The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

Green synthesis of metal nanoparticles using plants

Synthesis of metallic nanoparticles using plant extracts.

Leu-M

Elements Of X Ray Diffraction

Pear fruit extract-assisted room-temperature biosynthesis of gold nanoplates.

Thin films of tin oxide-intercalated polyaniline nanocomposite have been deposited at room temperature, through solution route technique. The as-grown films were studied for some of the useful physicochemical properties, making use of XRD, FTIR, SEM, etc. and optical methods. XRD studies showed peak broadening and the peak positions shift from standard values, indicating presence of tin oxide in nanoparticles form in the polyaniline (PANI) matrix. FTIR study shows presence of the Sn–O–Sn vibrational peak and characteristic vibrational peaks of PANI. Study of SEM micrograph revealed that the composite particles have irregular shape and size with micellar templates of PANI around them. AFM images show topographical features of the nanocomposite similar to SEM images but at higher resolution. Optical absorbance studies show shifting of the characteristics peaks for PANI, which may be due to presence of tin oxide in PANI matrix. On exposure to ammonia gas (100–500 ppm in air) at room temperature, it was found that the PANI film resistance increases, while that of the nanocomposite (PANI + SnO2) film decreases from the respective unexposed value. These changes on removal of ammonia gas are reversible in nature, and the composite films showed good sensitivity with relatively faster response/recovery time. © 2009 Elsevier B.V. All rights reserved.

Studies on tin oxide-intercalated polyaniline nanocomposite for ammonia gas sensing applications

Growth and characterization of tin disulfide (SnS2) thin film deposited by successive ionic layer adsorption and reaction (SILAR) technique

Nickel substituted cobalt ferrite nanoparticles with composition Co1−xNixFe2O4 (0.0 ≤ x ≤ 1.0) was synthesized using simple, low temperature auto combustion method. The X-ray diffraction patterns reveal the formation of cubic phase spinel structure. The crystallite size varies from 30-44 nm with the nickel content. Porous and agglomerated morphology of the bulk sample was displayed in the scanning electron microscopy. Micro Raman spectroscopy reveals continuous shift of Eg and Eg(2) stokes line up to 0.8 Ni substitution. The dispersion behavior of the dielectric constant with frequency and the semicircle nature of the impedance spectra show the cobalt nickel ferrite to have high resistance. The ferromagnetic nature is observed in all the samples, however, the maximum saturation magnetization was achieved by the 0.4 Ni substituted cobalt ferrite, which is up to the 92.87 emu/gm at 30K.

Nishad G. Deshpande

Papers

Pear fruit extract-assisted room-temperature biosynthesis of gold nanoplates.

Studies on tin oxide-intercalated polyaniline nanocomposite for ammonia gas sensing applications

Growth and characterization of tin disulfide (SnS2) thin film deposited by successive ionic layer adsorption and reaction (SILAR) technique

Structural, dielectric and magnetic properties of nickel substituted cobalt ferrite nanoparticles: Effect of nickel concentration

Physical, optical and electrical properties of copper selenide (CuSe) thin films deposited by solution growth technique at room temperature