scholarly journals Growth of Semi-Polar (101¯3) AlN Film on M-Plane Sapphire with High-Temperature Nitridation by HVPE

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1722
Author(s):  
Xu Li ◽  
Jianyun Zhao ◽  
Ting Liu ◽  
Yong Lu ◽  
Jicai Zhang
Keyword(s):  
High Temperature ◽  
Strong Dependence ◽  
Hydride Vapor Phase Epitaxy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aln Film ◽  
Negative Role ◽  
Average Size ◽  
Nitridation Temperature

Aluminum nitride (AlN) films were grown on the m-plane sapphire by high-temperature hydride vapor phase epitaxy (HVPE). The effect of high-temperature nitridation on the quality of AlN film was studied. The high-temperature nitridation is favorable for the formation of semi-polar single (101¯3) orientation AlN film, the quality of which shows strong dependence on the nitridation temperature. The full width at half maximum of X-ray diffraction for (101¯3) AlN film was only 0.343° at the optimum nitridation temperature of 1300 °C. It is found that the nano-holes were formed on the surface of substrates by the decomposition of sapphire in the process of high-temperature nitridation, which is closely related to the quality improvement of AlN. At the critical nitridation temperature of 1300 °C, the average size of the nano-holes is about 70 nm, which is in favor of promoting the rapid coalescence of AlN micro-grains in the early stages. However, the size of nano-holes will be enlarged with the further increase of nitridation temperature, which begins to play a negative role in the coalescence of AlN grains. As a result, the grain size will be increased and extended to the epilayer, leading to the deterioration of the AlN film.

scholarly journals X-ray diffraction analysis of kaolin M1 and M2 via the Williamson–Hall and Warren–Averbach methods

2021 ◽  
pp. 174751982098472
Author(s):  
Lalmi Khier ◽  
Lakel Abdelghani ◽  
Belahssen Okba ◽  
Djamel Maouche ◽  
Lakel Said
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Mechanical Resistance ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Mullite Phase

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

Annealing Time Dependence on 1.5μm Photoluminescence of Laser-Ablated β-FeSi2

2005 ◽  
Vol 891 ◽  
Author(s):  
Shin-ichiro Uekusa ◽  
Kunitoshi Aoki ◽  
Mohammad Zakir Hossain ◽  
Tomohiro Fukuda ◽  
Noboru Miura
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Thermal Diffusion ◽  
Annealing Time ◽  
Crystal Quality ◽  
Photoluminescence Intensity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Time

ABSTRACTWe prepared β-FeSi2 thin-films by using a Pulsed Laser Deposition (PLD) method and succeeded to observe photoluminescence (PL) around 1.5 μm corresponding to β-FeSi2 band from the long-time and high-temperature annealed β-FeSi2 thin-films. The β-FeSi2 thin-films were ablated on Si(111) substrates heated at 550°C. After ablation, long-time and high-temperature thermal annealing was performed in order to improve the crystal-quality. Annealing times were 5, 10, 20 and 40 hrs, and annealing temperature was kept at 900 °C. Crystallinity was evaluated by an X-ray diffraction (XRD) measurement. We have observed eminent improvement on crystal-quality of β-FeSi2 thin-films. Annealed samples show (220) or (202) X-ray diffraction signals of β-FeSi2 and the full width at half maximum (FWHM) of these peaks were 0.27° although the thickness of the samples decreased with annealing time. Thermal-diffusion of Si atoms was observed from substrate to thin-films. Fe atoms in the ablated thin-films also diffused into the substrate. The relationship between the thickness of β-FeSi2 thin-films and the thermal-diffusion were investigated with rutherford backscattering (RBS) measurement. Maximum photoluminescence intensity around 1.5 μm was observed from the thickest β-FeSi2 thin-film with only 5 hrs annealing.

Improvement of the Crystalline Quality of β-Ga2O3 Films by High-Temperature Annealing

2012 ◽  
Vol 725 ◽  
pp. 273-276
Author(s):  
Motoki Takahara ◽  
Suguru Funasaki ◽  
Jyun Kudou ◽  
Isao Tsunoda ◽  
Kenichiro Takakura ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Crystalline Quality ◽  
High Temperature Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Si Doped ◽  
Scanning Electron

For the purpose of improving the crystalline quality of undoped and Si doped β-Ga2O3 films, high temperature annealing at 900°C was performed. The crystalline quality of the films investigated using scanning electron microscopy and X-ray diffraction. Also the conductivity of the films is compared before and after the annealing. After the 900°C annealing, the XRD peaks intensity corresponding to β-Ga2O3 is increased. This result indicates that the crystalline quality improves by the high temperature annealing.

scholarly journals Reproducibility and Scalability of Magnetic Nanoheater Synthesis

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2059
Author(s):  
Jesus G. Ovejero ◽  
Alvaro Gallo-Cordova ◽  
Alejandro G. Roca ◽  
M. P. Morales ◽  
Sabino Veintemillas-Verdaguer
Keyword(s):  
High Temperature ◽  
Strong Dependence ◽  
General Rule ◽  
Magnetic Hyperthermia ◽  
Organic Media ◽  
Intrinsic Variability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Colloidal Crystallization ◽  
Magnetic Features

The application of magnetic nanoparticles requires large amounts of materials of reproducible quality. This work explores the scaled-up synthesis of multi-core iron oxide nanoparticles through the use of thermal decomposition in organic media and kilograms of reagents. To this end, we check the effect of extending the high temperature step from minutes to hours. To address the intrinsic variability of the colloidal crystallization nucleation process, the experiments were repeated and analyzed statistically. Due to the simultaneity of the nuclei growth and agglomeration steps, the nanostructure of the samples produced was a combination of single- and multi-core nanoparticles. The main characteristics of the materials obtained, as well as the reaction yields, were analyzed and compared. As a general rule, yield, particle size, and reproducibility increase when the time at high temperature is prolonged. The samples obtained were ranked in terms of the reproducibility of different structural, colloidal, and magnetic features. The capability of the obtained materials to act as nanoheaters in magnetic hyperthermia was assessed, showing a strong dependence on the crystallite size (calculated by X-ray diffraction), reflecting the nanoparticle volume with a coherent magnetization reversal.

scholarly journals Improvement of Crystal Quality of AlN Films with Different Polarities by Annealing at High Temperature

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 129
Author(s):  
Yang Yue ◽  
Maosong Sun ◽  
Jie Chen ◽  
Xuejun Yan ◽  
Zhuokun He ◽  
...  
Keyword(s):  
High Temperature ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Nitrogen Atmosphere ◽  
Crystal Quality ◽  
X Ray ◽  
Aln Film ◽  
Key Factor ◽  
Deep Ultraviolet

High-quality AlN film is a key factor affecting the performance of deep-ultraviolet optoelectronic devices. In this work, high-temperature annealing technology in a nitrogen atmosphere was used to improve the quality of AlN films with different polarities grown by magnetron sputtering. After annealing at 1400–1650 °C, the crystal quality of the AlN films was improved. However, there was a gap between the quality of non-polar and polar films. In addition, compared with the semi-polar film, the quality of the non-polar film was more easily improved by annealing. The anisotropy of both the semi-polar and non-polar films decreased with increasing annealing temperature. The results of Raman spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy revealed that the annihilation of impurities and grain boundaries during the annealing process were responsible for the improvement of crystal quality and the differences between the films with different polarities.

Synthesis of Ba(MgxNb1-x)O3 Nanoparticles by a Glycothermal Process

2006 ◽  
Vol 324-325 ◽  
pp. 1285-1288
Author(s):  
Rak Hee Kim ◽  
Jung Hoon Son ◽  
Dong Sik Bae
Keyword(s):  
High Temperature ◽  
Potassium Hydroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature And Pressure ◽  
Metal Nitrates ◽  
Aqueous Potassium Hydroxide ◽  
Temperature And Pressure ◽  
Diffraction Patterns ◽  
Average Size

Ba(MgxNb1-x)O3 nanoparticles were prepared under high temperature and pressure conditions by precipitation from metal nitrates with aqueous potassium hydroxide. Ba(MgxNb1-x)O3 nanoparticles were obtained in the temperature range of 170185 for 4 h. TEM and X-ray diffraction patterns showed that the synthesized particles were crystalline. The average size and size distribution of the synthesized particles were around 100 nm and broad, respectively.

Temperature Dependent Phenomena in Liquid LBE Alloy

2017 ◽  
Vol 884 ◽  
pp. 41-52 ◽  
Author(s):  
Matteo Amati ◽  
Santosh Kiran Balijepalli ◽  
Alessio Mezzi ◽  
Saulius Kaciulis ◽  
Roberto Montanari ◽  
...  
Keyword(s):  
High Temperature ◽  
Cluster Size ◽  
Short Range ◽  
Nuclear Reactors ◽  
Liquid Lead ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Extended Range ◽  
Average Size

The liquid lead-bismuth eutectic (LBE) alloy is of great interest for applications in future nuclear reactors. The structure and clustering of alloying elements have been investigated on an extended range of temperature (125-720 °C) by high temperature X-ray diffraction (HT-XRD), XPS and scanning photoemission microscopy (SPEM) at the ELETTRA synchrotron in Trieste. After melting the short-range order in liquid metal corresponds to a cuboctahedral arrangement of atoms that progressively evolves towards an icosahedral one as temperature increases. Such process, which is completed around 720 °C, is accompanied by a micro-chemical re-arrangement of atoms with changes of cluster size and composition. At high temperature the atom distribution results to be more homogeneous and the average size of clusters noticeably smaller.

scholarly journals Synthesis and Characterizations of 2D Platinum Diselenide

2020 ◽  
Vol 2 (1) ◽  
pp. 22
Author(s):  
Irnik Dionisiev ◽  
Vera Marinova ◽  
Krastyo Buchkov ◽  
Hristosko Dikov ◽  
Ivalina Avramova ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Strong Dependence ◽  
Chemical Vapor ◽  
Thickness Variation ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray

Platinum diselenide (PtSe2), which belongs to the transition metals dichalcogenide (TMDCs) class of 2D materials, is characterized with a transition from semimetal to semiconductor with a thickness variation from bulk to monolayer and found in versatile applications especially in sensors and mid-infrared detectors. In this study we report the large-scale synthesis of PtSe2 layers by thermally assisted selenization of pre-deposited platinum films in a horizontal quartz-tube Chemical Vapor Deposition (CVD) reactor. Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used for characterization of the obtained 2D PtSe2. It is observed that the Raman spectra of PtSe2 show strong dependence on the thickness (Pt deposition time). XPS analysis was applied to examine the chemical compositions in order to assess the quality of the synthesized PtSe2 films. All the studied properties reveal great potential to obtain continuous layers with a controlled thickness and composition and further potential for integration in functional heterostructures for future nanoelectronic and optoelectronic devices.

High temperature gas nitridation and wear resistance of TiAl based alloys

2000 ◽  
Vol 646 ◽  
Author(s):  
Bin Zhao ◽  
Jian Sun ◽  
Jiansheng Wu ◽  
Fei Wang
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Surface Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Factors Influencing ◽  
Ammonia Atmosphere ◽  
Major Factors ◽  
Nitride Layers ◽  
Nitridation Temperature

ABSTRACTGas nitridation of TiAl based alloys in an ammonia atmosphere was carried out in the present work. The nitride layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The evaluation of the surface hardness and wear resistance was performed to compare with those of the non-nitrided alloys. It is concluded that the nitride layers are composed of Ti2AlN as the inward-growing layer and TiN as the outward-growing layer. The nitridation temperature and time were two major factors influencing the thickness of the nitride layers of the alloys. The high temperature nitridation raised the surface hardness and the wear resistance of the TiAl based alloys markedly. The tribological behaviors of the nitrided alloys were also discussed.

scholarly journals Production of ZnO and CdO-ZnO thin Films by Extraction–Pyrolytic Method

2016 ◽  
Vol 53 (3) ◽  
pp. 57-66
Author(s):  
A. Cvetkovs ◽  
O. Kiselova ◽  
U. Rogulis ◽  
V. Serga ◽  
R. Ignatans
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Morphology ◽  
Quartz Glass ◽  
Zno Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Average Size

Abstract The extraction-pyrolytic method has been applied to produce the ZnO and CdO-ZnO thin films on glass and quartz glass substrates. According to X-ray diffraction measurements, the ZnO and CdO phases have been produced with an average size of crystallites about 8–42 nm in the films. The thickness of the layers measured by a profilometer has been up to 150 nm. The surface morphology measurements show that the surface of the films may be rough and non-continuous. The SEM results confirm the dependence between the preparation procedure and the quality of the thin film.

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