Dewi Suriyani Che Halin
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Preferred name
Dewi Suriyani Che Halin
Official Name
Halin, Dewi Suriyani Che
Alternative Name
Che Halin, Dewi Suriyani
Che Halin, D. S.
Suriyani Che Halin, Dewi
Halin, Dewi Suriyani Che
Halin, D. S.Che
Halin, D. S.C.
D. S., Che Halin
Main Affiliation
Scopus Author ID
36158106300
Researcher ID
AAC-9478-2019

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  • Publication
    Annealing effects on Polycrystalline Silicon Germanium (SiGe) thin films grown on nanostructured silicon substrates using thermal evaporation technique
    (Universiti Malaysia Perlis (UniMAP), 2022-10)
    Ayu Wazira Azhari
    ;
    Eop, T. S.
    ;
    Dewi Suriyani Che Halin
    ;
    Uda Hashim
    ;
    Sopian, K.
    ;
    Zaidi, S. H.
    Polycrystalline SiGe thin films have been formed after thermal annealing of formerly vacuum evaporated a-Ge layers. The a-Ge thin films were deposited onto nanostructured Si substrates via low-cost thermal evaporation method. Then, the films were annealed in a furnace at temperatures ranging from 400 °C to 1000 °C resulting in crystal growth of the SiGe layers. In general, the annealing temperature for polycrystalline SiGe is between 600 °C – 800 °C. The crystalline structure of the SiGe layer is improved as a function of increased temperature. This is shown by the low FWHM of about 5.27 as compared to the commercially available Ge substrates where the FWHM value is about 5.06. This method also produces more relax Ge layer where the strain value is 0.261.
  • Publication
    Effect of temperature and amount of Ag on TiO₂ thin film synthesised via sol–gel method
    (Springer, 2025-02)
    Dewi Suriyani Che Halin
    ;
    Kamrosni Abdul Razak
    ;
    Dharshini Karikalan
    ;
    Lukasz Kaczmarek
    ;
    Sebastian Miszczak
    ;
    Ayu Wazira Azhari
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Nur Izzati Muhammad Nadzri
    ;
    Juyana A. Wahab
    ;
    Mohd. Mustafa Al Bakri Abdullah
    TiO₂ sol was produced via the sol–gel method with different amounts of AgNO₃ as the source of Ag. The Ag/TiO₂ thin film was obtained by spin coating and was annealed at various annealing temperatures (300°C, 400°C and 500°C) for 1 h. The effect of different amounts of AgNO₃ and different annealing temperatures on the TiO₂ thin films was studied by characterising the phase composition, surface morphology and water contact angle. Results from the x-ray diffraction (XRD) pattern show that with the addition of AgNO₃, Ag/TiO₂ can be formed at low annealing temperatures (300°C). At increased annealing temperatures (400°C and 500°C) and amounts of AgNO₃ (1.0 ml and 1.5 ml), Ag₂O and Ag₃O4 phases were observed. Flakes or flaky islands were formed on the thin film due to thermal expansion mismatch between the film and substrate, residual stress within the film or the release of volatile species when annealed at a low temperature of ⁓300°C. Increasing the temperature to 500°C resulted in the growth and coalescence of the flaky islands by the surface diffusion of adsorbed atoms (adatoms) and their annexation to the surface of existing nuclei. The water contact angle provides valuable insight into the surface interactions between water droplets and the surface of Ag/TiO₂ thin films. It was found that at 1.5 ml AgNO₃, the increased annealing temperature from 300°C to 500°C decreased the water contact angle of Ag/TiO₂ thin films from 83.86° to 34.62°, forming superhydrophilic properties, which indicated its excellent potential as a photocatalyst.
  • Publication
    Microstructure evolution of Ag/TiO₂ thin film
    ( 2021)
    Dewi Suriyani Che Halin
    ;
    Kamrosni Abdul Razak
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Mohd Izrul Izwan Ramli
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Ayu Wazira Azhari
    ;
    Kazuhiro Nogita
    ;
    Hideyuki Yasuda
    ;
    Marcin Nabiałek
    ;
    Jerzy J. Wysłocki
    Ag/TiO₂ thin films were prepared using the sol-gel spin coating method. The microstructural growth behaviors of the prepared Ag/TiO₂ thin films were elucidated using real-time synchrotron radiation imaging, its structure was determined using grazing incidence X-ray diffraction (GIXRD), its morphology was imaged using the field emission scanning electron microscopy (FESEM), and its surface topography was examined using the atomic force microscope (AFM) in contact mode. The cubical shape was detected and identified as Ag, while the anatase, TiO₂ thin film resembled a porous ring-like structure. It was found that each ring that coalesced and formed channels occurred at a low annealing temperature of 280 °C. The energy dispersive X-ray (EDX) result revealed a small amount of Ag presence in the Ag/TiO₂ thin films. From the in-situ synchrotron radiation imaging, it was observed that as the annealing time increased, the growth of Ag/TiO₂ also increased in terms of area and the number of junctions. The growth rate of Ag/TiO₂ at 600 s was 47.26 µm2/s, and after 1200 s it decreased to 11.50 µm2/s and 11.55 µm2/s at 1800 s. Prolonged annealing will further decrease the growth rate to 5.94 µm2/s, 4.12 µm2/s and 4.86 µm2/s at 2400 s, 3000 s and 3600 s, respectively.
      3  17
  • Publication
    Effect of polyethylene glycol and sodium dodecyl sulphate on microstructure and self-cleaning properties of graphene oxide/TiO2 thin film
    ( 2020-09-01)
    Azani A.
    ;
    Dewi Suriyani Che Halin
    ;
    Kamrosni Abdul Razak
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Norsuria Mahmed
    ;
    Muhammad Mahyiddin Ramli
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Mohd Fairul Sharin Abdul Razak
    ;
    Ayu Wazira Azhari
    ;
    Chobpattana V.
    ;
    Kaczmarek L.
    In this study, a sol gel procedure for preparation of TiO2 thin films with graphene oxide (GO) was developed. The effect of PEG and SDS addition on the microstructure of the films as well as the photocatalytic activity of the thin film was also investigated. The morphology and surface structure of the films were studied by SEM and AFM while the photocatalytic activity of the films was analyzed by measuring the degradation of methylene blue under sunlight irradiation using UV-Vis spectrophotometer. It was found that GO/TiO2 thin film with PEG shows a smaller and porous particle while GO/TiO2 thin film with SDS formed a very smooth surface and very fine particles. Therefore, in AFM analysis reveals that surface roughness decreases with the addition of PEG and SDS. Finally, the photocatalytic activity showed that GO/TiO2 thin film with SDS have the most effective self-cleaning property which degrade 64% of methylene blue that act as model of contaminants.
      1
  • Publication
    Annealing Effects on Polycrystalline Silicon Germanium (SiGe) Thin Films grown on Nanostructured Silicon Substrates using Thermal Evaporation Technique
    ( 2022-10-01)
    Ayu Wazira Azhari
    ;
    Eop T.S.
    ;
    Dewi Suriyani Che Halin
    ;
    Sopian K.
    ;
    Uda Hashim
    ;
    Zaidi S.H.
    Polycrystalline SiGe thin films have been formed after thermal annealing of formerly vacuum evaporated a-Ge layers. The a-Ge thin films were deposited onto nanostructured Si substrates via low-cost thermal evaporation method. Then, the films were annealed in a furnace at temperatures ranging from 400 °C to 1000 °C resulting in crystal growth of the SiGe layers. In general, the annealing temperature for polycrystalline SiGe is between 600 °C – 800 °C. The crystalline structure of the SiGe layer is improved as a function of increased temperature. This is shown by the low FWHM of about 5.27 as compared to the commercially available Ge substrates where the FWHM value is about 5.06. This method also produces more relax Ge layer where the strain value is 0.261.
      30  2
  • Publication
    Numerical simulation of lead-free tin and germanium based all perovskite tandem solar cell
    ( 2023-12)
    Rae-Ann Lim Jia En
    ;
    Ayu Wazira Azhari
    ;
    Dewi Suriyani Che Halin
    ;
    Suhaila Sepeai
    ;
    Norasikin Ahmad Ludin
    The ability to customize the materials bandgaps makes perovskite solar cells a promising candidate for hybrid-tandem applications. This allows them to effectively utilize parts of the solar spectrum that silicon-based solar cells cannot efficiently capture, resulting in higher absorption coefficients. However, there is a lack of research on lead-free all-perovskite tandem solar cells, and secondary data on materials is limited. One of the main challenges in previous studies is the high cost and solid structure of traditional silicon-based solar cells, which require significant storage space. Additionally, lead-based perovskite solar cells pose environmental concerns due to their water solubility and potential harmful effects upon consumption. To address these issues, thin-film perovskite solar cells with liquid solvents are employed in the solar cell design. Lead is replaced with germanium and tin-based perovskites, which exhibit comparable photovoltaic performance to silicon. In the present work, the OghmaNano simulation tool was utilized to conduct numerical simulation of the perovskite design. The perovskite solar cell layers were structured as follows: FTO/ZnO/MAGeI3/Spiro-OMeTAD/FAMASnGeI3/Cu2O/Au. The variables considered included optimum layer thicknesses and bandgaps, as well as the most suitable materials for the ETL and HTL, aiming to obtain the highest efficiency. Based on the simulation results, the proposed perovskite structure shows remarkable photovoltaic parameters. The Voc was measured at 0.84 V Jsc of 16.1 mA/cm2, FF of 0.825, and PCE that reached 11.12%. This project contributes to future research on materials for the ETL and HTL of lead-free, tin and germanium based APTSCs.
      1  2
  • Publication
    Metal induced crystallization of polycrystalline silicon germanium: The morphological study between nickel and copper
    (AIP Publishing Ltd., 2023)
    T. S. Eop
    ;
    Ayu Wazira Azhari
    ;
    L. Mohamad Jazi
    ;
    K. S. Ting
    ;
    Dewi Suriyani Che Halin
    ;
    Abdul Kareem Thottoli
    In this study, metal induced crystallization technique is used in to obtain the lower temperature point in crystallization. Two different metals with one non-metal configuration as a baseline i.e. SiGe/Ni, SiGe/Cu and SiGe. A simple metal-assisted chemical etching method is used to fabricate the Si nanopillar, with Ag acting as a catalyst. Following by deposition of metal namely nickel (Ni) and copper (Cu) then undergo thermal annealing from 200 ℃ until 1000 ℃ to improve the crystallinity of the Ge layer. Morphological studies of surface area were conducted using scanning electron microscopy (SEM). The results show that the crystallization temperature of SiGe with Ni was obtained at 400 ℃ while the crystallization temperature of SiGe without any metal was obtained at 600 ℃. Meanwhile the crystallinity, for SiGe/Cu only occurs in very low level where the structure did not change until the annealing was conducted at 600 ℃. Based from these result, it is proved that the metal can help lowering the crystallization temperature and improving the defects of SiGe.
      15  1
  • Publication
    Effect of graphene oxide on microstructure and optical properties of TiO2 thin film
    ( 2019-01-01)
    Azani A.
    ;
    Dewi Suriyani Che Halin
    ;
    Razak K.A.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Mohd Salleh M.A.A.
    ;
    Abdul Razak M.F.S.
    ;
    Norsuria Mahmed
    ;
    Ramli M.M.
    ;
    Ayu Wazira Azhari
    ;
    Chobpattana V.
    GO/TiO2 thin films have been synthesized from titanium (IV) isopropoxide (TTIP) by a sol-gel method. The films were deposited onto a glass substrate using spin coating deposition technique then were subjected to annealed process at 350 °C. The different amount of graphene oxide (GO) was added into the parent solution of sol in order to investigate the microstructure, topography, optical band gap and photocatalytic activity of the thin films. The prepared thin films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), UV-VIS spectrophotometry and degradation of methylene blue (MB). AFM images reveal a rougher surface of GO/TiO2 thin film than bare TiO2 thin film due to GO particles. Moreover, the SEM images showed the formation of semispherical microstructure of bare TiO2 changes to some larger combined molecules with GO addition. The UV-Vis spectrophotometer results show that with optical direct energy gap decreases from 3.30 to 3.18 eV after GO addition due to the effect of high surface roughness and bigger grain size. Furthermore, the optical results also indicated that GO improved the optical properties of TiO2 in the visible range region.
      1  29
  • Publication
    Progress in tin-germanium perovskite solar cells: A review
    ( 2023-11-01)
    Azizman M.S.A.
    ;
    Ayu Wazira Azhari
    ;
    Dewi Suriyani Che Halin
    ;
    Ibrahim N.
    ;
    Sepeai S.
    ;
    Ludin N.A.
    ;
    Nor M.N.M.
    ;
    Ho L.N.
    The primary cause for concern in developing perovskite solar cells (PSCs) is the potential environmental repercussions of employing lead (Pb) as the absorber. The majority of studies hypothesised that the use of tin-based perovskite could be the key to creating environmentally and financially viable PSCs. This is because tin (Sn) and lead (Pb) are both elements in group 14 of the periodic table. Perovskite materials based on tin and lead also have nearly ideal direct band gaps, which range from 1.23 eV to 1.30 eV. Nonetheless, major challenges that may suppress the potential of Sn-based PSCs include the stability issue with low formation energy, high carrier density, and easily oxidised from Sn2+ to Sn4+ upon exposure to air. These limitations are anticipated to be vital impediments to creating a stable and effective Sn-based perovskite. Recent advances have shown that alloying with germanium (Ge) is one of the approaches to overcome stability issues and thus improve the overall efficiency of the PSCs. However, the stability and efficiency of these Ge-based PSCs are still unable to surpass those of Pb-based devices. This review covers the research interest in SnGe PSCs from the initial study to the current year by focusing on the methodology used and significant results. The output is believed to be useful in developing Pb-free PSCs using SnGe-based materials.
      2  2
  • Publication
    Synthesis of Ag-TiO2thin film - Molarity and temperature effect on Microstructure
    ( 2020-08-01)
    Dewi Suriyani Che Halin
    ;
    Razak K.A.
    ;
    Azani A.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Mahmed N.
    ;
    Ramli M.M.
    ;
    Ayu Wazira Azhari
    ;
    Chobpattana V.
    ;
    Kaczmarek
    Ag-TiO2thin films with different concentration of silver (Ag) added were successfully deposited onto Si-substrate via sol-gel spin coating method. The phase analysis and microstructures of Ag-TiO2thin films have been characterized by X-ray diffractometer and scanning electron microscope. X-ray diffraction spectra show existing different phases influenced by the concentration of the Ag and the annealing temperature. The micrograph of scanning electron microscopy revealed the thin films annealed at 600 °C with 7 mol% of Ag concentration which shows that the Ag particles were found like a white dot formed on the grain of TiO2thin films.
      8  23