Microstructural investigations of green-synthesized wurtzite-phase ZnMgO nanopowders and its defect-mediated ferromagnetism

Author(s):  
Gaurav Gupta ◽  
Shyama Rath
Keyword(s):  
2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Muhammad Ikram ◽  
Sidra Aslam ◽  
Ali Haider ◽  
Sadia Naz ◽  
Anwar Ul-Hamid ◽  
...  

AbstractVarious concentrations of Mg-doped ZnO nanorods (NRs) were prepared using co-precipitation technique. The objective of this study was to improve the photocatalytic properties of ZnO. The effect of Mg doping on the structure, phase constitution, functional groups presence, optical properties, elemental composition, surface morphology and microstructure of ZnO was evaluated with XRD, FTIR, UV–Vis spectrophotometer, EDS, and HR-TEM, respectively. Optical absorption spectra obtained from the prepared samples showed evidence of blueshift upon doping. XRD results revealed hexagonal wurtzite phase of nanocomposite with a gradual decrease in crystallite size with Mg addition. PL spectroscopy showed trapping efficiency and migration of charge carriers with electron–hole recombination behavior, while HR-TEM estimated interlayer d-spacing. The presence of chemical bonding, vibration modes and functional groups at the interface of ZnO was revealed by FTIR and Raman spectra. In this study, photocatalytic, sonocatalytic and sonophotocatalytic performance of prepared NRs was systematically investigated by degrading a mixture of methylene blue and ciprofloxacin (MBCF). Experimental results suggested that improved degradation performance was shown by Mg-doped ZnO NRs. We believe that the product synthesized in this study will prove to be a beneficial and promising photocatalyst for wastewater treatment. Conclusively, Mg-doped ZnO exhibited substantial (p < 0.05) efficacy against gram-negative (G-ve) as compared to gram-positive (G+ve) bacteria. In silico molecular docking studies of Mg-doped ZnO NRs against DHFR (binding score: − 7.518 kcal/mol), DHPS (binding score: − 6.973 kcal/mol) and FabH (− 6.548 kcal/mol) of E. coli predicted inhibition of given enzymes as possible mechanism behind their bactericidal activity.


2001 ◽  
Vol 48 (3) ◽  
pp. 535-542 ◽  
Author(s):  
M. Farahmand ◽  
C. Garetto ◽  
E. Bellotti ◽  
K.F. Brennan ◽  
M. Goano ◽  
...  

1999 ◽  
Vol 595 ◽  
Author(s):  
Giancarlo Salviati ◽  
Nicola Armani ◽  
Carlo Zanotti-Fregonara ◽  
Enos Gombia ◽  
Martin Albrecht ◽  
...  

AbstractYellow luminescence (YL) has been studied in GaN:Mg doped with Mg concentrations ranging from 1019 to 1021 cm−3 by spectral CL (T=5K) and TEM and explained by suggesting that a different mechanism could be responsible for the YL in p-type GaN with respect to that acting in n-type GaN.Transitions at 2.2, 2.8, 3.27, 3.21, and 3.44 eV were found. In addition to the wurtzite phase, TEM showed a different amount of the cubic phase in the samples. Nano tubes with a density of 3×109 cm−2 were also observed by approaching the layer/substrate interface. Besides this, coherent inclusions were found with a diameter in the nm range and a volume fraction of about 1%.The 2.8 eV transition was correlated to a deep level at 600 meV below the conduction band (CB) due to MgGa-VN complexes. The 3.27 eV emission was ascribed to a shallow acceptor at about 170-190 meV above the valence band (VB) due to MgGa.The 2.2 eV yellow band, not present in low doped samples, increased by increasing the Mg concentration. It was ascribed to a transition between a deep donor level at 0.8-1.1 eV below the CB edge due to NGa and the shallow acceptor due to MgGa. This assumption was checked by studying the role of C in Mg compensation. CL spectra from a sample with high C content showed transitions between a C-related 200 meV shallow donor and a deep donor level at about 0.9- 1.1 eV below the CB due to a NGa-VN complex. In our hypothesis this should induce a decrease of the integrated intensity in both the 2.2 and 2.8 eV bands, as actually shown by CL investigations.


Nanoscale ◽  
2017 ◽  
Vol 9 (36) ◽  
pp. 13554-13562 ◽  
Author(s):  
H. A. Fonseka ◽  
A. S. Ameruddin ◽  
P. Caroff ◽  
D. Tedeschi ◽  
M. De Luca ◽  
...  

Wurtzite phase InP–InxGa1−xAs nanowire radial quantum wells were grown for the first time, with tunable emission in the 1.3–1.55 μm optical communication wavelength range.


2008 ◽  
Vol 22 (16) ◽  
pp. 1599-1608
Author(s):  
M. REZAEE ROKN-ABADI ◽  
H. ARABSHAHI ◽  
M. R. BENAM

A finite discretization method in two dimensions has been developed and used to model electron transport in wurtzite phase GaN MESFETs. The model is based on the solutions of the highly-coupled nonlinear hydrodynamic partial differential equations. These solutions allow us to calculate the electron drift velocity and other device parameters as a function of the applied electric field. This model is able to describe inertia effects which play an increasing role in different fields of micro and optoelectronics where simplified charge transport models like drift-diffusion model and energy balance model are no longer applicable. Results of numerical simulations are shown for a two-dimensional GaN MESFET device which are in fair agreement with other theoretical or experimental methods.


2016 ◽  
Vol 18 (25) ◽  
pp. 17029-17036 ◽  
Author(s):  
Jiajun Wang ◽  
Jie Meng ◽  
Qunxiang Li ◽  
Jinlong Yang

Single-layer CdSe and CdTe sheets cut along the (001) lattice plane of the wurtzite phase are promising photocatalysts for water splitting.


2018 ◽  
Vol 23 (2) ◽  
Author(s):  
Patricia María Perillo ◽  
Mariel Nahir Atia ◽  
Daniel Fabián Rodríguez

ABSTRACT ZnO nanostructures were synthesized through a chemical method using different Zn precursors and hexamethylenetetramine (HMTA) at 90 °C. The effects of the reactants on the morphological evolution of ZnO nanorods were investigated. The samples were characterized by using XRD, SEM, EDX and BET. The hexagonal wurtzite phase of ZnO was confirmed by X-ray diffraction (XRD). The performed analysis indicated that different morphologies were obtained by changing the reactants.


2008 ◽  
Vol 22 (30) ◽  
pp. 5289-5297 ◽  
Author(s):  
H. ARABSHAHI

An ensemble Monte Carlo simulation is used to compare bulk electron ballistic transport in 6H - SiC and GaN materials. Electronic states within the conduction band valleys at Γ1, U, M, Γ3, and K are represented by nonparabolic ellipsoidal valleys centered on important symmetry points of the Brillouin zone. The large optical phonon energy (~120 meV) and the large intervalley energy separation between the Γ and satellite conduction band valleys suggest an increasing role for ballistic electron effects in 6H - SiC , especially when compared with most III-V semiconductors such as GaAs . Transient velocity overshoot has been simulated, with the sudden application of fields up to ~5×107 Vm -1, appropriate to the gate-drain fields expected within an operational field effect transistor. A peak-saturation drift velocity ratio of 2:1 is predicted for 6H - SiC material while that for GaN is 4:1. The electron drift velocity relaxes to the saturation value of ~2×105 ms -1 within 3 ps, for both crystal structures. The transient velocity overshoot characteristics are in fair agreement with other recent calculations.


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