Ayu Wazira Azhari
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Ayu Wazira Azhari
Official Name
Ayu Wazira, Azhari
Alternative Name
Ayu, A. W.
Azhari, Ayu W.
Main Affiliation
Scopus Author ID
24450001400
Researcher ID
ABA-7808-2020

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  • 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.
  • Publication
    Annealing effects on polycrystalline silicon germanium (SiGe) thin films grown on nanostructured silicon substrates using thermal evaporation technique
    ( 2022-10)
    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.
  • Publication
    A Study on the Environmental Impact During Distribution and Disposal Stages for the 3-Ply Face Masks by Using Life Cycle Assessment (LCA)
    ( 2022-01-01)
    Chow Suet Mun Christine
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Irnis Azura Zakaria
    ;
    Sara Yasina Yusuf
    ;
    Ayu Wazira Azhari
    ;
    Boboc M.
    The demand of face masks had increased tremendously due to pandemic outbreak of COVID-19, leading to the increment production rate of face masks in Malaysia. Waste is also produced at the same time, resulting impacts towards the environment. Due to the land scarcity issue in Malaysia, the end of life treatment for the waste is taken into consideration. The study tools used in this study is life cycle assessment (LCA) to identify the significant potential environmental impact produced during the life cycle stages for distribution and disposal through GaBi Education Software. The disposal stage between landfill and incineration of the 3-Ply face masks is studied to determine the end of life treatment for it. The impact assessment method selected in this study is CML 2001-Jan 2016 with the environmental indicator of Global Warming Potential (GWP), Acidification Potential (AP), Eutrophication Potential (EP) and Ozone Depletion Potential (ODP). GWP results in producing highest impact to the environment during both distribution and disposal stages. The impact of GWP also relates to the climate change. Modern incineration is recommended to overcome the issue of land scarcity in Malaysia as the amount of waste by 3-Ply face masks are increasing due to the pandemic COVID-19, reducing the impacts towards the environment.
  • 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.
  • Publication
    Fabrication and simulation of silicon nanogaps pH sensor as preliminary study for Retinol Binding Protein 4 (RBP4) detection
    ( 2025-01)
    M. I. Hashim
    ;
    Mohammad Nuzaihan Md Nor
    ;
    Mohamad Faris Mohamad Fathil
    ;
    M. Shaifullah A.S
    ;
    C. Y. Chean
    ;
    Nur Hamidah Abdul Halim
    ;
    Zarimawaty Zailan
    ;
    Mohd Khairuddin Md Arshad
    ;
    Muzamir Isa
    ;
    Ayu Wazira Azhari
    ;
    M. Syamsul
    ;
    Rozaimah A.T.
    In this research, a silicon nanogap biosensor has the potential to play a significant role in the field of biosensors for detecting Retinol Binding Protein 4 (RBP4) molecules due to its unique nanostructure morphology, biocompatibility features, and electrical capabilities. Additionally, as preliminary research for RBP4, a silicon nanogap biosensor with unique molecular gate control for pH measurement was developed. Firstly, using conventional lithography followed by the Reactive-ion etching (RIE) technique, a nanofabrication approach was utilized to produce silicon nanogaps from silicon-on-insulator (SOI) wafers. The critical aspects contributing to the process and size reduction procedures were highlighted to achieve nanometer-scale size. The resulting silicon nanogaps, ranging from 100 nm to 200 nm, were fabricated precisely on the device. Secondly, pH level detection was performed using several types of standard aqueous pH buffer solutions (pH 6, pH 7, pH 12) to test the electrical response of the device. The sensitivity of the silicon nanogap pH sensor was 7.66 pS/pH (R² = 0.97), indicating that the device has a wide range of pH detecting capacity. This also includes the silicon nanogap biosensor validated by simulation, with the sensitivity obtained being 3.24 μA/e.cm² (R² = 0.98). The simulation of the sensitivity is based on the interface charge (Qf) that represents the concentration of RBP4. The results reveal that the silicon nanogap biosensor has excellent characteristics for detecting pH levels and RBP4 with outstanding sensitivity performance. In conclusion, this silicon nanogap biosensor can be used as a new electrical RBP4 biosensor for biomedical diagnostic applications in the future.
  • 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
    Tin and germanium substitution in lead free perovskite solar cell: current status and future trends
    (IOP Publishing, 2020)
    Ayu Wazira Azhari
    ;
    Faith Shi Xin Then
    ;
    Dewi Suriyani Che Halin
    ;
    Suhaila Sepeai
    ;
    Norasikin Ahmad Ludin
    Tin and germanium-based perovskite solar cell is gaining interest in lead-free perovskite solar cells as it is less toxic as compared to lead but possess almost all the characteristics of a perfect solar cell materials. Within 5 years, the reported efficiency of tin-based solar cells has increased from 6.4% to 9%. Although facing with stability issues as it is easily oxidised in ambient air, several studies have proven that the stability issues can be reduced. One of it is by using cesium as the 'A' cation. On the other hand, although studies on germanium-based perovskite solar cells are rarely conducted, promising results are shown when it is alloyed with tin producing narrower bandgaps and better stability owing to the protection of the GeO2 surface layer.
  • 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.
  • Publication
    Role of tin (IV) oxide as cathodic catalyst on wastewater treatment and bioelectricity generation in a baffled microbial fuel cell
    ( 2023-01-01)
    Yap K.L.
    ;
    Ho Li Ngee
    ;
    Guo K.
    ;
    Liew Yun Ming
    ;
    Nabilah Aminah Lutpi
    ;
    Ayu Wazira Azhari
    ;
    Ong Soon An
    Microbial fuel cell (MFC) has attracted extensive attentions over the past decade because it able to treat wastewater and generate bioelectricity concurrently. However, the development of cost-effective cathodic catalysts to enhance the oxygen reduction reaction was vital for practical implementation. The effect of cathodic catalyst of tin (IV) oxide (SnO2) on the removal of synthetic wastewater and power generation in a baffled MFC was explored. SnO2 was synthesized using tin (IV) pentahydrate and sodium hydroxide through a hydrothermal method. SnO2 was characterized using X-ray diffractometer before applied on the carbon plate (CP) to identify the phase composition and crystal structure, respectively. Results indicated that the chemical oxygen demand removal of synthetic wastewater was increased up to 18 % under the presence of SnO2. The application of SnO2 on CP has significantly increased the oxygen reduction reaction reactivity in the cathodic chamber.
      1
  • 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