Fabrication and Characterization of Beaded SiC Quantum Rings with Anomalous Red Spectral Shift

Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802-6812, USA.
Advanced Materials (Impact Factor: 17.49). 11/2012; 24(41). DOI: 10.1002/adma.201202286
Source: PubMed

ABSTRACT Beaded SiC quantum rings can be prepared by introducing a carbonization reaction at the laser-induced Si plasma and ethanol interface (referred to as reactive laser ablation). An anomalous red spectral shift is observed when the diameter of SiC nanocrystals within the SiC quantum rings is smaller than 3 nm. Experimental results and theoretical calculations indicate that the observed anomalous red spectral shift is ascribed to the contributions from surface structures (e.g., surface composition, surface reconstruction, and exposed crystal planes).

Download full-text


Available from: Yanhui Zhao, Feb 24, 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Carbon nanodots (CDs) have been synthesized at gram scale with a high yield (41.8%) by carbonization of sucrose with oil acid in one simple step. The synthesized CDs are monodisperse with a narrow size distribution (average 1.84 nm in size), and show a high fluorescence quantum yield (21.6%) without passivation. The PL intensity of the obtained CDs is pH independent over a range of 2-8. Besides, their PL intensity remains unchanged even after six hours of UV excitation and six months of storage, exhibiting excellent stability. The obtained CDs have been used for cell imaging. The results demonstrate that the prepared CDs have great potential for real applications.
    Nanoscale 01/2013; 5(5). DOI:10.1039/c2nr32675b · 6.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have fabricated porous silicon nanopillar arrays over large areas with a rapid, simple, and low-cost technique. The porous silicon nanopillars show unique longitudinal features along their entire length and have porosity with dimensions on the single-nanometer scale. Both Raman spectroscopy and photoluminescence data were used to determine the nanocrystallite size to be <3 nm. The porous silicon nanopillar arrays also maintained excellent ensemble properties, reducing reflection nearly fivefold from planar silicon in the visible range without any optimization, and approaching superhydrophobic behavior with increasing aspect ratio, demonstrating contact angles up to 138°. Finally, the porous silicon nanopillar arrays were made into sensitive surface-enhanced Raman scattering (SERS) substrates by depositing metal onto the pillars. The SERS performance of the substrates was demonstrated using a chemical dye Rhodamine 6G. With their multitude of properties (i.e., antireflection, superhydrophobicity, photoluminescence, and sensitive SERS), the porous silicon nanopillar arrays described here can be valuable in applications such as solar harvesting, electrochemical cells, self-cleaning devices, and dynamic biological monitoring.
    Nanotechnology 05/2013; 24(24):245704. DOI:10.1088/0957-4484/24/24/245704 · 3.67 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report on a simple method for fabricating ultra-small nanodiamonds (NDs) with size tunability and uniformity by femtosecond laser ablation in solution. photoluminescence (PL) is tailored in a broad range from ultra-violet (UV) to red region through adjusting the carbon sources or solutions. The NDs also emit multiphoton luminescence. Comprehensive discussions based on the anomalous PL behavior and well-defined absorption and excitation peaks suggest that UV emission originates from radiative recombination through intrinsic direct transitions between highly localized pi states and blue or green emission originates from radiative recombination through defect energy trapping states.
    Carbon 08/2013; 62:374–381. DOI:10.1016/j.carbon.2013.06.019 · 6.16 Impact Factor
Show more