scholarly journals Synthesis and Characterization of MgO Doped ZnO Nanorods Prepared by Solution Immersion Method and their Effect on Energy Band Gap

2019 ◽  
Vol 7 (4.14) ◽  
pp. 186
Author(s):  
Z Khusaimi ◽  
N A.M. Asib ◽  
S Z. Umbaidilah ◽  
A N. Afaah ◽  
C N.E. Syafika ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Band Gap ◽  
Zno Nanorods ◽  
Annealing Treatment ◽  
Band Gap Energy ◽  
Powder Form ◽  
Immersion Method ◽  
Gap Energy ◽  
Tauc Plot ◽  
Doped Zno

In this research, solid powder form ZnO and MgO-doped ZnO were prepared by using solution immersion method. Mg divalent cation with different atomic percentage of 0.5%, 1.0% and 1.5% were added in 0.04 M of Zn2+ solution containing zinc nitrate hexahydrates as precursor and hexamethylene tetraamine as stabilizer. Annealing treatment was consequently carried out to transform the precursors into oxide forms. ZnO and MgO-doped ZnO were successfully obtained and the surface morphology, crystallite size and elemental composition were studied using Field Emission Scanning Electron Microscope (FESEM) and Energy dispersive X-Ray (EDX) respectively. The band gap energy was determined using Ultraviolet-Visible spectrophotometer (UV-Vis). FESEM images showed that the powder form of ZnO and MgO-doped ZnO consist of rod-like shape. A 0.5% of MgO-doped ZnO sample has smallest size of rods with higher aspect ratio compared to others. The EDX result revealed that the sample composed of Zn, O and Mg in the sample. The band gap energy for all samples was determined using Tauc plot and it was found that the band gap energy is reduced with 1.0 and 1.5 % doping while increased at 0.5% doping. The band gap energy was found to range between 3.23 eV to 3.26 eV. The 0.5% of Mg-doped ZnO with higher aspect ratio shows the highest band gap energy value.  

Effect of the ZnO Rods Growth Time to the Conductivity of ZnO Thin Film Combined with N3 Dye

2011 ◽  
Vol 383-390 ◽  
pp. 3286-3290
Author(s):  
Engku Abd Engku Ali Ghapur ◽  
W.A. Dhafina ◽  
S. Hasiah ◽  
N.A.N. Ali
Keyword(s):  
Thin Film ◽  
Aspect Ratio ◽  
Band Gap ◽  
Zno Nanorods ◽  
Hydrothermal Process ◽  
Hydrothermal Solution ◽  
Band Gap Energy ◽  
Growth Time ◽  
Gap Energy ◽  
Zno Rods

In this work, ZnO nanorod has been grown by hydrothermal solution method. The samples were prepared by two stages. The first stage was seeding process where the ZnO nanoparticles are spin-casted onto ITO coated glasses and the second stage was hydrothermal process. The morphology of nanorods were investigated by using scanning electron microscope (SEM) and different of length and diameter of nanorods with different growth durations have been observed. The differences of diameters and aspect ratio of nanorods have affected the optical and electrical properties of the ZnO-coated thin film with dye due to its surface area and morphologies of growth rod. Aspect ratio of ZnO nanorods increases by increasing the reaction time (growth time). From the band gap energy study, the thin film with the longest ZnO nanorods growth time has the lowest band gap energy (3.55 eV). The higher aspect ratio of the nanorod affected the conductivity, by increasing the conductivity when combined with N3 dye.

scholarly journals Band-Gap Energies of Choline Chloride and Triphenylmethylphosphoniumbromide-Based Systems

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1495 ◽  
Author(s):  
Alberto Mannu ◽  
Maria Enrica Di Pietro ◽  
Andrea Mele
Keyword(s):  
Hydrogen Bond ◽  
Ethylene Glycol ◽  
Band Gap ◽  
Lewis Acids ◽  
Choline Chloride ◽  
Band Gap Energy ◽  
Hydrogen Bond Acceptor ◽  
Gap Energy ◽  
Tauc Plot ◽  
Vis Spectroscopy

UV–VIS spectroscopy analysis of six mixtures containing choline chloride or triphenylmethylphosphonium bromide as the hydrogen bond acceptor (HBA) and different hydrogen bond donors (HBDs, nickel sulphate, imidazole, d-glucose, ethylene glycol, and glycerol) allowed to determine the indirect and direct band-gap energies through the Tauc plot method. Band-gap energies were compared to those relative to known choline chloride-containing deep band-gap systems. The measurements reported here confirmed the tendency of alcohols or Lewis acids to increment band-gap energy when employed as HBDs. Indirect band-gap energy of 3.74 eV was obtained in the case of the triphenylmethylphosphonium bromide/ethylene glycol system, which represents the smallest transition energy ever reported to date for such kind of systems.

Optical and Electronic Analysis of Pure and Fe-Doped ZnO Thin Films Using Spectroscopic Ellipsometry and Kramers–Kronig Method

2019 ◽  
Vol 18 (01) ◽  
pp. 1850013 ◽  
Author(s):  
Maryam Motallebi Aghgonbad ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spectroscopic Ellipsometry ◽  
Optical Band Gap ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Fe Doping ◽  
Gap Energy ◽  
Optical And Electronic Properties ◽  
Doped Zno

In the present work, pure and Fe-doped ZnO thin films were deposited on glass substrates by sol–gel method. Zinc acetate and iron nitrate were used as the starting material and dopant source, respectively. The concentration of Fe doping was 6[Formula: see text]at.% and 8[Formula: see text]at.%. The optical and electronic properties of pure and Fe-doped ZnO thin films such as refraction index, extinction coefficient, dielectric function and optical band gap energy of the layers were obtained by spectroscopic ellipsometry method in the wavelength range of 300–900[Formula: see text]nm. The incidence angle of the layers kept 70[Formula: see text]. Also data obtained by Kramers–Kronig relations were used for comparison. The influence of Fe-doping concentration on the optical and electronic properties of thin films was studied. The transmittance data of ZnO thin films showed that 6[Formula: see text]at.% Fe-doped ZnO thin film has the highest transmittance value. Dielectric function of pure ZnO films was found to be higher compared with Fe-doped ones. Also it can be deduced from the results that Fe doping influences the optical band gap energy of thin films.

Effect of band gap energy on the electrical conductivity in doped ZnO thin film

2014 ◽  
Vol 35 (7) ◽  
pp. 073001 ◽  
Author(s):  
Said Benramache ◽  
Okba Belahssen ◽  
Hachemi Ben Temam
Keyword(s):  
Thin Film ◽  
Electrical Conductivity ◽  
Band Gap ◽  
Band Gap Energy ◽  
Zno Thin Film ◽  
Gap Energy ◽  
Doped Zno

Optical Characterization of Al-doped ZnO Films via Sol-gel Method Using Spectroscopic Ellipsometry

2020 ◽  
Vol 10 (5) ◽  
pp. 642-648
Author(s):  
Ehsan M. Aghkonbad ◽  
Hassan Sedghi ◽  
Maryam M. Aghgonbad
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spectroscopic Ellipsometry ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Zno Films ◽  
Promising Alternative ◽  
Gap Energy ◽  
Doped Zno

Background: Al-doped ZnO thin films are considered as a promising alternative to ITO in optoelectronic applications. In this work, Al-doped ZnO thin films were prepared using sol-gel spin coating technique. Experimental: The optical properties of the films such as refractive index, extinction coefficient, dielectric function and the absorption coefficient were examined using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. The effect of Al doping on ZnO thin films with different Al concentrations was significant. Tauc relation was used to estimate the optical band gap energy of the films. Results: The calculated values of band gap energy were obtained between 3.10 to 3.25 eV. Also the fraction of voids was calculated using Aspnes theory. Conclusion: The free carrier concentration value was obtained in the order of 1019 cm-3.

scholarly journals Behavior of Ternary Mixtures of Hydrogen Bond Acceptors and Donors in Terms of Band Gap Energies

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3418
Author(s):  
Alberto Mannu ◽  
Francesca Cardano ◽  
Salvatore Baldino ◽  
Andrea Fin
Keyword(s):  
Hydrogen Bond ◽  
Band Gap ◽  
Choline Chloride ◽  
Band Gap Energy ◽  
Ternary Mixtures ◽  
Hydrogen Bond Donor ◽  
Multivariate Statistical ◽  
Gap Energy ◽  
Tauc Plot ◽  
Simple Lattice

Three ternary mixtures composed by choline chloride (ChCl), ethylene glycol (EG), and a second hydrogen bond donor (HBD) as ethanol (A), 2-propanol (B), and glycerol (C) were studied in terms of composition related to the band gap energy (BGE). A Design of Experiments (DoE) approach, and in particular a Simple Lattice three-components design, was employed for determining the variation of the BGE upon the composition of each system. UV-VIS analysis and subsequent Tauc plot methodology provided the data requested from the DoE, and multivariate statistical analysis revealed a drop of the BGE in correspondence to specific binary compositions for systems A and B. In particular, a BGE of 3.85 eV was registered for the mixtures ChCl/EtOH (1:1) and ChCl/2-propanol (1:1), which represents one of the lowest values ever observed for these systems.

Doping Induced Band-gap widening in Transition-metal doped ZnO Nanocrystals

MRS Advances ◽  
2018 ◽  
Vol 3 (42-43) ◽  
pp. 2643-2652
Author(s):  
Azimatu Seidu ◽  
Martin Egblewogbe ◽  
G. Gebreyesus ◽  
George Nkrumah-Buandoh
Keyword(s):  
Transition Metal ◽  
Band Gap ◽  
Density Functional ◽  
Doping Concentration ◽  
Band Gap Energy ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Gap Energy ◽  
Zno Nanocrystals ◽  
Doped Zno

AbstractPure and transition metal (TM)-doped ZnO nanocrystals were synthesized using a wet-chemical process. Synthesis was carried out in distilled water at 85 °C followed by calcining the as-prepared powders at 280 °C and 600 °C. Co, Mn and Fe doping at 4 and 8 mol % was achieved by adding CoCl2.6H2O, MnCl2 .4H2O and FeCl2 .4H2O respectively during the synthesis. Crystal phase characterization was carried out by X-ray powder diffraction (XRD) which confirmed the formation of ZnO in the wurtzite polymorph. The band gap energy of the nanocrystals was measured by both photoluminescence spectroscopy (using the Near Band Edge Emission) and UV-Vis absorption spectroscopy, using a modified version of the Tauc law. Widening of the band gap energy from 3.23 eV to 3.33 eV with increased doping concentration was observed for all the dopants. Ab-initio simulations of doped and undoped ZnO crystals using density functional theory as implemented in the Quantum Espresso package confirmed the increase in the band gap energies with doping concentration.

Effect of Detergent on the ZnO Nanorods Structures Synthesized via the Sol-Gel Method

2012 ◽  
Vol 545 ◽  
pp. 161-164
Author(s):  
Rusdi Roshidah ◽  
Abd Rahman Azilah ◽  
Norlida Kamarulzaman
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Inorganic Material ◽  
Sol Gel ◽  
Zno Nanorods ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gap Energy ◽  
Thermogravimetric Analyzer

ZnO is known as an inorganic material that has a variety of morphologies. The morphologies of the ZnO are much influenced by the synthesis route. In this work, two ZnO nanomaterials were prepared by the sol-gel route and the effect of detergent on the morphology and optical band gap of ZnO materials were investigated. The synthesized ZnO materials were characterized using Simultaneous Thermogravimetric Analyzer (STA), X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM). The UV-Vis spectrophotometer is used to determine the optical band gap. The results show that the presence of detergent affected the morphology of the ZnO from nanorods to nano-flakes. The band gap energy of the ZnO were also reduced from 3.14 ev to 2.98 eV from the nanorod to the nanoflakes.

scholarly journals PREPARATION AND CHARACTERIZATION OF ZnO NANOPARTICLES BY SOLVENT FREE METHOD

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Savka Janković ◽  
Dragana Milisavić ◽  
Tanja Okolić ◽  
Dijana Jelić
Keyword(s):  
Band Gap ◽  
Zno Nanoparticles ◽  
Band Gap Energy ◽  
Zinc Nitrate ◽  
Solvent Free ◽  
Band Model ◽  
Nitrate Hexahydrate ◽  
Gap Energy ◽  
Tauc Plot

ZnO nanoparticles have numerous applications as photo catalysts, gas sensors, UV lasers, as optoelectronic and microelectronic devices or in cosmetic field. ZnO nanoparticles were synthesized by solvent free method using zinc nitrate hexahydrate as precursor and glycerol as dispersant, without solvent present. This method proved to be very simple, economic and ecofriendly. Zinc nitrate and glycerol were mixed in different ratio in order to avoid and overcome a possibility of agglomeration. Characterization of samples was performed by UV/VIS and FTIR spectrophotometry. The strongest absorption appeared at wavelength 206 nm. Using combination of UV/VIS spectrophotometry and hyperbolic band model (HBM) particles size of ZnO particles were evaluated to 2.06 nm. Additionally, using Tauc plot, a band gap energy was determined. Band gap energy of ZnO nanoparticles amounted to 5.00 eV. IR spectrum showed existence of ZnO in interval 600- 400 cm-1.

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