High-temperature random lasing in ZnO nanoneedles

Yang, Hui Ying; Lau, Shu Ping; Yu, Siu Fung; Abiyasa, Agus Putu; Tanemura, Masaki; Okita, T.; Hatano, H.

doi:10.1063/1.2219419

Cited by 47 publications

(40 citation statements)

References 12 publications

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“…Zinc oxide (ZnO), a wide band gap semiconductor (3.37 eV), has a vast range of applications which include but are not limited to photocatalysts [8], varistors [9,10], pharmaceutical products [11], and lasers [12]. As a photocatalyst, in the presence of UV radiation, ZnO facilitates production of reactive oxygen species (ROS) on its surface [13].…”

Section: Introductionmentioning

confidence: 99%

Antibacterial properties of F-doped ZnO visible light photocatalyst

Podporska-Carroll

Myles

Quilty

et al. 2017

Journal of Hazardous Materials

208

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Section: Introductionmentioning

confidence: 99%

Antibacterial properties of F-doped ZnO visible light photocatalyst

Podporska-Carroll

Myles

Quilty

et al. 2017

Journal of Hazardous Materials

208

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“…[ 10 ] The need to characterize point defects in ZnO is further amplifi ed with the recent applications of ZnO nanoparticles as hosts of single emitters for quantum information processing [11][12][13] and their use in random lasing [ 14 ] and other advanced sensing technologies. [ 15 ] These applications require precise control over the defect engineering in ZnO nanoparticles.…”

mentioning

confidence: 99%

Photophysics of Point Defects in ZnO Nanoparticles

Choi

Phillips

Aharonovich

et al. 2015

Advanced Optical Materials

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including oxygen vacancies ( V O ), [ 6 ] and zinc vacancies ( V Zn ), [ 7 ] interstitials (Zn i , O i ), [ 8 ] and antisite defects (Zn O , O Zn ) [ 9 ] as well as chemical impurities such as Cu. [ 10 ] The need to characterize point defects in ZnO is further amplifi ed with the recent applications of ZnO nanoparticles as hosts of single emitters for quantum information processing [11][12][13] and their use in random lasing [ 14 ] and other advanced sensing technologies. [ 15 ] These applications require precise control over the defect engineering in ZnO nanoparticles. Consequently, correlative characterization of point defects will be valuable to explore the luminescence properties and affi liate them with their chemical and paramagnetic spin features.In this work we perform comprehensive studies on the formation and photophysical properties of point defects in ZnO nanoparticles. In particular, we employ correlative characterization techniques to assign the optical emission peaks and electron paramagnetic resonance (EPR) lines to specifi c defects in ZnO nanoparticles. Our results provide new insight into optical luminescence properties of ZnO nanoparticles and promote them as potential candidate for nanophotonic technologies. [ 16 ] Results and DiscussionAfter being annealed in an Ar or Zn vapor environment at 700-900 °C the as-received ZnO nanoparticles (diameter ≈ 20 nm) coalescence [ 17,18 ] and display faceted morphologies ( Figure 1 ). The nanoparticles increase in average size up to about 120 nm after annealing in inert gas (Ar) or oxygen, and up to 150 nm for annealing in Zn vapor at 900 °C [see Figures S1 and S2, Supporting Information for nanoparticle sizes obtained from scanning electron microscopy (SEM) image and X-ray diffraction (XRD) analysis]. Since the Bohr radius of ZnO is 2.34 nm, [ 19 ] the nanoparticles are large enough to avoid quantum size effects but still possess a suffi ciently large surface area to allow defect engineering.To investigate the occurrence of defects in ZnO nanoparticles, EPR spectroscopy was performed. Figure 2 a shows EPR spectra of the as-received, O 2 annealed, Zn vapor annealed ZnO nanoparticles and a bare Si(100) substrate for comparison. The as-received ZnO nanoparticles exhibit a strong signal at g = 1.96, which has been previously assigned to zinc vacancies (V Zn − ), [ 20 ] oxygen interstitials (O i − ), [ 20 ] zinc interstitials (Zn i + ) [ 21 ] and to electrons in weakly bound or conduction band (CB) Zinc oxide (ZnO) nanoparticles have recently been identifi ed as a promising candidate for advanced nanophotonics applications and quantum technologies. This work reports the formation of luminescent point defects and describes their photophysical properties. In particular, it is shown using correlative photoluminescence, cathodoluminescence, electron paramagnetic resonance (EPR), and X-ray absorption near-edge spectroscopy that green luminescence at 2.48 eV and an EPR line at g = 2.00 belong to a surface oxygen vacancy (V o,s + ) center, while a second green emi...

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“…ZnO, a wide band gap semiconductor (3.37 eV), has a range of potential applications as photocatalysts, 1 gas sensors, 2 lasers, 3 displays, 4 high-density optical storage devices 5 and varistors.…”

Section: Introductionmentioning

confidence: 99%

Microwave-assisted synthesis of ZnO micro-javelins

et al. 2009

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The microwave (MW)-assisted formation of ZnO micro-javelins from zinc nitrate and urea in aqueous solution is described. The particles (named as 'micro-javelins' because of their high aspect ratio and needle-like tips) grow hexagonally with well-defined facets in the h01 10i direction and pointed tips in (0001) direction. Powder X-ray diffraction patterns show the appearance of a strikingly dominant (1000) orientation. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations reveal the morphological evolution of these hexagonal ZnO particles with time. The effect of precursor concentrations, counterion type and MW irradiation power and their consequent influence on pH and Zn 2+ ion concentration are investigated. A mechanism for the formation of the micro-javelins is postulated. The microwave induced supersaturation of Zn(OH) + species under the weakly basic pH condition and the initial growth through the (000 1) direction (oxygen-rich face) are proposed to be the key factors that dictate the formation of these ZnO micro-javelins. The present one-step microwave process is a straightforward and a reproducible method for the bulk synthesis of defect-free ZnO micro-javelins, which would find potential applications in microelectronic devices (e.g. lasers, cantilevers in surface probing equipment, etc.).

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High-temperature random lasing in ZnO nanoneedles

Cited by 47 publications

References 12 publications

Antibacterial properties of F-doped ZnO visible light photocatalyst

Antibacterial properties of F-doped ZnO visible light photocatalyst

Photophysics of Point Defects in ZnO Nanoparticles

Microwave-assisted synthesis of ZnO micro-javelins

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