Optical transition properties, internal quantum efficiencies and temperature sensing of Er 3+ Doped BaGd 2 O 4 phosphor with low maximum phonon energy

2021 ◽  
Author(s):  
Mengyan Luo ◽  
Xuezhu Sha ◽  
Baojiu Chen ◽  
Xizhen Zhang ◽  
Hongquan Yu ◽  
...  
Keyword(s):  
Optical Transition ◽  
Temperature Sensing ◽  
Phonon Energy

scholarly journals Bi3+ Effects on Down-/up-conversion Luminescence, Temperature Sensing and Optical Transition Properties in Bi3+/Er3+ Co-doped YNbO4  Phosphors

2020 ◽  
Author(s):  
Xin Wang ◽  
Xiangping Li ◽  
Hongquan Yu ◽  
Sai Xu ◽  
Jiashi Sun ◽  
...  
Keyword(s):  
Near Infrared ◽  
Optical Transition ◽  
Green Emission ◽  
Radiative Transition ◽  
Solid State Reaction Method ◽  
Temperature Sensing ◽  
Infrared Light ◽  
Luminescence Spectra ◽  
Experimental Values ◽  
Co Doped

Abstract A series of Bi3+ single-doped and Bi3+/Er3+ co-doped YNbO4 phosphors with various concentrations of Bi3+ ions were prepared by a conventional high temperature solid-state reaction method. The results of XRD and Rietveld refinement confirmed that monoclinic phase YNbO4 samples were achieved. The down-/up-conversion luminescence of Er3+ ions were investigated under the excitation of ultraviolet light (327 nm) and near infrared light (980 nm). Under 327 nm excitation, broad visible emission band from Bi3+ ions and characteristic green emission peaks from Er3+ ions were simultaneously observed, while only strong green emissions from Er3+ ions were detected upon excitation of 980 nm. Remarkable emission enhancement was observed in down-/up-conversion luminescence processes by introducing Bi3+ ions into Er3+-doped YNbO4 phosphors. By analyzing the laser working current dependent up-conversion luminescence spectra, two-photon processes were confirmed to be responsible for both the green and the red up-conversion emissions of Er3+ ion. The temperature sensing property of Er3+ was studied by using the temperature dependent up-conversion luminescence spectra and it was found that the temperature sensitivity was sensitive to the doping concentration of Bi3+ ions. By comparing the experimental values of the radiative transition rate ratio of the two green emission levels of Er3+ ions and the theoretical values calculated by Judd-Ofelt (J-O) theory, it was concluded that energy level splitting had significant influences on the temperature sensing property of Er3+ ions.

A New Metastable Defect in Silicon, Optical Properties and an Investigation of the Mechanism Causing the Configurational Change

1989 ◽  
Vol 163 ◽  
Author(s):  
J. H. Svensson ◽  
B. Monemar
Keyword(s):  
Optical Properties ◽  
Metastable State ◽  
Optical Spectrum ◽  
Auger Recombination ◽  
Optical Transition ◽  
Phonon Energy ◽  
Czochralski Technique ◽  
Configurational Change ◽  
Related Defect ◽  
Metastable Defect

AbstractA new optical transition with a no-phonon energy of 0.615 eV discovered in electron-irradiated silicon grown by the Czochralski technique is investigated, revealing metastable properties of the related defect. The investigation is focused on the optical properties of the transition and its associated structure and on the mechanism governing the change of defect configuration. The transformation of the defect to the metastable state is suggested to be induced by excitonic Auger recombination. A pseudo-donor model is presented as an explanation of the optical spectrum.

Plasmon-assisted interaction of Si with light, for cancer hyperthermia and electromagnetic energy harvest

2020 ◽  
Vol 92 (2) ◽  
pp. 20101
Author(s):  
Behnam Kheyraddini Mousavi ◽  
Morteza Rezaei Talarposhti ◽  
Farshid Karbassian ◽  
Arash Kheyraddini Mousavi
Keyword(s):  
Silicon Nanowires ◽  
Metallic Nanoparticles ◽  
Near Infrared ◽  
Optical Transition ◽  
Electromagnetic Energy ◽  
Energy Harvest ◽  
Absorption Enhancement ◽  
Ir Absorption ◽  
Absorption Mechanism ◽  
Near Ir

Metal-assisted chemical etching (MACE) is applied for fabrication of silicon nanowires (SiNWs). We have shown the effect of amorphous sheath of SiNWs by treating the nanowires with SF6 and the resulting reduction of absorption bandwidth, i.e. making SiNWs semi-transparent in near-infrared (IR). For the first time, by treating the fabricated SiNWs with copper containing HF∕H2O2∕H2O solution, we have generated crystalline nanowires with broader light absorption spectrum, up to λ = 1 μm. Both the absorption and photo-luminescence (PL) of the SiNWs are observed from visible to IR wavelengths. It is found that the SiNWs have PL at visible and near Infrared wavelengths, which may infer presence of mechanisms such as forbidden gap transitions other can involvement of plasmonic resonances. Non-radiative recombination of excitons is one of the reasons behind absorption of SiNWs. Also, on the dielectric metal interface, the absorption mechanism can be due to plasmonic dissipation or plasmon-assisted generation of excitons in the indirect band-gap material. Comparison between nanowires with and without metallic nanoparticles has revealed the effect of nanoparticles on absorption enhancement. The broader near IR absorption, paves the way for applications like hyperthermia of cancer while the optical transition in near IR also facilitates harvesting electromagnetic energy at a broad spectrum from visible to IR.

A New Scanning Thermal Microprobe

1997 ◽  
Vol 503 ◽  
Author(s):  
Yongxia Zhang ◽  
Yanwei Zhang ◽  
Juliana Blaser ◽  
T. S. Sriiram ◽  
R. B. Marcus
Keyword(s):  
Thin Film ◽  
High Resolution ◽  
Thermal Response ◽  
Temperature Sensing ◽  
Thermal Sensor ◽  
Atomic Force ◽  
Thin Film Thermocouple ◽  
Processing Steps ◽  
Thermocouple Junction

ABSTRACTA thermal microprobe has been designed and built for high resolution temperature sensing. The thermal sensor is a thin-film thermocouple junction at the tip of an Atomic Force Microprobe (AFM) silicon probe needle. Only wafer-stage processing steps are used for the fabrication. The thermal response over the range 25–s 4.5–rovolts per degree C and is linear.

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.

OPTICAL TRANSITIONS IN A PARABOLIC GaAs/Ga1-xAlxAs SUPERLATTICES

2001 ◽  
Vol 08 (03n04) ◽  
pp. 321-325
Author(s):  
ŞAKIR ERKOÇ ◽  
HATICE KÖKTEN
Keyword(s):  
Transition Matrix ◽  
Optical Transition ◽  
Matrix Elements ◽  
Electron States ◽  
Parabolic Potential ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Transition Matrix Elements ◽  
Scf Calculations

We have performed self-consistent field (SCF) calculations of the electronic structure of GaAs/Ga 1-x Al x As superlattices with parabolic potential profile within the effective mass theory. We have calculated the optical transition matrix elements involving transitions from the hole states to the electron states, and we have also computed the oscillator strength matrix elements for the transitions among the electron states.

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