Optical band-gap of TiO2 nanopowders doped with Al2O3

2013 ◽  
Vol 1493 ◽  
pp. 281-286
Author(s):  
Keisuke Yoshimura ◽  
Tetsuya Hashimoto ◽  
Hiroshi Katsumata
Keyword(s):  
Band Gap ◽  
Ball Mill ◽  
Milling Time ◽  
Optical Band Gap ◽  
The Other ◽  
Mass Ratio ◽  
Quantum Size ◽  
Powder Mass ◽  
Tio2 Nanopowders ◽  
Good Agreement

ABSTRACTOptical band-gap and cathode luminescence (CL) properties of anatase TiO2 nanopowders mixed with γ- Al2O3 powders by planetary ball mill were evaluated as a function of a powder mass ratio (x=Al2O3/TiO2) of 0 to 0.5 and their correlation with XRD spectra was also investigated. The optical band-gap of TiO2 increased from 3.36 eV to 3.41eV with increasing milling time (tm) up to 600 min, which was in good agreement with the blue shifts observed in the CL spectra with increasing tm and it was interpreted as a quantum size effect. In addition, the optical band-gap of TiO2 powders mixed with Al2O3 with tm=60min greatly increased from 3.36 eV to 3.48 eV with increasing x up to x=0.5. On the other hand, the optical band-gap of all the powders was decreased by annealing at temperatures above 600°C, which was evidenced by the XRD spectra to be due to the growth of grain size.

Quantum size effects on the optical band gap of microcrystalline Si:H

1988 ◽  
Vol 38 (8) ◽  
pp. 5726-5729 ◽  
Author(s):  
Shoji Furukawa ◽  
Tatsuro Miyasato
Keyword(s):  
Band Gap ◽  
Size Effects ◽  
Optical Band Gap ◽  
Quantum Size Effects ◽  
Quantum Size

Influence of different materials on the microstructure and optical band gap of α-Fe2O3 nanoparticles

2014 ◽  
Vol 32 (2) ◽  
pp. 193-197 ◽  
Author(s):  
P. Mallick
Keyword(s):  
Band Gap ◽  
Crystallite Size ◽  
Optical Band Gap ◽  
Strain Analysis ◽  
The Other ◽  
Fe2o3 Nanoparticles ◽  
Direct Band Gap ◽  
Direct Band ◽  
Indirect Band Gap ◽  
Composite Samples

AbstractComposites of hematite (α-Fe2O3) nanoparticles with different materials (NiO, TiO2, MnO2 and Bi2O3) were synthesized. Effects of different materials on the microstructure and optical band gap of α-Fe2O3 nanoparticles were studied. Crystallite size and strain analysis indicated that the pure α-Fe2O3 nanoparticles were influenced by the presence of different materials in the composite sample. Crystallite size and strain estimated for all the samples followed opposite trends. However, the value of direct band gap decreased from ∼2.67 eV for the pure α-Fe2O3 nanoparticles to ∼2.5 eV for α-Fe2O3 composites with different materials. The value of indirect band gap, on the other hand, increased for all composite samples except for α-Fe2O3/Bi2O3.

QUANTUM SIZE EFFECT ON THE OPTICAL PROPERTIES OF RF MAGNETRON SPUTTERED NANOCRYSTALLINE CADMIUM OXIDE THIN FILMS

2011 ◽  
Vol 10 (04n05) ◽  
pp. 713-716 ◽  
Author(s):  
B. SAHA ◽  
R. THAPA ◽  
N. S. DAS ◽  
K. K. CHATTOPADHYAY
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Optical Band Gap ◽  
Quantum Confinement Effect ◽  
Cadmium Oxide ◽  
Quantum Size ◽  
Device Applications ◽  
Cdo Films ◽  
Different Thickness

CdO thin film with different thickness and different particle size are prepared through radio frequency magnetron sputtering technique. Quantum confinement effect causes the significant changes in their optical properties showing significant changes in the optical band gap. The CdO films are very highly conducting and transparent. Transparent and conducting thin films of CdO with effectively increased optical band gap are very useful for different device applications like solar cell, optoelectronic devices.

Fluorescent carbon nano dots from lignite: unveiling the impeccable evidence for quantum confinement

2016 ◽  
Vol 18 (17) ◽  
pp. 12065-12073 ◽  
Author(s):  
Senthil Kumar Thiyagarajan ◽  
Suresh Raghupathy ◽  
Dharmalingam Palanivel ◽  
Kaviyarasan Raji ◽  
Perumal Ramamurthy
Keyword(s):  
Laser Ablation ◽  
Size Effect ◽  
Band Gap ◽  
Quantum Confinement ◽  
Optical Band Gap ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Quantum Size Effect ◽  
Quantum Size ◽  
Fluorescent Carbon

Pulsed laser ablation of lignite in EDA solution exfoliates CDs (CD3) which exhibit the influence of quantum size effect in tuning the optical band gap of CDs.

Effects of Different Thermal Treatment on Optical Properties and Microstructure of ZnO Thin Films

2011 ◽  
Vol 197-198 ◽  
pp. 1766-1770 ◽  
Author(s):  
Dong Ping Zhang ◽  
Ping Fan ◽  
Zhuang Hao Zheng ◽  
Li Li Ru ◽  
Jian Jun Huang ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Constant Temperature ◽  
Room Temperature ◽  
Optical Band Gap ◽  
The Other ◽  
Zno Thin Films ◽  
Zno Films ◽  
Dc Reactive Magnetron Sputtering

ZnO thin films were prepared by DC reactive magnetron sputtering at room temperature. Two of them were annealed with different modes under vacuum condition. One was annealed with constant temperature of 300°C ; the other was annealed with temperature rising step by step from room temperature to 300°C . By comparing the microstructure and optical properties of the as-grown and annealed samples, the effects of different annealing modes on ZnO films performances were revealed. The experiment results investigated that the sample annealed with constant temperature of 300°C has the high grain size and surface roughness. Both of the two annealing modes could release the intrinsic stresses to some degree. The optical band gap of the samples narrowed after annealing, and the two annealed samples have almost the same band gap. Strong green emissions are observed for all the samples, but the emission intensity decreased of the sample annealed with the temperature rising step by step compared with that of other samples.

scholarly journals Влияние имплантации ионов Al-=SUP=-+-=/SUP=- на состав, электронную и кристаллическую структуру поверхности GaP(111)

2020 ◽  
Vol 54 (8) ◽  
pp. 716
Author(s):  
С.Б. Донаев ◽  
Б.Е. Умирзаков
Keyword(s):  
Single Crystal ◽  
Band Gap ◽  
Size Effects ◽  
Quantum Size Effects ◽  
Crystalline Structures ◽  
Quantum Size ◽  
The Relationship ◽  
Nanocrystalline Phases ◽  
Different Doses ◽  
Good Agreement

Nanocrystalline phases and GaAlP films were obtained by implanting Al+ ions with E0 = 1 keV at different doses on the surface of a GaP(111) single crystal, and their electronic and crystalline structures were studied. It is shown that the type and lattice parameters of a three-component nanostructure are in good agreement with those for the substrate. The relationship between the band gap Eg and the sizes of nanocrystalline phases is studied. It has been established that in the case of surface sizes of phases d less than 35–40 nm (thickness 3.5–4 nm), the quantum-size effects appear in the Ga0.6Al0.4P nanocrystalline phases.

scholarly journals Electron Irradiation Effects on the Optical and Electrical Properties of ZnO/Ag/SnO2 Thin Films

2020 ◽  
Vol 58 (3) ◽  
pp. 190-194 ◽  
Author(s):  
Yu-Sung Kim ◽  
Jin-Young Choi ◽  
Yun-je park ◽  
Su-Hyeon Choe ◽  
Byung-Chul Cha ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Band Gap ◽  
Electron Irradiation ◽  
Carrier Density ◽  
Optical Band Gap ◽  
The Other ◽  
Electrical Performance ◽  
Incident Electron Energy ◽  
Optical And Electrical Properties

Transparent conductive ZnO 50 nm/Ag 10 nm/SnO<sub>2</sub> 50 nm (ZAS) tri-layer films were deposited on glass substrates by magnetron sputtering, and then the surface was subjected to intense electron beam irradiation to investigate the effects of electron irradiation on the structural, optical, and electrical properties of the films. After deposition, the ZAS thin films were electron-irradiated for 10 minutes, with varying electron incident energies of 300, 600, and 900 eV. The films that were electron irradiated at 900 eV showed higher optical transmittance of 83.6% in the visible wavelength region, and lower resistivity, of 4.75 × 10<sup>-5</sup> Ωcm, than the other films. From the observed electrical properties and optical band gap, it was concluded that the optical band gap increased with the incident electron energy up to 600 eV. The optical band gap increased from 4.12 to 4.23 eV, with carrier density increasing from 7.09 to 8.55 × 10<sup>21</sup> cm<sup>−3</sup>. However, the film electron irradiated at 900 eV showed a decrease in optical band gap energy of 4.16 eV due to the decreased carrier density of 8.25 × 10<sup>21</sup> cm<sup>−3</sup>. The figure of merit revealed that the ZAS thin films electron-irradiated at 900 eV had higher optical and electrical performance than the other films prepared in this study.

Nanometer Size Lead Iodide Particles

1992 ◽  
Vol 242 ◽  
Author(s):  
Vivek Mehrotra ◽  
Eric Rodeghiero ◽  
Jens W. OTTO ◽  
Emmanuel P. Giannelis
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
X Ray Diffraction ◽  
Lead Iodide ◽  
Scanning Calorimetry ◽  
Porous Network ◽  
Nanometer Size ◽  
X Ray ◽  
Quantum Size ◽  
Guest Species

ABSTRACTNanometer size lead iodide particles have been synthesized in the porous network of a cross-linked polymer matrix. The optical band gap of the nanocrystals is shifted towards higher energy as compared to the bulk value. This shift is attributed to the quantum size effect on excitons. Intercalation with aniline leads to a further shift in the band gap which depends on the dipole moment of the intercalated guest species. Differential scanning calorimetry and high temperature x-ray diffraction have been used to analyze the ferroelectric transition in Pbl2.

Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

2015 ◽  
Vol 7 (3) ◽  
pp. 1923-1930
Author(s):  
Austine Amukayia Mulama ◽  
Julius Mwakondo Mwabora ◽  
Andrew Odhiambo Oduor ◽  
Cosmas Mulwa Muiva ◽  
Boniface Muthoka ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
Optical Transition ◽  
Bulk Material ◽  
Band Gap Energy ◽  
Optical Absorbance ◽  
Gap Energy ◽  
Constituent Elements

 Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the system’s network.

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