Synthesis of wurtzite ZnSe nanorings by thermal evaporation

Leung, Y. P.; Choy, Wallace C. H.; Markov, Ivan; Pang, G.K.H.; Ong, H. C.; Yuk, Tong I.

doi:10.1063/1.2200155

Cited by 53 publications

(53 citation statements)

References 28 publications

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“…[30][31][32] Following a similar explanation, wurtzite ZnSe nanorings have been synthesized by Leung et al, with dominant {0001} polar surfaces exposed. 7 However, this mechanism relies crucially on the existence of a large polar surface and is obviously not applicable to the as-grown samples here, since the dominant surfaces are nonpolar ((01 j 1). Screw dislocations have also been introduced to explain the formation of helical -Ga 2 O 3 nanowires 33 and SiC/SiO 2 core-shell nanowires.…”

Section: Formation Of Nanospirals With In-plane Bending Mediated By Lmentioning

confidence: 99%

“…For example, using the thermal evaporation method, pressure-controlled syntheses of ZnSe nanowires and nanorings can be separately achieved. 7 In contrast to the one-stage syntheses, two-stage fabrications are generally accompanied by variations (i.e., compositions, temperature, and reaction pressure) and thus offer more flexibility in combining different materials and allow separate controls over each material in the single stage. Novel {113} twinned ZnSe bicrystal nanobelts filled with 〈111〉 twinnings 11 and side-by-side ZnSe/ZnCdSe bicrystalline nanoribbons 12 have been successfully synthesized through this method.…”

Section: Introductionmentioning

confidence: 99%

“…1,2 Recently, due to the novel properties and promising applications of nanostructures, scientific interests have been renewed for fabricating various ZnSe nanostructures, as well as achieving well-defined interfaces. Different morphologies [4][5][6][7] and ZnSebased nanostructures 8 have been obtained by utilizing various growth techniques, such as metal-organic chemical vapor deposition, 9 molecular beam epitaxy, 10 thermal evaporation, 4,[6][7][8] etc. Among most of these, fabrications are through a one-stage process, since the experimental conditions are maintained throughout the growth.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Growth of ZnSe Nanospirals with Bending Mediated by Lomer−Cottrell Sessile Dislocations through Varying Pressure

Jin

Wang

Choy

2008

Crystal Growth & Design

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ZnSe nanospirals, with zinc blende structured building blocks exhibiting unconventional mosaic configuration, were successfully fabricated via a two-stage growth process, in which abrupt variation of reaction pressure was introduced. In-plane bending, with remarkable morphological difference from the commonly reported nanorings or nanohelixes induced by spontaneous polarization in II-VI semiconductors, has been observed, which can be mainly attributed to existence of numerous Lomer-Cottrell sessile dislocations with edge components. Investigations on morphological evolutions by applying different reaction pressure and growth time in the second stage imply that the formation of nanospirals is closely related to the pressure variation. The results may provide useful information for further understanding the strain release mechanism and mechanical response of ZnSe at the nanoscale.

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Section: Formation Of Nanospirals With In-plane Bending Mediated By Lmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Growth of ZnSe Nanospirals with Bending Mediated by Lomer−Cottrell Sessile Dislocations through Varying Pressure

Jin

Wang

Choy

2008

Crystal Growth & Design

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“…ZnSe, a direct band gap (2.8 eV) II-VI semiconductor with large exciton binding energy (21 meV), has been investigated for potential applications in optoelectronic devices such as light emitting diodes and laser diodes (Katayama et al 1998). ZnSe nanostructures with different morphologies such as wires, belts, rods and tetrapods have been synthesized by different techniques such as vapor transport, metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE) and solution growth (Ye et al 2004;Leung et al 2006;Shan et al 2006;Cai et al 2006;Mazher et al 2004). Among these techniques, vapor transport technique is more popular due to its simplicity in growing single crystalline nanostructures with different morphologies (Ye et al 2004;Leung et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Growth of ZnSe nano and microstructures at high vacuum by thermal evaporation

et al. 2013

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ZnSe nano and microstructures were grown on Si substrates in high vacuum by thermal evaporation at different source temperatures ranging from 850 to 950°C. Morphology, chemical composition and structural properties of these grown ZnSe nano and microstructures were studied using scanning electron microscope (SEM) and transmission electron microscope (TEM). SEM studies revealed that the morphology of grown structures contains nanowires, nanobelts and microcrystals. TEM studies showed that the grown nanowires and nanobelts are single crystalline in nature with growth direction along [110] of zinc blende structure. The room temperature photoluminescence (PL) spectra of these nanostructures grown at different temperatures exhibited a strong broad defect level (DL) emission peak and a weak narrow near band edge (NBE) emission peak. Further, the intensity of DL emission peak was found to increase with increase in source temperature.

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“…Fluorescent nanomaterials have been the subject of intensive research in recent years for their vast applications ranging from biomedical therapeutics and diagnostics to information storage and optoelectronics [1][2][3]. For fluorescence based applications, fluorescence efficiency, i.e.…”

Section: Introductionmentioning

confidence: 99%

Enhanced efficiency of a fluorescing nanoparticle with a silver shell

Choy

Chen

2009

J. Phys.: Conf. Ser.

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Abstract. Spontaneous emission (SE) rate and the fluorescence efficiency of a bare fluorescing nanoparticle (NP) and the NP with a silver nanoshell are analyzed rigorously by using a classical electromagnetic approach with the consideration of the nonlocal effect of the silver nano-shell. The dependences of the SE rate and the fluorescence efficiency on the core-shell structure are carefully studied and the physical interpretations of the results are addressed. The results show that the SE rate of a bare NP is much slower than that in the infinite medium by almost an order of magnitude and consequently the fluorescence efficiency is usually low. However, by encapsulating the NP with a silver shell, highly efficient fluorescence can be achieved as a result of a large Purcell enhancement and high out-coupling efficiency (OQE) for a well-designed core-shell structure. We also show that a higher SE rate may not offer a larger fluorescence efficiency since the fluorescence efficiency not only depends on the internal quantum yield but also the OQE. IntroductionFluorescent nanomaterials have been the subject of intensive research in recent years for their vast applications ranging from biomedical therapeutics and diagnostics to information storage and optoelectronics [1][2][3]. For fluorescence based applications, fluorescence efficiency, i.e. the external quantum efficiency (EQE) of the emitter, is an important issue. Due to the existence of pronounced nonradiative decay of excitons in the nanoscale structure, low EQE is an often-observed feature. Most of the strategies so far employed aim to reduce the nonradiative decay rate [4][5][6] for improving the fluorescence efficiency. The direct and effective approach to improve EQE is to increase radiative decay rate [7] and out-coupling efficiency (OQE) since EQE is the product of internal quantum yield (i.e. internal quantum efficiency) (IQE) and OQE. The enhancement of radiative decay rate results in the Purcell enhancement of IQE [8,9]. Here, we will address this issue. The radiative decay rate, i.e. spontaneous emission (SE) rate, can be enhanced by utilizing the surface plasmon effect [10][11][12] or the microcavity effect [13]. According to the near field nature of surface plasmon, the SE rate in a dielectric nanoparticle (NP) encapsulated with a metallic shell can be greatly enhanced. However, the metallic shell introduces extra absorption loss and may result in a small OQE. Consequently, fluorescence efficiency may still be low although the SE rate is greatly enhanced. Thus a rigorous theoretical study on the SE rate and OQE of emitters in nanoscale structure is desirable for getting a better physical understanding and optimal design of the nano-structure to

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Synthesis of wurtzite ZnSe nanorings by thermal evaporation

Cited by 53 publications

References 28 publications

Growth of ZnSe Nanospirals with Bending Mediated by Lomer−Cottrell Sessile Dislocations through Varying Pressure

Growth of ZnSe Nanospirals with Bending Mediated by Lomer−Cottrell Sessile Dislocations through Varying Pressure

Growth of ZnSe nano and microstructures at high vacuum by thermal evaporation

Enhanced efficiency of a fluorescing nanoparticle with a silver shell

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