Synthesis of nanocrystalline material by sputtering and laser ablation at low temperatures

Ayyub, Pushan; Chandra, Ramesh; Taneja, Praveen; Sharma, Ajay; Pinto, R.

doi:10.1007/s003390100833

Cited by 135 publications

(59 citation statements)

References 2 publications

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“…In particular, the presence of clusters or particulates in the ablation plume can have an adverse effect on the quality of homogeneous thin films grown in PLD [2], whereas formation of debris and redeposition of ejected particulates can cause problems in manufacturing of surface microstructures. On the other hand, generation of clusters in laser ablation can be turned to useful account in production of nano-and micrometer-sized particles, ultra-fine powders, nanocomposites, and thick coatings [6][7][8]. A possible important role of the ejection of molecular clusters in ionization in MALDI has been recently discussed and supported by experimental observations [9][10][11][12].…”

Section: Introductionmentioning

confidence: 76%

Dynamics of the plume formation and parameters of the ejected clusters in short-pulse laser ablation

Zhigilei

2003

Applied Physics A: Materials Science & Processing

292

197

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The dynamics of the early stages of the ablation plume formation and the mechanisms of cluster ejection are investigated in large-scale molecular dynamics simulations. The cluster composition of the ablation plume has a strong dependence on the irradiation conditions and is defined by the interplay of a number of processes during the ablation plume evolution. At sufficiently high laser fluences, the phase explosion of the overheated material leads to the formation of a foamy transient structure of interconnected liquid regions that subsequently decomposes into a mixture of liquid droplets, gasphase molecules, and small clusters. The ejection of the largest droplets is attributed to the hydrodynamic motion in the vicinity of the melted surface, especially active in the regime of stress confinement. Spatially resolved analysis of the dynamics of the plume formation reveals the effect of segregation of the clusters of different sizes in the expanding plume. A relatively low density of small/medium clusters is observed in the region adjacent to the surface, where large clusters are being formed. Medium-size clusters dominate in the middle of the plume and only small clusters and monomers are observed near the front of the expanding plume. Despite being ejected from deeper under the surface, the larger clusters in the plume have substantially higher internal temperatures as compared to the smaller clusters. The cluster-size distributions can be relatively well described by a power law Y(N) ∼ N −τ with exponents different for small, up to ∼ 15 molecules, and large clusters. The decay is much slower in the high-mass region of the distribution.

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Section: Introductionmentioning

confidence: 76%

Dynamics of the plume formation and parameters of the ejected clusters in short-pulse laser ablation

Zhigilei

2003

Applied Physics A: Materials Science & Processing

292

197

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“…15 The larger band gap component in our nanocomposite was ZnO ͑E g = 3.44 eV at 300 K͒, a semiconductor with a crystal structure similar to CdS. Nanostructured films ͑average grain size Ϸ2-20 nm͒ of most metals, semiconductors, and oxides can be sputtered onto desired substrates by dc/rf sputtering 16 at relatively high gas pressures ͑Ϸ10-200 mTorr͒ and low substrate temperatures ͑77-300 K͒. In particular, uniform, nanocrystalline films of pure CdS can be synthesized by this technique, 17 but need to be chemically passivated by a prolonged in situ exposure to H 2 +N 2 gas mixture.…”

Section: Synthesis and Microstructurementioning

confidence: 99%

Photoluminescence enhancement in nanocomposite thin films of CdS–ZnO

Ayyub

Vasa

Taneja

et al. 2005

Journal of Applied Physics

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We show that the photoluminescence emitted from a dense, two-component quantum dot ensemble on a thin film is significantly higher and decays much faster than that from quantum dots of either of the two pure systems ͑CdS and ZnO͒. The semiconductor nanocomposite, in which the characteristic grain size of each species was 2 -3 nm, was deposited directly on Si wafers by high-pressure magnetron sputtering, and exhibits a single, relatively sharp optical absorption edge.

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“…Production of nanoparticles can be achieved through chemical and physical method [2,3]. In bio nanotechnology the source of synthesis like microorganisms, enzyme, plants and plant extracts as possible methods to avoid the use of toxic chemical and expensive physical tools.…”

Section: Introductionmentioning

confidence: 99%

Antioxidant Activity and Biogenic Synthesis of Selenium Nanoparticles Using the Leaf Extract of Aloe Vera

Vyas

Rana²

2017

Int J Curr Pharm Sci

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Objective: The objective of this present study were to the biogenic synthesis of selenium nanoparticles using Aloe vera extract and check it's antioxidant potential by ABTS, DPPH and FRAP assays. Methods:In this study we investigated the clove of Aloe vera, which is used for the synthesis of selenium nanoparticles were characterized by using UV-Visible (UV-VIS) spectrophotometer, Transmission electron microscopy (TEM), Fourier transform spectroscopy (FTIR) and Energy dispersive XRay spectroscopy (EDAX) and ABTS, DPPH and FRAP assays for checked it's antioxidant potential.Results: The present study was carried out to synthesis of Selenium nanoparticles using extract of Aloe vera. UV-Vis Spectra at 350 nm with Aloe vera extract and observed as hollow and spherical particles in size ranging 7-48 nm which is found more stable more than two months. EDAX analysis was carried out to check the presoak of Selenium in nanoparticles. Results of EDAX, confirmed its present. TEM and SEAD represented addition evidence of formation of nanoparticles whereas SEAD indicates the particles were crystalline in nature. FT-IR analysis was carried out to identify the possible bio molecules and Aloe vera extract-metal ions interaction responsible for formation and stabilization of selenium nanoparticles. FRAP, ABTS and DPPH assay results sequester that Selenium nanoparticles prepared using Aloe vera extract possess more activity than extract alone. Conclusion:The bio molecules of Aloe vera extract acted as stabilizing as well as capping agent leading to the formation of Selenium nanoparticles. Selenite has been proven to have antioxidant activity and is being used as chemoprevention agent in cancer diagnosis but same time it is toxic also. Elemental Selenium i.e. Selenium nanoparticles are less toxic form of selenium.

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Synthesis of nanocrystalline material by sputtering and laser ablation at low temperatures

Cited by 135 publications

References 2 publications

Dynamics of the plume formation and parameters of the ejected clusters in short-pulse laser ablation

Dynamics of the plume formation and parameters of the ejected clusters in short-pulse laser ablation

Photoluminescence enhancement in nanocomposite thin films of CdS–ZnO

Antioxidant Activity and Biogenic Synthesis of Selenium Nanoparticles Using the Leaf Extract of Aloe Vera

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