Conference Publications

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https://hdl.handle.net/20.500.14170/208

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Browsing Conference Publications by Department "Faculty of Electronic Engineering & Technology"
  • Publication
    Influence of Sn dopant on ZnO thin film for Formaldehyde detection
    (IOP Publishing, 2020)
    Ishak, Syafiqah
    ;
    Shazlina Johari
    ;
    Muhammad Mahyiddin Ramli
    In this work, structural, morphological, electrical and gas sensing of ZnO and Sn doped ZnO thin film at different atomic percentage (0.5at%, 1.0at% and 1.5at%) had been studied. The precursor was prepared by sol-gel method and deposited on an IDE glass substrate by using spin coating technique. The effects of the dopant was then characterized through XRD, AFM, SEM and Agilent LCR Meter. Based on the XRD results, it was found that all films showed the highest diffraction peak intensity at (002) with crystallite size in the range of 8-33nm. Meanwhile the morphological properties from AFM and SEM showed an improvement in surface roughness from 16.7nm to 5.48nm and decrease the grain size from 45.42nm to 40.99nm in the presence of Sn dopant. Based on the image, the grains were uniformly distributed and ZnO thin film showed the hexagonal wurtzite structure, which proved the XRD result. Among all the samples, 1.0at% Sn doped showed the best result for detection of formaldehyde at 0.6ppm which up to 96% compare to undoped, 26.04% at 150°C. The response and recovery time was between 4-16 seconds. This showed that the presence of Sn can help to improve the conductivity of the ZnO thin film.
      2  13
  • Publication
    Shielding efficiency study of sodium based chitosan polymer with different types of filler
    (Institute of Electrical and Electronics Engineers (IEEE), 2020)
    N.N. Mazu
    ;
    M.A.H. Mohd Abdul Majid
    ;
    N.H. Osman
    ;
    J.Y.C Liew
    ;
    Muhammad Mahyiddin Ramli
    Sodium based chitosan (CH/Na) polymer was prepared with four different fillers and the suitability for electromagnetic interference (EMI) shielding were tested based on its electrical conductivity and shielding efficiency. The sodium based chitosan polymer was prepared by mixing the chitosan powder with sodium ion solution (Na) and the selected filler was added to the mixture in order to further improve the electrical properties of the composite. The fillers selected for this work were Copper (II) Selenite (CuSe), Iron (III) oxide (Fe3O4), Zinc Oxide (ZnO) and Fe-doped ZnO (FeZnO). Results show that using the Na and additional filler will increase the conductivity of pure chitosan film from reported 10-4 μS/cm to 10-5 S/cm. The CH/Na polymer with CuSe filler shows the highest electrical conductivity at 5.23×10-5 S/cm, followed by Fe3O4, ZnO and FeZnO. The CH/Na/CuSe polymer are also tested at different thickness with a high of 1.5 dB of shielding obtained. Increasing the (w/v)% of CuSe further increased the shielding efficiency to up to 19.55 dB.
      11  1
  • Publication
    Sn doped ZnO thin film for formaldehyde detection
    (AIP Publishing, 2020)
    S. Ishak
    ;
    Shazlina Johari
    ;
    Muhammad Mahyiddin Ramli
    In this work, sol-gel with spin coating technique was applied in order to produce undoped and Sn doped ZnO thin film with different doping concentration of 0.5 at%, 1.0at% and 1.5at%. The starter material used was zinc acetate dehydrate (Zn(CH3COO)22H2O). The thin film was deposited on an interdigitated electrodes (IDE) for 5 hours and annealed at the temperatue of 500°C. The crystallite size of the film decreased when dopant was introduced, as well as the surface roughness of the thin film. XRD was used to identify the crystallinity, crystallographic orientation and phase evaluation of undoped and Sn doped ZnO. From the XRD pattern, it was observed that the peaks and diffraction correspond to the wurtzite-structured of ZnO. Sensing results indicate that the gas sensing response increase from undoped to doped ZnO thin film as a function of operating temperature where the maximum response for formaldehyde detection was at 130°C (∼95%) for doping concentration of 1.5at%. The response time for 0.4ppm of formaldehyde was 17sec followed with 16sec, 12sec and 13 sec for 0.6ppm, 0.8ppm and 1.0ppm respectively.
      7  1