scholarly journals Optical and sensing properties of Fe doped ZnO nanocrystalline thin films

2016 ◽  
Vol 34 (2) ◽  
pp. 354-361 ◽  
Author(s):  
R.K. Shukla ◽  
Anchal Srivastava ◽  
Nishant Kumar ◽  
Akhilesh Pandey ◽  
Mamta Pandey
Keyword(s):  
Optical Band Gap ◽  
Dopant Concentration ◽  
Precursor Solution ◽  
Hexagonal Wurtzite Structure ◽  
Zinc Nitrate ◽  
Maximum Sensitivity ◽  
Zno Films ◽  
Spray Pyrolysis Method ◽  
Doped Zno ◽  
Nanocrystalline Thin Films

AbstractUndoped and Fe doped ZnO films of different molarities deposited by spray pyrolysis method using zinc nitrate and ferric chloride as precursors show polycrystalline nature and hexagonal wurtzite structure. Crystallite size decreases with an increase in dopant concentration from 0 at.% to 3 at.%. Doping improves the transmission of the films whereas it reduces the optical band gap of ZnO from 3.28 eV to 3.17 eV. The morphology resembles flake-like structures which collapse when the dopant is introduced. The samples are found to be sensitive to CO2 gas. Undoped ZnO shows maximum sensitivity at 350 °C for higher concentration of CO2. Doped samples show maximum sensitivity at 200 °C for all CO2 concentrations i.e. from 500 ppm to 4000 ppm. Maximum sensitivity is achieved at temperatures 350 °C, 250 °C, 300 °C and 450 °C for the samples prepared using precursor solution of 0.1 M molarity.

scholarly journals Optical and Sensing Properties of Cu Doped ZnO Nanocrystalline Thin Films

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
R. K. Shukla ◽  
Anchal Srivastava ◽  
Nishant Kumar ◽  
Akhilesh Pandey ◽  
Mamta Pandey
Keyword(s):  
Optical Band Gap ◽  
Gas Sensing ◽  
Hexagonal Wurtzite Structure ◽  
Zinc Nitrate ◽  
Zno Films ◽  
In Doping ◽  
Doped Zno ◽  
Sensing Characteristics ◽  
Nanocrystalline Thin Films ◽  
Morphology Changes

Undoped and Cu doped ZnO films of two different molarities deposited by spray pyrolysis using zinc nitrate and cupric chloride as precursors show polycrystalline nature and hexagonal wurtzite structure of ZnO. The crystallite size varies between 10 and 21 nm. Doping increases the transmittance of the films whereas the optical band gap of ZnO is reduced from 3.28 to 3.18 eV. With increment in doping the surface morphology changes from irregular shaped grains to netted structure with holes and then to net making needle-like structures which lends gas sensing characteristics to the films. Undoped ZnO shows maximum sensitivity at 400°C for higher concentration of CO2. The sensitivity of Cu doped sample is maximum at 200°C for all CO2concentrations from 500 to 4000 ppm.

Structural and Optical Properties of F-Doped ZnO Nanoparticles Synthesized by Co-Precipitation Process

2016 ◽  
Vol 675-676 ◽  
pp. 69-72
Author(s):  
Krisana Chongsri ◽  
Wanichaya Mekprasart ◽  
Wisanu Pecharapa
Keyword(s):  
Zno Nanoparticles ◽  
Fluoride Concentration ◽  
Precursor Solution ◽  
Hexagonal Wurtzite Structure ◽  
Ammonium Fluoride ◽  
Zinc Nitrate ◽  
Precipitation Process ◽  
Vis Spectroscopy ◽  
Doped Zno ◽  
Co Precipitation

In this work, we reported the preparation of F-doped ZnO nanoparticles by facile precipitation process using zinc nitrate and ammonium fluoride as starting precursors for Zn and F, respectively dissolved in deionized water. The precursor solution was prepared at various fluoride composition ranging from 1-5 wt%. The as-precipitated powders were calcined at different temperature from 500 °C to 700 °C for 2 h. Effect of calcination temperature and fluoride concentration on structural, morphologies, optical and electrical properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis spectroscopy, respectively. XRD results indicated the complete formation of hexagonal wurtzite structure of ZnO. SEM micrographs showed the agglomeration for each sample that noticeably influenced by fluoride content.

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

2018 ◽  
Vol 35 (4) ◽  
pp. 824-829 ◽  
Author(s):  
Yasemin Caglar ◽  
Saliha Ilican ◽  
Mujdat Caglar
Keyword(s):  
Surface Morphology ◽  
Band Gap ◽  
Optical Band Gap ◽  
Hexagonal Wurtzite Structure ◽  
Bath Temperature ◽  
Xrd Analysis ◽  
Zno Films ◽  
Si Substrates ◽  
Doped Zno ◽  
B Doping

Abstract 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.

Influence of Precursor Solution Concentration on Structure and Magnetic Properties of Zinc Oxide Thin Films

2016 ◽  
Vol 724 ◽  
pp. 43-47
Author(s):  
H.S. Sindhu ◽  
Sumanth Joishy ◽  
B.V. Rajendra ◽  
P.D. Babu
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Magnetic Properties ◽  
Precursor Solution ◽  
Hexagonal Wurtzite Structure ◽  
Solution Concentration ◽  
Zno Films ◽  
Spray Pyrolysis Method ◽  
Oxide Thin Films ◽  
Deposited Films

Zinc oxide thin films were deposited on glass substrate at a substrate temperature of 673K by spray pyrolysis method using different concentration of 0.0125M, 0.025M and 0.05M of Zinc acetate solutions. The effect of molar concentrations on structure, surface morphology and magnetic properties of ZnO films were investigated using x-ray diffraction, scanning electron microscopy and vibrating sample magnetometer. All deposited films were polycrystalline in nature with hexagonal wurtzite structure having a preferential growth orientation along (101) plane. An improvement of crystallinity in the deposits with increasing concentration of sprayed solution was noticed. All deposit exhibit fibrous structure which increases with increase of precursor concentration solutions. At room temperature, all deposited films were shown diamagnetic character but when cooled to 5K, they have shown paramagnetic characteristics.

Structural and Optical Studies of Molarity Based ZnO Thin Films

2017 ◽  
Vol 17 ◽  
pp. 140-148 ◽  
Author(s):  
A. Jacquiline Regina Mary ◽  
S. Arumugam
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Visible Region ◽  
Precursor Solution ◽  
Hexagonal Wurtzite Structure ◽  
Solution Concentration ◽  
Molar Concentration ◽  
Zno Thin Films ◽  
Zno Films ◽  
Average Grain Size

Zinc Oxide thin films were prepared for different precursor solution molarities from 0.025M to 0.1M by spray pyrolysis deposition technique. A comprehensive study was carried out to realize the effect of concentration of precursor on ZnO thin films. The optimized temperature of the glass substrate was 300°C. From the XRD data it is inferred that the films are polycrystalline and hexagonal wurtzite structure . The degree of preferred orientation were along diffraction planes (100), (002) and (101) for all the ZnO films. The intensity of the diffraction peak prepared with 0.1M concentration is higher than those prepared at lower concentrations. The grain size (D) was calculated using Debye-Scherrer formula. It was found that the average grain size increases, when the molar concentration increases. As the solution concentration increases, the band gap decreases. The films are transparent in the visible region (85%), and the transmittance decreases as the molar concentration increases, which is caused by optical scattering at grain boundaries.

scholarly journals Effect of Gallium Incorporation on the Properties of ZnO Thin Films

2019 ◽  
Author(s):  
Sema Kurtaran ◽  
Serhat Aldağ ◽  
Göksu Öföfoğlu
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Zno Thin Films ◽  
Visible Range ◽  
Zno Films ◽  
Spray Pyrolysis Method ◽  
Chemical Spray Pyrolysis ◽  
Atomic Force ◽  
Doped Zno ◽  
Ga Doping

Ga doped ZnO thin films were formed by the Ultrasonic Chemical Spray Pyrolysis method onto substrates using zinc acetate and gallium (III) nitrate hydrate as precursors. The structural, optical, surface and electrical properties were studied as a function of increasing Ga doping concentration from 0 to 6 at %. Structural studies were shown polycrystalline with a hexagonal crystal structure. The transparency in the visible range was around 85% for thin film deposited using 6 at % Ga doping. With the aim of determining surface images and surface roughness of the films atomic force microscope images were taken. Ga doping of ZnO thin films could markedly decrease surface roughness. Electrical resistivity was determined by four point method. The resistivity 2.0% Ga doped ZnO film was the lowest resistivity of 1.7 cm. In the photoluminescence measurements of the films, existence of UV and defect emission band was observed. As a result, Ga doped ZnO films have advanced properties and promising materials for solar cells.

Optical Properties of Cu-Doped ZnO Films Prepared by Cu Solution Coating

2015 ◽  
Vol 15 (10) ◽  
pp. 7664-7670 ◽  
Author(s):  
Bunyod Allabergenov ◽  
Seok-Hwan Chung ◽  
Sungjin Kim ◽  
Byeongdae Choi
Keyword(s):  
Grain Size ◽  
Optical Properties ◽  
Hexagonal Wurtzite Structure ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Coating Method ◽  
Higher Temperature ◽  
Doped Zno ◽  
Process Energy ◽  
Beam Deposition

This work demonstrates the fabrication of Cu-doped ZnO films by Cu solution coating method. Cu ink was spin coated on ZnO thin films prepared by e-beam deposition. After curing and annealing at high temperatures, structural, morphological and optical properties of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectrofluorometer, respectively. The XRD results showed that ZnO films formed polycrystalline with a hexagonal wurtzite structure, and the grain size increased with increasing the annealing temperature from 500 to 850 °C. The changes in lattice parameters were caused by grain size, strain, and residual stress. Morphological analysis have revealed that the Cu-doped ZnO film after annealing at 500 °C has flat surface with uniformly distributed grain size, which became porous after higher temperature annealing process. Energy dispersive spectroscopy (EDS) and photoluminescence spectras have shown the presence of Zn, Cu, and O elements, and combined violet, blue, green and weak red emissions between 350 and 650 nm in the ZnO films, respectively.

scholarly journals Influence of Argon/oxygen Ratio on Linear and Nonlinear Optical Properties of Copper Doped ZnO Films

2019 ◽  
Vol 26 (2) ◽  
pp. 121-126
Author(s):  
Xing WEN ◽  
Yue HAN ◽  
Cheng-Bao YAO ◽  
Ke-Xin ZHANG ◽  
Jin LI ◽  
...  
Keyword(s):  
Thin Films ◽  
Nonlinear Absorption ◽  
Gas Flow ◽  
Hexagonal Wurtzite Structure ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Flow Rates ◽  
Doped Zno ◽  
Diffraction Patterns ◽  
Oxygen Ratio

Copper (Cu)-doped ZnO (CZO) films were grown by simultaneous direct current and radio frequency magnetron sputtering technique under the situation of different gas flow rates of Ar: O2 (1:1, 2:1 and 1:0). The X-ray diffraction patterns revealed the naturally polycrystalline ZnO films with the predominant reflection (002) peak, which referred to the hexagonal wurtzite structure toward c-axis. The elemental composition of thin films was analyzed by energy dispersive spectroscopy (EDS). The Cu concentrations in thin films increased with Ar ratio of up to 1:0. The EDS spectra of three kinds of elements indicate that Cu-doping has obvious and sophisticated effect on the chemical state of oxygen, but less effect on those of copper and zinc. Furthermore, the nonlinear absorption of CZO films was investigated by the way of Z-scan technique. These films demonstrated good nonlinear absorption behavior for the different gas flow rates of Ar: O2.

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