Analysis of oxygen vacancy in Co-doped ZnO using the electron density distribution obtained using MEM

Park, Ji Hun; Lee, Yeong Ju; Bae, Jong‐Sup; Kim, Bum-Su; Cho, Chae-Ryong; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Lee, Seunghun; Jeong, Se–Young

doi:10.1186/s11671-015-0887-2

Cited by 45 publications

(19 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar results have been obtained for a cobaltdoped ZnO lattice, where a reduction in the defect density (oxygen vacancies, V O , and zinc interstitials, Zn i ) was observed due to the easy substitution of Co 2+ at the Zn 2+ sites. 27 To further elucidate the effect of the sulfur modification on the particle shape and size, transmission electron microscopy (TEM) analysis was performed. Figure 2d,e shows the TEM images of the host and corresponding S-modified (0.08 mM) lattices.…”

Section: Resultsmentioning

confidence: 99%

Stabilization of Lead–Tin-Alloyed Inorganic–Organic Halide Perovskite Quantum Dots

Mehta

Kim

et al. 2018

ACS Nano

View full text Add to dashboard Cite

Recently, lead−tin-based alloyed halide perovskite quantum dots (QDs) with improved stability and less toxicity have been introduced. However, the perovskite QDs containing tin are still unstable and exhibit low photoluminescence quantum yields (PLQYs), owing to the presence of defects in the alloyed system. Here, we have attempted to introduce sulfur anions (S 2− ) into the host lattice (MAPb 0.75 Sn 0.25 Br 3 ) as a promising route to stable alloyed perovskite QDs with improved stability and PLQY. In this study, we used elemental sulfur as a sulfur precursor. The successful incorporation of sulfur anions into the host lattice resulted in a highly improved PLQY (>75% at room temperature), which is believed to be due to a reduction in the defect-related non-radiative recombination centers present in the host lattice. Furthermore, we found that the emission property could be tuned between the bright green and cyanbluish regions without compromising on color quality. This work invigorates the perovskite research community to prepare stable, bright, and color-tunable alloyed inorganic−organic perovskite QDs without compromising on their phases and color quality, which can lead to considerable advances in display technology.

show abstract

Section: Resultsmentioning

confidence: 99%

Stabilization of Lead–Tin-Alloyed Inorganic–Organic Halide Perovskite Quantum Dots

Mehta

Kim

et al. 2018

ACS Nano

View full text Add to dashboard Cite

show abstract

“…The electron densities were analyzed using 122 structure factors obtained from the synchrotron XRD data via the visualization program VESTA 64 . The calculations were carried out using the ENIGMA software package 65, 66 , with 66 × 66 × 104 pixels. A reliability factor of R F < 0.8% was obtained for all samples, which is small enough to trace changes in the electron density following hydrogen incorporation and consequent electronic interactions with neighboring Co atoms 67, 68 .…”

Section: Methodsmentioning

confidence: 99%

Formation of ferromagnetic Co–H–Co complex and spin-polarized conduction band in Co-doped ZnO

Lee

Park

Kim

et al. 2017

Sci Rep

Self Cite

View full text Add to dashboard Cite

Magnetic oxide semiconductors with wide band gaps have promising spintronic applications, especially in the case of magneto-optic devices. Co-doped ZnO (ZnCoO) has been considered for these applications, but the origin of its ferromagnetism has been controversial for several decades and no substantial progress for a practical application has been made to date. In this paper, we present direct evidence of hydrogen-mediated ferromagnetism and spin polarization in the conduction band of ZnCoO. Electron density mapping reveals the formation of Co–H–Co, in agreement with theoretical predictions. Electron spin resonance measurement elucidates the ferromagnetic nature of ZnCoO by the formation of Co–H–Co. We provide evidence from magnetic circular dichroism measurements supporting the hypothesis that Co–H–Co contributes to the spin polarization of the conduction band of hydrogen-doped ZnCoO.

show abstract

“…This enhancement in O a can be due to the effective binding of TM metals and oxygen due to greater electronegativity (ζ) of Co (ζ = 1.88) and Ni (ζ = 1.91) than that of Zn (ζ = 1.65). The O 2- ions will favorably form the bonds with TM ions in the host lattice, thereby suppressing the formation of oxygen vacancies in the oxygen-cation bonds [ 24 , 31 , 49 ]. The second component of O-1s was symbolized as O b (∼531 ± 0.2 eV) and is known to arise from O 2- ions in the oxygen-deficient regions (where oxygen vacancies are present) of the ZnO matrix.…”

Section: Resultsmentioning

confidence: 99%

Ultraviolet Photodetection Based on High-Performance Co-Plus-Ni Doped ZnO Nanorods Grown by Hydrothermal Method on Transparent Plastic Substrate

Ajmal¹,

Khan²,

Nam³

et al. 2020

Nanomaterials

View full text Add to dashboard Cite

A growth scheme at a low processing temperature for high crystalline-quality of ZnO nanostructures can be a prime stepping stone for the future of various optoelectronic devices manufactured on transparent plastic substrates. In this study, ZnO nanorods (NRs) grown by the hydrothermal method at 150 °C through doping of transition metals (TMs), such as Co, Ni, or Co-plus-Ni, on polyethylene terephthalate substrates were investigated by various surface analysis methods. The TM dopants in ZnO NRs suppressed the density of various native defect-states as revealed by our photoluminescence and X-ray photoelectron spectroscopy analysis. Further investigation also showed the doping into ZnO NRs brought about a clear improvement in carrier mobility from 0.81 to 3.95 cm2/V-s as well as significant recovery in stoichiometric contents of oxygen. Ultra-violet photodetectors fabricated with Co-plus-Ni codoped NRs grown on an interdigitated electrode structure exhibited a high spectral response of ~137 A/W, on/off current ratio of ~135, and an improvement in transient response speed with rise-up and fall-down times of ~2.2 and ~3.1 s, respectively.

show abstract

Analysis of oxygen vacancy in Co-doped ZnO using the electron density distribution obtained using MEM

Cited by 45 publications

References 36 publications

Stabilization of Lead–Tin-Alloyed Inorganic–Organic Halide Perovskite Quantum Dots

Stabilization of Lead–Tin-Alloyed Inorganic–Organic Halide Perovskite Quantum Dots

Formation of ferromagnetic Co–H–Co complex and spin-polarized conduction band in Co-doped ZnO

Ultraviolet Photodetection Based on High-Performance Co-Plus-Ni Doped ZnO Nanorods Grown by Hydrothermal Method on Transparent Plastic Substrate

Contact Info

Product

Resources

About