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Thickness effect of nanostructured ZnO thin films prepared by spray method on structural, morphological and optical properties
, Article Microelectronic Engineering ; Volume 151 , 2016 , Pages 19-23 ; 01679317 (ISSN) ; Taheri, O ; Hosseini, Z. S ; Sharif University of Technology
Elsevier
Abstract
In this study, nanostructure zinc oxide (ZnO) films with different thicknesses were sprayed on glass substrates by controlling deposition time. Morphology and roughness of the films were investigated with scanning electron and atomic force microscopes as well as X-ray diffractometer. Considering with structure and surface roughness, two different growth modes as a function of spray time were determined: lateral and vertical modes which were illustrated schematically. Optical properties including photoluminescence, transmission, optical band gap and refractive index as a function of film's thickness and structure were studied. It was observed that the average transmittance is more than 80% in...
Detecting hydrogen using graphene quantum dots/WO3 thin films
, Article Materials Research Express ; Volume 3, Issue 11 , 2016 ; 20531591 (ISSN) ; Iraji Zad, A ; Hosseini, Z. S ; Hatamie, S ; Sharif University of Technology
Institute of Physics Publishing
Abstract
In the present work we report an approach to resistive hydrogen sensing based on graphene quantum dots(GQDs)/WO3 thin films that work reproducibly at low temperatures. GQDs were chemically synthesized and evenly dispersed in WO3 solution with 1:1 molar ratio. The structural evaluation and crystallization of the prepared films was studied by X-ray diffraction, Raman and scanning electron microscopy (SEM) techniques. The SEM images showed uniform distribution of the GQDs in WO3 films with sizes around 50 nm. Raman experiment showed the GQDs are partially reduced with high edge defects as hydroxyl and carboxyl groups which involve both in bridging between WO3 grains via bindings as well as...
Decorated CNT based on porous silicon for hydrogen gas sensing at room temperature
, Article RSC Advances ; Volume 6, Issue 50 , 2016 , Pages 44410-44414 ; 20462069 (ISSN) ; Razi Astaraei, F ; Fardindoost, S ; Hosseini, Z. S ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
A new triple-component sensor for detection of H2 was developed based on porous silicon and CNTs. An increase in deposition of CVD catalysis was shown to promote a high and fast response. Also, it was shown that the composite system exhibited good selectivity
Characterization of three-dimensional reduced graphene oxide/copper oxide heterostructures for hydrogen sulfide gas sensing application
, Article Journal of Alloys and Compounds ; Volume 740 , 2018 , Pages 1024-1031 ; 09258388 (ISSN) ; Iraji zad, A ; Hosseini, Z. S ; Jokar, E ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Three-dimensional reduced graphene oxide (3D-rGO) structures decorated with CuO particles (GCu) are synthesized through a simple and scalable method for detection of hydrogen sulfide (H2S) gas. For characterization and investigation of porous structure various techniques were employed. Decorated 3D structures demonstrated higher sensitivity and selectivity in comparison to pure structure. Optimized structure for sensing was obtained through introducing different amounts of CuO. The GCu heterostructures containing 35 μmol of CuO powder demonstrated reproducible response of about 30% to the concentration of 10 ppm at room temperature, while complete recovery was obtained through heating to 150...