Subhash Singh

Publications (18) View all

• Article: Effect of oxygen injection on the size and compositional evolution of ZnO/Zn(OH)2 nanocomposite synthesized by pulsed laser ablation in distilled water

  S. C. Singh
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  ABSTRACT: Zinc oxide/hydroxide nanocomposite materials are synthesized by pulsed laser ablation of zinc in double distilled water. Effect of simultaneous flow of oxygen in the closed vicinity of laser ablated plasma plume on the size, morphology, crystallinity, and composition of synthesized oxide/hydroxide nanocomposite structures is investigated. As synthesized nanocomposite materials are characterized using UV–visible absorption, Scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), Differential thermal analysis (DTA), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and photoluminescence spectroscopic methods. It is observed that injection of oxygen induces a new mechanism in the particle synthesis, which causes decrease in particle size, distribution as well as Zn(OH)2/ZnO ratio and increase of order of crystallinity of product. There are some novel findings in the direction of development of pulsed laser ablation in aqueous media (PLAAM) for the synthesis of nanostructured materials. KeywordsZinc oxide/hydroxide nanocomposite–Pulsed laser ablation at solid liquid interface–Optical characterization–X-ray diffraction–Thermal analysis–Oxygen injection–Synthesis nanomaterials
  Journal of Nanoparticle Research 04/2012; 13(9):4143-4152. · 3.29 Impact Factor
• Source

  Available from: Raj kUmar Swarnkar

  Article: Zn/ZnO core/shell nanoparticles synthesized by laser ablation in aqueous environment: Optical and structural characterizations

  S. C. Singh, R. K. Swarnkar, R. Gopal
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  ABSTRACT: Zn/ZnO core/shell nanoparticles are synthesized by pulsed laser ablation (PLA) of Zn metal plate in the aqueous environment of sodium dodacyl sulfate (SDS). Solution of nanoparticles is found stable in the colloidal form for a long time, and is characterized by UV-visible absorption, transmission electron microscopy (TEM), photoluminescence (PL) and Raman spectroscopic techniques. UV-visible absorption spectrum has four peaks at 231, 275, 356, and 520 nm, which provides primary information about the synthesis of core-shell and elongated nanoparticles. TEM micrographs reveal that synthesized nanoparticles are monodispersed with three different average sizes and size distributions. Colloidal solution of nanoparticles has significant absorption in the green region, therefore, it absorbs 514·7 nm light of Ar+ laser and emits in the blue region centred at 350 and 375 nm, violet at 457 nm and green at 550 nm regions. Raman shift is observed at 300 cm−1 with PL spectrum, which corresponds to 3E2N and E3L mode of vibrations of ZnO shell layer. Synthesis mechanism of Zn/ZnO core/shell nanoparticles is discussed. KeywordsPulsed laser ablation in aqueous media-II-VI semiconductor-core-shell nanoparticles-green photoluminescence-Raman scattering
  Bulletin of Materials Science 04/2012; 33(1):21-26. · 0.88 Impact Factor
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  Available from: Raj kUmar Swarnkar

  Article: Laser ablative approach for the synthesis of cadmium hydroxide–oxide nanocomposite

  S. C. Singh, R. K. Swarnkar, R. Gopal
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  ABSTRACT: Cadmium hydroxide/oxide nanocomposite material is synthesized by pulsed laser ablation of cadmium metal in double distilled water. As-synthesized cadmium hydroxide/oxide particles transforms into pure oxide after annealing at 350°C for 9h. As-obtained particles are spherical in shape with 15nm average diameter, while spherical as well as rod shaped nanostructures are formed after annealing. PL spectrum of annealed powder has peaks corresponding to the defect levels rather than the band gap transitions.
  Journal of Nanoparticle Research 04/2012; 11(7):1831-1838. · 3.29 Impact Factor
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  Available from: Subhash Singh

  Article: Zinc nanoparticles in solution by laser ablation technique

  S. C. Singh, R. Gopal
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  ABSTRACT: Colloidal zinc metallic nanoparticles are synthesized using pulsed laser ablation of metal plate in an aqueous solution of suitable surfactant to prevent aggregation. UV-visible absorption, TEM, small angle X-ray diffraction and wide-angle X-ray diffraction are used for the characterization of colloidal zinc metallic nanoparticles. Colloidal nanoparticles are found highly stable for a long time.
  Bulletin of Materials Science 04/2012; 30(3):291-293. · 0.88 Impact Factor
• Conference Proceeding: Influence of surfactant on shape and oxidation of copper nanoparticles

  R. Gopal, R.K. Swarnkar, S.C. Singh
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  ABSTRACT: Influence of surfactant on shape and oxidation of copper nanoparticles synthesized by pulsed laser ablation in aqueous medium has been studied. The ablation of copper is done by using focused output of 1064 nm of pulsed Nd:YAG laser in 1mM concentration of CTAB and SDS. It is found that the nanostructures synthesized in CTAB have elongated shape having size range of 40 – 60 nm, while that of in SDS have ring shaped geometry with inner diameter in the range of 15–25 nm. CTAB induces more oxidation as compared to SDS with aging and causes conversion of Cu into Cu 2 O.
  Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), 2010 Conference on; 06/2010