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The role of color luminescence centers Mn, Cu, Co in the semicondutors with wide band gap ZnS, ZnO and their applications

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In this paper, we study the role of color luminescence centers Cu, Mn, Co in the semiconductors with wide band gap of ZnS, ZnO and test application of ZnS:Cu material.. Bulk samples of ZnS, ZnS:Cu (x Cu mol. ZnS:Mn (x Mn mol%) were prepared by the solid state reaction method in argon and ZnO:Co (x Co mol%) in air enviroment. Nanocrystalline sample ZnS:Mn (x Mn mol%) was prepared by the co-precipitated method with initial chemical ZnCl 2 , Na 2 S and MnCl 2 and annealed in argon[15]..

Compact Triple-Band MIMO Antenna with High Isolation for Handheld Application

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Recently, DGS structure is one of techniques that widely is used in MIMO antenna designs to improve isolation between antenna elements because this structure uses the dielectric as a band gap structure to suppress mutual coupling as well as to get a more compact size. As illustrated in Figure 9, the proposed “slot and variation” DGS structure with 8-shape and periodic loop shape makes three stop-bands that is able to suppress mutual coupling for triple-band MIMO antenna.

Synthesis and Characterization of Ni2+ -doped TiO2 Nanowires

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Indirect and direct band gap energies of Ni 2+ -doped TiO 2 with different doping concentration were found to be in the range from 3.24 to 2.99 eV and 3.54 to 3.35 eV, respectively.. Keywords: TiO 2 :Ni 2+ nanowires, hydrothermal, diffuse reflection, band gap energy.. This is due to its wide band gap [6, 7].

Theoretical prediction of the structural and electronic properties of a single layer graphene-like two-dimensional janus Janus GaInSTe

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The band gap of Janus GaInSTe monolayer calculated by PBE and HSE06 is 0.80 eV and 1.50 eV, respectively. It should be noted that the traditional PBE functional always underestimates the band gap of materials. While the hybrid functional HSE06 can be used to acquire an accurate band gap. To have a deep insight into the band structure, we further calculate the weighted band structure of Janus GaInSTe monolayer, as shown in Figure 4. The weighted band structure of all atoms in Janus GaInSTe..

Theoretical Prediction of ZnO Nanoporous Allotropes with Triangular Hollow

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Further we also observed the week dependence of band gap on the hollow size and considerable dependence on the wall thickness which follow up the rule of quantum confinement as stated in [37] as decreasing the wall thickness increasing the band-gap energy. For smaller gap in the first structure of some series, e.g. ascribed to the in-gap surface states appearing inside the gap region.

Effects of strain stiffening and electrostriction on tunable elastic waves in compressible dielectric elastomer laminates

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Numerical calculations indicate that the fre- quency of the first-order shear wave band gap is relatively low, but that of the pressure wave band gap is a little higher. Thus, consideration of dissipation can potentially improve the predictions of the first-order pressure wave band gap, which demands further research.. (A.1) where 𝜀 = 𝜀 0 𝜀 𝑟 is the material permittivity in the undeformed state..

Optical Properties of PbS and Au-PbS Core-Shell Nanoparticles

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The observed blue-shift of the absorption edge and the band gap energy E g of the synthesized PbS nanoparticles can be attributed to the quantum confinement effect of PbS nanoparticles. There are several theoretical models such as the effective mass model, hyperbolic band model, cluster model … which can be used to explain the dependence of the band gap energy on the size of PbS nanoparticle [15].

Effects of ZnO nanoparticles and graphene oxide on properties of acrylic polymer nanocomposite coating

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To determine direct band gap energies of ZnO nanoparticles and GO/ZnO nanocomposite, their UV-Vis diffuse reflectance spectra were recorded and then a Kubelka-Munk model was used to calculate direct band gap energies [14].

Synthesis and some optical results of long chain substituted phthalocyanines

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The optical energy band gap E g is calculated according to the following relation [1]:. The band gap value is determined by extrapolating the straight line portion of (αhν) 2 to the hν axis. The optical energy band gap values range from 4.48 to 4.51 eV for Pc thin films of indium, zinc, and derived from their mixture. It is seen that the energy band gap values of the Pc thin films obtained by mixing the two solutions are slightly changed.

VL màng mỏng - Màng dẫn điện

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Metal Oxides have a large Optical Band Gap. Indium Oxide (In2O3). Zinc Oxide (ZnO). Tin doped Indium Oxide (ITO). and many more: all are metal oxides Metal oxides are transparent to visible light nm). The optical band gap is 3.1 - 6.0 eV. It forms a NON Stoichiometric Metal Oxide film. Charge Neutrality condition MUST be satisfied :Over all, the Oxygen vacancies (+vely charged) balance the charge neutrality. The TCO Thin films are. Wide band gap materials.

Enhanced photocatalytic activity using near visible light of ZnO nanorods by doping with Mn2+ ions

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Absorption band edge was observed at 390 nm for pure ZnO NRs. For Mn-doped ZnO NRs, the absorption edge shifted toward the long wavelength as well as the visible light. It was attributed to the narrow optical band gap due to the presence of Mn energy level located inside the ZnO NRs band gap. Figure S1 supporting information clearly shows the calculation of the optical band gap of pure ZnO NRs and doped ZnO NRs through Tauc’s method.

Synthesis and characterization of new thiophene–benzimidazole-based electrochromes

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Optical properties of the polymer films in Figure 7.. of benzimidazole causes a red shift in the optical absorption in the resulting polymers, with the corresponding decrease in the band gap.. Changing the F atom on the benzene ring of BIM from meta- (P2) to para- (P1) position causes a 31-nm red shift in the optical absorption, corresponding to a 0.05-eV decrease in the band gap.

Ideas of Quantum Chemistry P50

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The electric properties of a crystal depend on the energy gap between them (i.e. band gap. pare for they often undergo spontaneous dimerization of the lattice (known as the.

Effect of Neodymium and Transition Metals Co-doped on Structural, Optical and Magnetic Properties of BiFeO3 Materials

8.pdf

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The slight decrease of optical band gap in doped and co-doped samples can be explained by the appearance of Nd impurity band in the energy band gap. 4a also exhibit a weak absorption peak at 750 nm for doped and co-doped BFO samples which can be assigned to electron transitions from the ground state 4 I 9/2 to the excited levels ( 4 F 7/2 + 4 S 3/2 ) of Nd 3+ ion [36].. (a) UV–Vis absorption spectrum of the BFO, BNFO, BNFNO and BNFCO samples.

Preparation by forced hydrolysis method and the optical properties of Zn1−xNixO powder

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Figure 7 shows the near band edge PL spectra of 450 0 C annealed Zn 1−x Ni x O (x measured at different temperatures from 10K to 250K. These shifts can be assigned by the change of band gap of the material with the temperature. The tem- perature is dependent on band gap energy E g is showed in the figure 8 and can be fitted to the following familiar equation [11]:. The β is dependent on Debye temperature θ D of the material..

Dependence of hydrothermal time on structural characteristics and photocatalytic properties of SnO2 nanoparticles

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Hence, the band gap energy of the SnO 2 semiconductor can be obtained from the plot (𝛼ℎ𝜈) 2 as a function of optical energy (E) by extrapolating the linear parts of the graph intersecting the photon energy axis [16,17]. The 𝐸 𝑔 values of the samples were and 3.30 eV, respectively. The increase in band gap energy can be due to the decrease in the defective energy levels produced in the band gap of SnO 2 as the hydrothermal time increases..

Effect of polyvinyl alcohol/chitosan blend ratios on morphological, optical, and thermal properties of electrospun nanofibers

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In addition, the optical band gap of the electrospun fibers at various flow rates was determined in the range from 2.68 to 2.93 eV and the optical band gap of fibers increased with the increase of flow rate. 31 The optical band gap of the blend film was found as 2.30 eV and this result was in accordance with our results.. These results indicated that the optical band gap of the electrospun fiber decreased with the increase of. Optical data of the electrospun fibers.. PVA/CS 1% (w/w .

Optical Networks: A Practical Perspective - Part 23

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Figure 3.59 A lithium niobate external modulator using a Mach-Zehnder interferom- eter (MZI) configuration. modulator uses a material such that under normal conditions, its band gap is higher than the photon energy of the incident light signal. Applying an electric field to the modulator results in shrinking the band gap of the material, causing the incident photons to be absorbed by the material.. This chirp can be controlled precisely in lithium niobate modulators.).

Aspect ratio dependent air stability of PbSe nanorods and photovoltaic applications

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In this sense, NR band gap shows a strong dependence on the NR diameter due to a significant influence of the lateral confinement on the band gap [25–28]. In line with those studies, the absorbance and PL peak points blue shift as the diameter of the NRs decreases. Stokes shift has been reported to be depen- dent on the NR energy fluctuations as a result of the length and diameter distribution [29].

Abnormal magnetic property in Fe-doped BaTio3 multiferroics

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The inset shows schematically the band structure in the presence of impurity bands As has been well known that undoped BaTiO 3. is a material of wide band gap of about 3.2 eV, this can be seen clearly with an absorption edge in the absorption spectrum in the UV region for the sample x=0.0 shown in Fig. At low Fe dopant content, the distances between these bands and those between the valence band and the lowest impurity band act like effective band gaps..