Ge Related Defect-Complex Induced Luminescence in InGaAsP

1987 ◽  
Vol 104 ◽  
Author(s):  
B. M. Arora ◽  
S. Chakravarty ◽  
S. S. Chandvankar ◽  
R. Rajalakshmi ◽  
A. K. Srivastava
Keyword(s):  
Activation Energy ◽  
Liquid Phase ◽  
Broad Band ◽  
Emission Spectra ◽  
Integrated Intensity ◽  
Coordinate Model ◽  
Related Defect ◽  
Ge Doping ◽  
Type Conduction ◽  
Configuration Coordinate

ABSTRACTGermanium doping of InGaAsP epitaxial layers grown by liquid phase epitaxy produces n type conduction with a net distribution coefficient KGe∼ 5×10-3. In addition, Ge doping introduces a broad band (∼0.2eV) of efficient luminescence which is red shifted with respect to the band edge. The intensity of this band grows with increasing Ge concentration. In all the samples, the integrated intensity of the broad band varies relatively less in the temperature range 15K to about 90K. At higher temperatures, the intensity falls exponentially with an activation energy of 0.05 - 0.07 eV. The emission spectra are compared with the configuration-coordinate model of the emission from a Ge related complex.

Spherical BaMgAl10O17:Eu2+ Phosphor Particles by Liquid Phase Synthesis

2007 ◽  
Vol 124-126 ◽  
pp. 391-394
Author(s):  
Ha Kyun Jung ◽  
Dae Won Lee ◽  
Yoon Chang Park
Keyword(s):  
Liquid Phase ◽  
Emission Intensity ◽  
Broad Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Phase Reaction ◽  
Uniform Size ◽  
Synthetic Process ◽  
Preparation Conditions ◽  
Blue Phosphor

To improve luminescent properties of the phosphor, spherical BaMgAl10O17:Eu2+ particles have been synthesized using a liquid phase reaction composed of two-stage precipitations. This phosphor particles exhibited uniform size (0.4 ㎛) with narrow distribution and were well-dispersed without agglomeration. The single phase of phosphor was formed by firing at the temperature of about 1350°C. The preparation conditions in this synthetic process for spherical BaMgAl10O17:Eu2+ particles were optimized on the basis of emission intensity by the excitation at 147 nm. The emission spectra showed the typical broad band due to the transition of Eu2+ activator from 4f65d1 to 4f7 in BaMgAl10O17:Eu2+. The maximum emission intensity for this spherical blue phosphor was obtained by reduction treatment at 1450°C.

Photoluminescence Study of Defects in GaN Grown by Molecular Beam Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Michael A. Reshchikov ◽  
Manhong H. Zhang ◽  
Jie Cui ◽  
Paolo Visconti ◽  
Feng Yun ◽  
...  
Keyword(s):  
Activation Energy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Green Band ◽  
Photoluminescence Study ◽  
Coordinate Model ◽  
Pl Intensity ◽  
Increasing Temperature ◽  
Configuration Coordinate

ABSTRACTDefect related photoluminescence (PL) in unintentionally doped GaN layers grown by molecular beam epitaxy (MBE) was studied. Under certain growth conditions, we observed new defect-related bands: a red band with a maximum at about 1.88 eV and a green band with a maximum at about 2.37 eV. The quenching of these bands with increasing temperature took place with an activation energy of about 120-140 meV at temperatures above 100 K. Moreover, the red band exhibited an increase of PL intensity with an activation energy of 1.2 meV in the range of 10-60 K. The observed behavior is explained by invoking a configuration coordinate model and that we speculate the defects to be partially nonradiative and related to Ga atoms.

Effect of ionizing radiation on the kinetics of hydrogenation on the Ni-MgO mixed catalyst

1982 ◽  
Vol 47 (7) ◽  
pp. 1780-1786 ◽  
Author(s):  
Rostislav Kudláček ◽  
Jan Lokoč
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Liquid Phase ◽  
Ionizing Radiation ◽  
Oxide Catalyst ◽  
Absorbed Dose ◽  
Hydrogenation Rate ◽  
Solution Composition ◽  
Mixed Catalyst ◽  
Kinetics Of

The effect of gamma pre-irradiation of the mixed nickel-magnesium oxide catalyst on the kinetics of hydrogenation of maleic acid in the liquid phase has been studied. The changes of the hydrogenation rate are compared with the changes of the adsorbed amount of the acid and with the changes of the solution composition, activation energy, and absorbed dose of the ionizing radiation. From this comparison and from the interpretation of the experimental data it can be deduced that two types of centers can be distinguished on the surface of the catalyst under study, namely the sorption centres for the acid and hydrogen and the reaction centres.

Preparation and Luminescence Property of LaMgAl11O19

2012 ◽  
Vol 519 ◽  
pp. 224-227 ◽  
Author(s):  
Xin Min ◽  
Ming Hao Fang ◽  
Yan Gai Liu ◽  
Zhao Hui Huang
Keyword(s):  
Solid State ◽  
Luminescence Property ◽  
Broad Band ◽  
Emission Spectra ◽  
Synthesis Temperature ◽  
Solid State Lasers ◽  
Broad Band Emission ◽  
Band Emission ◽  
Air Atmosphere ◽  
Fluorescent Lamps

Lanthanum magnesium hexaaluminate (LaMgAl11O19, LMA) has attracted much interest as its widely used in solid state lasers, TV phosphors and fluorescent lamps. In this paper, LaMgAl11O19 ceramic was pressureless sintered at 1650 °C for 10 h in air atmosphere using LaMgAl11O19 powders prepared by solid-state reaction at 1500 °C for 4 h. The result indicated that the synthesis temperature of LaMgAl11O19 powders was about 1500 °C. The LMA ceramic sample was dense and had a microstructure of platelet-like gains. The excitation spectrum shows two wide bands with the peaks at about 254 nm and 265 nm by monitoring the strongest 362 nm emission, and the emission spectra is consisted of a broad band emission with their peaks near 362 nm with a half-width about 5 nm exciting with 265 nm wavelength.

Effect of crystal orientation and doping on the activation energy for GaAs oxide growth by liquid phase method

2000 ◽  
Vol 87 (5) ◽  
pp. 2629-2633 ◽  
Author(s):  
Hwei-Heng Wang ◽  
Dei-Wei Chou ◽  
Jau-Yi Wu ◽  
Yeong-Her Wang ◽  
Mau-Phon Houng
Keyword(s):  
Activation Energy ◽  
Liquid Phase ◽  
Crystal Orientation ◽  
Phase Method ◽  
Oxide Growth ◽  
Liquid Phase Method

Hole-Like Defects in n-Channel 4H-SiC MESFETs Observed by Current Transient Spectroscopy

2005 ◽  
Vol 483-485 ◽  
pp. 865-868
Author(s):  
Jean Marie Bluet ◽  
M. Gassoumi ◽  
I. Dermoul ◽  
F. Chekir ◽  
H. Maaref ◽  
...  
Keyword(s):  
Activation Energy ◽  
Electron Emission ◽  
Interfacial Layer ◽  
Broad Band ◽  
Current Transient ◽  
Linear Regime ◽  
Saturation Regime ◽  
Transient Spectroscopy ◽  
Different Levels

Conductance DLTS measurements have been performed on 4H-SiC MESFETs. A broad band due to electron emission by different levels is observed. An additional “hole-like” level with activation energy of 0.9 eV is obtained in linear regime but not in saturation regime. From the results, it is proposed that this “hole-like” signal is due to capture of electron present at a conductive SiC/SiO2 interfacial layer.

A New Deep Red-Emitting Mn2+-Activated SrLaGa3S6O Phosphor

2012 ◽  
Vol 531-532 ◽  
pp. 145-148 ◽  
Author(s):  
Rui Jin Yu ◽  
Jin Young Park ◽  
Hyun Kyoung Yang ◽  
Byung Kee Moon ◽  
Byung Chun Choi ◽  
...  
Keyword(s):  
Broad Band ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
White Led ◽  
Photoluminescence Excitation ◽  
Led Lighting ◽  
Display Devices ◽  
Chromaticity Coordinates ◽  
Standard Values ◽  
Cie Chromaticity

A new deep red-emitting Mn2+-activated SrLaGa3S6O phosphor was first prepared by a solid-state reaction method. Their luminescence properties were investigated by photoluminescence excitation and emission spectra. The emission spectrum shows a broad band with an emission maximum at 668 nm under the host excitation of 340 nm. The full width at half maximum (FWHM) of the emission peak is about 83 nm. The CIE chromaticity coordinates (x = 0.673 and y = 0.312) shows that the phosphor emission is in the deep red region and were very near to the NTSC standard values for red. Since the excitation band of the phosphor lies in the near UV excitable region, giving a deep red emission, it can be used for applications in near UV phosphor converted white LED lighting and display devices.

Optimization of Rare Earth Dope on MAl2O4 (M = Ba, Sr) by Self-Propagating High Temperature Synthesis

2012 ◽  
Vol 488-489 ◽  
pp. 442-446 ◽  
Author(s):  
Taschaporn Sathaporn ◽  
Sutham Niyomwas
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Broad Band ◽  
Emission Spectra ◽  
Rare Earth Ions ◽  
Ocean Optics ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Microscope Technique

The Eu2+ doped barium aluminate (BaAl2O4:Eu2+) and strontium aluminate (SrAl2O4:Eu2+) with high brightness were synthesized by self-propagating high temperature synthesis (SHS) method. The influence of doping rare earth ions (Eu2+) on the luminescence of MAl2O4:Eu2+ were described in this study. The reactions were carried out in a SHS reactor under static argon gas at a pressure of 0.5 MPa. The morphologies and the phase structures of the products have been characterized by X-ray diffraction (XRD) and scanning electron microscope technique (SEM). The emission spectra of the products have been measured by an Ocean optics spectrometer at room temperature. Broad band UV excited luminescence was observed for BaAl2O4:Eu2+ and SrAl2O4:Eu2+ in the green region peak at λmax = 501 nm and 523 nm, respectively. The optimum Eu2+ doping ratio were 10.5 mol% and 6 mol% for BaAl2O4:Eu2+ and SrAl2O4:Eu2+, respectively

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