Temperature behavior of X-Ray luminescence spectra of ZnSe

2022 ◽  
Author(s):  
I. Abbasov ◽  
M. Musayev ◽  
D. Askerov ◽  
J. Huseynov ◽  
E. Gavrishuk ◽  
...  
Keyword(s):  
Thermal Quenching ◽  
Chemical Vapor ◽  
Temperature Behavior ◽  
Luminescence Spectra ◽  
Uv Laser ◽  
Green Band ◽  
Spectra Analysis ◽  
X Ray ◽  
Temperature Dependences ◽  
The Given

In the given paper, the temperature dependences ([Formula: see text]–300 K) of the green band intensity at wavelengths [Formula: see text] nm and [Formula: see text] nm have been measured and observed, respectively, from the polished and unpolished surface (PS and unPS) of a polycrystalline CVD (chemical vapor deposition) ZnSe sample upon excitation by X-ray quanta ([Formula: see text]. In both cases, the activation energy of thermal quenching has been determined, and the reasons for thermal quenching have been considered in detail. Along with XRL spectra analysis, the temperature behavior of the green band observed upon excitation by an ultraviolet (UV) laser (He–Cd, [Formula: see text] nm) from the PS and unPS in the temperature range [Formula: see text]–200 K has been discussed in more detail.

Photoluminescence Characteristics of Sol–Gel Derived ZnTiO3 Doped with Ni2+ Ion

2013 ◽  
Vol 544 ◽  
pp. 360-363 ◽  
Author(s):  
You Hua Yu ◽  
Meng Xia ◽  
Li Li Liu ◽  
Wei Jie Wu
Keyword(s):  
Sol Gel ◽  
Luminescent Properties ◽  
Host Lattice ◽  
Deionized Water ◽  
Luminescence Spectra ◽  
X Ray Diffraction ◽  
Spectra Analysis ◽  
X Ray ◽  
Water As Solvent ◽  
Sol Gel Process

ZnTiO3 doped with Ni 2+ ion has been prepared at a relatively low temperature of 600°C from the precursor derived from sol-gel process using deionized water as solvent. X-ray diffraction analysis indicates that the doped samples exhibit a hexagonal ZnTiO3 structure. From the luminescence spectra analysis, the introduction of Ni2+ ions into ZnTiO3 results in novel luminescent properties. And the relative intensity of the bands varies with the concentration of Ni2+ ions. It is demonstrated that the Ni2+ ion has taken the place of Zn2+ ion in the host lattice of ZnTiO3.

scholarly journals The Spectra of X-ray and Photoluminescence of High-Resistance Crystals of ZnSe

2018 ◽  
Vol 63 (6) ◽  
pp. 557 ◽  
Author(s):  
M. Alizadeh ◽  
V. Ya. Degoda
Keyword(s):  
High Resistance ◽  
Luminescence Band ◽  
Luminescence Spectra ◽  
Wavelength Shift ◽  
Spectral Maximum ◽  
Luminescent Center ◽  
X Ray ◽  
Band Form ◽  
Temperature Dependences ◽  
Different Temperatures

The luminescence spectra of high-resistance ZnSe crystals consist of two main bands with maxima at 630 nm (1.92 eV) and 970 nm (1.28 eV). The planned comparison has been carried out between the spectra of X-ray luminescence and photoluminescence of ZnSe among themselves in the spectral region from 400 to 1200 nm at different excitation intensities and different temperatures (8, 85, 295, and 420 K). It is found that the forms of luminescence bands do not depend on the excitation intensities. The band form with a maximum at 970 nm also does not depend on the excitation type, and the band at 630 nm differs slightly under the X-ray and UV excitations. The temperature dependences of the spectral positions of bands’ maxima and their half-widths are analyzed. A conclusion is drawn that the 970-nm emission band is elementary. A short-wavelength shift of the spectral maximum of the 630-nm band with increasing the temperature makes it possible to conclude that this luminescence band is non-elementary. This correlates with the previously discovered feature of this band related to the realization of two recombination mechanisms (electron and hole) at this luminescent center.

Interactions of Ge Atoms with High- ê Oxide Dielectric Surfaces

2005 ◽  
Vol 879 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt
Keyword(s):  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Tungsten Filament ◽  
X Ray ◽  
Dielectric Surfaces ◽  
Temperature Programmed ◽  
The Stability ◽  
Ge Nanocrystals

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.

Nitrogen (N2) Implantation to Suppress Growth of Interfacial Oxide in Mocvd Bst and Sputtered Bst Films

1999 ◽  
Vol 567 ◽  
Author(s):  
Renee Nieh ◽  
Wen-Jie Qi ◽  
Yongjoo Jeon ◽  
Byoung Hun Lee ◽  
Aaron Lucas ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Interfacial Layer ◽  
Gate Dielectric ◽  
Nitrogen Concentration ◽  
Chemical Vapor ◽  
Future Generation ◽  
Oxide Thickness ◽  
Layer Growth ◽  
X Ray ◽  
Bst Films

ABSTRACTBa0.5Sr0.5TiO3 (BST) is one of the high-k candidates for replacing SiO2 as the gate dielectric in future generation devices. The biggest obstacle to scaling the equivalent oxide thickness (EOT) of BST is an interfacial layer, SixOy, which forms between BST and Si. Nitrogen (N2) implantation into the Si substrate has been proposed to reduce the growth of this interfacial layer. In this study, capacitors (Pt/BST/Si) were fabricated by depositing thin BST films (50Å) onto N2 implanted Si in order to evaluate the effects of implant dose and annealing conditions on EOT. It was found that N2 implantation reduced the EOT of RF magnetron sputtered and Metal Oxide Chemical Vapor Deposition (MOCVD) BST films by ∼20% and ∼33%, respectively. For sputtered BST, an implant dose of 1×1014cm−;2 provided sufficient nitrogen concentration without residual implant damage after annealing. X-ray photoelectron spectroscopy data confirmed that the reduction in EOT is due to a reduction in the interfacial layer growth. X-ray diffraction spectra revealed typical polycrystalline structure with (111) and (200) preferential orientations for both films. Leakage for these 50Å BST films is on the order of 10−8 to 10−5 A/cm2—lower than oxynitrides with comparable EOTs.

scholarly journals Aluminide Thermal Barrier Coating for High Temperature Performance of MAR 247 Nickel Based Superalloy

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 48
Author(s):  
Mateusz Kopec ◽  
Dominik Kukla ◽  
Xin Yuan ◽  
Wojciech Rejmer ◽  
Zbigniew L. Kowalewski ◽  
...  
Keyword(s):  
High Temperature ◽  
Stress Amplitude ◽  
Aluminide Coating ◽  
Chemical Vapor ◽  
Fatigue Tests ◽  
Protective Atmosphere ◽  
X Ray ◽  
Nickel Based Superalloy ◽  
Barrier Coating ◽  
Aluminide Layer

In this paper, mechanical properties of the as-received and aluminide layer coated MAR 247 nickel based superalloy were examined through creep and fatigue tests. The aluminide layer of 20 µm was obtained through the chemical vapor deposition (CVD) process in the hydrogen protective atmosphere for 8 h at the temperature of 1040 °C and internal pressure of 150 mbar. A microstructure of the layer was characterized using the scanning electron microscopy (SEM) and X-ray Energy Dispersive Spectroscopy (EDS). It was found that aluminide coating improve the high temperature fatigue performance of MAR247 nickel based superalloy at 900 °C significantly. The coated MAR 247 nickel based superalloy was characterized by the stress amplitude response ranging from 350 MPa to 520 MPa, which is twice as large as that for the uncoated alloy.

scholarly journals Optical Constant and Conformality Analysis of SiO2 Thin Films Deposited on Linear Array Microstructure Substrate by PECVD

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 510
Author(s):  
Yongqiang Pan ◽  
Huan Liu ◽  
Zhuoman Wang ◽  
Jinmei Jia ◽  
Jijie Zhao
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Deposition Rate ◽  
Optical Constant ◽  
Photoelectron Spectroscopy ◽  
Linear Array ◽  
Chemical Vapor ◽  
Rf Plasma ◽  
X Ray ◽  
Sio2 Thin Film

SiO2 thin films are deposited by radio frequency (RF) plasma-enhanced chemical vapor deposition (PECVD) technique using SiH4 and N2O as precursor gases. The stoichiometry of SiO2 thin films is determined by the X-ray photoelectron spectroscopy (XPS), and the optical constant n and k are obtained by using variable angle spectroscopic ellipsometer (VASE) in the spectral range 380–1600 nm. The refractive index and extinction coefficient of the deposited SiO2 thin films at 500 nm are 1.464 and 0.0069, respectively. The deposition rate of SiO2 thin films is controlled by changing the reaction pressure. The effects of deposition rate, film thickness, and microstructure size on the conformality of SiO2 thin films are studied. The conformality of SiO2 thin films increases from 0.68 to 0.91, with the increase of deposition rate of the SiO2 thin film from 20.84 to 41.92 nm/min. The conformality of SiO2 thin films decreases with the increase of film thickness, and the higher the step height, the smaller the conformality of SiO2 thin films.

Characterization ofa‐SiC:H films produced in a standard plasma enhanced chemical vapor deposition system for x‐ray mask application

1992 ◽  
Vol 72 (7) ◽  
pp. 3110-3115 ◽  
Author(s):  
A. Jean ◽  
M. Chaker ◽  
Y. Diawara ◽  
P. K. Leung ◽  
E. Gat ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
X Ray

scholarly journals Mechanochemical treatment of Serbian kaolin clay to obtain high reactive pozzolana

2013 ◽  
Vol 78 (4) ◽  
pp. 579-590 ◽  
Author(s):  
Aleksandra Mitrovic ◽  
Miodrag Zdujic
Keyword(s):  
Hardened Steel ◽  
Pozzolanic Activity ◽  
Mechanochemical Treatment ◽  
Kaolin Clay ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Milling Parameters ◽  
Milling Medium ◽  
The Given

Mechanochemical treatment of Serbian kaolin clay was carried out in a planetary ball mill using two different milling media, hardened steel or zirconia vials and balls. The samples obtained with various milling times were characterized by the particle size laser diffraction (PSLD), X-ray diffraction (XRD), differential scanning calorimetry/thermogravimetry (DTA/TGA) and Fourier-transform infrared (FTIR) analyses. Mechanochemical treatment induced amorphization of the kaolinite phase accompanied by dehydroxylation. It was found that for the given milling parameters, amorphization mainly took place in the milling period up to 15 min, and was completed after about 30 min of milling for both milling media used. The pozzolanic activities were determined by the Chapelle method. Milling in the hardened steel milling medium had no significant influence on pozzolanic activity, even though there was accumulated iron contamination. For both milling media, pozzolanic activity of 0.79 was obtained for the samples milled for 15 min and it remained almost unchanged with prolonged milling. The determined pozzolanic activity values are close to these of commercial metakaolinite or metakaolinite obtained by the calcination of the same clay, therefore, indicating possibility for obtaining high reactive pozzolana by mechanochemical treatment of Serbian kaoline clay.

Tuning the Photophysical Properties of Cyclometalated Ir(III) Complexes by a Trifluoroacetyl Group

2012 ◽  
Vol 67 (3) ◽  
pp. 213-218 ◽  
Author(s):  
Bihai Tong ◽  
Jiayan Qiang ◽  
Qunbo Mei ◽  
Hengshan Wang ◽  
Qianfeng Zhang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Electron Acceptor ◽  
Photophysical Properties ◽  
Red Shift ◽  
Luminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Absorption And Luminescence Spectra ◽  
Homo Lumo

Four cationic Ir(III) complexes, [Ir(dpq)2(bpy)]PF6 (1), [Ir(dpq)2(phen)]PF6 (2), [Ir(tfapq)2- (bpy)]PF6 (3), and [Ir(tfapq)2(phen)]PF6 (4) (dpqH = 2,4-diphenylquinoline, tfapqH = 2-(4ʹ-trifluoroacetylphenyl)- 4-phenylquinoline, bpy = 2,2ʹ-bipyridine, phen = 1,10-phenanthroline) have been synthesized and fully characterized. The structure of 4 was also confirmed by single-crystal X-ray diffraction. The electron-acceptor character of the trifluoroacetyl unit leads to a reduced HOMO-LUMO gap and consequently a red-shift of the UV/Vis absorption and luminescence spectra. The solvophobic character of the trifluoroacetyl unit gives rise to a molecule assembly in solution.

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