Luminescence of II-VI Semiconductor Nanoparticles

2014 ◽  
Vol 222 ◽  
pp. 1-65 ◽  
Author(s):  
B.P. Chandra ◽  
V.K. Chandra ◽  
Piyush Jha
Keyword(s):  
Band Gap ◽  
Data Storage ◽  
Quantum Confinement Effect ◽  
Ultrafine Particle ◽  
Surface States ◽  
Emission Spectra ◽  
Volume Ratio ◽  
Blue Shift ◽  
Band Gap Energy ◽  
Molecular Engineering

Nanoparticle or an ultrafine particle is a small solid whose physical dimension lies between 1 to 100 nanometers. Nanotechnology is the coming revolution in molecular engineering, and therefore, it is curiosity-driven and promising area of technology. The field of nanoscience and nanotechnology is interdisciplinary in nature and being studied by physicists, chemists, material scientists, biologists, engineers, computer scientists, etc. Research in the field of nanoparticles has been triggered by the recent availability of revolutionary instruments and approaches that allow the investigation of material properties with a resolution close to the atomic level. Strongly connected to such technological advances are the pioneering studies that have revealed new physical properties of matter at a level intermediate between atomic/molecular and bulk. Quantum confinement effect modifies the electronic structure of nanoparticles when their sizes become comparable to that of their Bohr excitonic radius. When the particle radius falls below the excitonic Bohr radius, the band gap energy is widened, leading to a blue shift in the band gap emission spectra, etc. On the other hand, the surface states play a more important role in the nanoparticles, due to their large surface-to-volume ratio with a decrease in particle size (surface effects). From the last few years, nanoparticles have been a common material for the development of new cutting-edge applications in communications, energy storage, sensing, data storage, optics, transmission, environmental protection, cosmetics, biology, and medicine due to their important optical, electrical, and magnetic properties.

Band-Gap Energy Dependence of Emission Spectra in Rare Earth-Doped Zn(1-x)CdxS Thin Film Electroluminescent Devices

1992 ◽  
Vol 31 (Part 1, No. 2A) ◽  
pp. 295-300 ◽  
Author(s):  
Noboru Miura ◽  
Takashi Sasaki ◽  
Hironaga Matsumoto ◽  
Ryotaro Nakano
Keyword(s):  
Thin Film ◽  
Rare Earth ◽  
Band Gap ◽  
Energy Dependence ◽  
Emission Spectra ◽  
Band Gap Energy ◽  
Electroluminescent Devices ◽  
Gap Energy ◽  
Rare Earth Doped

scholarly journals Exchange-mediated magnetic blue-shift of the band-gap energy in the antiferromagnetic semiconductor MnTe

2020 ◽  
Vol 22 (8) ◽  
pp. 083029
Author(s):  
D Bossini ◽  
M Terschanski ◽  
F Mertens ◽  
G Springholz ◽  
A Bonanni ◽  
...  
Keyword(s):  
Band Gap ◽  
Blue Shift ◽  
Band Gap Energy ◽  
Gap Energy

scholarly journals Preparation and Characterization of Zno Nano particles Prepared by Hydrothermal Method

2019 ◽  
Vol 24 (3) ◽  
pp. 91
Author(s):  
Mohammed Ajmi Abd1 ◽  
Khalid Hamdi Razeg1 ◽  
Raad M.S Al-haddad2
Keyword(s):  
Quantum Confinement Effect ◽  
Hydrothermal Process ◽  
Blue Shift ◽  
Band Gap Energy ◽  
Zinc Nitrate ◽  
Nano Particles ◽  
Surface Topology ◽  
Nitrate Hexahydrate ◽  
X Ray Diffraction ◽  
Afm Analysis

In this study,the nanoparticles of zinc oxide were readily prepared  through Hydrothermal process by using zinc nitrate hexahydrate, and Sodium hydroxide as aprecursors. The surface topology, and crystalline structure of prepared ZnO nanoparticles were studied. X-ray diffraction (XRD) revealed that the prepared ZnO nano particles is highly crystalline, having (wurtzite) crystal structure.  The optical analysis by UV–vis showed that these ZnO nano particles have considerable blue shift in the optical band gap energy (Eg = 4.9eV), and this may be to the  quantum confinement effect of nano particles. The FT-IR results shows the  existence of OH, COO, H2O groups the characteristic vibrational modes of Zn–O were identified. and AFM analysis showed that the diameters of the ZnO particles is in ananometer range of (70-74)nm.   http://dx.doi.org/10.25130/tjps.24.2019.052 

scholarly journals Optical Studies of Organically Functionalized Mn doped ZnS Quantum Dots

2021 ◽  
Vol 33 (12) ◽  
pp. 2972-2976
Author(s):  
Anju Bala ◽  
Rajeev Sehrawat ◽  
Renu Bala ◽  
Ashutosh Dixit
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement Effect ◽  
Emission Spectra ◽  
Blue Shift ◽  
Capping Agent ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Uv Visible ◽  
Mn Doped

Organically functionalized manganese doped zinc sulfide (ZnS/Mn) quantum dots were prepared by simple chemical method with polypyrrole (PPy) used as a capping agent. Prepared quantum dots were characterized with Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction microscope (XRD), UV-visible spectroscopy and photoluminescence spectroscopy. Crystalline size of PPy capped ZnS/Mn quantum dots for various concentrations of PPy were approximate 2 nm as analyzed by XRD and TEM analysis. The absorption spectra revealed the occurrence of a blue shift in the peak of absorption and an increase in the band gap value due to the quantum confinement effect. FTIR spectroscopy confirmed that shifting of broad peak at 2335.8 cm–1 was due to S-H stretching vibrations, which confirmed interaction of hydrogen and sulphur in ZnS/Mn/PPy nanocomposites. Uncapped ZnS/Mn and PPy capped ZnS/Mn quantum dots reveal the effective photoluminescence emission spectra in the range of 300-700 nm. With increase the value of capping agent in ZnS/Mn quantum dots, photoluminescence spectra going to red shifting. The photoluminescence properties of the organically functionalized ZnS nanoparticles are favourable for the application in optoelectronic devices.

Optical Constants, Critical Points, and Phonon Modes of GaAsN Single Layers

2000 ◽  
Vol 639 ◽  
Author(s):  
G. Leibiger ◽  
V. Gottschalch ◽  
A. Kasik ◽  
B. Rheinländer ◽  
J. Šik ◽  
...  
Keyword(s):  
Band Gap ◽  
Dielectric Function ◽  
Critical Points ◽  
Optical Constants ◽  
Blue Shift ◽  
Band Gap Energy ◽  
Phonon Modes ◽  
Transition Energies ◽  
Infrared Spectral Range ◽  
Infrared Spectral

ABSTRACTSpectroscopic ellipsometry (SE) is employed to study the optical properties of GaAs1−yNy [0% ≤ y ≤ 3.7%] single layers for photon energies from 0.75 eV to 4.5 eV and for wavenumbers from 100 cm−1 to 600 cm−1. We provide parametric model functions for the dielectric function spectra of GaAsN in both photon energy ranges. The model functions for photon energies from 0.75 eV to 4.5 eV excellently match dielectric function data obtained from a numerical wavelength-by-wavelength inversion of the experimental data. Criticalpoint analysis of the ellipsometric data is performed in the spectral regions of the fundamental band gap and the critical points E1 and E1+δ1. The band-gap energy is red shifted whereas the E1 and E1+δ1 transition energies are blue shifted with increasing y. For y ≤ 1.65% the observed blue shift of the E1 energy is well explained by the sum of the effects of biaxial (001) strain and alloying. The GaAsN layers show two-mode behaviour in the infrared spectral range (100 cm−1 to 600 cm−1). We detect the transverse GaAs- and GaN- sublattice modes at wavenumbers of about 267 cm−1 and 470 cm−1, respectively. The polar strength of the GaN TO mode increases linearly with y. This effect can be used to monitor the nitrogen composition in GaAsN layers.

The dependence of emission spectra of rare earth ion on the band-gap energy of MgxZn1−xO alloy

2003 ◽  
Vol 249 (1-2) ◽  
pp. 163-166 ◽  
Author(s):  
Dongxu Zhao ◽  
Yichun Liu ◽  
Dezhen Shen ◽  
Jiying Zhang ◽  
Youming Lu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Band Gap ◽  
Emission Spectra ◽  
Band Gap Energy ◽  
Rare Earth Ion ◽  
Gap Energy

Luminescence Properties of Cerium Doped Iron Calcium Boroaluminate Glass

2017 ◽  
Vol 268 ◽  
pp. 72-76
Author(s):  
S. Akmar Roslan ◽  
Ramli Arifin ◽  
Sib Krishna Ghoshal
Keyword(s):  
Band Gap ◽  
Emission Spectra ◽  
Green Emission ◽  
Band Gap Energy ◽  
Glass System ◽  
Optical Measurements ◽  
Excitation Wavelength ◽  
Gap Energy ◽  
Quenching Method ◽  
Indirect Band Gap

Borate glass system of composition (100-x)B2O3-15Al2O3-20CaO-0.4Fe2O3-xCeO2 with x = 0, 0.25, 0.50, 0.75, and 1.0 mol% were prepared using conventional melt-quenching method. Optical measurements were carried out at room temperature to determine the Cerium (Ce3+) ions concentration dependent absorption and luminescence emission properties of such glass system. Optical energy band gap of the glass system were evaluated as a function of Ce3+ ions content. Indirect band gap energy was found to be lower than the direct band gap energy. Urbach energy was ranged between 0.12-0.17 eV. An increased broad absorption is observed in the UV region with increasing Ce3+ ions concentration. The emission spectra of the glass system recorded with 380 nm excitation wavelength revealed prominent cyan-green emission.

The Effect of Growth Temperature on Atomic Ordering in Gao.5 2Ino.48P Epilayers Grown on GaAs (001) Substrates by GS-MBE

1996 ◽  
Vol 441 ◽  
Author(s):  
C. Meenakarn ◽  
A. E. Staton-Bevan ◽  
M. D. Dawson ◽  
G. Duggan ◽  
A. H. Kean ◽  
...  
Keyword(s):  
Band Gap ◽  
Data Storage ◽  
Growth Temperature ◽  
Domain Size ◽  
Antiphase Domain ◽  
Band Gap Energy ◽  
Optical Data Storage ◽  
Optical Data ◽  
Gas Source ◽  
Transmission Electron

AbstractA Transmission Electron Microscopy (TEM), Photoluminescence (PL) and Photoluminescence Excitation Spectroscopy (PLE) investigation has been conducted on Ga0 52In0.48P epilayers, grown on GaAs(001) by Gas-Source Molecular Beam Epitaxy. Selected area diffraction in the TEM shows that epilayers grown at temperatures between 480°C and 535°C exhibit CuPt-type ordering with the antiphase domain size increasing with increasing growth temperature. PLE data shows that, in the temperature range 480°C to 535°C the band gap energy of Ga0.52In0-48P epilayers increases with increasing growth temperature from 1.971 to 2.003 (±0.001 eV). For high band gap optical data storage applications these values compare well with the highest band gap energies reported for epilayers grown by MOCVD.

Synthesis and Characterization of Mn2+ Doped ZnS Using Reverse Miceller Method

2014 ◽  
Vol 970 ◽  
pp. 283-287
Author(s):  
Rahizana Mohd Ibrahim ◽  
Markom Masturah ◽  
Huda Abdullah
Keyword(s):  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Blue Shift ◽  
Band Gap Energy ◽  
Confinement Effect ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Size Of Particles ◽  
Absorbance Spectra

In this work we synthesized the monodisperse of Zn1-xMnxS with x =0.00,0.02,0.04,0.06,0.08 and 0.10 nanoparticles by reverse micelle method using sodium bis (2-ethylhexyl) sulfosuccinate (AOT) as surfactant. The prepared particles were characterized using UV-Visible Spectroscopy, X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Photoluminescence (PL) for size, morphology and optical of the samples .UV-vis absorbance spectra for all of the synthesized nanoparticles show the maximum absorption for all samples is observed at range 210 - 300 nm . The absorption edge shifted to lower wavelengths when doping with ion Mn as per UV-Vis spectroscopy. The band gap energy values were increase from 4.50eV to 4.90 eV. This blue shift is attributed to the quantum confinement effect. The size of particles is found to be 3-5nm range. The Mn2+ doped ZnS nanoparticles using reverse micelles method shows the enhance of PL intensity results in monodisperse nanoparticles. Keywords: Nanoparticles; UV-vis absorbance spectra; quantum confinement effect; photoluminescence.

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

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