Selective MOCVD growth of ZnO nanotips

Muthukumar, Sriram; Sheng, H.; Zhong, Jiaming; Zhang, Zheng; Emanetoglu, Nuri W.; Lu, Yicheng

doi:10.1109/tnano.2003.809120

Cited by 110 publications

(62 citation statements)

References 11 publications

(15 reference statements)

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“…1 The combination of high excitonic and biexcitonic oscillator strength and good high temperature characteristics make ZnO a promising material for optical applications. 2 It has been used as a visible and ultraviolet photoconductor and as fluorescent material, apart from its usefulness in optical waveguides, acousto-optic devices, thin film transistors, etc. 3,4 Its wide band gap of 3.37 eV at room temperature makes ZnO suitable for shortwavelength optoelectronic devices, including light-emitting diodes ͑LEDs͒ and laser diodes ͑LDs͒.…”

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confidence: 99%

Resonance enhancement of optical second harmonic generation in a ZnO nanowire

Prasanth

Vugt

Vanmaekelbergh

et al. 2006

Applied Physics Letters

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Two-photon absorption measurement has been carried out in a single 80 nmϫ 10 m ZnO nanowire using femtosecond laser pulses in the wavelength range of 700-800 nm. In addition to the deep-level green emission around 530 nm due to surface defects and the near band-edge ultraviolet emission around 360 nm due to the exciton, a second harmonic peak has been observed. The strength of the frequency-doubled component is found to enhance while the two-photon absorption wavelength is tuned towards the exciton wavelength of the nanowire. This behavior can be ascribed to the resonant exciton absorption in ZnO nanowires. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2200230͔Semiconductor nanocrystals have attracted much interest due to their fundamental importance in bridging the gap between bulk matter and molecular species. Zinc oxide is a remarkable II-VI semiconductor with potential applications owing to its diverse properties. 1 The combination of high excitonic and biexcitonic oscillator strength and good high temperature characteristics make ZnO a promising material for optical applications. 2 It has been used as a visible and ultraviolet photoconductor and as fluorescent material, apart from its usefulness in optical waveguides, acousto-optic devices, thin film transistors, etc. 3,4 Its wide band gap of 3.37 eV at room temperature makes ZnO suitable for shortwavelength optoelectronic devices, including light-emitting diodes ͑LEDs͒ and laser diodes ͑LDs͒. ZnO has a high exciton binding energy of 60 meV, which renders it more applicable for making room-temperature UV laser devices. 5 Small-diameter ZnO nanowires are expected to further lower the lasing threshold because quantum effects result in enhancement of density of states near the band edges and radiative recombination due to carrier confinement. The high exciton binding energy of ZnO at room temperature makes it a promising material for polariton lasers. 6-8 Among nanomaterials, a nanowire has the additional advantage of propagating these photon-exciton pairs due to better optical and carrier confinement. 9,10 However, the possibility of generating exciton-photon pairs by two-photon absorption process is not yet reported in ZnO nanowire. The goal of our research is to investigate the prospect to generate polariton modes that has huge importance for quantum optics and optical information transfer in photonic circuits. High optical nonlinearity due to the unequal atomic size of Zn and O is reported by Levine. 11 The acentrically located bond charge contributes a homopolar energy gap. Since nonlinear susceptibility is more sensitive to the crystal potentials, ZnO is found to be highly nonlinear. This high optical nonlinearity produces second harmonic photon, while the two-photon absorption creates excitons in ZnO nanowire. By tuning the second harmonic photon energy towards the exciton resonance, an enhancement in second harmonic generation ͑SHG͒ is revealed in the present investigation.The II-VI semiconductors are efficient second harmonic generators sin...

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confidence: 99%

Resonance enhancement of optical second harmonic generation in a ZnO nanowire

Prasanth

Vugt

Vanmaekelbergh

et al. 2006

Applied Physics Letters

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“…ZnO layers may take the form of nanostructures with complex shapes, e.g. nanorods, nanotubes, nanopropellers, nanoflowers, nanodots and nanotops, as shown in [16][17][18][19][20][21]. What more, they differ in their sensibility to effects of the gaseous environment.…”

Section: Introductionmentioning

confidence: 99%

Optical investigations of ZnO layers affected by some selected gases in the aspect of their application in optical gas sensors

Struk¹,

Pustelny²,

Gołaszewska³

et al. 2015

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. The paper presents the results of investigations of zinc oxide (ZnO) layers as a potential sensing material, being affected by certain selected gaseous environments. The investigations concerned the optical transmission through thin ZnO layers in wide spectral ranges from ultraviolet to the near infrared. The effect of the gaseous environment on the optical properties of zinc oxide layers with a thickness of ∼400 nm was analyzed applying various technologies of ZnO manufacturing. Three kinds of ZnO layers were exposed to the effect of the gaseous environment, viz.: layers with relatively slight roughness (RMS several nm), layers with a considerable surface roughness (RMS some score of nm) and layers characterized by porous ZnO structures. The investigations concerned spectral changes in the transmission properties of the ZnO layers due to the effect of such gases as: ammonia (NH3), hydrogen (H2), and nitrogen dioxide (NO2) in the atmosphere of synthetic air. The obtained results indicated the possibility of applying porous ZnO layered structures in optical gas sensors.

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“…A wide range of techniques including chemical vapor deposition (CVD), metalorganic chemical vapor deposition (MOCVD), thermal pyrolysis, etc. are generally used to synthesize zinc oxide (ZnO) nanoparticles and films [16][17][18]. In most of the cases, it is reported that ZnO nanostructures are resulted from epitaxial growth rather than isotropic nucleation.…”

Section: Introductionmentioning

confidence: 99%

ZnO Nanoparticles to Nanowires and Nanobundles

Hossain

2013

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Abstract. Nanosized Zinc oxide (ZnO) possesses unique electrical, optoelectronics and photochemical characteristics and thus it is a potential candidate for different applications in next generation of optoelectronic device. In this work, a novel sol-gel route for the synthesis of ZnO nanoparticles and its transformation into wires and bundles has been reported. The process is adopted from a simple and hand-on route that also shows the power of green chemistry in nanomaterials synthesis. ZnO nanoparticles (~30 nm in diameter) were synthesized from bottom-up approach followed by a further process to obtain nanometric wires and bundles under controlled conditions. The nanowires and bundles are speculated to initiate from anisotropic agglomeration of nanometric particles and agglomeration of these nanometric wires into bundles respectively. Control of these agglomeration processes is a key challenge for application of nanowires and bundles into useful devices.

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Selective MOCVD growth of ZnO nanotips

Cited by 110 publications

References 11 publications

Resonance enhancement of optical second harmonic generation in a ZnO nanowire

Resonance enhancement of optical second harmonic generation in a ZnO nanowire

Optical investigations of ZnO layers affected by some selected gases in the aspect of their application in optical gas sensors

ZnO Nanoparticles to Nanowires and Nanobundles

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