Zn vacancy induced green luminescence on non-polar surfaces in ZnO nanostructures

Fabbri, Filippo; Villani, Marco; Catellani, Alessandra; Calzolari, Arrigo; Cicero, Giancarlo; Calestani, Davide; Calestani, G.; Zappettini, A.; Dierre, Benjamin; Sekiguchi, Takashi; Salviati, G.

doi:10.1038/srep05158

Cited by 154 publications

(134 citation statements)

References 52 publications

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“…An enhancement in the UV peak intensity occurs only when radiative and/or non-radiative defect centers within the band gap are reduced. Green emission is the most notorious one affecting the intensity of the UV emission and the former being caused by the Zn vacancy (V Zn ) defects [54][55][56][57]. In our Sn doped films, some Sn 4+ ions are probably causing charge compensation by making a complex with V Zn [37].…”

Section: Electrical and Photoluminescence Propertiesmentioning

confidence: 96%

An insight into doping mechanism in Sn–F co-doped transparent conducting ZnO films by correlating structural, electrical and optical properties

Mallick

Sarkar

Ghosh

et al. 2015

Journal of Alloys and Compounds

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On the face of massively growing market of transparent optoelectronics, developing ZnO-based transparent conductive thin films as a promising substitute for indium-free transparent electrode is extremely important. However, the detailed function of the dopants, especially co-dopants acting on the electrical and optical properties of ZnO-based transparent conductive thin films is not clear yet. We present a detailed comparative investigation on the structural, electrical and optical properties of pulsed laser deposited ZnO thin films co-doped with Sn and F for the first time. An unexpected expansion in the lattice structure has been observed when Zn 2+ are replaced by Sn 4+ having smaller ionic radius. Electrical measurements show that there is no anticipated change in the carrier concentration with the dopant concentration. A minimum resistivity of 2.56×10 -3 Ohm-cm with a carrier concentration of 4.41×10 20 cm -3 has been obtained for 1 at% each Sn-F co-doped film. Most interestingly, a significant improvement in the ultraviolet (UV)/visible (VIS) photoluminescence peak intensity in Sn doped and Sn-F co-doped films in correlation with the structural and electrical properties allows us to propose that Sn doping into ZnO lattice causes a screening of the native Zn vacancy defects. While the presence of F co-dopant induces Sn 2+ to occupy the lattice sites, as evidenced from the lattice expansion, an insignificant increase in the carrier concentration as well as enhanced UV emission of the co-doped films. The results obtained in this study shed light on the development of ZnO-based transparent electrodes.

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Section: Electrical and Photoluminescence Propertiesmentioning

confidence: 96%

An insight into doping mechanism in Sn–F co-doped transparent conducting ZnO films by correlating structural, electrical and optical properties

Mallick

Sarkar

Ghosh

et al. 2015

Journal of Alloys and Compounds

View full text Add to dashboard Cite

show abstract

“…In the visible emission spectrum, different defects are attributed to the green, yellow, and orange-red emissions [16,27]. The green emission band is attributed to a variety of defects including singly ionised oxygen vacancies [28][29][30][31], antisite oxygen [17,32,33], zinc interstitials [34], and zinc vacancies [35]. Given that there is no consensus in the mechanism for green emission, this shows how highly debated the origins of the luminescence are for ZnO [36,37].…”

Section: Introductionmentioning

confidence: 99%

Room-temperature single-photon emission from zinc oxide nanoparticle defects and their in vitro photostable intrinsic fluorescence

et al. 2016

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Zinc oxide (ZnO) is a promising semiconductor that is suitable for bioimaging applications due to its intrinsic defect fluorescence. However, ZnO generally suffers from poor photostability. We report room-temperature single-photon emission from optical defects found in ZnO nanoparticles (NPs) formed by ion implantation followed by thermal oxidation in a silica substrate. We conduct a thorough investigation into the photophysics of a particularly bright defect and identify other single emitters within the NPs. Photostability was observed when the NPs were removed from the growth substrate and taken up by skin cells for in vitro imaging.

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“…However, with regard to nanostructured ZnO, Djurišić et al 8 and Fabbri et al 17 19 reported that the DLE arises mainly from surface layer, whereas Chang et al 20 have suggested that it originates from the bulk. We assume that this disagreement could be associated with the penetration depth of the excitation light for the specific ZnO nanostructures, in which the defect states vary with the depth.…”

Section: Resultsmentioning

confidence: 95%

Geometrical Separation of Defect States in ZnO Nanorods and Their Morphology-Dependent Correlation between Photoluminescence and Photoconductivity

2015

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An understanding of the morphology-dependent correlation between photoluminescence and photoconductivity in the nanostructured ZnO is important for elucidating the carrier dynamics and expanding its use in optoelectrical applications. In this study, we investigated this relationship using distinctly different ZnO nanorods with diameters greater than 100 nm, which were produced by a hydrothermal method. Further, in order to study the effects of its defect states on the correlation, we thoroughly characterised the defect states of the ZnO nanorods in terms of the light-penetration depth during photoluminescence. The photoconductivities of the nanorods were measured using light sources with wavelengths of 355, 405, and 532 nm to confirm the influences of the visible-emission-generating defects on carrier transport. We found that the intensity of the near-band-edge emission was almost comparable to the amount of photocurrent generated under ultraviolet (UV) light; this could be attributed to the crystallinity of the inside of ZnO nanorods. However, the concentration of the surface defects resulting from the size and morphology probably had an effect leading to the observed differences in the photocurrent sensitivity under low-intensity UV light, the dark current level, the amount of photocurrent under a specific wavelength of light within the visible range, and the persistent photoconductivity. The results of this study could aid research on carrier dynamics in nanostructured ZnO and further its use in optoelectronics.

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Zn vacancy induced green luminescence on non-polar surfaces in ZnO nanostructures

Cited by 154 publications

References 52 publications

An insight into doping mechanism in Sn–F co-doped transparent conducting ZnO films by correlating structural, electrical and optical properties

An insight into doping mechanism in Sn–F co-doped transparent conducting ZnO films by correlating structural, electrical and optical properties

Room-temperature single-photon emission from zinc oxide nanoparticle defects and their in vitro photostable intrinsic fluorescence

Geometrical Separation of Defect States in ZnO Nanorods and Their Morphology-Dependent Correlation between Photoluminescence and Photoconductivity

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