Will UV Lasers Beat the Blues?

Service, Robert F.

doi:10.1126/science.276.5314.895

Cited by 508 publications

(212 citation statements)

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“…15 In addition, the shoulder at 3.375 eV, indicated by the dashed arrow in the figure, is probably attributed to a transition from a free exciton (EX) since a similar peak was also observed in singly crystalline ZnO. [2][3][4]15 However, quantum confinement effects in the ZnO nanoparticle array were not observed, presumably because of the relatively large diameter of the nanoparticle. [5][6][7] In conclusion, we successfully demonstrated the synthesis of photoluminescent ZnO nanoparticles in an ordered array on the solid substrate conserving the dimensional order of PS-PVP diblock copolymer micelles.…”

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confidence: 99%

Self-assembled arrays of zinc oxide nanoparticles from monolayer films of diblock copolymer micelles

et al. 2004

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A hexagonal array of optically active ZnO nanoparticles was synthesized in situ on the solid substrate by utilizing a singlelayered film of diblock copolymer micelles as a nanostructured template.During the last decade, research on semiconductor nanoparticles has been a wide and interdisciplinary field of science to elucidate and utilize their novel material properties. 1 Zinc oxide, a wideband-gap semiconductor oxide, is a very fascinating material due to its large exciton binding energy and bond strength, 2,3 which make it applicable for a blue or ultraviolet optical device. [2][3][4] Nanoparticles of zinc oxide can be effectively synthesized in aqueous or organic solutions. Colloidal synthetic routes for ZnO nanoparticles usually involve the reaction of Zn 21 salts in basic solutions. [5][6][7] For their applications, however, controlled deposition of ZnO nanoparticles from solutions to solid substrates is necessary. To place nanoparticles on a substrate in a specific arrangement, templates have been utilized, which can be lithographically fabricated or self-assembled. [8][9][10][11][12][13][14] In the case of self-assembled templates, a periodic nanostructure of diblock copolymers or their micelles was successfully employed to arrange nanoparticles with a considerable stability. [10][11][12][13][14] For example, the nanometre-sized micelles of diblock copolymers in a selective solvent for one of the blocks were transferred onto silicon wafers to form a hexagonally ordered monolayer film, which served as a structured template to direct the spatial location of nanoparticles. [10][11][12][13][14] In addition, an ordered array of metal or oxide nanoparticles was directly synthesized by employing plasma treatments as a successful method of oxidation or reduction of precursors of nanoparticles as well as removal of copolymer templates. Möller and coworkers demonstrated arrays of gold nanoparticles on various substrates with a combination of diblock copolymer micelles and plasma treatments. 11 Similarly, we reported an array of iron oxide nanoparticles surrounded by gold nanoparticles from a monolayer film of diblock copolymer micelles with subsequent exposure to oxygen plasma. 13 The fabricated arrays of nanoparticles from diblock copolymer micelles, however, were applied mostly to passive applications such as an etching resistant mask. As an active nanopattern, an array of cobalt nanoparticles was recently synthesized from diblock copolymer micelles although magnetic properties of the array were not reported. 12 In this communication, we demonstrate instant synthesis of optically active ZnO nanoparticles in a hexagonal order from a single-layered film of diblock copolymer micelles with oxygen plasma treatment. The near-band-edge emission was observed for the array of ZnO nanoparticles.For a monolayer film of diblock copolymer micelles, polystyrene-block-poly(4-vinylpyridine), PS-PVP (M n PS~4 7.6 kg mol 21 , M n PVP~2 0.4 kg mol 21 , polydispersity index~1.14) was dissolved in toluene and stirred for 3 h at room ...

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Self-assembled arrays of zinc oxide nanoparticles from monolayer films of diblock copolymer micelles

et al. 2004

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“…Among the various known semiconductors, ZnO has several advantages compared to other wide-band-gap semiconductors. It has a direct band gap of 3.37 eV and large exciton binding energy of 60 meV at room temperature [1]. Due to these unique properties, it finds applications in antireflection coatings, transparent electrodes in solar cells, ultraviolet (UV) light emitters, diode lasers, varistors, piezoelectric devices, spin-electronics, surface acoustic wave propagation, and also in sensing of gas [2].…”

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confidence: 99%

Synthesis and optical characterization of porous ZnO

et al. 2013

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Abstract:In this paper, a simple and cheap method to prepare porous ZnO by using zinc nitrate, ethanol and triethanolamine (TEA) is reported. The as-prepared sample consisted of nano and micro pores. The sample was calcined at 300 ℃, 400 ℃ and 500 ℃ with different heating rates. At 500 ℃, the nano pores disappeared but the sample maintained its micro porosity. Field emission scanning electron microscopy (FE-SEM) pictures confirmed that the size and growth of ZnO nanoparticles depended on the heating conditions. The infrared (IR) absorption peak of Zn-O stretching vibration positioned at 457 cm 1 was split into two peaks centered at 518 cm 1 and 682 cm 1 with the change of morphology. These results confirmed that Fourier transform infrared (FT-IR) spectrum was sensitive to variations in particle size, shape and morphology. The photoluminescence (PL) spectrum of porous ZnO contained five emission peaks at 397 nm, 437 nm, 466 nm, 492 nm and 527 nm. Emission intensity enhanced monotonously with increase of temperature and the change was rapid between temperatures of 300 ℃ and 500 ℃. This was due to the elimination of organic species and improvement in the crystallanity of the sample at 500 ℃.

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“…Recently, ZnO has attracted much interest as a promising material for blue and ultraviolet (UV) light emitting diodes (LEDs) and laser diodes (LDs), since it has a wide direct band gap of 3.37 eV and a large exciton binding energy of 60 meV at room temperature [1,2]. It is well known that undoped ZnO exhibits mostly n-type conduction, whereas growth of high-conductivity p-type ZnO is very difficult because of the problems such as deep acceptor level, low solubility of the acceptor dopants and a strong selfcompensating effect induced by the presence of native defects such as zinc interstitials (Zn i ), oxygen vacancies (V O ) and hydrogen impurities [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and properties of Sb-doped ZnO thin films grown by radio frequency (RF) magnetron sputtering

Wang

Chen

Yin

et al. 2006

Journal of Crystal Growth

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Sb-doped and undoped ZnO thin films were deposited on Si (1 0 0) substrates by radio frequency (RF) magnetron sputtering. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses revealed that all the films had polycrystalline wurtzite structure and c-axis preferred orientation. Room temperature Hall measurements showed that the as-grown films were n-type and conducting (r$1-10 O cm). Annealing in a nitrogen ambient at 400 1C for 1 h made both samples highly resistive (r410 3 O cm). Increasing the annealing temperature up to 800 1C, the resistivity of the undoped ZnO film decreased gradually, but it increased for the Sb-doped ZnO film. In the end, the Sb-doped ZnO film annealed at 800 1C became semi-insulating with a resistivity of 10 4 O cm. In addition, the effects of annealing treatment and Sb-doping on the structural and electrical properties are discussed. r

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Will UV Lasers Beat the Blues?

Cited by 508 publications

References 0 publications

Self-assembled arrays of zinc oxide nanoparticles from monolayer films of diblock copolymer micelles

Self-assembled arrays of zinc oxide nanoparticles from monolayer films of diblock copolymer micelles

Synthesis and optical characterization of porous ZnO

Fabrication and properties of Sb-doped ZnO thin films grown by radio frequency (RF) magnetron sputtering

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