Articles written in Bulletin of Materials Science
Volume 31 Issue 3 June 2008 pp 263-276
Various nanocomposites were synthesized using either a silica-based glass or mica crystallites as the medium. In some cases by an oxidation or a sulfidation treatment a core-shell nanostructure could be generated. Iron–iron oxide core-shell structured nanocomposites exhibited excellent humidity sensing behaviour. Gold–gold sulfide core-shell nanorods exhibited a number of optical absorption peaks which arose because of their structural characteristics. Nanoparticles of silver and silver oxide could be aligned in a polymethylmethacrylate film by an a.c. electric field of 1 MHz frequency. The composites showed large sensitivity to relative humidity. Lead sulfide nanowires of diameter, 1.2 nm, were grown within the nanochannels of Na-4 mica. These exhibited a semiconductor to metal transition at around 300 K. This arose because of high pressure generated on the nanowires. Copper sulfide nanowires grown within the Na-4 mica channels showed metallic behaviour. Silver core–silver orthosilicate shell nanostructures developed within a silicate glass medium showed discontinuous changes in resistivity at some specific temperatures. This was explained as arising due to excitation of Lamb modes at certain pressures generated because of thermal expansion mismatch of the core and the shell phases. Optical properties of iron core–iron oxide shell nanocomposites when analysed by effective medium theory led to the result of a metal non-metal transition for particle diameters below a critical value. Similar results were obtained from optical absorption data of silver nanoparticles grown in a tetrapeptide solution.
Volume 32 Issue 3 June 2009 pp 353-360
Ti decorated BC_4N nanotube has been studied using first-principles density functional approach, to explore the storage of molecular hydrogen. It combines the advantages of carbon nanotube, together with the thermal stability of BN nanotube. The local structural unit of BN3 and NB3 linked with B–N bonds are responsible for the extra stability of BC_4N nanotube as compared with CNT. While the host carbon nanotube is metallic, the substitutional doping of B and N with a large enough concentration (33%) turns it to semiconducting. Endohedral decoration, although energetically favourable, encounters a rather high barrier height of ∼4 eV, as obtained from our nudge elastic band calculation of the minimum energy path. Exohedral Ti@BC4N can bind up to four H2 molecules. For full Ti coverage, the system can absorb up to 5.6 wt% of hydrogen.
Volume 35 Issue 3 June 2012 pp 365-368
Diethyl germanium bis-picolinate, [Et2Ge(O2CC5H4N)2], and trimethyl germanium quinaldate, [Me3Ge(O2CC9H6N)], have been used as precursors for deposition of thin films of germanium by aerosol assisted chemical vapour deposition (AACVD). The thermogravimetric analysis revealed complete volatilization of complexes under nitrogen atmosphere. Germanium thin films were deposited on silicon wafers at 700°C employing AACVD method. These films on oxidation under an oxygen atmosphere at 600°C yield GeO2. Both Ge and GeO2 films were characterized by XRD, SEM and EDS measurements. Their electrical properties were assessed by current–voltage (𝐼–𝑉) characterization.
Volume 45, 2022
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Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
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