El-Maghraby E.M.

University of Toyama Repository

Prep議ratio悶andChar設cterizatio闘ofIn203 and Sn02路袋路osrt棋は盟問$外国人研究員五M.日開Mag如ぬyWe have synthesized In203 nanostructures grown at three different growth temperatures; 700, 800 and 900 °C for 1 h reaction time by using the thermal evaporation method. Samples have been prepared inside a quartz tube in which Ar was introduced. Source material (In metal) and substrates were located within an alumina boat placed in the central part of the quartz tubeラwhichwas inserted into a tubular・furnace.We used argon gas of 100 sccm as carrier gas in our furnace system. Before heatingラArgas was introduced in the tube for 20 min at a flow rate of 100 sccm. For characterization of as-grown samplesラweused field”emission scanning electron microscopy (FιSEMラJEOLJSM 6700F) and transmission electron microscopy (TEMラJEOL JEM 2010F) to investigate the morphology and microstructur・e. The compositions were analyzed using energy dispersive spectrometry (EDS) attached to the TEM. Selected area electron diffraction (SAED) confirmed the crystal orientation of In203 nanocrystals. The analysis of crystallographic structure was performed by the XRD measurement with CuKαradiation using a diffractometer (Shimadzu XRD 6100). The amount of nanostructure was found to be dependent on the growth temperatures and position of the substrate. Glancing at the FE-SEM image of the samples deposited at 700 °C in the center of the furnace, we find morphology resembling nanowires (See Fig. (a) below). At a higher magnificationラ wesaw a beautiful capped like-monuments nanostructure. On a substrate 2mm from the center, aggr・egationof the source was precipitated, and on a substrate 4mm far・fromthe center of the furnace we observed no materials. This work is now under publication. In an FE-SEM image of the samples deposited at 800 °C on a substrate at the center of the furnaceラananotower structure was observed (Fig. (b ). A higher FE田SEMshowed a variety of nano-tower shapes. FE-SE恥fimage of the samples deposited at 900 °C in the center of the furnace clearly showed densely deposited nano-pencils with high crystallinity (Fig. (c). The nano自pencilsare well国facettedラandthe edges and corners are distinguished. Also large-scale synthesis of In203 nanoparticles, nanowires and nanorods were realized by improved chemical v叩ordeposition method on Au-coated silicon substrate. Field emission scanning electron microscopy revealed that the flow of carrier argon gas has profound effect on the shape and mo中hologyof In203 nanostructures. Detailed structural analysis showed that the In203 nanostruc加resare single crystalline with a cubic crystal structure. Room temperature PL spectrum showed broad and intense blue emission at 3 7 5 nm. The In203 nanowires sensor can successfully detect hydrogen gas 82 with response time as low short as 50 s at 250°C. This work was accepted for publication. Also, we grew tin oxide (Sn02) nanostructures at 900 °C for 1 h on Si02 substrates with Au coating and without Au coating. During growthう Argas was introduced at a flow rate of 100 sccm in the quartz tube inserted into the furnace. After the furnace was cooled down naturally to room temperatureラtheAr gas was turned of. White wool-like products were observed around the Sn grains as a raw material. The gas sensing property of this material will be investigated soon. (a) ー ， ???? ，?、 (c) FE-SEM images (a), (b), and (c) are for In203 nanostructures deposited on a substrate placed at the center of the heating furnace at temperatures of 700, 800ラ and900 °Cラrespectively. Publications A Generic Approach for Controlled Synthesis ofln203 Nanostr・ucturesfor Gas Sensing Applications Ahsanulh叫 Qurashiラ日 M.El制Maghrabyう ToshinariYamazakiラYanbaiShen, Toshio Kikuta Journal of Alloys and Compoundsラacceptedfor publication. Catalyst-Free Shape Controlled Synthesis of ln203 Pyramids and Octahedron: Structural Properties and Growth Mechanism Ahsanulhaq Qurashi, E. M. EトMaghrabyラToshinariYamazaki, Toshio Kikuta Journal of Alloys and Compounds, accepted for publication. 83 

Preparation and Characterization of  In2O3 and SnO2 nanostructures

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Preparation and Characterization of In2O3 and SnO2 nanostructures

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