below the conduction band. We have used curve fitting method for the evaluation of the trap parameters of the alloy films. The values of attempt-to-escape frequency
ν, capture cross-section
S and concentration of the traps
N
t
have been determined.
