Tuning Paramagnetic effect of Co-Doped CdS diluted magnetic semiconductor quantum dots

Ibraheem, Fatma; Mahdy, Manal A.; Mahmoud, E. A.; Ortega, J. Enrique; Rogero, Celia; Mahdy, Iman A.; El-Sayed, Afaf

doi:10.1016/j.jallcom.2020.155196

Cited by 25 publications

(9 citation statements)

References 28 publications

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“…As shown in Fig. 3, the E g values can be predicted by extrapolating the linear portion of (αhυ) 2 to zero along an x-axis. Undoped and Co-doped CdS have energy gaps of 2.26 and 2.15 eV, respectively, Fig.…”

Section: Resultsmentioning

confidence: 99%

“…II-VI-based chalcogenides, such as sulfides, selenides, and tellurides, have received a lot of attention. [1][2][3] Over the past two decades, they played a vital role in spintronic applications, solar-energy conversion, non-linear optics and photochemical catalysis. 4 Among the transition metal chalcogenides, CdS, pure and doped, is a promising candidate for technological applications, because of its nonlinear optical and luminescence properties and as a diluted magnetic semiconductors (DMS).…”

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confidence: 99%

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Impact of Cobalt-Doping on the Optical, Magnetic, and Electronic Features of Hexagonal Cadmium Sulfide

Heiba,

Abd Ellatief,

Mohamed

et al. 2024

ECS J. Solid State Sci. Technol.

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CdS and Cd0.9Co0.1S samples were prepared under an N2 atmosphere. The structural analysis was conducted using X-ray diffraction. The structural and microstructure parameters were determined using Rietveld refinement method. The incorporation of cobalt ions into CdS matrix was confirmed by energy-dispersive spectroscopy and Fourier-transform infrared analysis. CdS sample has a non-magnetic feature while the Co-doped sample exhibited a magnetic behavior. The origin of magnetic property transformation has been investigated, revealing the emergence of ferromagnetic ordering and the conversion to a diluted magnetic semiconductor (DMS) with a calculated magnetic moment of 2.56 μB upon Co doping. We also investigated how this Cobalt-doping-driven transformation affected optical, photoluminescence, and electronic properties. These effects correlated with the emergence of hyper-deep defect states. Electronic properties were calculated using density functional theory (DFT) with the HSE06 hybrid functional approximation. The calculated energy bandgaps for both Co-doped and pure CdS were 2.13 and 2.12 eV, respectively, while experimental measurements from our UV analysis yielded values of 2.26 and 2.15 eV. DFT calculations were employed to explore the magnetic properties, absorption coefficients, refractive indices, real and imaginary dielectric components, and energy loss spectra in both samples.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Impact of Cobalt-Doping on the Optical, Magnetic, and Electronic Features of Hexagonal Cadmium Sulfide

Heiba,

Abd Ellatief,

Mohamed

et al. 2024

ECS J. Solid State Sci. Technol.

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“…From the Table, it is clear that the absorption band edges were initially shifted towards lower wavelengths and then shifted to higher wavelengths with increasing Co 2+ concentration in the doped samples. A redshift has been observed in the band edge, which indicates the narrowing of the band gap (9,16) . The Tauc's plots of as-prepared nanoparticles are shown in Figure 5.…”

Section: Uv-vis Spectramentioning

confidence: 96%

Tailoring the Inherent Magnetism of N:CdS Nanoparticles with Co2+ Doping

Reddy¹,

Vandana²,

Kumar³

2023

IJST

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Objectives:The purpose of this study is to report the changes in structural, electrical, optical, and magnetic properties of N: CdS nanoparticles with Co 2+ doping, which have applications in the fields of opto-magnetic and spintronic devices. Methods: Nitrogen and cobalt-co-doped CdS nanoparticles (NPs) have been prepared using the surfactant-assisted chemical co-precipitate method. Findings: The X-Ray Diffraction (XRD) studies with X'pert High Score Plus software confirm the existence of multiphase and the size of the as prepared particles in the nanorange (1-2 nm). UV-VIS. absorption spectral analysis showed a considerable blue shift with the inclusion of nitrogen and a further Burstein-mass effect, i.e., a red shift with increasing Co 2+ ion concentration. The strong green light emissions observed in photoluminescence (PL) studies are attributed to the trapping of Co 2+ and N 3ions in F-centers. The characteristic g = 1.995 obtained from electron paramagnetic resonance (EPR) studies confirms the inclusion of nitrogen in the tetrahedral sites of the CdS core and the increased stability of nanoparticles. The vibrating sample magnetometer (VSM) studies revealed novel magnetic behaviour of nanoparticles at low fields. Novelty: Tunable band gap variations, ferromagnetic nature at low fields are the unique features observed in NPs with useful applications in the fields of opto-magnetic and spintronic applications. Nitrogen and cobalt-co-doped CdS nanoparticles (NPs) have been prepared using the surfactant assisted chemical co-precipitate method. The X-ray diffraction (XRD) studies with X'pert high score plus software confirm the existence of multiple phases and the size of the as prepared particles in the nanorange (1-2nm). UV-VIS absorption spectral analysis showed a considerable blue shift with the inclusion of nitrogen and a further Burstein-mass effect, i.e., a red shift with increasing Co 2+ ion concentration. The strong green light emission observed in photoluminescence (PL) studies is attributed to the trapping of Co 2+ , N 3ions in F-centers. The characteristic g = 1.995 obtained from electron paramagnetic resonance (EPR) studies confirms the inclusion of nitrogen in the tetrahedral sites of the CdS core and the increased stability of nanoparticles. The vibrating sample magnetometer (VSM) studies revealed novel magnetic behaviour of nanoparticles at low fields.

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“…In such diluted doping/alloying regime, some basic characteristics of the host material are barely affected, while emerging hybrid properties inherited by the dopant come into play. Diluted magnetic semiconductors are such examples, where traces of transition metal (TM) dopant can induce room temperature (RT) ferromagnetism in the otherwise nonmagnetic material [25,28] .…”

Section: Introductionmentioning

confidence: 99%

Precise determination of optical band gap in Cr-doped semiconductor nanowires

et al. 2022

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Pristine and chromium-doped ZnO nanowires were prepared following the traditional coprecipitation method. X-ray diffraction data identified a pure wurtzite hexagonal crystal structure characteristic for ZnO, irrespective of the doping level. The particle size, as deduced form Williamson-Hall plots, was found to be 45-55 nm for all samples. Scanning electron microscopy revealed a clear nanowires morphology for the pure and doped samples, while elemental analysis ensured the successful Cr-doping. Distinct spectroscopic signatures of Cr-doping were revealed from a detailed deconvolution process applied to optical spectra of doped samples, where Cr 3+ optical transitions were unambiguously identified at ~420 and ~665 nm. Particularly relevant, is the spectral decomposition here performed for the superimposed absorption edge (~385 nm) and Cr 3+ optical resonance at ~420 nm, allowing to claim practically doping-independent optical band gap behavior in the present doping regime. This is further supported by identifying the characteristic ZnO near edge photoluminescence peak (~ 392 nm) which maintains fixed wavelength after Crdoping. These findings contrast earlier studies on Cr-doped semiconductor nanoparticles and glass systems where the optical band gap has been largely underestimated. We attribute the inconsistence band gap values reported in literature for Cr-doped semiconductors to the proximity of Cr optical transitions to the semiconductor absorption edge.

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Tuning Paramagnetic effect of Co-Doped CdS diluted magnetic semiconductor quantum dots

Cited by 25 publications

References 28 publications

Impact of Cobalt-Doping on the Optical, Magnetic, and Electronic Features of Hexagonal Cadmium Sulfide

Impact of Cobalt-Doping on the Optical, Magnetic, and Electronic Features of Hexagonal Cadmium Sulfide

Tailoring the Inherent Magnetism of N:CdS Nanoparticles with Co2+ Doping

Precise determination of optical band gap in Cr-doped semiconductor nanowires

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