Influence of Co Content on Raman and Photoluminescence Spectra of Co Doped ZnO Nanowires

a b s t r a c tPure and Co substituted ZnO nano crystalline particles were prepared by solution combustion technique using l-Valine as a fuel. As synthesized powder samples were characterized by X-ray diffractometer and SQUID magnetometer to confirm the formation of single phase wurtzite structure and to study the bulk magnetic response of the sample, respectively. Magnetic studies show that Co doped ZnO nanoparticles exhibit ferromagnetism (FM) at room temperature (RT). Furthermore, the electronic structure and element specific magnetic properties were investigated by near-edge X-ray absorption fine structure (NEXAFS) and X-ray magnetic circular dichroism (XMCD) measurements, respectively. The effect of Co substitution on the spectral features of Co-ZnO at O K-edge, Co L 3,2 edge, Zn L 3,2 edge have been investigated. The spectral features of NEXAFS at Co L 3,2 edge is entirely different from the spectral features of metallic clusters and other impurity phases, which rules out the presence of impurity phases. The valence state of 'Co' ion is found to be in +2 state. The FM nature of the sample was confirmed through XMCD spectra, which is due to the incorporation of divalent 'Co' ions. Hence the presented results confirm the substitution of 'Co' ions at 'Zn' site in the host lattice, which is responsible for the RTFM.

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“…Hence, the variations in lattice parameters are not that significant. These results are in agreement with those reported in literature [24,25].…”

Section: Resultssupporting

confidence: 94%

Spectroscopic investigation of an intrinsic room temperature ferromagnetism in Co doped ZnO nanoparticles

Srinatha

Angadi

Nair

et al. 2014

Journal of Electron Spectroscopy and Related Phenomena

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“…Raman spectroscopy has been used to understand consequences of impurity doping on host lattice characteristics, and modification of lattice vibrational modes, as well as to investigate secondary phase formation that might not be detectable by conventional characterization methods like XRD due to detectability limit of the measurement (Chang et al 2012;Zhou et al 2007;Thakur et al 2007). Substitution of the dopant atoms would introduce additional vibrational modes.…”

Section: Ramanmentioning

confidence: 99%

“…5. The broad, low-intensity peak at 331 cm -1 and the peaks observed at 378 and 436 cm -1 for pure ZnO can be indexed to the second-order scattering, A 1 (TO), and E 2-(high), respectively; where E 2 (high) mode dominates and indicates highly crystalline wurtzite ZnO (Chang et al 2012;Sesha et al 2012;Wang et al 2007). The frequency of 331 cm -1 mode matches with the difference of E 2-(high)-E 2 (low) modes.…”

Section: Ramanmentioning

confidence: 99%

“…Studies (Ohtomo et al 1998;Matei et al 2010;Yin et al 2004;Liu et al 2008;Lawes et al 2005;Jug and Tikhomirov 2009). Among these materials, Co-doped ZnO crystals receive growing attention (Matei et al 2010;Liu et al 2008;Chang et al 2012;Bohle and Spina 2010;Yao and Zeng 2009). Although engineering the bandgap of ZnO crystals with Co doping has been shown to alter the electronic properties compared to the parent materials, the results are controversial.…”

Section: Introductionmentioning

confidence: 99%

“…Although engineering the bandgap of ZnO crystals with Co doping has been shown to alter the electronic properties compared to the parent materials, the results are controversial. For example, the defect related visible emissions of ZnO has been reported to be both enhanced (Chang et al 2012) and quenched (Bohle and Spina 2010) with increasing cobalt amount in the structure. Consequently, understanding the influence of cobalt dopant on the optical properties of ZnO remains as an open question.…”

Section: Introductionmentioning

confidence: 99%

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Hydrothermal–electrochemical growth of heterogeneous ZnO: Co films

Yilmaz

Ünal

2017

Appl Nanosci

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This study demonstrates the preparation of heterogeneous ZnO: Co nanostructures via hydrothermalelectrochemical deposition at 130°C and -1.1 V (vs Ag/ AgCl (satd)) in dimethyl sulfoxide (DMSO)-H 2 O mixture. Under the stated conditions, ZnO: Co nanostructures grow preferentially along (002) direction. Strength of directional growth progressively increases with the increasing concentration of Co(II) in the deposition bath. Films are composed of hexagonal Wurtzite ZnO, metallic cobalt, and mixed cobalt oxide on the surface and cobalt(II) oxide in deeper levels. Increasing the Co(II) concentration in the deposition bath results in different morphological features as well as phase separation. Platelets, sponge-like structures, cobalt-rich spheres, microislands of cobalt-rich spheres which are interconnected by ZnO network can be synthesized by adjusting [Co(II)]: [Zn(II)] ratio. Growth mechanisms giving rise to these particular structures, surface morphology, crystal structure, phase purity, chemical binding characteristics, and optical properties of the deposits are discussed in detail.

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Exploring LiZnNbO₄ as a Host for New Colored Compounds: Synthesis, Structure, and Material Properties of NbZn_1‐x M_x LiO₄ (M=Mn, Co, Ni, Fe) and Nb_1‐ySb_y Zn_1‐x M_x LiO₄ (M=Co, Ni)

Malik,

Natarajan

2023

Eur J Inorg Chem

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The non ‐ centrosymmetric tetragonal inverse spinel structure of LiZnNbO4 has been explored with a view to prepare new colored compounds. The substitution of Co2+, Ni2+, Fe2+, Mn2+, and Cu2+ ions were attempted in the place of Zn2+ ions and Sb5+ ions in place of Nb5+ ions. The studies indicated that 0.75 Zn2+ ions in LiZnNbO4 can be replaced by Co2+ ions and 0.5 Zn2+ ions in LiZnNb0.5Sb0.5O4 compound. The substitution of Co2+ ions gives rise to different shades of blue color in Li(Zn1‐xCox)NbO4 compounds and from ink blue to blue‐green color in Li(Zn1‐xCox)(Nb0.5Sb0.5)O4 compounds. The different colors observed in the present study were explained by the traditional allowed d‐d transitions as well as the metal‐to‐metal charge transfer (MMCT) transitions involving Nb5+ (4d0) ions and partially filled 3d electrons. The SHG studies indicate that the prepared compounds are SHG active. All the compounds exhibit reasonable dielectric behavior with low loss. The XPS studies confirm the oxidation states of the different substituted ions. Raman studies indicate variations in the bands due to the substitutions in the parent LiZnNbO4 phase. Magnetic studies on the Co2+ ions substituted compounds suggest anti – ferromagnetic behavior

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Influence of Co Content on Raman and Photoluminescence Spectra of Co Doped ZnO Nanowires

Cited by 48 publications

References 21 publications

Spectroscopic investigation of an intrinsic room temperature ferromagnetism in Co doped ZnO nanoparticles

Spectroscopic investigation of an intrinsic room temperature ferromagnetism in Co doped ZnO nanoparticles

Hydrothermal–electrochemical growth of heterogeneous ZnO: Co films

Exploring LiZnNbO₄ as a Host for New Colored Compounds: Synthesis, Structure, and Material Properties of NbZn_1‐x M_x LiO₄ (M=Mn, Co, Ni, Fe) and Nb_1‐ySb_y Zn_1‐x M_x LiO₄ (M=Co, Ni)

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Influence of Co Content on Raman and Photoluminescence Spectra of Co Doped ZnO Nanowires

Cited by 48 publications

References 21 publications

Spectroscopic investigation of an intrinsic room temperature ferromagnetism in Co doped ZnO nanoparticles

Spectroscopic investigation of an intrinsic room temperature ferromagnetism in Co doped ZnO nanoparticles

Hydrothermal–electrochemical growth of heterogeneous ZnO: Co films

Exploring LiZnNbO4 as a Host for New Colored Compounds: Synthesis, Structure, and Material Properties of NbZn1‐x Mx LiO4 (M=Mn, Co, Ni, Fe) and Nb1‐ySby Zn1‐x Mx LiO4 (M=Co, Ni)

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Product

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Exploring LiZnNbO₄ as a Host for New Colored Compounds: Synthesis, Structure, and Material Properties of NbZn_1‐x M_x LiO₄ (M=Mn, Co, Ni, Fe) and Nb_1‐ySb_y Zn_1‐x M_x LiO₄ (M=Co, Ni)