Enhancement of dielectric constant in transition metal doped ZnO nanocrystals

Singh, Swati; Dey, P.; Roy, Jitendra Nath; Mandal, S. K.

doi:10.1063/1.4894722

Cited by 21 publications

(5 citation statements)

References 25 publications

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“…However, with a further increase in dopant amount to 12%, the dielectric constant decreases in the present work. A similar type of behavior is reported in literature where a sharp increase in dielectric constant occurs with the introduction of dopant ions into the host material and then a decrement in dielectric constant takes place after a certain concentration of dopant ions [40,41]. This might be due to the increased concentration of metallic ions leading to enhanced conductivity and decreased dielectric constant [40].…”

Section: Dielectric Measurementssupporting

confidence: 82%

ZnS nanoparticles: role of Ga³⁺ ions substitution on the structural, morphological, optical, and dielectric properties

Kapoor

Kumar

et al. 2023

Phys. Scr.

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Due to their dynamic features, nanoparticles of semiconductor materials have been created rapidly in the past few decades and are being investigated for potential uses in a variety of disciplines. The present study focuses on the substitution of Ga3+ ions in ZnS nanoparticles to modify their structural, morphological, compositional, optical, and dielectric properties. The Ga-doped (ZnS:Ga) nanoparticles for various Ga3+ ions concentrations (i.e., 0%, 2%, 4%, 6%, 8%, 10% & 12%) are synthesized using direct co-precipitation technique and utilizing precursor solutions of Zn(CH3COO)2, Na2S and Ga2(SO4)3 along with EDTA as a stabilizing agent. The structural analysis reveals that the synthesized nanoparticles exhibit a cubic crystal structure with high crystallinity and preferred (111) orientation. Fluctuations in different structural parameters have been noticed without any alteration in crystal structure after the substitution of Ga ions in ZnS matrix. The surface morphology exposes spherical-shaped ZnS:Ga nanoparticles whose compactness varies with doping concentrations. FT-IR and EDS spectra of the nanoparticles identify the presence of different functional groups and elements in the expected compositions. A blueshift in the absorption edge has been observed for all the concentrations of ZnS:Ga w.r.t. pristine ZnS indicating quantum confinement in the synthesized nanoparticles which further results in the broadening of optical bandgap in comparison to bulk value for ZnS. The room temperature dielectric measurements for ZnS:Ga nanoparticles show a high dielectric constant value up to doping level 8% beyond which it decreased. The ac conductivity values in this study varied from 10-4 Ω-1m-1 for pristine to 9.66×10-3 Ω-1m-1 for ZnS:Ga 12%.

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Section: Dielectric Measurementssupporting

confidence: 82%

ZnS nanoparticles: role of Ga³⁺ ions substitution on the structural, morphological, optical, and dielectric properties

Kapoor

Kumar

et al. 2023

Phys. Scr.

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“…The 377-cm −1 peak is due to an E 1 (TO) mode. Also, the sharpest and the strongest peak at 437 cm −1 can be assigned E 2 (high) due to the high-frequency branch of E 2 mode of ZnO, which is the strongest and characteristic mode of wurtzite crystal structure [ 50 – 55 ]. Raman peak corresponding to the high-energy range observed between ≈1030 and 1190 cm −1 is assigned to the E 2 (LO) second-order polar mode [ 56 ].…”

Section: Resultsmentioning

confidence: 99%

Structural and Magnetic Properties of Transition-Metal-Doped Zn 1−x Fe x O

Abdel‐Baset

Fang

Anis³

et al. 2016

Nanoscale Res Lett

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The ability to produce high-quality single-phase diluted magnetic semiconductors (DMS) is the driving factor to study DMS for spintronics applications. Fe-doped ZnO was synthesized by using a low-temperature co-precipitation technique producing Zn 1−xFexO nanoparticles (x= 0, 0.02, 0.04, 0.06, 0.08, and 0.1). Structural, Raman, density functional calculations, and magnetic studies have been carried out in studying the electronic structure and magnetic properties of Fe-doped ZnO. The results show that Fe atoms are substituted by Zn ions successfully. Due to the small ionic radius of Fe ions compared to that of a Zn ions, the crystal size decreases with an increasing dopant concentration. First-principle calculations indicate that the charge state of iron is Fe 2+ and Fe 3+ with a zinc vacancy or an interstitial oxygen anion, respectively. The calculations predict that the exchange interaction between transition metal ions can switch from the antiferromagnetic coupling into its quasi-degenerate ferromagnetic coupling by external perturbations. This is further supported and explains the observed ferromagnetic bahaviour at magnetic measurements. Magnetic measurements reveal that decreasing particle size increases the ferromagnetism volume fraction. Furthermore, introducing Fe into ZnO induces a strong magnetic moment without any distortion in the geometrical symmetry; it also reveals the ferromagnetic coupling.

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“…In recent time also, a lot of work has been published on magnetic ground state of TM doped ZnO as DMSs system. 33 Although room temperature ferromagneticlike Zn 0.9 Fe 0.1 O sample also shows an enhancement of dielectric constant, however, the observed increase is only by approximately ten times from that of pure ZnO. We have observed that net interaction for Mn, Co, and Ni doped ZnO nanoparticles, prepared by chemical reaction technique, is antiferromagnetic like.…”

Section: Introductionmentioning

confidence: 63%

“…Chakraborti et al 19 reported room temperature ferromagnetism in (Co, Cu) codoped ZnO thin films prepared by pulse laser deposition technique. 33 Here, we should mention that ZnFeCoO nanoparticles exhibit an enhancement of dielectric constant by $400 times a) Electronic mail: saniitkgp2007@gmail.com from that of pure ZnO. [20][21][22][23][24][25][26][27] In our earlier work on TM (¼ Fe, Co, Mn, and Ni) doped ZnO nanoparticles, we carried out our study on single TM doped ZnO.…”

Section: Introductionmentioning

confidence: 99%

AC and DC electrical transport studies of (Fe, Co) codoped ZnO nanoparticles

Mandal

Dey

Nath

2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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High temperature ferromagnetism and optical properties of Co doped ZnO nanoparticles J. Appl. Phys. 108, 084322 (2010); 10.1063/1.3500380Microstructural and magnetic properties of ZnO:TM ( TM = Co , Mn ) diluted magnetic semiconducting nanoparticlesThe authors have presented microstructural, ac-and dc-electrical properties, and magnetic and optical studies of Zn 1-x Fe x/2 Co x/2 O (x ¼ 0.1 and 0.2) semiconducting nanoparticles, prepared through low temperature chemical "pyrophoric reaction process." Structural characterizations confirm the formation of single phase (at a calcination temperature of 300 C), chemically homogeneous, nanometric sample ($7 nm). Electrical studies on those samples have been carried out using an ac impedance spectroscopy and dc resistivity technique. Temperature dependent relaxation processes have been investigated by studying complex impedance spectroscopy. The authors have also estimated activation energy from both ac and dc resistivity data of those nanoparticles. Magnetic data clearly reveal the presence of some sort of magnetic behavior, even up to room temperature, in the x ¼ 0.2 sample, whereas for x ¼ 0.1 sample, there in no such magnetic behavior. This feature has been explained through magnetic polaron percolation theory. The authors have also estimated semiconducting band gap of those nanoparticles using recorded absorbance spectra.

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Enhancement of dielectric constant in transition metal doped ZnO nanocrystals

Abstract: A possibility to obtain room temperature ferromagnetism by transition metal doping of ZnO nanoparticles

Cited by 21 publications

References 25 publications

ZnS nanoparticles: role of Ga³⁺ ions substitution on the structural, morphological, optical, and dielectric properties

ZnS nanoparticles: role of Ga³⁺ ions substitution on the structural, morphological, optical, and dielectric properties

Structural and Magnetic Properties of Transition-Metal-Doped Zn 1−x Fe x O

AC and DC electrical transport studies of (Fe, Co) codoped ZnO nanoparticles

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Enhancement of dielectric constant in transition metal doped ZnO nanocrystals

Abstract: A possibility to obtain room temperature ferromagnetism by transition metal doping of ZnO nanoparticles

Cited by 21 publications

References 25 publications

ZnS nanoparticles: role of Ga3+ ions substitution on the structural, morphological, optical, and dielectric properties

ZnS nanoparticles: role of Ga3+ ions substitution on the structural, morphological, optical, and dielectric properties

Structural and Magnetic Properties of Transition-Metal-Doped Zn 1−x Fe x O

AC and DC electrical transport studies of (Fe, Co) codoped ZnO nanoparticles

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Product

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ZnS nanoparticles: role of Ga³⁺ ions substitution on the structural, morphological, optical, and dielectric properties

ZnS nanoparticles: role of Ga³⁺ ions substitution on the structural, morphological, optical, and dielectric properties