Optical Activity of Yb3+ in MeV Ion-Implanted InP.

1993 ◽  
Vol 301 ◽  
Author(s):  
S. Uekusa ◽  
A. Majima ◽  
H. Katsumata ◽  
Y. Noyori ◽  
M. Kumagai
Keyword(s):  
Band Gap ◽  
Photon Energy ◽  
Luminescence Intensity ◽  
Annealing Temperature ◽  
Rare Earth Ions ◽  
Excitation Wavelength ◽  
Photoluminescence Excitation ◽  
Efficient Energy Transfer ◽  
Transfer Processes ◽  
Impurities And Defects

ABSTRACTFor the evaluation of an implanted layer, photoluminescence (PL) and photoluminescence excitation (PLE) measurements, which are nondestructive and sensitive methods for identifying impurities and defects, were performed. Yb3+ -related sharp luminescence was observed at a wavelength of 1002nm, due to the transitions which occurred between the spin-orbit levels 2F5/2→2F7/2 of Yb3+ (4f13). Most efficient luminescence of Yb3+ was achieved at an excitation wavelength of around 880nm. The luminescence intensity of this peak (Yb3+) decreased with an increase in annealing temperature. Since the peak has not been observed for good samples in crystallinity, it may indicate that new, efficient energy transfer processes to rare-earth ions occur through the defect energy level. Especially, for the sample annealed at 600°C, Yb-related luminescence intensity excited by the photon energy below the band gap is about 3 times larger than that of excited by the photon energy above the band gap.

TWO PHOTON PHOTOCONDUCTIVITY OF ZnS USING XeCl LASER

2003 ◽  
Vol 17 (24) ◽  
pp. 1265-1270 ◽  
Author(s):  
R. D. SINGH ◽  
D. S. AHLAWAT ◽  
ARUN GAUR
Keyword(s):  
Band Gap ◽  
Photon Energy ◽  
Xecl Laser ◽  
Two Photon ◽  
Comparison Of Results ◽  
Photon Excitation ◽  
Enhanced Mobility ◽  
Two Photon Excitation

Log Q versus log I ph characteristics and laser enhanced mobility in the case of ZnS have been studied using a XeCl laser. The comparison of results in this case with multiphoton photoconductivity of other materials indicates two photon excitation from a lower valance band, wherefrom one-photon excitation is forbidden but two-photon excitation is allowed. Since the band-gap of ZnS is smaller than the photon energy of the XeCl laser, the result seems to be interesting.

scholarly journals Luminescent Characteristics of InGaAsP/InP Multiple Quantum Well Structures by Impurity-Free Vacancy Disordering

2001 ◽  
Vol 692 ◽  
Author(s):  
J. Zhao ◽  
X. D. Zhang ◽  
Z. C. Feng ◽  
J. C. Deng ◽  
P. Jin ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Band Gap ◽  
Annealing Temperature ◽  
Multiple Quantum Well ◽  
Blue Shift ◽  
Multiple Quantum ◽  
Quantum Well Structures ◽  
Cladding Layer ◽  
Cap Layer ◽  
Free Vacancy

AbstractInGaAsP/InP multiple quantum wells have been prepared by Impurity-Free Vacancy Disordering (IFVD). The luminescent characteristics was investigated using photoluminescence (PL) and photoreflectance (PR), from which the band gap blue shift was observed. Si3N4, SiO2 and SOG were used for the dielectric layer to create the vacancies. All samples were annealed by rapid thermal anne aling (RTA). The results indicate that the band gap blue shift varies with the dielectric layers and annealing temperature. The SiO2 capping was successfully used with an InGaAs cladding layer to cause larger band tuning effect in the InGaAs/InP MQWs than the Si3N4 capping with an InGaAs cladding layer. On the other hand, samples with the Si3N4-InP cap layer combination also show larger energy shifts than that with SiO2-InP cap layer combination.

Kathodo- und Photolumineszenz der Seltenerd-aktivierten Wirtsgitter Ba2La2B2+Te2O12 (B = Zn, Mg)

1986 ◽  
Vol 41 (6) ◽  
pp. 866-870 ◽  
Author(s):  
H.-D. Autenrieth ◽  
S. Kemmler-Sack
Keyword(s):  
Electronic Structure ◽  
Rare Earth ◽  
Visible Region ◽  
Host Lattice ◽  
Rare Earth Ions ◽  
New Host ◽  
Emission Efficiency ◽  
Transfer Processes ◽  
Trivalent Rare Earth ◽  
Host Lattices

By activation of the new host lattices Ba2La2B2+Te2O12 (B = Zn, Mg) with trivalent rare earth ions Ln3+ = Pr. Sm, Eu, Tb, Dy, Ho, Tm an emission in the visible region is observed. The influence of the electronic structure and concentration on the relative emission efficiency as well as the host lattice participation in the energy transfer processes are discussed.

scholarly journals Кинетика нарастания ап-конверсионной люминесценции кристалла LiY-=SUB=-0.8-=/SUB=-Yb-=SUB=-0.2-=/SUB=-F-=SUB=-4-=/SUB=- : Tm-=SUP=-3+-=/SUP=- (0.2 at.%) при импульсном возбуждении

2019 ◽  
Vol 61 (5) ◽  
pp. 953
Author(s):  
А.В. Михеев ◽  
Б.Н. Казаков
Keyword(s):  
Regression Analysis ◽  
Energy Transfer ◽  
Rare Earth ◽  
Laser Diode ◽  
Rare Earth Ions ◽  
Experimental Conditions ◽  
Pulsed Excitation ◽  
Transfer Processes ◽  
Dipole Interactions ◽  
Kinetics Of

AbstractThe regression analysis of the rise kinetics of up-conversion luminescence of the LiY_0.8Yb_0.2F_4:Tm^3+ (0.2 at %) crystal is performed. The kinetics curve is obtained with rectangular pulsed excitation by radiation from a laser diode (IR LD) with a wavelength of λ_ p = 933 nm. The most important—in these experimental conditions—mechanisms of the energy transfer from Yb^3+ ions to Tm^3+ ions are established, which are responsible for the transitions between the ground ^3 H _6 and excited ^3 F _4, ^3 H _4, ^1 G _4, ^1 D _2, and ^1 I _6 terms of the Tm^3+ ions. The durations of the relevant energy transfer processes are determined. It is shown that the energy transfer between rare earth ions in the LiY_0.8Yb_0.2F_4:Tm^3+ (0.2 at %) crystal occurs through the dipole–dipole interactions.

Giant enhancement of photoluminescence and tertiary emission in a chiral nematic by matching photonic band gap and excitation wavelength

2018 ◽  
Vol 262 ◽  
pp. 354-362 ◽  
Author(s):  
Marlin Baral ◽  
S. Krishna Prasad ◽  
Himali Patel ◽  
A.S. Achalkumar ◽  
C.V. Yelamaggad
Keyword(s):  
Band Gap ◽  
Photonic Band Gap ◽  
Excitation Wavelength ◽  
Chiral Nematic ◽  
Photonic Band

scholarly journals Air Annealing Effect on Oxygen Vacancy Defects in Al-doped ZnO Films Grown by High-Speed Atmospheric Atomic Layer Deposition

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5043
Author(s):  
Chia-Hsun Hsu ◽  
Xin-Peng Geng ◽  
Wan-Yu Wu ◽  
Ming-Jie Zhao ◽  
Xiao-Ying Zhang ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
High Speed ◽  
Oxygen Vacancies ◽  
Annealing Temperature ◽  
Atomic Layer ◽  
Zno Films ◽  
X Ray ◽  
Layer Deposition

In this study, aluminum-doped zinc oxide (Al:ZnO) thin films were grown by high-speed atmospheric atomic layer deposition (AALD), and the effects of air annealing on film properties are investigated. The experimental results show that the thermal annealing can significantly reduce the amount of oxygen vacancies defects as evidenced by X-ray photoelectron spectroscopy spectra due to the in-diffusion of oxygen from air to the films. As shown by X-ray diffraction, the annealing repairs the crystalline structure and releases the stress. The absorption coefficient of the films increases with the annealing temperature due to the increased density. The annealing temperature reaching 600 °C leads to relatively significant changes in grain size and band gap. From the results of band gap and Hall-effect measurements, the annealing temperature lower than 600 °C reduces the oxygen vacancies defects acting as shallow donors, while it is suspected that the annealing temperature higher than 600 °C can further remove the oxygen defects introduced mid-gap states.

BAND GAP SHIFT DUE TO NITROGEN DOPING, COMPOSITION GAS PRESSURE AND MICROWAVE POWER OF a-C:N THIN FILMS GROWN BY NEWLY-DEVELOPED SURFACE WAVE MICROWAVE PLASMA CVD

2004 ◽  
Vol 11 (06) ◽  
pp. 559-562
Author(s):  
M. RUSOP ◽  
S. ADHIKARI ◽  
A. M. M. OMER ◽  
S. ADHIKARY ◽  
H. UCHIDA ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Wave ◽  
Film Thickness ◽  
Band Gap ◽  
Microwave Power ◽  
Annealing Temperature ◽  
Optical Band Gap ◽  
Microwave Plasma ◽  
Gas Pressure ◽  
Developed Surface

This paper reports the band gap shifting due to nitrogen ( N 2) doping, microwave power and composition gas pressure of nitrogenated amorphous carbon ( a - C : N ) thin films deposited by newly-developed surface wave microwave plasma chemical vapor deposition (SWMP-CVD). Results show that the optical band gap decreased from 4.1 eV to 2.4 eV corresponding to the increase of N 2 doping from 0 to 5% in the gas ratio. However, further increase of N 2 doping beyond 5% did not decrease the band gap. It was found that composition gas pressure and launched MW power during film deposition also largely control the optical band gap. Investigation of annealing effects on optical band gap and film thickness of the N 2 doped films revealed that both band gap and film thickness decrease significantly with increase of annealing temperature. The optical band gap decreased from 2.4 eV to 1.1 eV, while film thickness decreases from 320 nm to 50 nm corresponding to 200 to 400°C annealing temperature. The results revealed that the properties of a - C : N can be tuned by changing the annealing temperature, composition gas pressure and microwave power of the SWMP-CVD system.

scholarly journals Fluoroindate glasses co-doped with Pr3+/Er3+ for near-infrared luminescence applications

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Wojciech A. Pisarski ◽  
Joanna Pisarska ◽  
Marta Kuwik ◽  
Marcin Kochanowicz ◽  
Jacek Żmojda ◽  
...  
Keyword(s):  
Rare Earth ◽  
Near Infrared ◽  
Rare Earth Ions ◽  
Luminescence Spectra ◽  
Nonradiative Relaxation ◽  
Transfer Processes ◽  
Direct Excitation ◽  
Infrared Luminescence ◽  
Doped Glass ◽  
Co Doped

AbstractFluoroindate glasses co-doped with Pr3+/Er3+ ions were synthesized and their near-infrared luminescence properties have been examined under selective excitation wavelengths. For the Pr3+/Er3+ co-doped glass samples several radiative and nonradiative relaxation channels and their mechanisms are proposed under direct excitation of Pr3+ and/or Er3+. The energy transfer processes between Pr3+ and Er3+ ions in fluoroindate glasses were identified. In particular, broadband near-infrared luminescence (FWHM = 278 nm) associated to the 1G4 → 3H5 (Pr3+), 1D2 → 1G4 (Pr3+) and 4I13/2 → 4I15/2 (Er3+) transitions of rare earth ions in fluoroindate glass is successfully observed under direct excitation at 483 nm. Near-infrared luminescence spectra and their decays for glass samples co-doped with Pr3+/Er3+ are compared to the experimental results obtained for fluoroindate glasses singly doped with rare earth ions.

Ambient Energy Harvesting of Piezoelectric ZnO Thin Film Dependence of Spin Speed and Annealing Temperature

2020 ◽  
Vol 981 ◽  
pp. 51-58
Author(s):  
Agus Geter Edy Sutjipto ◽  
Yit Pei Shian ◽  
Ali Shaitir ◽  
Mohamad Ashry Jusoh ◽  
Ari Legowo
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Energy Harvesting ◽  
Band Gap ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Oxide Thin Film ◽  
Zno Film ◽  
Zinc Oxide Thin Film ◽  
Spin Speed

This research deals with ambient energy harvesting by using zinc oxide thin film. The objectives of this thesis are to prove the ZnO film as a piezoelectric material can produce electric when vibration is applied and determine its optimal voltage. The thesis describes the sol gel spin coating technique to fabricate zinc oxide thin film. Zinc acetate dehydrate, absolute ethanol and diethanolamine were used in this thesis to act as sol gel precursor. Sol gel was coated on glass slide which wrapped by aluminum foil. The thin film was formed after preheating and annealing. The thin film was characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Photoluminescence spectroscopy (PL) and Ultraviolet-visible spectroscopy (UV-Vis) as well as analyzed using vibration technique. From XRD results, the films were preferentially diffracted at around 65° which corresponding to (1 1 2) diffraction phase. From FESEM results, it was observed that when the spin speed was increased at same annealing temperature, the thickness was also decreased. When the annealing temperature was increased at same spin speed, both grain size and thickness were increased. From the PL results, there was only film with spin speed of 2000 rpm and annealing temperature of 300 °C had slightly left wavelength which was 380 nm. Annealing temperature would affect only the intensity of PL wavelength. From the results of UV-Vis, it was observed that when the spin speed was increased at same annealing temperature, the band gap was decreased. When the annealing temperature was increased at same spin speed, the band gap was decreased. Piezoelectric test had proven the ZnO film could produce electricity. The maximum voltage (20.7 mV) was produced by the ZnO film with spin speed of 2000 rpm and annealing temperature of 300 °C.

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