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.

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 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.

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.

Effect of cobalt doping on microstructures and dielectric properties of ZnO

2019 ◽  
Vol 97 (3) ◽  
pp. 227-232 ◽  
Author(s):  
Ye Zhao ◽  
Fan Tong ◽  
Mao Hua Wang
Keyword(s):  
Zno Nanoparticles ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Sem Analysis ◽  
Co Doping ◽  
In Doping ◽  
Zno Powders ◽  
Doped Zno ◽  
Zno Crystal ◽  
Co Doped

Pure and cobalt-doped ZnO nanoparticles (2.5, 5, 7.5, and 10 atom % Co) are synthesized by sol–gel method. The as-synthesized nanoparticles are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE-SEM) analysis. The nanoparticles of 0, 2.5, and 5 atom % Co-doped ZnO exhibited hexagonal wurtzite structure and have no other phases. Moreover, the (101) diffraction peaks position of Co-doped ZnO shift toward a smaller value of diffraction angle compared with pure ZnO powders. The results confirm that Co ions were well incorporated into ZnO crystal lattice. Simultaneously, Co doping also inhibited the growth of particles, and the crystallite size decreased from 43.11 nm to 36.63 nm with the increase in doping concentration from 0 to 10 atom %. The values of the optical band gap of all Co-doped ZnO nanoparticles gradually decreased from 3.09 eV to 2.66 eV with increasing Co content. Particular, the dielectric constant of all Co-doped ZnO ceramics gradually increased from 1.62 × 103 to 20.52 × 103, and the dielectric loss decreased from 2.36 to 1.28 when Co content increased from 0 to 10 atom %.

Correlating the magnetism and gas sensing properties of Mn-doped ZnO films enhanced by UV irradiation

RSC Advances ◽  
2016 ◽  
Vol 6 (31) ◽  
pp. 26227-26238 ◽  
Author(s):  
David E. Motaung ◽  
Ioannis Kortidis ◽  
Gugu H. Mhlongo ◽  
Mart-Mari Duvenhage ◽  
Hendrik. C. Swart ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Gas Sensing ◽  
Zno Films ◽  
Schematic Diagram ◽  
Sensing Properties ◽  
Tof Sims ◽  
Gas Sensing Properties ◽  
Doped Zno ◽  
Mn Concentration ◽  
Mn Doped

Schematic diagram showing the 2D TOF SIMS overlays of Si+, Mn+and Zn+. The insert corresponds to the correlation between the sensing response and FMR signal as a function of Mn concentration when exposed to various gases.

Thermal, optical and gas sensing properties of ZnO films prepared by different techniques

2018 ◽  
Vol 81 (1) ◽  
pp. 10101 ◽  
Author(s):  
Sonik Bhatia ◽  
Neha Verma ◽  
Munish Aggarwal
Keyword(s):  
Gas Sensor ◽  
Recovery Time ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Effect Of Temperature ◽  
Zno Films ◽  
Sensing Properties ◽  
Response And Recovery

Nowadays, for environmental protection, the use of portable gas sensor is essential to detect toxic gases. To control this problem of hazardous gases, metal oxide based sensors plays a vital role. In this recent study, Indium (2 at.wt.%) doped ZnO films has been prepared by sol gel spin coating and thermal evaporation techniques on glass substrates. To enhance the sensing properties, indium (In) was used as dopant and their annealing effect of temperature was observed. Thermal properties have shown the fruitful result that prepared films are useful for the fabrication of solar cell. Electrical properties revealed that capacitance and dielectric constant decreases with increase in frequency. X-ray Diffraction showed hexagonal wurtzite structure highly oriented along (1 0 1) plane. Field emission scanning electron microscope of these synthesis films prepared by different have shown the morphology as nanospheres having size of the order of 40–60 nm. 2.0 at.% of indium as modifier resulted in highest response and selectivity towards 5 ppm of NO2 gas at different operating temperature (50–200 °C). Highest sensitivity was obtained at operating temperature of 150 °C. Prepared films have quick response and recovery time in the range of 14–27 s and 67–63 s. The highest response and recovery time of gas sensor was explained by valence ion mechanism.

scholarly journals Performances of spin coated silver doped ZnO photoanode based dye sensitized solar cell

2017 ◽  
Vol 11 (3) ◽  
pp. 213-219 ◽  
Author(s):  
Amrik Singh ◽  
Devendra Mohan ◽  
Singh Ahlawat ◽  
R Richa
Keyword(s):  
Solar Cells ◽  
Dye Sensitized Solar Cells ◽  
Zno Films ◽  
Zno Film ◽  
Dye Sensitized ◽  
Tauc Plot ◽  
In Doping ◽  
Two Samples ◽  
Doped Zno ◽  
Sensitized Solar Cells

Dye sensitized solar cells (DSSCs) were fabricated using silver doped ZnO films deposited on ITO glass by spin coating method. The crystalline nature of ZnO films was analysed with XRD and SEM technique was used for morphological studies. The XRD pattern confirmed the presence of single phase hexagonal wurtzite ZnO structure, without the presence of secondary phase. The crystallite size of ZnO decreased from 31 nm to 25 nm with increase in doping to 1.5mol% of silver. The UV-visible transmission of the prepared ZnO film was found to be 70-90% and it decreased with increase in doping to 0.5mol% Ag and increased in the film doped with 1.5mol% Ag. The band gap values of the ZnO films with 0, 0.5 and 1.5mol% of silver, determined from Tauc plot, were 3.269, 3.235 and 3.257 eV, respectively. The absorbance peaks of the N719 dye loaded ZnO films were obtained at the wavelengths 310, 350 and 538 nm. The N719 dye loaded ZnO film doped with 0.5mol% Ag has the highest absorbance in the visible region as compared to other two samples. The fill factor values of the pure and ZnO doped with 0.5 and 1.5mol% Ag were 0.47, 0.48 and 0.42, respectively. The short circuit density values for ZnO, ZnO:Ag0.5% and ZnO:Ag1.5% were found to be 1.50, 1.55 and 1.15 A?m/cm2, respectively. The calculated photon to electron efficiencies for the ZnO films with 0, 0.5 and 1.5mol% of silver were 0.42%, 0.44% and 0.27%, respectively. Consequently future prospective of such type of dopants in ZnO film based dye sensitized solar cells seems to be bright.

scholarly journals Influence of Al Doping on the Morphological, Structural and Gas Sensing Properties of Electrochemically Deposited ZnO Films on Quartz Resonators

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 81
Author(s):  
Gergana Alexieva ◽  
Konstantin Lovchinov ◽  
Miroslav Petrov ◽  
Rositsa Gergova ◽  
Nikolay Tyutyundzhiev
Keyword(s):  
Gas Sensing ◽  
Zno Films ◽  
Active Surface Area ◽  
Average Roughness ◽  
Sensing Properties ◽  
Developed Surface ◽  
Gas Sensing Properties ◽  
Electrochemically Deposited ◽  
Doped Zno ◽  
Quartz Resonators

The detection of hazardous gases at different concentration levels at low and room temperature is still an actual and challenging task. In this paper, Al-doped ZnO thin films are synthesized by the electrochemical deposition method on the gold electrodes of AT-cut quartz resonators, vibrating at 10 MHz. The average roughness, surface morphology and gas sensing properties are investigated. The average roughness of Al-doped ZnO layers strongly depends on the amount of the doping agent Al2(SO4)3 added to the solution. The structural dependence of these films with varying Al concentrations is evident from the scanning electron microscopy images. The sensing properties to ethanol and ammonia analytes were tested in the range of 0–12,800 ppm. In the analysis of the sensitivity to ammonia, a dependence on the concentration of the added Al2(SO4)3 in the electrochemically deposited layers is also observed, as the most sensitive layer is at 3 × 10−5 M. The sensitivity and the detection limit in case of ammonia are, respectively, 0.03 Hz/ppm and 100 ppm for the optimal doping concentration. The sensitivity depends on the active surface area of the layers, with those with a more developed surface being more sensitive. Al-doped ZnO layers showed a good long-term stability and reproducibility towards ammonia and ethanol gases. In the case of ethanol, the sensitivity is an order lower than that for ammonia, as those deposited with Al2(SO4)3 do not practically react to ethanol.

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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