Особенности оптических и энергетических свойств тонких пленок CdSe

The paper presents the results of experimental and theoretical studies of the optical and energy properties of thin CdSe films obtained by the closed space sublimation. The synthesis method, the results of structural and optical studies of thin CdSe films deposited on the surface of a quartz substrate are presented. The quality of the films was analyzed by x-ray diffraction, energy dispersive analysis and scanning electron microscopy. Within the framework of the pseudopotential method, the dynamics of changes in the parameters of the CdSe films electronic subsystem is theoretically studied. The direct-gap nature of the forbidden gap of the film is established. Based on the density of states, the genesis of the conduction band and the valence band is established. Using the Kramers – Kronig relation, we obtained spectra of optical dielectric functions, optical reflection, refractive and extinction indexes, which satisfactorily correlate with the obtained experimental data.

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Preparation and Photocatalytic Performance of Flower-Shaped Zno/GO/Fe3O4 on Degradation of Rhodamine B

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.407.161 ◽

2021 ◽

Vol 407 ◽

pp. 161-172

Author(s):

Mahbboobeh Rezaei ◽

Ali Shokuhfar ◽

Nikta Shahcheraghi

Keyword(s):

Rhodamine B ◽

Synthesis Method ◽

Spectrophotometric Analysis ◽

Precipitation Method ◽

X Ray Diffraction ◽

Photodegradation Efficiency ◽

Time And Being ◽

Co Precipitation ◽

Uv C

In this work, a flower-shaped ZnO/GO/Fe3O4 ternary nanocomposite was synthesized via the co-precipitation method. Two significant goals of the study were boosting the degradation efficiency of ZnO and achieving a fast and simple synthesis approach. The structure, properties, and morphology of the product were characterized, and the effect of the ZnO flower-shaped structure in combination with GO nanosheets and magnetite nanoparticles was investigated on the photocatalytic activity. The structure and quality of the prepared nanocomposite were assessed by X-ray diffraction pattern, UV-visible DRS spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM). The catalytic activity of the nanocomposite was assessed by spectrophotometric analysis. The developed nanocomposite offered high photodegradation efficiency in Rhodamine B degradation under UV-C light in comparison with pure ZnO. At a specific period, the efficiency of the synthesized sample was about two times greater than that of pristine ZnO particles. Our nanocomposite is anticipated to have practical benefits in wastewater treatment given its good performance, economic savings through reducing the amount of catalyst consumption and saving time, and being a facile and fast synthesis method.

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One-step synthesis of nitrogen-grafted copper-gallic acid for enhanced methylene blue removal

Scientific Reports ◽

10.1038/s41598-021-91484-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shella Permatasari Santoso ◽

Vania Bundjaja ◽

Artik Elisa Angkawijaya ◽

Chintya Gunarto ◽

Alchris Woo Go ◽

...

Keyword(s):

Methylene Blue ◽

Adsorption Capacity ◽

Gallic Acid ◽

Synthesis Method ◽

Molar Ratio ◽

X Ray Diffraction ◽

Temperature Dependent ◽

One Step ◽

Detailed Assessment ◽

Higher Temperature

AbstractNitrogen-grafting through the addition of glycine (Gly) was performed on a metal- phenolic network (MPN) of copper (Cu2+) and gallic acid (GA) to increase its adsorption capacity. Herein, we reported a one-step synthesis method of MPN, which was developed according to the metal–ligand complexation principle. The nitrogen grafted CuGA (Ng-CuGA) MPN was obtained by reacting Cu2+, GA, and Gly in an aqueous solution at a molar ratio of 1:1:1 and a pH of 8. Several physicochemical measurements, such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), N2 sorption, X-ray diffraction (XRD), and thermal gravimetry analysis (TGA), were done on Ng-CuGA to elucidate its characteristics. The analysis revealed that the Ng-CuGA has non-uniform spherical shaped morphology with a pore volume of 0.56 cc/g, a pore size of 23.25 nm, and thermal stability up to 205 °C. The applicational potential of the Ng-CuGA was determined based on its adsorption capacity against methylene blue (MB). The Ng-CuGA was able to adsorb 190.81 mg MB per g adsorbent at a pH of 6 and temperature of 30 °C, which is 1.53 times higher than the non-grafted CuGA. Detailed assessment of Ng-CuGA adsorption properties revealed their pH- and temperature-dependent nature. The adsorption capacity and affinity were found to decrease at a higher temperature, demonstrating the exothermic adsorption behavior.

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Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽

10.3390/photonics8060215 ◽

2021 ◽

Vol 8 (6) ◽

pp. 215

Author(s):

Rajeev R. Kosireddy ◽

Stephen T. Schaefer ◽

Marko S. Milosavljevic ◽

Shane R. Johnson

Keyword(s):

Molecular Beam Epitaxy ◽

Molecular Beam ◽

Optical Quality ◽

X Ray Diffraction ◽

Interface Quality ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron ◽

Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

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

Journal of Chemical Research ◽

10.1177/1747519820984729 ◽

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.

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Stationary Traffic as a Factor of Tourist Destination Quality and Sustainability

Sustainability ◽

10.3390/su13073965 ◽

2021 ◽

Vol 13 (7) ◽

pp. 3965

Author(s):

Robert Maršanic ◽

Edna Mrnjavac ◽

Drago Pupavac ◽

Ljudevit Krpan

Keyword(s):

Synthesis Method ◽

Hotel Industry ◽

Point Of View ◽

Tourist Destination ◽

Scientific Methods ◽

Tourist Destinations ◽

Analysis And Synthesis ◽

The Republic ◽

Method Analysis

Since the Republic of Croatia is one of the most popular European and world tourist destinations, the aim of this paper is, from the user’s (n = 596) point of view, to research the importance of stationary traffic in tourist destinations. The purpose of this paper is to point out the possibilities of improving the tourist destination quality and sustainability through an adequate parking service. In order to corroborate constructed scientific hypotheses, a larger number of scientific methods were used from which a polling method, analysis and synthesis method, descriptive statistics method, t-test, and analysis of variance (ANOVA) should be singled out. The major finding of this paper indicates a relatively big importance of stationary traffic (M = 6.51; SD = 2.21) as an element of tourist destination quality. Moreover, regarding the quality of tourist destination, the results of this paper suggest that the parking space availability is more important than the way parking or parking payment are organized. Between the experienced parking problem in a tourist destination and age on one side and evaluation of the importance of stationary traffic as an element of tourist destination quality on the other side, a statistically important connection was established. Gained knowledge can be particularly helpful to hotel industry managers but also to traffic managers whose duty is to provide an adequate number of parking spaces in tourist destinations.

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Green synthesis and characterization of hexaferrite strontium-perovskite strontium photocatalyst nanocomposites

Main Group Metal Chemistry ◽

10.1515/mgmc-2020-0004 ◽

2020 ◽

Vol 43 (1) ◽

pp. 26-42 ◽

Cited By ~ 2

Author(s):

Zahra Hajian Karahroudi ◽

Kambiz Hedayati ◽

Mojtaba Goodarzi

Keyword(s):

Magnetic Properties ◽

Green Synthesis ◽

Sol Gel ◽

Synthesis Method ◽

Combustion Method ◽

Lemon Juice ◽

X Ray Diffraction ◽

X Ray ◽

Auto Combustion

AbstractThis study presents a preparation of SrFe12O19– SrTiO3 nanocomposite synthesis via the green auto-combustion method. At first, SrFe12O19 nanoparticles were synthesized as a core and then, SrTiO3 nanoparticles were prepared as a shell for it to manufacture SrFe12O19–SrTiO3 nanocomposite. A novel sol-gel auto-combustion green synthesis method has been used with lemon juice as a capping agent. The prepared SrFe12O19–SrTiO3 nanocomposites were characterized by using several techniques to characterize their structural, morphological and magnetic properties. The crystal structures of the nanocomposite were investigated via X-ray diffraction (XRD). The morphology of SrFe12O19– SrTiO3 nanocomposite was studied by using a scanning electron microscope (SEM). The elemental composition of the materials was analyzed by an energy-dispersive X-ray (EDX). Magnetic properties and hysteresis loop of nanopowder were characterized via vibrating sample magnetometer (VSM) in the room temperature. Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed the molecular bands of nanoparticles. Also, the photocatalytic behavior of nanocomposites has been checked by the degradation of azo dyes under irradiation of ultraviolet light.

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Novel Multilayer SAW Temperature Sensor for Ultra-High Temperature Environments

Micromachines ◽

10.3390/mi12060643 ◽

2021 ◽

Vol 12 (6) ◽

pp. 643

Author(s):

Xuhang Zhou ◽

Qiulin Tan ◽

Xiaorui Liang ◽

Baimao Lin ◽

Tao Guo ◽

...

Keyword(s):

High Temperature ◽

Temperature Sensor ◽

X Ray Diffraction ◽

Aero Engine ◽

Before And After ◽

Application Potential ◽

Passive Sensors ◽

Temperature Exposure ◽

Engine Systems

Performing high-temperature measurements on the rotating parts of aero-engine systems requires wireless passive sensors. Surface acoustic wave (SAW) sensors can measure high temperatures wirelessly, making them ideal for extreme situations where wired sensors are not applicable. This study reports a new SAW temperature sensor based on a langasite (LGS) substrate that can perform measurements in environments with temperatures as high as 1300 °C. The Pt electrode and LGS substrate were protected by an AlN passivation layer deposited via a pulsed laser, thereby improving the crystallization quality of the Pt film, with the function and stability of the SAW device guaranteed at 1100 °C. The linear relationship between the resonant frequency and temperature is verified by various high-temperature radio-frequency (RF) tests. Changes in sample microstructure before and after high-temperature exposure are analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis confirms that the proposed AlN/Pt/Cr thin-film electrode has great application potential in high-temperature SAW sensors.

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Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽

10.3390/catal10060640 ◽

2020 ◽

Vol 10 (6) ◽

pp. 640

Author(s):

Hideaki Sasaki ◽

Keisuke Sakamoto ◽

Masami Mori ◽

Tatsuaki Sakamoto

Keyword(s):

Electron Microscopy ◽

Solid Solution ◽

Solid Solutions ◽

Photoelectron Spectroscopy ◽

Synthesis Method ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Co Precipitation ◽

Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

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Structural, Morphological, Magnetic and Self-Heating Studies of One-Step Polyol Synthesized Manganese Ferrite (MnFe2O4) Nanoparticles

International Journal of Nanoscience ◽

10.1142/s0219581x19500030 ◽

2019 ◽

Vol 19 (01) ◽

pp. 1950003

Author(s):

P. R. Ghutepatil ◽

S. H. Pawar

Keyword(s):

Room Temperature ◽

Synthesis Method ◽

Average Crystallite Size ◽

Superparamagnetic Nanoparticles ◽

Polyol Synthesis ◽

X Ray Diffraction ◽

Self Heating ◽

Transmission Electron ◽

One Step ◽

Mnfe2o4 Nanoparticles

In this paper, uniform and superparamagnetic nanoparticles have been prepared using one-step polyol synthesis method. Structural, morphological and magnetic properties of obtained MnFe2O4 nanoparticles have been investigated by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM) and thermogravimetric analysis (TGA) techniques. Structural investigation showed that the average crystallite size of obtained nanoparticles was about 10[Formula: see text]nm. Magnetic study revealed that the nanoparticles were superparamagnetic at room temperature with magnetization 67[Formula: see text]emu/g at room temperature. The self-heating characteristics of synthesized MnFe2O4 nanoparticles were studied by applying external AC magnetic field of 167.6 to 335.2[Formula: see text]Oe at a fixed frequency of 265[Formula: see text]kHz. The SAR values of MnFe2O4 nanoparticles were calculated for 2, 5, 10[Formula: see text]mg[Formula: see text]mL[Formula: see text] concentrations and it is observed that the threshold hyperthermia temperature is achieved for all concentrations.

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