scholarly journals Structural, Magnetic, and Optical Properties of Mn2+ Doping in ZnO Thin Films

Surfaces ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 268-278
Author(s):  
Monika Sharma ◽  
Kakoli Bera ◽  
Ruby Mishra ◽  
Alka V. Kuanr
Keyword(s):  
Thin Films ◽  
Magnetic Measurements ◽  
Magnetic Loss ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Zno Films ◽  
Visible Absorption ◽  
Spintronic Devices ◽  
Glass Substrates ◽  
Mn Concentration

MnxZn1−xO thin films (x = 0%, 1%, 3%, and 5%) were grown on corning glass substrates using sol–gel technique. Single-phase hexagonal wurtzite structure was confirmed using X-ray diffraction. Raman analysis revealed the presence of Mn content with an additional vibrational mode at 570 cm−1. The surface morphology of the samples was observed by scanning electron microscopy which suggested that the grain size increases with an increase in Mn concentration. The optical bandgap increases with increasing Mn concentration due to a significant blueshift in UV–visible absorption spectra. The alteration of the bandgap was verified by the I–V measurements on ZnO and Mn-ZnO films. The various functional groups in the thin films were recorded using FTIR analysis. Magnetic measurements showed that MnxZn1−xO films are ferromagnetic, as Mn induces a fully polarised state. The effect of Mn2+ ions doping on MnxZn1−xO thin films was investigated by extracting various parameters such as lattice parameters, energy bandgap, resistivity, and magnetisation. The observed coercivity is about one-fifth of the earlier published work data which indicates the structure is soft in nature, having less dielectric/magnetic loss, and hence can be used as ultra-fast switching in spintronic devices.

Microstructural and Electrical Conductivity of Annealed ZnO Thin Films

2014 ◽  
Vol 970 ◽  
pp. 120-123 ◽  
Author(s):  
Peh Ly Tat ◽  
Karim bin Deraman ◽  
Wan Nurulhuda Wan Shamsuri ◽  
Rosli Hussin ◽  
Zuhairi Ibrahim
Keyword(s):  
Thin Films ◽  
Low Cost ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Dip Coating ◽  
Zno Thin Films ◽  
Zno Films ◽  
Axis Orientation ◽  
Glass Substrates ◽  
Afm Micrographs

Undoped nanocrystalline ZnO thin films were deposited onto the glass substrates via the low cost sol-gel dip coating method. The as-grown ZnO films were annealed at the temperatures ranging from 400 °C to 550 °C. The X-ray diffraction (XRD) pattern revealed that the annealed ZnO films were polycrystalline with hexagonal wurtzite structure and majority preferentially grow along (002) c-axis orientation. Atomic force microscopy (AFM) micrographs showed the improvement of RMS roughness and grain size as annealing temperature increased. The ZnO films that annealed at 500 oC exhibited the lowest resistivity value.

Structural and Optical Properties of Nickel-Doped and Undoped Zinc Oxide Thin Films Deposited by Sol-Gel Method

2014 ◽  
Vol 895 ◽  
pp. 250-253 ◽  
Author(s):  
Siti Hajar Basri ◽  
Mohd Arif Mohd Sarjidan ◽  
Wan Haliza Abd Majid
Keyword(s):  
Thin Films ◽  
Zinc Acetate ◽  
Zinc Acetate Dihydrate ◽  
Sol Gel ◽  
Chelating Agent ◽  
Zno Films ◽  
Ni Doping ◽  
Gel Method ◽  
Sol Gel Method ◽  
Glass Substrates

ZnO thin films with and without Ni-doping were successfully deposited by sol-gel method with zinc acetate dihydrate as inorganic precursor, and nickel (II) acetate tetrahydrate as dopant. The solutions were prepared by dissolving zinc acetate and nickel (II) acetate in ethanol and diethanolamine (DEA) as its chelating agent. Thin films were fabricated by using spin-coating method on glass substrates. ZnO films were obtained by pre-heating and post-heating at 300 °C for 10 minutes and 500 °C for 1 h respectively. The films were analyzed by X-ray diffraction (XRD), UV-Vis transmittance and photoluminescence (PL). All samples exhibit high transparency in visible. Ni dopant does not alter so much ZnO structure, which due to the ion substitution between Ni and Zn. However, the Ni tends to create a dopant energy interlayer in ZnO energy band gap which cause significant change in PL intensity.

Spectral Features of Zn1-xMgxO Thin Films Synthesized by the Sol-Gel Route

2013 ◽  
Vol 669 ◽  
pp. 296-301 ◽  
Author(s):  
Feng Lin Xian ◽  
Xiang Yin Li
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Phase Segregation ◽  
Hexagonal Wurtzite Structure ◽  
Blue Shift ◽  
Content Increase ◽  
Ultraviolet Emission ◽  
Glass Substrates ◽  
Structure Morphology ◽  
Probe Microscope

Zn1-xMgxO (x=0, 0.05, 0.1, 0.2 and 0.3, respectively) thin films have been synthesized by sol-gel method on glass substrates. The structure, morphology and optical properties of the samples have been studied by X-ray diffractonmeter (XRD), scanning probe microscope, UV-visible spectrophotometer, fluorescence spectrophotometer and spectroscopic ellipsometer, respectively. The XRD result shows that all the films have hexagonal wurtzite structure; no phase segregation is observed. The surfaces of Zn1-xMgxO thin films are smooth and the root mean square (RMS) roughness of the samples is only several nanometers. The transmittance spectra reveal that all samples have high transmittance above 90%, with Mg doping content increase, the optical band gap increases from 3.27eV to 3.77eV. The photoluminescence spectra show that all samples have two emission peaks in ultraviolet and violet region, a blue shift of ultraviolet emission is observed. The refractive indexes of all samples decrease with the increase of wavelength ranging from 350nm to 900nm. The refractive index changes apparently by varying Mg content, which has potential application in research of optical materials and the design of optical devices.

scholarly journals Sol-Gel Derived Cds Nanocrystalline Thin Films: Optical and Photoconduction Properties

2018 ◽  
Vol 36 (2) ◽  
pp. 235-241 ◽  
Author(s):  
Ziaul Raza Khan ◽  
Anver Aziz ◽  
Mohd. Shahid Khan ◽  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Solution Temperature ◽  
Nanocrystalline Phase ◽  
Glass Substrates ◽  
Coating Method ◽  
Potential Applications ◽  
Nanocrystalline Thin Films

Abstract High-quality CdS nanocrystalline thin films were grown by sol-gel spin coating method at different solution temperatures on glass substrates. As-deposited films exhibited nanocrystalline phase with hexagonal wurtzite structure and showed good adhesion and smooth surface morphology. It was clearly observed that the crystallinity of the thin films improved with the increase in solution temperature. Crystallites sizes of the films also increased and were found to be in the range of 10 mm to 17 nm. The influence of the growth mechanism on the band and sub-band gap absorption of the films was investigated using UV-Vis and photothermal deflection spectroscopy (PDS). The band gap values were calculated in the range of 2.52 eV to 2.75 eV. The band gap decreased up to 9 % with the increase in solution temperature from 45 °C to 75 °C. Absorption coefficients estimated by PDS signal showed the significant absorption in low photon energy region of 1.5 eV to 2.0 eV. The dark and illuminated I-V characteristics revealed that the films were highly photosensitive. The results demonstrated the potential applications of sol-gel grown CdS nanocrystalline thin films as photoconductors and optical switches.

Optical Studies on the Effect of Different Layers of TiO2 Seeded-Template to the Growth of Nanostructured ZnO

2015 ◽  
Vol 1109 ◽  
pp. 587-592
Author(s):  
N.A.M. Asib ◽  
Aadila Aziz ◽  
A.N. Afaah ◽  
M. Rusop ◽  
Zuraida Khusaimi
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Visible Region ◽  
High Ratio ◽  
Structural Defects ◽  
Zno Films ◽  
Zno Nanostructures ◽  
Immersion Method ◽  
Glass Substrates ◽  
Vis Spectroscopy

In this study, Zinc oxide (ZnO) nanostructures have been fabricated on glass substrates coated with Titanium dioxide (TiO2) of different layers, which act as seeded-template, by a solution-immersion method. The substrates were coated with TiO2 by using sol-gel spin coating at five different layers of TiO2: 1, 3, 5, 7 and 9. The effects of the layers to the growth of ZnO nanostructures were observed by using Ultraviolet-Visible (UV-Vis) spectroscopy, Raman spectroscopy and Photoluminescence (PL) spectroscopy. UV-vis spectra of films display the increasing of absorbance properties at visible region as the TiO2 layers increase, as well as at UV region. Meanwhile, at visible region the transparency of TiO2: ZnO films reduce as the layers of TiO2 increase from 1 layer to 9 layers. Raman analysis shows the presence of ZnO in all the TiO2 seeded-templates. From the result, it is confirmed the existence of mixed crystalline structure of both materials in these TiO2: ZnO thin films and PL spectra of the films show seeded TiO2 thin films has lower intensity of visible emission and high ratio of IUV/IVIS compared to the non-seeded TiO2 This contributes to the lower structural defects, oxygen vacancies, impurities and has the most improved optical properties.

Ultraviolet Photoresponse of Pure and Al doped ZnO Polycrystalline Thin Films by Inkjet Printing

2009 ◽  
Vol 1161 ◽  
Author(s):  
Yan Wu ◽  
Takahiko Tamaki ◽  
Wolfgang Voit ◽  
Lyubov M. Belova ◽  
K. V. Rao
Keyword(s):  
Thin Films ◽  
Uv Irradiation ◽  
Inkjet Printing ◽  
Hexagonal Wurtzite Structure ◽  
Zno Films ◽  
Acetate Solution ◽  
Glass Substrates ◽  
Polycrystalline Thin Films ◽  
Decay Times ◽  
Doped Zno

AbstractPure ZnO, and Al doped ZnO, 120 -300 nm thin films on glass substrates, were synthesized by inkjet printing technique using zinc and aluminum acetate solution as precursors and a two stage heat treatment process to obtain polycrystalline hexagonal wurtzite structure with the mean grain size of 25 and 30 nm respectively. All films exhibit a transmittance above 85-90% in the visible wavelength range below 700 nm. In the Al doped films the UV absorption spectra show a strong absorption onset below 380nm followed by shoulders centered around 325 nm depending on the film thickness. The electrical conductivity of Al doped ZnO thin films is larger by two orders of magnitude than that for pure ZnO films while the photoconductivity increases by about three orders of magnitude under UV irradiation. The photoresponse of the films with UV irradiation in terms of the rise and decay times in the frequency range from 5 to 500 Hz is also presented and discussed.

SCANNING ELECTRON MICROSCOPE AND X-RAY DIFFRACTION STUDIES ON THE LATTICE CONSTANT OF SPIN-COATED Zn1-xMgxO THIN FILMS OF SOL-GEL METHOD

2005 ◽  
Vol 12 (04) ◽  
pp. 605-610 ◽  
Author(s):  
M. RUSOP ◽  
K. UMA ◽  
T. SOGA ◽  
T. JIMBO
Keyword(s):  
Thin Films ◽  
Lattice Constant ◽  
Zinc Acetate Dihydrate ◽  
Sol Gel ◽  
Zno Films ◽  
Silicon Substrates ◽  
Acetate Dihydrate ◽  
Glass Substrates ◽  
Sol Gel Process ◽  
Coating Method

ZnO and Zn 1-x Mg x O thin films were prepared on glass and silicon substrates by spin coating method using 2-methoxyethanol solution of zinc acetate dihydrate and magnesium acetate dihydrate stabilized by monoethanolamine. The effects of drying and annealing condition of structural and optical properties of the films were studied. It was found that the samples annealed at 650°C improves the crystallographic orientation of the ZnO films grown by the sol-gel process significantly. Two types of substrates were used to examine the substrate effects of the growth of Zn 1-x Mg x O thin films. In corning glass substrates, the lattice constant decreased by a little with increasing concentration of Mg , whereas in the case of silicon substrates, the lattice constant decreased rapidly with x when compared to the glass substrates. The optical band energy gaps of Zn 1-x Mg x O thin films were slightly increased with increasing concentration of Mg .

Effect of Mn Doping on Structural and Optical Properties of ZnO Thin Films Prepared on Glass Substrates by Sol-Gel Method

2013 ◽  
Vol 750-752 ◽  
pp. 1038-1043
Author(s):  
Peng Liu ◽  
Qiu Ying Shen ◽  
Hong Hu ◽  
Bin Yang
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Blue Shift ◽  
Doping Content ◽  
Mn Doping ◽  
Lattice Constants ◽  
Glass Substrates ◽  
Xrd Patterns

Thin films of Zn1-xMnxO (x = 0.00, 0.03, 0.07, 0.10) were prepared onto glass substrates by sol-gel spin-coating technique. The structural, morphologic and optical properties of these samples were studied respectively. The XRD patterns show the thin films are all polycrystalline with hexagonal wurtzite structure and no preferred orientation. With the increase of Mn doping, the c-axis lattice constants of the samples shift towards higher values until the doping concentration reaches up to 7%. This indicates that Mn2+substituted for Zn2+of ZnO host. Moreover, the grain size decreases gradually with the increase of Mn doping content. The AFM results indicate surface roughness increases with the increase of Mn doping level. The photoluminescence spectra reveal Mn doping causes a blue shift of the UV peak. The intensity of UV emission peaks increases at the beginning and then decreases with the increase of Mn doping content.

Growth and Characterisation of Nanocrystalline ZnO Thin Films by Dip Coating Technique

2013 ◽  
Vol 832 ◽  
pp. 368-373
Author(s):  
Mohd Firdaus Malek ◽  
Mohamad Hafiz Mamat ◽  
Mohd Zainizan Sahdan ◽  
Musa Mohamed Zaihidi ◽  
Zuraida Khusaimi ◽  
...  
Keyword(s):  
Thin Films ◽  
Zinc Acetate ◽  
Sol Gel ◽  
Homogeneous Solution ◽  
Nir Spectroscopy ◽  
Dip Coating ◽  
Zno Thin Films ◽  
Molar Ratio ◽  
Zno Films ◽  
Glass Substrates

Nanocrystalline zinc oxide (ZnO) thin films have been obtained by the sol gel process. A stable and homogeneous solution was prepared by dissolving zinc acetate dehydrate as a starting material in a solution of 2-methoxyethanol and monoethanolamine (MEA). The molar concentration of zinc acetate was fixed at 0.6 mol/L while the molar ratio of MEA to zinc acetate was kept at 1:1. The films were deposited by various deposition speeds by dip-coating on glass substrates, and subsequently transformed into nanocrystalline pure ZnO films after a thermal treatment. Various deposition speeds were selected as the parameter to optimize the thin films quality. The structural and optical properties of the ZnO films were studied by X-ray diffraction (XRD), UV-Vis-NIR spectroscopy, respectively. The electrical properties of the ZnO thin films were characterised by dc 2 probing system and power supply (Advantest R6243). It was found that the deposition speed affects the resultant properties of ZnO thin films.

The Effect of Various ZnO Layer towards Sensing Performance as an Electrolyte-Insulator-Semiconductor pH Sensor

2020 ◽  
Vol 307 ◽  
pp. 37-44
Author(s):  
Ensaf Mohammed Al-Khalqi ◽  
Muhammad Azmi Abdul Hamid ◽  
Roslinda Shamsudin ◽  
Naif H. Al-Hardan ◽  
Lim Kar Keng
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Ph Sensor ◽  
Hexagonal Wurtzite Structure ◽  
Radiation Sensitivity ◽  
Grain Structure ◽  
Zno Films ◽  
Near Band Edge ◽  
Three Samples ◽  
Reliability Performance

Multilayers zinc oxide thin films were synthesized by the sol–gel spin coating process to fabricate sensing membranes in an electrolyte-insulator-semiconductor (EIS) sensor for pH detection. The effect of various layers (single, three and five layers) on the crystallinity, morphological and optical properties of ZnO films were investigated by XRD, FE-SEM, and Photoluminescence respectively. The ZnO thin films grown were polycrystalline with hexagonal wurtzite structure. The films were not smooth, with grains and porosity in between them, and become denser as film thickness increased. The PL spectra exhibit two main emission peaks at near band edge 360-380 nm region (strong and sharp UV radiation) and 450–600 nm region (broad blue, green, and yellow radiation). Sensitivity, linearity was measured to determine the sensing and reliability performance of fabricated devices. The result confirmed that, the sensitivity for the three samples increased with increased layer from 48.3 mV/pH to 82.58 mV/pH. Compared to single and three layers of the ZnO electrolyte-insulator-semiconductor (EIS), ZnO grown with five layers exhibits a higher sensitivity of 82.58 mV/pH in solutions from pH 2–12 and linearity of 99.015 %. This is due to the increased of ZnO thickness, which produces dense surface and a well-crystallized grain structure.

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