Solid-state electronics

We have investigated the influences of aluminum and gallium dopants (0 to 2.0 mol%) on zinc oxide (ZnO) thin films regarding crystallization and electrical and optical properties for application in transparent conducting oxide devices. Al- and Ga-doped ZnO thin films were deposited on glass substrates (corning 1737) by sol–gel spin-coating process. As a starting material, AlCl3⋅6H2O, Ga(NO3)2, and Zn(CH3COO)2⋅2H2O were used. A lowest sheet resistance of 3.3 × 103 Ω/□ was obtained for the GZO thin film doped with 1.5 mol% of Ga after post-annealing at 650°C for 60 min in air. All the films showed more than 85% transparency in the visible region. We have studied the structural and microstructural properties as a function of Al and Ga concentrations through X-ray diffraction and scanning electron microscopy analysis. In addition, the optical bandgap and photoluminescence were estimated.

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Comparative studies of Al-doped ZnO and Ga-doped ZnO transparent conducting oxide thin films

Electrodeposition of Ni-Fe alloys, composites, and nano coatings–A review

Detection of chemicals and biological species is an important issue to human health and safety. In this paper, we report the hydrothermal synthesis at 95 °C of Cu-doped ZnO low-dimensional rods for room-temperature (RT) sensing applications and enhanced sensor performances. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman and photoluminescence are used to characterize the material properties. To demonstrate the suitability of the Cu-doped ZnO rods for gas sensor applications and for comparison with pure ZnO, we fabricated a double rod device using Focused Ion Beam. The responses of pure-ZnO and Cu-doped ZnO rods studied in exactly the same condition are reported. We found that Cu-ZnO sensors have enhanced RT sensitivity, faster response time, and good selectivity. Miniaturized Cu-ZnO rod-based sensors can serve as a good candidate for effective H2 detectors with low power consumption.

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Synthesis and characterization of Cu-doped ZnO one-dimensional structures for miniaturized sensor applications with faster response

A review on recent advances in photodegradation of dyes using doped and heterojunction based semiconductor metal sulfide nanostructures for environmental protection

Thickness dependence of structural, electrical and optical properties of sprayed ZnO:Cu films

ZnSe thin films have been deposited on high cleaned glass substrate by spray 
pyrolysis technique within the glass substrate temperature range (400 ○C 
to 450 ○C). The structural properties of ZnSe thin films have been 
investigated by (XRD) X-ray diffraction techniques. The X-ray diffraction 
spectra showed that ZnSe thin films are polycrystalline and have a cubic 
(zinc blende) structure. The most preferential orientation is along the 
(111) direction for all spray deposited ZnSe films together with 
orientations in the (220) and (311) planes also being abundant. The film 
thickness was determined by an interferometric method. The lattice 
parameter, grain size, microstrain and dislocation densities were calculated 
and correlated with the substrate temperature (TS). The optical 
properties of ZnSe thin films have been investigated by UV/VIS spectrometer 
and the direct band gap values were found to be in the region of 2.65 eV to 
2.70 eV. The electrical properties of ZnSe thin films have been investigated 
using the Van der Pauw method and the high quality ZnSe thin films were 
observed to develop at 430 ○C with a resistivity of 56,4×105 ohm cm, a conductivity of 1.77×10-7 (Ω cm)-1 and a hall 
mobility of 0.53 cm2/Vsec.

Investigations on structural, optical and electrical parameters of spray deposited ZnSe thin films with different substrate temperature

Zinc sulfide (ZnS) thin films were deposited on a glass substrate by the spray pyrolysis technique. The films were doped with copper using the direct method, consisting in addition of a copper salt (CuCl2) to the spray solution of ZnS. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermoluminescence (TL). XRD as well as SEM techniques have been employed to investigate the structure and surface morphology of as-deposited and doped films. Optical properties, such as transmission and the band gap have been analyzed. A drastic change in the resistivity has been observed due to the incorporation of Cu dopant and the results are discussed in detail. The effect of the spraying time on the electrical and optical properties of the films has been studied.

Characterization of copper-doped sprayed ZnS thin films

InP film samples were prepared by spray pyrolysis technique using aqueous solutions of InCl3 and Na2HPO4, which were atomized with compressed air as carrier gas onto glass substrates at 500° C with different thicknesses of the films. It is found that the resistivity of the polycrystalline films strongly depends on the grain size. It is observed that the grain size of the films increase with the decrease of the energy band gap and strain of the film. The changes observed in the energy band gap and strain related to the film grain size of the films are discussed in detail.

Mustafa Öztaş

Papers

Thickness dependence of structural, electrical and optical properties of sprayed ZnO:Cu films

Investigations on structural, optical and electrical parameters of spray deposited ZnSe thin films with different substrate temperature

Characterization of copper-doped sprayed ZnS thin films

Influence of Grain Size on Electrical and Optical Properties of InP Films

Effect of sample producing conditions on the thermoluminescence properties of ZnS thin films developed by spray pyrolysis method