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FESEM, XRD and DRS studies of electrochemically deposited boron doped ZnO films

Caglar Y., Ilican S., Caglar M.

Materials Science Poland

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2017

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Vol. 35, No. 4

824--829

EN

In this study, the effect of boron (B) incorporation into zinc oxide (ZnO) has been investigated. The undoped, 2 at.%. and 4 at.% B doped ZnO films were deposited on p-type silicon (Si) substrates by electrodeposition method using chronoamperometry technique. Electrochemical depositions were performed by applying a constant potentiostatic voltage of 1.1 V for 180 min at 90 °C bath temperature. To analyze the surface morphology, field emission scanning electron microscopy (FESEM) was used and the results revealed that while a small amount of boron resulted in smoother surface, a little more incorporation of boron changed the surface morphology to dandelion-like shaped rods on the whole surface. By using X-ray diffraction (XRD) analysis, the crystal structures of the films were detected and the preferred orientation of the ZnO, which exhibited polycrystalline and hexagonal wurtzite structure, changed with B doping. For the estimation of the optical band gap of obtained films, UV-Vis diffuse reflectance spectra (DRS) of the films were taken at room temperature and these data were applied to the Kubelka-Munk function. The optical band gap of ZnO narrowed due to incorporation of B, which was confirmed by red-shift.

2

Fekete-Szego problem for certain subclasses of analytic functions

Orhan H., Deniz E., Caglar M.

Demonstratio Mathematica

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2012

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Vol. 45, nr 4

835-846

EN

In this present investigation, authors introduce certain subclasses of star like and convex functions of complex order b, using a linear multiplier differential operator (…). In this paper, for these classes the Fekete-Szegö problem is completely solved. Various new special cases of our results are also pointed out.

3

Effect of Sn dopants on the optical and electrical properties of ZnO films

Aksoy S., Caglar Y., Ilican S., Caglar M.

Optica Applicata

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2010

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Vol. 40, nr 1

7--14

EN

The undoped and tin (Sn) doped ZnO films were deposited by a spray pyrolysis method onto the glass substrates. 0.2 M solution of zinc acetate in a mixture of ethanol and deionised water, in a volume proportion of 3 : 1, was employed. Dopant source was tin chloride. The atomic percentage of dopant in solution were Sn/Zn = 1%, 3% and 5%. The effect of tin doping on the optical and electrical properties of ZnO films was studied. The optical transmittance was about 76% in a visible range for Sn-doped ZnO films. The optical band gaps of the films were calculated. This suggests that the absorption edge shifts to the lower wavelengths with Sn dopant. Optical constants of the films were determined. These parameters changed with Sn dopant.

4

Determination of the thickness and optical constants of transparent indium-doped ZnO thin films by the envelope method

Ilican S., Caglar M., Caglar Y.

Materials Science Poland

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2007

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Vol. 25, No. 3

709--718

EN

Transparent indium-doped ZnO thin films were deposited by the spray pyrolysis method onto glass substrates. The content of indium in the starting solution was 0.5 at. %. The crystallographic structure of the film was studied by X-ray diffraction (XRD). XRD measurement shows that the film is crystallized in the wurtzite phase and presents a preferential orientation along the c-axis. The texture coefficient (TC), grain size value and lattice constants have been calculated. The absorption coefficient and the thickness of the films were calculated from interference of transmittance spectra. Optical constants such as the refractive index n and extinction coefficient k have been determined from transmittance spectrum in the ultraviolet-visible-near infrared (UV-VIS-NIR) regions using the envelope method. The thickness of the films strongly influences the optical constants.

5

Optical characterization of the CdZn(S1-x Sex )2 thin films deposited by spray pyrolysis method

Ilican S., Zor M., Caglar Y., Caglar M.

Optica Applicata

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2006

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Vol. 36, nr 1

29-37

EN

CdZn(S1-xSex )2 thin films have been deposited onto glass substrates by the spray pyrolysis method at a 275°C substrate temperature. The average optical transmittance of all the films was over 65% in the wavelength range 450-800 nm. The optical absorption studies reveal that the transition is direct with band gap energy values between 2.47-3.04 eV. The optical constants such as refractive index, extinction coefficient and dielectric constants have been calculated for these films. The dispersion parameters such as Eo (single-oscillator energy) and Ed (dispersive energy) have been discussed in terms of the Wemple-DiDomenico single-oscillator model. The values obtained by this method are suitable for many scientific studies and technological applications, such as gas sensors, heat mirrors, transparent electrodes, solar cells and piezoelectric devices.